JP5725222B2 - Wireless transmission system, wireless communication device, and wireless communication method - Google Patents

Description

  The present invention relates to a wireless transmission system, a wireless communication apparatus, and a wireless communication method.

  For example, LVDS (Low Voltage Differential Signaling) is known as a technique for realizing high-speed signal transmission between electronic devices arranged within a relatively short distance (for example, within a few centimeters to several tens of centimeters). ing. However, with recent increase in transmission data capacity and speed, there are problems such as an increase in power consumption, an increase in the influence of signal distortion due to reflection, an increase in unnecessary radiation, and the like. For example, LVDS has reached its limit when signals such as video signals (including imaging signals) and computer images are transmitted at high speed (in real time) within the device.

  In order to cope with the problem of high-speed transmission data, it is conceivable to increase the number of wires and reduce the transmission speed per signal line by parallelizing signals. However, this countermeasure leads to an increase in input / output terminals. As a result, it is required to increase the complexity of the printed circuit board and cable wiring and to increase the size of the semiconductor chip. Also, so-called electromagnetic field interference becomes a problem when high-speed and large-capacity data is routed by wiring.

  The problems in the LVDS and the method of increasing the number of wirings are all caused by transmitting signals through electric wiring. Therefore, as a technique for solving the problems caused by transmitting signals through the electrical wiring, a technique of transmitting the electrical wiring wirelessly has been proposed (see, for example, Patent Documents 1 to 4).

JP-A-2005-204221 Japanese Patent Laid-Open No. 2005-223411 Japanese Patent Laid-Open No. 10-256478 US Pat. No. 5,754,948

  In Patent Documents 1 and 2, it is proposed to perform signal transmission in the housing wirelessly and to apply a UWB (Ultra Wide Band) communication method. Patent Documents 3 and 4 indicate that a carrier frequency in the millimeter wave band is used.

  However, the UWB communication systems in Patent Documents 1 and 2 have a problem in size such as a low carrier frequency, which is not suitable for high-speed communication such as transmitting a video signal, and an antenna becomes large. Further, since the frequency used for transmission is close to the frequency of other baseband signal processing, there is a problem that interference easily occurs between the radio signal and the baseband signal. Further, when the carrier frequency is low, it is easily affected by drive system noise in the device, and it is necessary to deal with it.

  On the other hand, as in Patent Documents 3 and 4, when a carrier frequency in a millimeter wave band with a shorter wavelength is used, problems of antenna size and interference can be solved.

  Here, when wireless transmission using the millimeter wave band is applied, if a wireless method (wireless communication method) used in general outdoors (outdoors) is applied, high stability is required for the carrier frequency. The This means that a complicated oscillation circuit having a circuit configuration with high frequency stability is required, and that the system configuration as a whole is also complicated.

  For example, when an external reference component, a frequency multiplier circuit, a PLL circuit, or the like is used in order to realize a carrier signal having a high stability in the order of ppm (parts per million), the circuit scale becomes large. In addition, when trying to realize the entire oscillation circuit including a tank circuit (a resonance circuit composed of an inductor and a capacitor) with a silicon integrated circuit, it is actually difficult to form a tank circuit with a high Q value and the Q value A high tank circuit must be arranged outside the integrated circuit.

  However, when it is considered to realize high-speed signal transmission by radio between electronic devices arranged in a relatively short distance or in an electronic device in a shorter wavelength band (for example, millimeter wave band), the carrier frequency It is considered unwise to seek high stability. Rather, it would be better to consider using an oscillation circuit with a simple circuit configuration by relaxing the stability of the carrier frequency and simplifying the overall system configuration.

  However, if the stability of the carrier frequency is simply relaxed, depending on the modulation / demodulation method, frequency fluctuation (difference between the carrier frequency used in the transmission circuit and the carrier frequency used in the reception circuit) becomes a problem, and an appropriate signal There is a concern that transmission is not possible (cannot be demodulated properly).

  The present invention has been made in view of the above circumstances, and provides a mechanism capable of appropriately performing signal transmission while relaxing the stability of the carrier frequency in wireless signal transmission between devices or within devices. With the goal.

  In one aspect of a wireless transmission system, a wireless communication apparatus, and a wireless communication method according to the present invention, first, a transmission communication unit and a reception communication unit are arranged in a housing of an electronic device.

  A wireless signal transmission path that enables wireless information transmission is configured between the transmission communication unit and the reception communication unit. The radio signal transmission path may be air (so-called free space), but preferably has a waveguide structure that transmits a radio signal while confining the radio signal in the transmission path.

  Incidentally, the wireless transmission system may be configured by a combination of a plurality of electronic devices each having a communication unit on the transmission side and the reception side so that a pair is formed on the transmission side and the reception side, or one electronic device transmits In some cases, one electronic device is a wireless transmission system itself. The wireless communication apparatus includes a communication unit on the transmission side or the reception side. For example, a wireless communication device is provided as a semiconductor integrated circuit and is mounted on a circuit board in an electronic device.

  In the transmission communication unit, the transmission target signal is frequency-converted with the modulation carrier signal to generate a modulation signal, and the generated modulation signal is sent to the radio signal transmission path. The receiving communication unit generates a demodulation carrier signal synchronized with the modulation carrier signal using the signal received via the radio signal transmission path as an injection signal, and receives the modulation signal received via the radio signal transmission path. The signal to be transmitted is demodulated by frequency-converting the signal with a carrier signal for demodulation.

  In short, the communication unit on the transmission side arranged in the housing of the electronic device and the reception arranged in the case of the same electronic device (the same or different from the electronic device on which the communication unit on the transmission side is arranged) are possible. A wireless signal transmission path is formed with the communication unit on the side, and wireless signal transmission is performed between the two communication units.

  At this time, in the mechanism according to the present invention, the receiving side uses the received signal as an injection signal to generate a demodulation carrier signal synchronized with the modulation carrier signal, and the demodulation carrier signal. Is used to demodulate the transmission target signal by frequency conversion (down-conversion).

  It should be noted that only the modulated signal obtained by frequency conversion (up-conversion) on the transmission side may be transmitted and used as an injection signal for receiving the modulated signal and generating a carrier signal for demodulation. The reference carrier signal used for the modulation is also sent together with the modulation signal, and the receiving side is preferably injection-synchronized with the received reference carrier signal.

  In the mechanism according to the present invention, the modulation carrier signal used for up-conversion and the demodulation carrier signal used for down-conversion are reliably synchronized. Therefore, the signal to be transmitted can be appropriately demodulated even if the signal stability is reduced by reducing the frequency stability of the carrier signal for modulation.

  In down-conversion, it is easy to apply synchronous detection, and not only amplitude modulation but also phase modulation and frequency modulation can be applied by developing and using synchronous detection for quadrature detection. This means that the data transmission rate can be increased by, for example, orthogonalizing the modulation signal.

  According to one aspect of the present invention, when wireless signal transmission is performed between devices or within a device (housing), even if the stability of the frequency of the modulation carrier signal is relaxed, the reception side can appropriately transmit The signal can be demodulated.

  Since the stability of the frequency of the carrier signal may be relaxed, an oscillation circuit with a simple circuit configuration can be used, and the overall system configuration can be simplified.

  Since the stability of the frequency of the carrier signal may be relaxed, the entire oscillation circuit including the tank circuit (and the frequency conversion unit) can be formed on the same semiconductor substrate. A one-chip oscillation circuit (semiconductor integrated circuit) with a built-in tank circuit and a one-chip communication circuit (semiconductor integrated circuit) with a built-in tank circuit are realized.

It is a figure explaining the signal interface of a radio transmission system from functional composition. It is a figure explaining multiplexing of the signal in a wireless transmission system. It is a figure explaining the comparative example of the modulation function part in a communication processing system, and a demodulation function part. It is a figure explaining the example of basic composition of the modulation function part of this embodiment, and its peripheral circuit. It is a figure explaining the basic structural example of the demodulation function part of this embodiment, and its peripheral circuit. It is a figure explaining the phase relationship of injection locking. It is a figure explaining the basics of a demodulation process in case a carrier signal and a reference carrier signal have the same frequency and the same phase. It is a figure explaining the fundamental of a demodulation process in case a carrier signal and a reference | standard carrier signal are the same frequency, and a phase has an orthogonal relationship. It is a figure explaining the fundamental of the circuit structure of a demodulation process in case a carrier signal and a reference | standard carrier signal are the same frequency, and a phase has an orthogonal relationship. It is FIG. (1) explaining the specific example of a demodulation process in case a carrier signal and a reference | standard carrier signal are the same frequency, and a phase has an orthogonal relationship. (2) explaining a specific example of the demodulation process when the carrier signal and the reference carrier signal have the same frequency and the phases are orthogonal. (3) for explaining a specific example of demodulation processing when the carrier signal and the reference carrier signal have the same frequency and the phases are orthogonal to each other. FIG. 14 is a diagram (No. 4) illustrating a specific example of the demodulation process when the carrier signal and the reference carrier signal have the same frequency and the phases are orthogonal to each other. It is a figure explaining 1st Embodiment (1st example) of the structural example by the side of the transmitter which applies an injection locking system. It is a figure explaining 1st Embodiment (2nd example) of the structural example by the side of the transmitter which applies an injection locking system. It is a figure explaining 1st Embodiment of the structural example by the side of the receiver which applies an injection locking system. It is a figure explaining 2nd Embodiment (1st example) of the structural example by the side of the transmitter which applies an injection locking system. It is a figure explaining 2nd Embodiment (2nd example) of the structural example by the side of the transmitter which applies an injection locking system. It is a figure explaining 2nd Embodiment (1st example) of the structural example by the side of the receiver to which an injection locking system is applied. It is a figure explaining 2nd Embodiment (2nd example) of the structural example by the side of the receiver which applies an injection locking system. It is a figure explaining the circuit pattern of an oscillation circuit, and the layout pattern example on CMOS of an inductor circuit. It is a figure explaining the detail of the layout pattern example on CMOS of an inductor circuit. It is a figure explaining the relationship between multi-channeling and injection locking. It is a figure explaining the 1st example of the wireless-transmission-path structure of this embodiment. It is a figure explaining the 2nd example of the wireless-transmission-path structure of this embodiment. It is a figure explaining the 3rd example of the wireless-transmission-path structure of this embodiment. It is a figure explaining the 1st application example of the wireless transmission system of this embodiment. It is a figure explaining the 2nd application example of the wireless transmission system of this embodiment. It is a figure explaining the 3rd application example (the 1-1) of the radio transmission system of this embodiment. It is a figure explaining the 3rd application example (the 1-2) of the radio transmission system of this embodiment. It is a figure explaining the 3rd application example (the 2) of the radio transmission system of this embodiment. It is a figure explaining the 4th application example (the 1) of the radio transmission system of this embodiment. It is a figure explaining the 4th application example (the 2) of the radio transmission system of this embodiment.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

The description will be given in the following order.
1. Communication processing system: Basic Modulation and demodulation: comparative example Modulation and demodulation: Basic (application of injection locking method)
4). 4. Relationship between phase of reference carrier signal and demodulation process Injection locking method: first embodiment 6. 6. Injection locking method: second embodiment 7. Configuration example of oscillation circuit 8. Relationship between multi-channel and injection locking Transmission path structure (inside the case, between mounted / mounted devices)
Ten. System configuration: First application example (single channel)
11． System configuration: Second application example (broadcast communication)
12． System configuration: Third application example (frequency division multiplexing: 2 channels)
13. System configuration: 4th application example (frequency division multiplexing: full duplex bidirectional communication)

<Communication processing system: Basic>
1A to 1A are diagrams illustrating a wireless transmission system according to this embodiment. Here, FIG. 1 is a diagram illustrating a signal interface of the wireless transmission system 1 from the functional configuration side. FIG. 1A is a diagram for explaining signal multiplexing in the wireless transmission system 1.

  The carrier frequency used in the wireless transmission system of the present embodiment will be described in the millimeter wave band, but the mechanism of the present embodiment is not limited to the millimeter wave band, and uses a carrier frequency of a shorter wavelength, for example, a sub millimeter wave band. It is also applicable to The wireless transmission system of this embodiment is used in, for example, a digital recording / reproducing device, a terrestrial television receiver, a mobile phone device, a game device, a computer, and the like.

[Function configuration]
As shown in FIG. 1, in the wireless transmission system 1, a first communication device 100 that is an example of a first wireless device and a second communication device 200 that is an example of a second wireless device are connected to a millimeter wave signal transmission path 9. And is configured to perform signal transmission in the millimeter wave band. The millimeter wave signal transmission path 9 is an example of a radio signal transmission path. A signal to be transmitted is frequency-converted to a millimeter wave band suitable for wideband transmission and transmitted.

  The first communication unit (first millimeter wave transmission device) and the second communication unit (second millimeter wave transmission device) constitute a wireless transmission device (system). And between the 1st communication part and the 2nd communication part arrange | positioned at a comparatively short distance, after converting the signal of transmission object into a millimeter wave signal, this millimeter wave signal is sent to a millimeter wave signal transmission path. To transmit via. The term “wireless transmission” in the present embodiment means that a signal to be transmitted is transmitted wirelessly (in this example, millimeter wave) instead of general electrical wiring (simple wire wiring).

  “Relatively close” means that the distance is short compared to the distance between communication devices in the outdoors (outdoors) used in broadcasting and general wireless communication, and the transmission range is closed. Any material that can be substantially specified may be used. “Closed space” means a space where there is little leakage of radio waves from the inside of the space to the outside, and conversely, there is little arrival (intrusion) of radio waves from the outside to the inside of the space. The entire space is surrounded by a casing (case) that has a shielding effect against radio waves.

  For example, a plurality of electronic devices are integrated, such as inter-board communication within a housing of one electronic device, inter-chip communication on the same substrate, or a state in which the other electronic device is mounted on one electronic device. This corresponds to communication between devices in a connected state.

  Note that “integral” is typically a state in which both electronic devices are in complete contact with each other, but as described above, the transmission range between both electronic devices can be substantially specified as a closed space. Anything is acceptable. This includes the case where both electronic devices are arranged at a predetermined position in a state where they are somewhat separated (relatively close distance: for example, within several centimeters to several tens of centimeters) and can be regarded as being “substantially” integral. The point is that there is little leakage of radio waves from the inside of the space where the radio waves composed of both electronic devices can propagate, and conversely, the state where the arrival (intrusion) of radio waves from the outside to the inside of the space is small. .

  Hereinafter, signal transmission within a casing of one electronic device is referred to as signal transmission within the casing, and signal transmission in a state in which a plurality of electronic devices are integrated (hereinafter also including “substantially integrated”) is performed. This is called inter-signal transmission. In the case of signal transmission within the housing, the communication device on the transmission side (communication unit: transmission unit) and the communication device on the reception side (communication unit: reception unit) are accommodated in the same housing, and the communication unit (transmission unit and reception unit) The wireless transmission system of this embodiment in which a wireless signal transmission path is formed between them is an electronic device itself. On the other hand, in the case of signal transmission between devices, the communication device on the transmission side (communication unit: transmission unit) and the communication device on the reception side (communication unit: reception unit) are accommodated in different electronic device casings. When the electronic device is arranged at a predetermined position and integrated, a wireless signal transmission path is formed between the communication units (transmitting unit and receiving unit) in both electronic devices, and the wireless transmission system of this embodiment is constructed. The

  In each communication device provided with a millimeter wave signal transmission line interposed therebetween, a transmission unit and a reception unit are paired and arranged. Signal transmission between one communication device and the other communication device may be one-way (one-way) or two-way. For example, when the first communication unit is the transmission side and the second communication unit is the reception side, the transmission unit is arranged in the first communication unit and the reception unit is arranged in the second communication unit. When the second communication unit is the transmission side and the first communication unit is the reception side, the transmission unit is arranged in the second communication unit and the reception unit is arranged in the first communication unit.

  The transmission unit includes, for example, a transmission-side signal generation unit (a signal conversion unit that converts a transmission target electrical signal into a millimeter wave signal) that processes a transmission target signal to generate a millimeter wave signal, and a millimeter wave It is assumed that a transmission-side signal coupling unit that couples a millimeter-wave signal generated by the transmission-side signal generation unit to a transmission path (millimeter-wave signal transmission path) for transmitting the above signal is provided. Preferably, the signal generator on the transmission side is integrated with a functional unit that generates a signal to be transmitted.

  For example, the signal generator on the transmission side has a modulation circuit, and the modulation circuit modulates a signal to be transmitted. The signal generator on the transmission side converts the frequency of the signal after being modulated by the modulation circuit to generate a millimeter wave signal. In principle, it is conceivable to directly convert a signal to be transmitted into a millimeter wave signal. The signal coupling unit on the transmission side supplies the millimeter wave signal generated by the signal generation unit on the transmission side to the millimeter wave signal transmission path.

  On the other hand, the receiving unit includes, for example, a reception-side signal coupling unit that receives a millimeter-wave signal transmitted via the millimeter-wave signal transmission path, and a millimeter-wave signal ( It is assumed that a reception-side signal generation unit (a signal conversion unit that converts a millimeter-wave signal into a transmission target electrical signal) that processes an input signal) to generate a normal electrical signal (transmission target signal) is provided. . Preferably, the signal generation unit on the reception side is integrated with a function unit that receives a signal to be transmitted. For example, the signal generation unit on the receiving side has a demodulation circuit, generates a signal to be transmitted by frequency-converting a millimeter wave signal to generate an output signal, and then the demodulation circuit demodulates the output signal. In principle, it is conceivable to directly convert a millimeter wave signal into a signal to be transmitted.

  In other words, when the signal interface is used, the signal to be transmitted is transmitted by a millimeter wave signal without contact or cable (not transmitted by electric wiring). Preferably, at least signal transmission (especially a video signal or high-speed clock signal requiring high-speed transmission or large-capacity transmission) is transmitted by a millimeter wave signal. In short, in the present embodiment, signal transmission, which has been performed by electrical wiring in the past, is performed by a millimeter wave signal. By performing signal transmission in the millimeter wave band, high-speed signal transmission on the order of Gbps can be realized, the range covered by the millimeter wave signal can be easily limited, and an effect due to this property can be obtained.

  Here, each signal coupling unit may be any unit that allows the first communication unit and the second communication unit to transmit a millimeter wave signal via the millimeter wave signal transmission path. For example, it may be provided with an antenna structure (antenna coupling portion), or may be coupled without an antenna structure.

  The “millimeter wave signal transmission path for transmitting a millimeter wave signal” may be air (so-called free space), but preferably has a structure for transmitting a millimeter wave signal while confining the millimeter wave signal in the transmission path. What you have is good. By actively utilizing this property, it is possible to arbitrarily determine the routing of the millimeter wave signal transmission line such as an electrical wiring.

  As such a structure, for example, a so-called waveguide is typically considered, but the structure is not limited thereto. For example, one made of a dielectric material capable of transmitting a millimeter wave signal (referred to as a dielectric transmission line or an in-millimeter wave dielectric transmission line) or a shield that constitutes a transmission line and suppresses external radiation of the millimeter wave signal A hollow waveguide in which the material is provided so as to surround the transmission path and the inside of the shielding material is hollow is preferable. The millimeter wave signal transmission path can be routed by providing flexibility to the dielectric material and the shielding material.

  Incidentally, in the case of air (so-called free space), each signal coupling portion has an antenna structure, and signals are transmitted in a short distance by the antenna structure. On the other hand, when it is assumed that it is made of a dielectric material, an antenna structure can be taken, but this is not essential.

  Hereinafter, the mechanism of the wireless transmission system 1 of the present embodiment will be specifically described. As a most preferable example, an example in which each functional unit is formed in a semiconductor integrated circuit (chip) will be described, but this is not essential.

  The first communication device 100 is provided with a semiconductor chip 103 capable of millimeter wave band communication, and the second communication device 200 is also provided with a semiconductor chip 203 capable of millimeter wave band communication.

  In the present embodiment, only signals that require high speed and large capacity are used as signals for communication in the millimeter wave band. Not converted to millimeter wave signal. For signals (including power supply) that are not converted into millimeter wave signals, the signals are connected between the substrates by the same mechanism as before. The original electrical signals to be transmitted before being converted into millimeter waves are collectively referred to as baseband signals.

[First communication device]
In the first communication device 100, a semiconductor chip 103 capable of millimeter wave band communication and a transmission path coupling unit 108 are mounted on a substrate 102. The semiconductor chip 103 is a system LSI (Large Scale Integrated Circuit) in which an LSI function unit 104 and a signal generation unit 107 (millimeter wave signal generation unit) are integrated. Although not shown, the LSI function unit 104 and the signal generation unit 107 may not be integrated. In the case of separate bodies, regarding the signal transmission between them, there is a concern about problems caused by transmitting signals by electric wiring, so it is preferable to integrate them. In the case of separate bodies, two chips (between the LSI function unit 104 and the signal generation unit 107) are arranged at a short distance, and the adverse effect is reduced by wiring the wire bonding length as short as possible. It is preferable.

  The signal generation unit 107 and the transmission path coupling unit 108 are configured to have bidirectional data. For this reason, the signal generation unit 107 includes a transmission-side signal generation unit and a reception-side signal generation unit. The transmission path coupling unit 108 may be provided separately for the transmission side and the reception side, but here it is assumed to be used for both transmission and reception.

  In the “bidirectional communication” shown here, the millimeter-wave signal transmission path 9 which is a millimeter-wave transmission channel is one-line (one-core) single-core bidirectional transmission. For this realization, a half-duplex method to which time division multiplexing (TDD) is applied, frequency division multiplexing (FDD: Frequency Division Duplex: FIG. 1A), and the like are applied.

  In the case of time division multiplexing, transmission and reception are separated by time division. Therefore, signal transmission from the first communication device 100 to the second communication device 200 and signal transmission from the second communication device 200 to the first communication device 100 are performed. Simultaneous "bidirectional communication simultaneous (single-core simultaneous bidirectional transmission)" is not realized, and single-core simultaneous bidirectional transmission is realized by frequency division multiplexing. However, since frequency division multiplexing uses different frequencies for transmission and reception as shown in FIG. 1A (1), it is necessary to widen the transmission bandwidth of the millimeter wave signal transmission line 9.

  Instead of directly mounting the semiconductor chip 103 on the substrate 102, the semiconductor chip 103 is mounted on the interposer substrate, and a semiconductor package in which the semiconductor chip 103 is molded with a resin (for example, epoxy resin) is mounted on the substrate 102. You may do it. That is, the interposer substrate is a chip mounting substrate, and the semiconductor chip 103 is provided on the interposer substrate. For the interposer substrate, a sheet member having a specific dielectric constant within a certain range (about 2 to 10), for example, a combination of a heat reinforced resin and a copper foil may be used.

  The semiconductor chip 103 is connected to the transmission line coupling unit 108. As the transmission line coupling unit 108, for example, an antenna structure including an antenna coupling unit, an antenna terminal, a microstrip line, an antenna, and the like is applied. Note that the transmission path coupling unit 108 can also be incorporated into the semiconductor chip 103 by applying a technique for forming the antenna directly on the chip.

  The LSI function unit 104 is responsible for main application control of the first communication device 100, and includes, for example, a circuit for processing various signals desired to be transmitted to the other party and a circuit for processing various signals received from the other party.

  The signal generation unit 107 (electric signal conversion unit) converts the signal from the LSI function unit 104 into a millimeter wave signal, and performs signal transmission control via the millimeter wave signal transmission path 9.

  Specifically, the signal generation unit 107 includes a transmission side signal generation unit 110 and a reception side signal generation unit 120. The transmission side signal generation unit 110 and the transmission line coupling unit 108 constitute a transmission unit (transmission side communication unit), and the reception side signal generation unit 120 and the transmission line coupling unit 108 constitute a reception unit (reception side communication unit). Is done.

  The transmission-side signal generation unit 110 includes a multiplexing processing unit 113, a parallel-serial conversion unit 114, a modulation unit 115, a frequency conversion unit 116, and an amplification unit 117 in order to perform signal processing on the input signal to generate a millimeter wave signal. Have. Note that the modulation unit 115 and the frequency conversion unit 116 may be combined into a so-called direct conversion system.

  The reception-side signal generation unit 120 performs signal processing on the millimeter-wave electrical signal received by the transmission path coupling unit 108 to generate an output signal, so that an amplification unit 124, a frequency conversion unit 125, a demodulation unit 126, a serial parallel conversion A unit 127 and a unification processing unit 128. The frequency conversion unit 125 and the demodulation unit 126 may be combined into a so-called direct conversion system.

  The parallel-serial conversion unit 114 and the serial-parallel conversion unit 127 are provided in the case of a parallel interface specification using a plurality of signals for parallel transmission when this embodiment is not applied, and are of a serial interface specification. It is not necessary in some cases.

  The multiplexing processing unit 113 performs time division multiplexing, frequency division multiplexing, code processing, when there are a plurality of types (N1) of signals to be communicated in the millimeter wave band among the signals from the LSI function unit 104. By performing multiplexing processing such as division multiplexing, a plurality of types of signals are combined into one system signal. For example, a plurality of types of signals that are required to be high speed and large capacity are combined into one system as a target of millimeter wave transmission.

  In the case of time division multiplexing or code division multiplexing, the multiplexing processing unit 113 is provided in the preceding stage of the parallel-serial conversion unit 114, and may be supplied to the parallel-serial conversion unit 114 as a single signal. In the case of time division multiplexing, it is only necessary to provide a change-over switch that supplies time to the parallel-serial conversion unit 114 by dividing the time into a plurality of types of signals _ @ (@ is 1 to N).

  On the other hand, in the case of frequency division multiplexing, modulation is performed at different carrier frequencies and converted to frequencies in different frequency bands F_ @ to generate millimeter wave signals, and these different carrier frequencies are used. It is necessary to transmit the millimeter wave signal in the same direction or in the opposite direction. For this reason, for example, when transmitting in the same direction as shown in FIG. 1A (2), a parallel-serial conversion unit 114, a modulation unit 115, a frequency conversion unit 116, and an amplification unit 117 are provided separately for a plurality of types of signals _ @. In addition, an addition processing unit may be provided as the multiplexing processing unit 113 after each amplification unit 117. Then, a millimeter-wave electrical signal in the frequency band F_1 +... + F_N after the frequency multiplexing processing may be supplied to the transmission line coupling unit 108. As the addition processing unit, as shown in FIG. 1A (2), a so-called coupler may be used when millimeter wave signals using different carrier frequencies are transmitted in the same direction.

  As can be seen from FIG. 1A (2), it is necessary to widen the transmission bandwidth in frequency division multiplexing in which a plurality of systems of signals are combined into one system by frequency division multiplexing. As shown in FIG. 1A (3), when a plurality of systems of signals are combined into one system by frequency division multiplexing and combined with a full duplex system using different frequencies for transmission and reception, the transmission bandwidth is further widened. There is a need to.

  The parallel / serial conversion unit 114 converts the parallel signal into a serial data signal and supplies the serial data signal to the modulation unit 115. The modulation unit 115 modulates the transmission target signal and supplies it to the frequency conversion unit 116. The modulation unit 115 may be any unit that modulates at least one of amplitude, frequency, and phase with a transmission target signal, and any combination of these may be employed.

  For example, in the case of an analog modulation system, there are, for example, amplitude modulation (AM) and vector modulation. Vector modulation includes frequency modulation (FM) and phase modulation (PM). In the case of a digital modulation system, for example, amplitude transition modulation (ASK: Amplitude shift keying), frequency transition modulation (FSK: Frequency Shift Keying), phase transition modulation (PSK: Phase Shift Keying), amplitude phase for modulating amplitude and phase There is modulation (APSK: Amplitude Phase Shift Keying). As amplitude phase modulation, quadrature amplitude modulation (QAM: Quadrature Amplitude Modulation) is typical.

  The frequency conversion unit 116 frequency-converts the transmission target signal after being modulated by the modulation unit 115 to generate a millimeter-wave electric signal and supplies it to the amplification unit 117. A millimeter-wave electrical signal refers to an electrical signal having a frequency in the range of approximately 30 GHz to 300 GHz. The term “substantially” may be a frequency at which the effect of millimeter wave communication can be obtained, and the lower limit is not limited to 30 GHz, and the upper limit is not limited to 300 GHz.

  Although various circuit configurations can be employed as the frequency conversion unit 116, for example, a configuration including a frequency mixing circuit (mixer circuit) and a local oscillation circuit may be employed. The local oscillation circuit generates a carrier wave (carrier signal, reference carrier wave) used for modulation. The frequency mixing circuit multiplies (modulates) the millimeter wave band carrier wave generated by the local oscillation circuit with the signal from the parallel-serial conversion unit 114 to generate a millimeter wave band modulation signal, and supplies the modulation signal to the amplification unit 117.

  The amplifying unit 117 amplifies the millimeter wave electric signal after frequency conversion and supplies the amplified signal to the transmission line coupling unit 108. The amplifying unit 117 is connected to the bidirectional transmission line coupling unit 108 via an antenna terminal (not shown).

  The transmission path coupling unit 108 transmits the millimeter wave signal generated by the transmission side signal generation unit 110 to the millimeter wave signal transmission path 9 and receives the millimeter wave signal from the millimeter wave signal transmission path 9 to receive the millimeter wave signal. The signal is output to the signal generator 120.

  The transmission line coupling unit 108 includes an antenna coupling unit. The antenna coupling unit constitutes an example or a part of the transmission path coupling unit 108 (signal coupling unit). The antenna coupling part means a part for coupling an electronic circuit in a semiconductor chip and an antenna arranged in the chip or outside the chip in a narrow sense. In a broad sense, the antenna coupling part includes the semiconductor chip and the millimeter wave signal transmission line 9. This is the part where signals are combined. For example, the antenna coupling unit includes at least an antenna structure. When transmission / reception is performed by time division multiplexing, the transmission line coupling unit 108 is provided with an antenna switching unit (antenna duplexer).

  The antenna structure refers to a structure at a coupling portion with the millimeter wave signal transmission path 9 and may be anything that couples a millimeter wave band electrical signal to the millimeter wave signal transmission path 9 and does not mean only the antenna itself. . For example, the antenna structure includes an antenna terminal, a microstrip line, and an antenna. When the antenna switching unit is formed in the same chip, the antenna terminal and the microstrip line excluding the antenna switching unit constitute the transmission line coupling unit 108.

  The transmitting antenna radiates an electromagnetic wave based on the millimeter wave signal to the millimeter wave signal transmission path 9. The receiving antenna receives an electromagnetic wave based on a millimeter wave signal from the millimeter wave signal transmission path 9. The microstrip line connects between the antenna terminal and the antenna, transmits a millimeter wave signal on the transmission side from the antenna terminal to the antenna, and transmits a millimeter wave signal on the reception side from the antenna to the antenna terminal.

  The antenna switching unit is used when the antenna is shared for transmission and reception. For example, when transmitting a millimeter-wave signal to the second communication device 200 that is the counterpart, the antenna switching unit connects the antenna to the transmission-side signal generation unit 110. In addition, when receiving a millimeter wave signal from the second communication apparatus 200 that is the counterpart, the antenna switching unit connects the antenna to the reception-side signal generation unit 120. The antenna switching unit is provided on the substrate 102 separately from the semiconductor chip 103, but is not limited thereto, and may be provided in the semiconductor chip 103. When the transmitting antenna and the receiving antenna are provided separately, the antenna switching unit can be omitted.

  For example, the millimeter wave signal transmission path 9 that is a millimeter wave propagation path may be configured as a free space transmission path that propagates through a space in a housing. In addition, it is preferable that it is configured by a waveguide structure such as a waveguide, a transmission line, a dielectric line, or a dielectric body and has a characteristic of efficiently transmitting an electromagnetic wave in the millimeter wave band. For example, the dielectric transmission line 9A may be configured to include a dielectric material having a specific dielectric constant within a certain range and a dielectric loss tangent within a certain range. For example, by filling the entire casing with a dielectric material, a dielectric transmission line 9A is arranged between the transmission line coupling unit 108 and the transmission line coupling unit 208 instead of the free space transmission line. In addition, dielectric transmission is performed by connecting the antenna of the transmission path coupling unit 108 and the antenna of the transmission path coupling unit 208 with a dielectric line that is a linear member having a certain wire diameter made of a dielectric material. It is also conceivable to configure the path 9A.

  The “certain range” may be a range in which the relative permittivity and the dielectric loss tangent of the dielectric material can obtain the effects of the present embodiment, and may be a predetermined value as long as it is within that range. In other words, the dielectric material may be any material that can transmit millimeter waves having such characteristics that the effects of the present embodiment can be obtained. Although it is not determined only by the dielectric material itself and is also related to the transmission path length and the millimeter wave frequency, it is not necessarily determined clearly, but as an example, it is as follows.

  In order to transmit a millimeter-wave signal at high speed in the dielectric transmission line 9A, the dielectric material has a relative dielectric constant of about 2 to 10 (preferably 3 to 6), and a dielectric loss tangent of 0.00001 to 0. It is desirable to set it to about 0.01 (preferably 0.00001 to 0.001). As the dielectric material satisfying such conditions, for example, those made of acrylic resin, urethane resin, epoxy resin, silicone, polyimide, cyanoacrylate resin, and liquid crystal polymer can be used.

  Such a range of the relative permittivity of the dielectric material and its dielectric loss tangent is the same in this embodiment unless otherwise specified. As the millimeter wave signal transmission line 9 configured to confine the millimeter wave signal in the transmission line, in addition to the dielectric transmission line 9A, the transmission line may be surrounded by a shielding material and the inside thereof may be a hollow hollow waveguide. Good.

  A reception-side signal generator 120 is connected to the transmission line coupler 108. The receiving-side amplification unit 124 is connected to the transmission path coupling unit 108, amplifies the millimeter-wave electrical signal received by the antenna, and supplies the amplified signal to the frequency conversion unit 125. The frequency conversion unit 125 frequency-converts the amplified millimeter-wave electrical signal and supplies the frequency-converted signal to the demodulation unit 126. The demodulator 126 demodulates the frequency-converted signal to acquire a baseband signal, and supplies the baseband signal to the serial-parallel converter 127.

  The serial / parallel conversion unit 127 converts serial reception data into parallel output data and supplies the parallel output data to the unification processing unit 128.

  The unification processing unit 128 corresponds to the multiplexing processing unit 113, and separates signals collected in one system into a plurality of types of signals _ @ (@ is 1 to N). For example, a plurality of data signals collected in one system of signals are separated and supplied to the LSI function unit 1104.

  When frequency division multiplexing is combined into one system, millimeter-wave electrical signals in the frequency band F_1 +... + F_N after frequency multiplexing processing are received, separated separately, and transmitted in the same direction. It is necessary to process each band F_ @. For this reason, as shown in FIG. 1A (2), an amplification unit 224, a frequency conversion unit 225, a demodulation unit 226, and a serial / parallel conversion unit 227 are provided separately for a plurality of types of signals _b, and a single stage is provided in front of each amplification unit 224. A frequency separation unit may be provided as the unification processing unit 128. Then, the separated millimeter-wave electrical signal in each frequency band F_b may be supplied to the corresponding system in the frequency band F_b. As the frequency separator, as shown in FIG. 1A (2), a so-called distributor may be used to separate each of the multiplexed carrier wave millimeter wave signals.

  1A (2) uses the frequency division multiplexing method in which a plurality of sets of transmission units and reception units are used, and each set transmits signals in the same direction using different carrier frequencies. Although it is a system, the usage form of the frequency division multiplexing system is not limited to this. For example, in FIG. 1, the first carrier frequency is used in the set of the transmission side signal generation unit 110 of the first communication device 100 and the reception side signal generation unit 220 of the second communication device 200, and the reception of the first communication device 100 is performed. Full-duplex bidirectional communication in which the second carrier frequency is used in the set of the side signal generation unit 120 and the transmission side signal generation unit 210 of the second communication device 200, and each set simultaneously performs signal transmission in the opposite directions. It can also be. In this case, what is necessary is just to use what is called a circulator which can perform signal transmission to both simultaneously as an antenna switching part of the transmission-line coupling | bond part 108,208 in FIG.

  In addition, it is also possible to employ a mode in which the same direction and the reverse direction are combined by using a larger number of sets of transmission units and reception units, and using different carrier frequencies in each group. In this case, in FIG. 1A (2), the transmission path coupling units 108 and 208 may be configured to use the multiplexing processing units 113 and 213 and the unification processing units 128 and 228 while using circulators.

  When the semiconductor chip 103 is configured in this way, the input signal is parallel-serial converted and transmitted to the semiconductor chip 203 side, and the received signal from the semiconductor chip 203 side is serial-parallel converted, so that the number of millimeter wave conversion target signals Is reduced.

  When the original signal transmission between the first communication device 100 and the second communication device 200 is in a serial format, the parallel / serial conversion unit 114 and the serial / parallel conversion unit 127 may not be provided.

[Second communication device]
The second communication device 200 has substantially the same functional configuration as the first communication device 100. Each functional unit is provided with a reference number in the 200th series, and the same or similar functional unit as that of the first communication apparatus 100 is provided with the same reference numbers as the first communication apparatus 100 in the 10th and 1st series. The transmission side signal generation unit 210 and the transmission line coupling unit 208 constitute a transmission unit, and the reception side signal generation unit 220 and the transmission line coupling unit 208 constitute a reception unit.

  The LSI function unit 204 is responsible for main application control of the second communication device 200, and includes, for example, a circuit for processing various signals desired to be transmitted to the other party and a circuit for processing various signals received from the other party.

[Connection and operation]
The technique of frequency-converting an input signal and transmitting the signal is generally used in broadcasting and wireless communication. In these applications, α) how far you can communicate (S / N problem with thermal noise), β) how to deal with reflection and multipath, γ) how to suppress interference and interference with other channels. A relatively complicated transmitter or receiver that can cope with such problems is used. On the other hand, the signal generators 107 and 1207 used in the present embodiment have millimeters in a higher frequency band than the frequency used by complicated transmitters and receivers generally used in broadcasting and wireless communication. Since it is used in the waveband and the wavelength λ is short, it is easy to reuse the frequency, and a device suitable for communication between many devices in the vicinity is used.

  In the present embodiment, unlike the signal interface using the conventional electrical wiring, the signal transmission is performed in the millimeter wave band as described above, so that high speed and large capacity can be flexibly dealt with. For example, only signals that require high speed and large capacity are targeted for communication in the millimeter wave band. Depending on the system configuration, the communication devices 100 and 200 may be used for low-speed, small-capacity signals or power supply. A part of the interface (connection by a terminal / connector) by conventional electric wiring is provided.

  The signal generation unit 107 performs signal processing on the input signal input from the LSI function unit 104 to generate a millimeter wave signal. The signal generation unit 107 is connected to the transmission line coupling unit 108 via a transmission line such as a microstrip line, a strip line, a coplanar line, or a slot line, for example, and the generated millimeter wave signal passes through the transmission line coupling unit 108. It is supplied to the millimeter wave signal transmission line 9.

  The transmission path coupling unit 108 has an antenna structure, and has a function of converting a transmitted millimeter wave signal into an electromagnetic wave and transmitting the electromagnetic wave. The transmission path coupling unit 108 is coupled to the millimeter wave signal transmission path 9, and an electromagnetic wave converted by the transmission path coupling unit 108 is supplied to one end of the millimeter wave signal transmission path 9. The other end of the millimeter wave signal transmission line 9 is coupled to the transmission line coupling unit 208 on the second communication device 200 side. By providing the millimeter wave signal transmission line 9 between the transmission line coupling unit 108 on the first communication device 100 side and the transmission line coupling unit 208 on the second communication device 200 side, the millimeter wave signal transmission line 9 has a millimeter wave band. Electromagnetic waves will propagate.

  The millimeter wave signal transmission line 9 is coupled to the transmission line coupling unit 208 on the second communication device 200 side. The transmission path coupling unit 208 receives the electromagnetic wave transmitted to the other end of the millimeter wave signal transmission path 9, converts it to a millimeter wave signal, and supplies it to the signal generation unit 207 (baseband signal generation unit). The signal generation unit 207 performs signal processing on the converted millimeter wave signal to generate an output signal (baseband signal), and supplies the output signal to the LSI function unit 204.

  Here, the case of signal transmission from the first communication device 100 to the second communication device 200 has been described, but the same applies to the case of transmitting a signal from the LSI function unit 204 of the second communication device 200 to the first communication device 100. You only need to think about it, and you can transmit millimeter-wave signals in both directions.

  Here, the signal transmission system that performs signal transmission via the electrical wiring has the following problems.

   i) Large capacity and high speed of transmission data are required, but there are limits to the transmission speed and capacity of electrical wiring.

  ii) To cope with the problem of high-speed transmission data, it is conceivable to increase the number of wires and reduce the transmission speed per signal line by parallelizing signals. However, this countermeasure leads to an increase in input / output terminals. As a result, complicated printed circuit boards and cable wiring, increased physical size of connectors and electrical interfaces, etc. are required, their shapes become complicated, their reliability decreases, and costs increase. Happens.

 iii) With the increase in the amount of information such as movie images and computer images, the problem of EMC (electromagnetic compatibility) becomes more apparent as the band of the baseband signal becomes wider. For example, when electrical wiring is used, the wiring becomes an antenna, and a signal corresponding to the tuning frequency of the antenna is interfered. Also, reflection or resonance due to wiring impedance mismatch or the like causes unnecessary radiation. If there is resonance or reflection, it tends to be accompanied by radiation, and the problem of EMI (electromagnetic induction interference) becomes serious. In order to cope with such a problem, the configuration of the electronic device is complicated.

  iv) In addition to EMC and EMI, when there is reflection, transmission errors due to interference between symbols on the receiving side and transmission errors due to jumping in interference also become a problem.

  On the other hand, the wireless transmission system 1 according to the present embodiment performs signal transmission using millimeter waves instead of electrical wiring. A signal from the LSI function unit 104 to the LSI function unit 204 is converted into a millimeter wave signal, and the millimeter wave signal is transmitted between the transmission line coupling units 108 and 208 via the millimeter wave signal transmission line 9.

  For wireless transmission, there is no need to worry about the wiring shape and connector position, so there are not many restrictions on the layout. Signals replaced with millimeter wave signal transmission have a short wavelength and a limited range of wavelength lengths, so that the problems of EMC and EMI can be easily solved. In general, there is no other functional unit that uses a millimeter-wave band frequency in the communication apparatuses 100 and 200, and therefore, measures against EMC and EMI can be easily realized.

  Since wireless transmission is performed in a state where the first communication device 100 and the second communication device 200 are close to each other and signal transmission is performed between fixed positions or in a known positional relationship, the following advantages can be obtained.

  1) It is easy to properly design a propagation channel (waveguide structure) between the transmission side and the reception side.

  2) By combining the dielectric structure of the transmission line coupling part that seals the transmission side and the reception side and the propagation channel (waveguide structure of the millimeter wave signal transmission line 9), it is more reliable than free space transmission. High good transmission is possible.

  3) Since control of the controller (in this example, the LSI function unit 104) that manages wireless transmission does not need to be performed dynamically and frequently as in general wireless communication, the overhead due to control is higher than that in general wireless communication. Can be made smaller. As a result, miniaturization, low power consumption, and high speed can be achieved.

  4) If the wireless transmission environment is calibrated at the time of manufacture or design and the variation of the individual is grasped, higher quality communication becomes possible by referring to the data and transmitting it.

  5) Even if there is a reflection, it is a fixed reflection, so its influence can be easily removed on the receiving side with a small equalizer. The equalizer can also be set by presetting or static control, which is easy to implement.

  In addition, the following advantages can be obtained by wireless communication in the millimeter-wave band with a short wavelength.

  a) Since the millimeter wave communication can take a wide communication band, it is easy to increase the data rate.

  b) The frequency used for transmission can be separated from the frequency of other baseband signal processing, and interference between the millimeter wave and the frequency of the baseband signal hardly occurs.

  c) Since the millimeter wave band has a short wavelength, it is possible to reduce the size of an antenna or a waveguide structure that depends on the wavelength. In addition, since the distance attenuation is large and the diffraction is small, electromagnetic shielding is easy to perform.

  d) In normal outdoor wireless communication, there are strict regulations on carrier stability in order to prevent interference and the like. In order to realize such a highly stable carrier wave, a highly stable external frequency reference component, a multiplier circuit, a PLL (phase locked loop circuit), and the like are used, and the circuit scale increases. However, with millimeter waves (especially when used in conjunction with signal transmission between fixed positions or with known positional relationships), millimeter waves can be easily shielded and not leaked to the outside, and low-stability carriers are used for transmission. Thus, an increase in circuit scale can be suppressed. In order to demodulate a signal transmitted by a carrier wave with a low degree of stability with a small circuit on the receiving side, it is preferable to employ an injection locking method (details will be described later).

  In the present embodiment, a system that performs communication in the millimeter wave band is illustrated as an example of a wireless transmission system, but the application range is not limited to that that performs communication in the millimeter wave band. A centimeter wave having a longer wavelength than the millimeter wave band (preferably closer to the millimeter wave) or a sub-millimeter wave having a shorter wavelength than the millimeter wave band (preferably closer to the millimeter wave) may be applied. However, in the signal transmission within the housing and the signal transmission between devices, the injection locking method is adopted, and the millimeter wave band is used in that the entire oscillation circuit including the tank circuit is formed on the CMOS chip. It is considered the most effective.

<Modulation and demodulation: comparative example>
FIG. 2 is a diagram illustrating a comparative example of the modulation function unit and the demodulation function unit in the communication processing system.

[Modulation function: Comparative example]
FIG. 2A shows the configuration of a modulation function unit 8300X of a comparative example provided on the transmission side. A signal to be transmitted (for example, a 12-bit image signal) is converted into a high-speed serial data sequence by the parallel-serial conversion unit 114 and supplied to the modulation function unit 8300X.

  The modulation function unit 8300X can take various circuit configurations depending on the modulation method. For example, in the case of a method that modulates amplitude or phase, the modulation function unit 8300X includes a frequency mixing unit 8302 and a transmission-side local oscillation unit 8304. Adopt it.

  Transmission-side local oscillation unit 8304 (first carrier signal generation unit) generates a carrier signal (modulated carrier signal) used for modulation. The frequency mixing unit 8302 (first frequency conversion unit) multiplies (modulates) a carrier wave in the millimeter wave band generated by the transmission-side local oscillation unit 8304 with a signal from the parallel-serial conversion unit 8114 (corresponding to the parallel-serial conversion unit 114). ) To generate a modulation signal in the millimeter wave band and supply it to the amplifying unit 8117 (corresponding to the amplifying unit 117). The modulated signal is amplified by the amplifying unit 8117 and radiated from the antenna 8136.

[Demodulation function section: comparative example]
FIG. 2B shows the configuration of a demodulation function unit 8400X of a comparative example provided on the receiving side. The demodulation function unit 8400X can employ various circuit configurations in a range corresponding to the modulation method on the transmission side, but here the amplitude and phase are modulated so as to correspond to the above description of the modulation function unit 8300X. This will be described in the case of the method.

  The demodulation function unit 8400X of the comparative example includes a two-input type frequency mixing unit 8402 (mixer circuit), and uses a square detection circuit that obtains a detection output proportional to the square of the amplitude of the received millimeter wave signal (envelope). It is also conceivable to use a simple envelope detection circuit having no square characteristic instead of the square detection circuit. In the illustrated example, a filter processing unit 8410, a clock recovery unit 8420 (CDR: Clock Data Recovery), and a serial / parallel conversion unit 8127 (SP: serial / parallel conversion unit 127) are arranged after the frequency mixing unit 8402. And corresponding). The filter processing unit 8410 is provided with, for example, a low-pass filter (LPF).

  The millimeter-wave reception signal received by the antenna 8236 is input to a variable gain type amplifying unit 8224 (corresponding to the amplifying unit 224), and after amplitude adjustment, is supplied to the demodulation function unit 8400X. The amplitude-adjusted received signal is simultaneously input to two input terminals of the frequency mixing unit 8402 to generate a square signal, and is supplied to the filter processing unit 8410. The square signal generated by the frequency mixing unit 8402 generates a waveform (baseband signal) of the input signal sent from the transmission side by removing high-frequency components by the low-pass filter of the filter processing unit 8410. , And supplied to the clock reproduction unit 8420.

  The clock regenerator 8420 (CDR) regenerates a sampling clock based on this baseband signal, and generates a received data sequence by sampling the baseband signal with the regenerated sampling clock. The generated reception data series is supplied to the serial / parallel conversion unit 8227 (SP), and a parallel signal (for example, a 12-bit image signal) is reproduced. There are various clock recovery methods, for example, a symbol synchronization method is adopted.

[Problems of comparative example]
Here, when the wireless transmission system is configured by the modulation function unit 8300X and the demodulation function unit 8400X of the comparative example, there are the following problems.

  First, the oscillation circuit has the following drawbacks. For example, in outdoor (outdoor) communication, it is necessary to consider multi-channeling. In this case, since it is affected by the frequency fluctuation component of the carrier wave, the required specification of the stability of the carrier wave on the transmission side is strict. When transmitting data in millimeter waves for signal transmission within a housing or signal transmission between devices, using the normal method used in outdoor wireless communication on the transmission side and reception side makes the carrier stable. Therefore, a highly stable millimeter wave oscillation circuit having a frequency stability number on the order of ppm (parts per million) is required.

  In order to realize a carrier signal with high frequency stability, for example, it is conceivable to realize a millimeter wave oscillation circuit with high stability on a silicon integrated circuit (CMOS). However, since a silicon substrate used in a normal CMOS has low insulation, a tank circuit having a high Q factor (Quality Factor) cannot be easily formed, and it is not easy to realize. For example, as shown in Reference A, when an inductance is formed on a CMOS chip, the Q value is about 30 to 40.

  Reference A: A. Niknejad, “mm-Wave Silicon Technology 60GHz and Beyond” (especially 3.1.2 Inductors pp70-71), ISBN 978-0-387-76558-7

  Therefore, in order to realize an oscillation circuit with high stability, for example, a high Q value tank circuit is provided outside the CMOS where the main body of the oscillation circuit is configured using a crystal oscillator or the like to oscillate at a low frequency. It is conceivable to adopt a technique of multiplying the oscillation output to the millimeter wave band. However, it is not preferable to provide such an external tank in all chips in order to realize a function of replacing signal transmission by wiring such as LVDS (Low Voltage Differential Signaling) with signal transmission by millimeter waves.

  If a method of modulating the amplitude, such as OOK (On-Off-Keying), is used, it is only necessary to perform envelope detection on the receiving side, so that no oscillation circuit is required and the number of tank circuits can be reduced. However, the reception amplitude decreases as the signal transmission distance increases, and the method using the square detection circuit as an example of envelope detection has a disadvantage that the effect of the decrease in reception amplitude becomes significant and signal distortion affects. It is. In other words, the square detection circuit is disadvantageous in terms of sensitivity.

  As another method for realizing a carrier signal having a high frequency stability number, for example, it is conceivable to use a frequency multiplier circuit or a PLL circuit with high stability, but the circuit scale increases. For example, in Reference B, a push-push oscillator circuit is used to eliminate the 60 GHz frequency divider to reduce power consumption. However, still a 30 GHz oscillation circuit and frequency divider are still used. A phase frequency detector (PFD), an external reference (117 MHz in this example), etc. are necessary, and the circuit scale is clearly large.

  Reference B: “A 90nm CMOS Low-Power 60GHz Tranceiver with Intergrated Baseband Circuitry”, ISSCC 2009 / SESSION 18 / RANGING AND Gb / s COMMUNICATION / 18.5, 2009 IEEE International Solid-State Circuits Conference, pp314-316

  Since the square wave detection circuit can extract only the amplitude component from the received signal, the modulation method that can be used is limited to a method that modulates the amplitude (for example, ASK such as OOK), and it is difficult to adopt a method that modulates the phase and frequency. . When it becomes difficult to adopt the phase modulation method, the data transmission rate cannot be increased by orthogonalizing the modulation signal.

  Further, when realizing multi-channel by the frequency division multiplexing method, the method using the square detection circuit has the following problems. Although it is necessary to arrange a band pass filter for frequency selection on the reception side in the previous stage of the square detection circuit, it is not easy to realize a steep band pass filter in a small size. In addition, when a steep bandpass filter is used, the required specifications for the stability of the carrier frequency on the transmission side become strict.

<Modulation and demodulation: Basic>
3 to 4A are diagrams for explaining the basic configuration of the modulation function and the demodulation function in the communication processing system. Here, FIG. 3 shows a transmission side signal generation unit 8110 (transmission) composed of the modulation function unit 8300 (modulation units 115 and 215 and frequency conversion units 116 and 216) of the present embodiment provided on the transmission side and its peripheral circuits. It is a figure explaining the example of a basic composition of the communication part of the side. FIG. 4 shows a reception side signal generation unit 8220 (communication on the reception side) composed of a demodulation function unit 8400 (frequency conversion units 125 and 225 and demodulation units 126 and 226) of the present embodiment provided on the reception side and its peripheral circuits. FIG. FIG. 4A is a diagram illustrating the phase relationship of injection locking.

  As a countermeasure against the problem in the comparative example described above, the demodulation function unit 8400 of the present embodiment employs an injection locking (injection lock) system.

  In the case of adopting the injection locking method, it is preferable that an appropriate correction process is performed on the modulation target signal in advance so as to facilitate injection locking on the receiving side. Typically, modulation is performed after suppressing the DC component near the modulation target signal, that is, by modulating (cutting) the low frequency component near DC (DC) and then modulating the signal. The modulation signal component is made as small as possible to facilitate injection locking on the receiving side. It is better to suppress not only DC but also the surroundings. In the case of the digital system, for example, DC-free encoding is performed in order to eliminate occurrence of a DC component due to continuation of the same code.

  It is also desirable to send out a reference carrier signal used as a reference for injection locking on the receiving side corresponding to the carrier signal used for modulation together with the signal modulated in the millimeter wave band (modulated signal). The reference carrier signal is a signal whose frequency and phase (and more preferably the amplitude) corresponding to the carrier signal used for modulation output from the transmission-side local oscillator 8304 is always constant (invariant), and is typically modulated. However, the present invention is not limited to this, as long as it is at least synchronized with the carrier signal. For example, a signal having a different frequency (for example, a harmonic signal) synchronized with the carrier signal used for modulation or a signal having the same frequency but a different phase (for example, an orthogonal carrier signal orthogonal to the carrier signal used for modulation) may be used.

  Depending on the modulation method and the modulation circuit, a carrier signal is included in the output signal itself of the modulation circuit (for example, standard amplitude modulation or ASK), and a carrier wave is suppressed (carrier-suppression amplitude modulation, ASK, or PSK). and so on. Therefore, the circuit configuration for transmitting the reference carrier signal together with the signal modulated in the millimeter wave band from the transmission side is based on the type of the reference carrier signal (whether the carrier signal itself used for modulation is used as the reference carrier signal). Or a circuit configuration corresponding to a modulation method or a modulation circuit.

[Modulation function]
FIG. 3 shows a basic configuration of the modulation function unit 8300 and its peripheral circuits. A modulation target signal processing unit 8301 is provided in the preceding stage of the modulation function unit 8300 (frequency mixing unit 8302). Each example shown in FIG. 3 shows a configuration example corresponding to the case of the digital system, and the modulation target signal processing unit 8301 performs DC conversion on the data supplied from the parallel-serial conversion unit 8114 by continuation of the same sign. In order to eliminate the occurrence of components, DC-free encoding such as 8-9 conversion encoding (8B / 9B encoding), 8-10 conversion encoding (8B / 10B encoding), and scramble processing is performed. . Although not shown, in the analog modulation method, it is preferable to perform high-pass filter processing (or band-pass filter processing) on the modulation target signal.

  In 8-10 conversion encoding, 8-bit data is converted into a 10-bit code. For example, among the 1024 types of 10-bit codes, the same number of “1” and “0” as much as possible is adopted as the data code so as to have a DC free characteristic. Some 10-bit codes that are not employed as data codes are used as special codes indicating, for example, idle or packet delimiters. In the scramble processing, for example, 64B / 66B encoding adopted in the 10 GBase-X family (IEEE802.3ae etc.) is known.

  Here, the basic configuration 1 shown in FIG. 3A is provided with a reference carrier signal processing unit 8306 and a signal synthesis unit 8308, and an output signal (modulation signal) of the modulation circuit (first frequency conversion unit) and the reference carrier. An operation of combining (mixing) signals is performed. It can be said that this is a versatile system that does not depend on the type of reference carrier signal, the modulation system, or the modulation circuit. However, depending on the phase of the reference carrier signal, the synthesized reference carrier signal may be detected as a DC offset component during demodulation on the receiving side and affect the reproducibility of the baseband signal. In that case, the receiver side takes measures to suppress the DC component. In other words, it is preferable to use a reference carrier signal having a phase relationship that does not require removal of the DC offset component during demodulation.

  The reference carrier signal processing unit 8306 adjusts the phase and amplitude of the modulated carrier signal supplied from the transmission-side local oscillation unit 8304 as necessary, and supplies the output signal to the signal synthesis unit 8308 as a reference carrier signal. . For example, the output signal itself of the frequency mixing unit 8302 is essentially a method that does not include a carrier signal whose frequency and phase are always constant (a method that modulates the frequency and phase), or the harmonics of the carrier signal used for modulation. This basic configuration 1 is employed when a wave signal or a quadrature carrier signal is used as a reference carrier signal.

  In this case, the harmonic signal or orthogonal carrier signal of the carrier signal used for modulation can be used as the reference carrier signal, and the amplitude and phase of the modulation signal and the reference carrier signal can be adjusted separately. That is, the amplifying unit 8117 performs gain adjustment focusing on the amplitude of the modulation signal, and at the same time, the amplitude of the reference carrier signal is also adjusted, but the reference carrier signal processing unit is set so as to have a preferable amplitude in relation to injection locking. At 8306, only the amplitude of the reference carrier signal can be adjusted.

  In the basic configuration 1, the signal synthesizer 8308 is provided to synthesize the modulation signal and the reference carrier signal. However, this is not essential, and as shown in the basic configuration 2 in FIG. And the reference carrier signal may be sent to the receiving side by the separate antennas 8136_1 and 8136_2, preferably by the separate millimeter wave signal transmission line 9 so as not to cause interference. In the basic configuration 2, a reference carrier signal whose amplitude is always constant can be transmitted to the receiving side, which can be said to be an optimum method from the viewpoint of easy injection locking.

  In the case of the basic configurations 1 and 2, there is an advantage that the amplitude and phase of the carrier signal used for modulation (in other words, the modulation signal to be transmitted) and the reference carrier signal can be adjusted separately. Therefore, it is suitable to prevent the DC output from being generated in the demodulated output by setting the modulation axis on which the transmission target information is placed and the axis of the reference carrier signal used for injection locking (reference carrier axis) not to be in phase but to different phases. It can be said that it is a proper configuration.

  When the output signal itself of the frequency mixing unit 8302 can include a carrier signal having a constant frequency and phase, the basic configuration 3 shown in FIG. 3 (3) without the reference carrier signal processing unit 8306 and the signal synthesis unit 8308. Can be adopted. Only the modulation signal modulated in the millimeter wave band by the frequency mixing unit 8302 may be transmitted to the reception side, and the carrier signal included in the modulation signal may be handled as the reference carrier signal. There is no need to add a carrier signal and send it to the receiver. For example, this basic configuration 3 can be adopted in the case of a method for modulating the amplitude (for example, the ASK method). At this time, it is preferable to perform DC-free processing.

  However, also in amplitude modulation and ASK, the frequency mixing unit 8302 is actively changed to a carrier wave suppression circuit (for example, a balanced modulation circuit or a double balanced modulation circuit), and the output signal ( A reference carrier signal may be sent together with the modulation signal.

  Even in the case of a method of modulating the phase and frequency, modulation (frequency conversion) is performed in the millimeter wave band by the modulation function unit 8300 (for example, using quadrature modulation) as in the basic configuration 4 shown in FIG. It is also conceivable to send out only the modulated signal. However, whether or not injection locking can be achieved on the receiving side is also related to the injection level (the amplitude level of the reference carrier signal input to the oscillation circuit of the injection locking method), the modulation method, the data rate, the carrier frequency, etc. There are limitations.

  In any of the basic configurations 1 to 4, as indicated by the dotted line in the figure, information based on the result of injection locking detection on the reception side is received from the reception side, and the frequency of the modulated carrier signal and the millimeter wave (in particular, the injection signal on the reception side). (For example, a reference carrier signal or a modulation signal) and a mechanism for adjusting the phase of the reference carrier signal can be employed. Transmission of information from the reception side to the transmission side is not essential using millimeter waves, and any method may be used regardless of wired or wireless.

  In any of the basic configurations 1 to 4, the frequency of the modulated carrier signal (or the reference carrier signal) is adjusted by controlling the transmission-side local oscillator 8304.

  In the basic configurations 1 and 2, the amplitude and phase of the reference carrier signal are adjusted by controlling the reference carrier signal processing unit 8306 and the amplification unit 8117. In the basic configuration 1, it is conceivable to adjust the amplitude of the reference carrier signal by the amplifying unit 8117 that adjusts the transmission power. However, in this case, there is a difficulty that the amplitude of the modulation signal is also adjusted.

  In the basic configuration 3 suitable for the method of modulating the amplitude (analog amplitude modulation or digital ASK), the DC component of the modulation target signal is adjusted, or the modulation degree (modulation rate) is controlled to control the modulation signal. The carrier frequency component (corresponding to the amplitude of the reference carrier signal) is adjusted. For example, consider a case where a signal obtained by adding a DC component to a transmission target signal is modulated. In this case, when the modulation degree is made constant, the amplitude of the reference carrier signal is adjusted by controlling the direct current component. When the DC component is constant, the amplitude of the reference carrier signal is adjusted by controlling the modulation degree.

  However, in this case, it is not necessary to use the signal synthesizer 8308, and only the modulated signal output from the frequency mixing unit 8302 is sent to the receiving side. And a carrier signal used for modulation are transmitted as a mixed signal. Inevitably, the reference carrier signal is placed on the same axis as the modulation axis on which the transmission target signal of the modulation signal is placed (that is, in phase with the modulation axis). On the receiving side, the carrier frequency component in the modulated signal is used as a reference carrier signal for injection locking. Here, although details will be described later, when considered in the phase plane, the modulation axis for carrying the transmission target information and the axis of the carrier frequency component (reference carrier signal) used for injection locking are in phase, and the demodulation output includes the carrier frequency. A DC offset due to the component (reference carrier signal) occurs.

[Demodulation function section]
FIG. 4 shows the basic configuration of the demodulation function unit 8400 and its peripheral circuits. The demodulation function unit 8400 of this embodiment includes a reception-side local oscillation unit 8404, and supplies an injection signal to the reception-side local oscillation unit 8404, thereby obtaining an output signal corresponding to the carrier signal used for modulation on the transmission side. To do. Typically, an oscillation output signal synchronized with the carrier signal used on the transmission side is acquired. Then, a frequency mixing unit 8402 multiplies (synchronously detects) a carrier signal for demodulation (demodulated carrier signal: referred to as a reproduction carrier signal) based on the received millimeter wave modulation signal and the output signal of the reception-side local oscillation unit 8404. The synchronous detection signal is acquired with. The synchronous detection signal is subjected to the removal of the high frequency component by the filter processing unit 8410, whereby the waveform (baseband signal) of the input signal sent from the transmission side is obtained. Hereinafter, it is the same as that of a comparative example.

  The frequency mixing unit 8402 obtains advantages such as excellent bit error rate characteristics by applying frequency conversion (down-conversion / demodulation) by synchronous detection, and applying phase modulation and frequency modulation by developing to quadrature detection. It is done.

  When supplying the reproduction carrier signal based on the output signal of the reception-side local oscillation unit 8404 to the frequency mixing unit 8402 and demodulating it, it is necessary to consider a phase shift, and it is important to provide a phase adjustment circuit in the synchronous detection system. Become. For example, as shown in Reference C, there is a phase difference between the received modulation signal and the oscillation output signal output by injection locking in the reception-side local oscillation unit 8404.

  Reference C: L. J. Paciorek, “Injection Lock of Oscillators”, Proceeding of the IEEE, Vol. 55 NO. 11, November 1965, pp1723-1728

  In this example, the demodulation function unit 8400 is provided with a phase amplitude adjustment unit 8406 that has not only the function of the phase adjustment circuit but also the function of adjusting the injection amplitude. The phase adjustment circuit may be provided for any of the injection signal to the reception-side local oscillation unit 8404 and the output signal of the reception-side local oscillation unit 8404, or may be applied to both. The reception side local oscillation unit 8404 and the phase amplitude adjustment unit 8406 constitute a demodulation side (second) carrier signal generation unit that generates a demodulation carrier signal synchronized with the modulation carrier signal and supplies the demodulation carrier signal to the frequency mixing unit 8402.

  As indicated by a dotted line in the figure, the subsequent stage of the frequency mixing unit 8402 includes synchronous detection according to the phase of the reference carrier signal combined with the modulation signal (specifically, when the modulation signal and the reference carrier signal are in phase). A direct current component suppression unit 8407 for removing a direct current offset component that can be included in the signal is provided.

  Here, based on Reference C, the free-running oscillation frequency of the reception-side local oscillation unit 8404 is fo (ωo), the center frequency of the injection signal (the frequency in the case of the reference carrier signal) is fi (ωi), and the reception side When the injection voltage to the local oscillation unit 8404 is Vi, the free-running oscillation voltage of the reception-side local oscillation unit 8404 is Vo, and the Q value (Quality Factor) is Q, the lock range is represented by the maximum pull-in frequency range Δfomax. A). From equation (A), it can be seen that the Q value affects the lock range, and the lower the Q value, the wider the lock range.

  Δfomax = fo / (2 * Q) * (Vi / Vo) * 1 / sqrt (1- (Vi / Vo) ^ 2) (A)

  From equation (A), the reception-side local oscillator 8404 that acquires the oscillation output signal by injection locking can be locked (synchronized) with the component within Δfomax of the injection signal, but is locked with the component outside Δfomax. It is understood that it has a bandpass effect. For example, when a modulation signal having a frequency band is supplied to the reception-side local oscillation unit 8404 and an oscillation output signal is obtained by injection locking, an oscillation output signal synchronized with the average frequency of the modulation signal (the frequency of the carrier signal) is obtained. , Components outside Δfomax are removed.

  Here, when the injection signal is supplied to the reception-side local oscillation unit 8404, the received millimeter wave signal is supplied to the reception-side local oscillation unit 8404 as an injection signal as in the basic configuration 1 shown in FIG. It is possible. In this case, it is desirable that the frequency component within Δfomax is small. The reason that “the smaller one is desirable” is based on the fact that injection locking is possible by appropriately adjusting the signal input level and frequency even if it exists to some extent. In other words, since frequency components unnecessary for injection locking can be supplied to the reception-side local oscillation unit 8404, there is a concern that it is difficult to achieve injection locking. However, if modulation is performed after suppressing low-frequency components (DC-free encoding or the like) for the signal to be modulated in advance on the transmission side, if no modulation signal components exist near the carrier frequency, The basic configuration 1 may be used.

  Further, as in the basic configuration 2 shown in FIG. 4 (2), the frequency separation unit 8401 is provided, and the modulation signal and the reference carrier signal are frequency separated from the received millimeter wave signal, and the separated reference carrier signal component is used as the injection signal. It can be considered that the signal is supplied to the reception-side local oscillation unit 8404. Since frequency components unnecessary for injection locking are supplied after being suppressed in advance, injection locking can be easily achieved.

  The basic configuration 3 shown in FIG. 4 (3) corresponds to the case where the transmission side adopts the basic configuration 2 shown in FIG. 3 (2). In this method, the modulated signal and the reference carrier signal are received by the separate antennas 8236_1 and 8236_2, and preferably by the separate millimeter wave signal transmission lines 9 so as not to cause interference. In the basic configuration 3 on the reception side, a reference carrier signal having a constant amplitude can be supplied to the reception-side local oscillation unit 8404, which can be said to be an optimal method from the viewpoint of easy injection locking.

  The basic configuration 4 shown in FIG. 4 (4) corresponds to the case where the basic configuration 4 shown in FIG. 3 (4) is adopted in the case where the transmission side uses the phase and frequency modulation method. Although the configuration is the same as the basic configuration 1, the configuration of the demodulation function unit 8400 is actually a demodulation circuit that supports phase modulation and frequency modulation, such as a quadrature detection circuit.

  The millimeter wave signal received by the antenna 8236 is supplied to the frequency mixing unit 8402 and the reception-side local oscillation unit 8404 by a distributor (demultiplexer) not shown. The reception-side local oscillating unit 8404 outputs a reproduction carrier signal synchronized with the carrier signal used for modulation on the transmission side by the injection locking function.

  Here, whether or not injection locking can be achieved on the receiving side (a reproduction carrier signal synchronized with the carrier signal used for modulation can be acquired on the transmitting side) is determined based on the injection level (reference carrier input to the injection locking type oscillation circuit). Signal amplitude level), modulation method, data rate, carrier frequency, and the like are also related. In addition, it is important that the modulation signal is outside the band that can be injection-locked. For this purpose, the center (average) frequency of the modulation signal is obtained by performing DC-free coding on the transmission side. Is approximately equal to the carrier frequency and the center (average) phase is approximately equal to zero (the origin on the phase plane).

  For example, Reference D discloses an example in which a modulated signal itself modulated by a BPSK (Binary Phase Shift Keying) method is used as an injection signal. In the BPSK system, a phase change of 180 degrees occurs in the injection signal to the reception-side local oscillation unit 8404 according to the symbol time T of the input signal. Even in such a case, in order for the reception-side local oscillation unit 8404 to be injection-locked, if the maximum drawing frequency range width of the reception-side local oscillation unit 8404 is Δfomax, for example, the symbol time T satisfies T <1 / (2Δfomax). Is needed. This means that the symbol time T must be set short with a margin, but such a short symbol time T means that the data rate should be increased. This is convenient for applications aiming at high-speed data transfer.

  Reference D: P. Edmonson, et al., “Injection Locking Techniques for a 1-GHz Digital Receiver Using Acoustic-Wave Devices”, IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, Vol. 39, No. 5, September , 1992, pp631-637

  Reference E discloses an example in which a modulated signal itself modulated by 8PSK (8-Phase Shift Keying) is used as an injection signal. This reference E also shows that when the injection voltage and the carrier frequency are the same, a higher data rate facilitates injection locking, which is also convenient for applications aiming at high-speed data transfer.

  Reference E: Tarar, MA; Zhizhang Chen, “A Direct Down-Conversion Receiver for Coherent Extraction of Digital Baseband Signals Using the Injection Locked Oscillators”, Radio and Wireless Symposium, 2008 IEEE, Volume, Issue, 22-24 Jan. 2008 , Pp57-60

  In any of the basic configurations 1 to 4, the lock range is controlled by controlling the injection voltage Vi and the free-running oscillation frequency fo based on the formula (A). In other words, it is important to adjust the injection voltage Vi and the free-running oscillation frequency fo so that injection locking can be achieved. For example, an injection locking control unit 8440 is provided at the subsequent stage of the frequency mixing unit 8402 (the subsequent stage of the DC component suppression unit 8407 in the example of the figure), and injection locking is performed based on the synchronous detection signal (baseband signal) acquired by the frequency mixing unit 8402. Are determined, and each part to be adjusted is controlled so as to achieve injection locking based on the determination result.

  At that time, as shown by the dotted line in the figure, a method to deal with on the receiving side and supply information that contributes to control to the transmitting side (not only the control information but also a detection signal that is the source of the control information) Either one of the methods to be dealt with on the transmission side or a combination thereof may be adopted. The method to deal with on the receiving side is that the millimeter wave signal (especially the reference carrier signal component) is not transmitted with a certain level of strength, so that the injection side cannot be locked on the receiving side. However, there is an advantage that can be dealt with only on the receiving side.

  On the other hand, the method to deal with on the transmission side requires transmission of information from the reception side to the transmission side, but can transmit millimeter-wave signals with the minimum power that can be injection-locked on the reception side. There are advantages such as being able to reduce and improving interference resistance.

  The following advantages can be obtained by applying the injection locking method in the signal transmission within the casing and the signal transmission between devices. The transmission-side local oscillation unit 8304 on the transmission side can relax the required specification of the stability of the frequency of the carrier signal used for modulation. As is clear from the equation (A), the reception-side local oscillation unit 8404 on the injection locking side needs to have a low Q value that can follow the frequency fluctuation on the transmission side.

  This is convenient when the entire receiving-side local oscillation unit 8404 including the tank circuit (inductance component and capacitance component) is formed on the CMOS. On the reception side, the reception-side local oscillation unit 8404 may have a low Q value, but this is also the case with the transmission-side local oscillation unit 8304 on the transmission side, and the transmission-side local oscillation unit 8304 has low frequency stability. Or a low Q value.

  CMOS will be further miniaturized in the future, and its operating frequency will further increase. In order to realize a broadband and small transmission system, it is desired to use a high carrier frequency. Since the injection locking method of this example can relax the required specifications for the oscillation frequency stability, a carrier signal having a higher frequency can be easily used.

  The fact that the frequency stability may be low (in other words, the Q value may be low) although it is a high frequency, in order to realize a carrier signal having a high frequency and high stability, a frequency multiplier circuit with high stability. It is not necessary to use a PLL circuit for carrier synchronization or the like, and a communication function can be simply realized with a small circuit scale even at a higher carrier frequency.

  The reception-side local oscillation unit 8404 acquires a reproduction carrier signal synchronized with the carrier signal used on the transmission side, supplies it to the frequency mixing unit 8402, and performs synchronous detection. Therefore, a bandpass for wavelength selection is provided before the frequency mixing unit 8402. A filter may not be provided. The selection operation of the reception frequency may be effected by controlling the transmission / reception local oscillation circuit to be completely synchronized (that is, enabling injection locking), and the reception frequency can be easily selected. In the millimeter wave band, the time required for injection locking can be shortened compared to a low frequency, and the selection operation of the reception frequency can be completed in a short time.

  Since the local oscillation circuit for transmission and reception is completely synchronized, the fluctuation component of the carrier frequency on the transmission side is canceled out, so various modulation methods such as phase modulation can be easily applied. For example, in digital modulation, phase modulation such as QPSK (Quadrature Phase Shift Keying) modulation and 16QAM (Quadrature Amplitude Modulation) modulation is widely known. These phase modulation systems perform quadrature modulation between a baseband signal and a carrier wave. In the quadrature modulation, the input data is converted into I-phase and Q-phase baseband signals and subjected to quadrature modulation, that is, the I- and Q-axis carrier signals are individually modulated by the I-phase signal and the Q-phase signal. In addition to application in 8PSK modulation as described in Reference E, injection locking can also be applied to orthogonal modulation schemes such as QPSK and 16QAM, and the data transmission rate can be increased by orthogonalizing the modulation signal.

  If injection locking is applied, multiple operations such as multi-channel and full-duplex bi-directional operation can be performed without using a wavelength-selective bandpass filter on the receiving side in combination with synchronous detection. Even when the transmission / reception pairs simultaneously transmit independently, they are less susceptible to interference problems.

[Relationship between injection signal and oscillation output signal]
FIG. 4A shows the phase relationship of each signal in injection locking. Here, as a basic example, the case where the phase of the injection signal (here, the reference carrier signal) is in phase with the phase of the carrier signal used for modulation is shown.

  The operation of the reception-side local oscillation unit 8404 can take two modes, an injection locking mode and an amplifier mode. In adopting the injection locking method, the basic operation is to use the injection locking mode, and to use the amplifier mode in a special case. A special case is when the reference carrier signal is used as the injection signal and the phase of the carrier signal used for modulation and the reference carrier signal are different (typically in an orthogonal relationship).

  When the reception-side local oscillation unit 8404 operates in the injection locking mode, there is a phase difference between the received reference carrier signal SQ and the oscillation output signal SC output from the reception-side local oscillation unit 8404 by injection locking as shown in the figure. . In order to perform quadrature detection in the frequency mixing unit 8402, it is necessary to correct this phase difference. As can be seen from the figure, the phase shift that is adjusted by the phase amplitude adjustment unit 8406 so that the phase of the modulation signal SI substantially matches the output signal of the reception-side local oscillation unit 8404 is “θ−φ” in the figure. It is.

  In other words, the phase amplitude adjustment unit 8406 performs injection locking of the phase of the output signal Vout when the reception side local oscillation unit 8404 operates in the injection locking mode with the injection signal Sinj to the reception side local oscillation unit 8404. The phase may be shifted so as to cancel out the phase difference “θ−φ” from the output signal Vout. Incidentally, the phase difference between the injection signal Sinj to the reception-side local oscillation unit 8404 and the free-running output Vo of the reception-side local oscillation unit 8404 is θ, and the output signal Vout of the reception-side local oscillation unit 8404 when the injection is synchronized. The phase difference from the free-running output Vo of the reception-side local oscillation unit 8404 is φ.

<Relationship between reference carrier signal phase and demodulation processing>
[Basic]
5 to 5B are diagrams for explaining the relationship between the phase of the reference carrier signal and the demodulation process. Here, FIG. 5 is a diagram for explaining the basics of demodulation processing when the carrier signal and the reference carrier signal have the same frequency and the same phase. FIG. 5A is a diagram illustrating the basics of demodulation processing when the carrier signal and the reference carrier signal have the same frequency and the phases are orthogonal, and FIG. 5B is a diagram illustrating the basic circuit configuration.

  When the injection locking method is applied, a reference carrier signal corresponding to (at least synchronized with) the carrier signal used for modulation is also sent to the receiving side together with the modulation signal obtained by modulating the carrier signal with the processed input signal. Is desirable. Typically, a signal having the same frequency as the carrier signal used for modulation is used as the reference carrier signal. At this time, depending on how the phase relationship between the carrier signal used for modulation and the reference carrier signal is set, an unnecessary component (particularly a DC offset component) is generated during demodulation on the reception side. In the following, the relationship between the phase of the reference carrier signal and the demodulation process when a signal having the same frequency as the carrier signal used for modulation is used as the reference carrier signal will be described.

  In the ASK system, the amplitude of the carrier signal is modulated by the transmission target signal. It can be considered that one of the I-phase signal and the Q-phase signal is used on the phase plane represented by the I-axis and the Q-axis, and the signal amplitude of the modulation signal is given in the range of 0 to + F. In the simplest case, modulation is performed with binary values of 0 and + F, and when the modulation degree is 100%, OOK is obtained. “F” is considered to be “1” by normalization, and binary ASK is realized.

  Consider a case where a signal having the same frequency and the same phase as the carrier signal used for modulation is used as the reference carrier signal. For example, as shown in FIG. 5A, when information is to be transmitted on the I axis, the reference carrier signal is also in phase (I axis).

  By the way, when the phase of the carrier signal used for modulation and the phase of the reference carrier signal is in phase, for example, the following method can be employed.

  The first example shown in FIG. 5 (2) is an example of a technique that applies the basic configuration 1 shown in FIG. 3 (1). The frequency mixing unit 8302 is supplied with the transmission target signal a (t) and the carrier signal c (t) = cosωt. The frequency mixing unit 8302 uses a balanced modulation circuit or a double balanced modulation circuit to perform amplitude modulation for carrier wave suppression, thereby generating d (t) = a (t) cos ωt and supplying it to the signal synthesis unit 8308. The transmission target signal a (t) is binary of 0 and +1. The reference carrier signal processing unit 8306 sets the amplitude of the carrier signal c (t) = cos ωt output from the transmission-side local oscillator 8304 to Co (within a range of 0 to 1), and sets the reference carrier signal e (t) = Cocos ωt. The data is supplied to the synthesis unit 8308. The signal synthesizer 8308 generates a transmission signal f (t) by performing signal synthesis of d (t) + e (t). Co = 0 is equivalent to 100% modulation.

  The second example shown in FIG. 5 (3) and the third example shown in FIG. 5 (4) are examples of techniques for applying the basic configuration 3 shown in FIG. 3 (3). As the frequency mixing unit 8302, a circuit configuration to which carrier wave suppression is not applied is used, and amplitude modulation is performed by a signal g (t) obtained by adding a DC component b0 to the transmission target signal b (t), thereby h (t) = g ( t) Generate cos ωt. The transmission target signal b (t) has binary values of −1 and +1. The amplitude B of the transmission target signal b (t) corresponds to the modulation degree (modulation rate).

  Here, the second example shown in FIG. 5 (3) is a case where the modulation degree B is constant (= 1), and the amplitude of the reference carrier signal is controlled by controlling the DC component b0 within a range of 1 to 2. (Amplitude in the period of b (t) = − 1) is adjusted. The third example shown in FIG. 5 (4) is a case where the DC component b0 is constant (= 1). By controlling the modulation degree B within a range of 0 to 1, the amplitude (b ( t) = amplitude in the period of −1).

  In any of the first to third examples, the reference carrier signal is also in phase (I-axis) when information is transmitted only on the I-axis. In this case, FIG. ), A DC offset component is generated on the receiving side.

  For example, assuming that the I-axis is a real component and the Q-axis is an imaginary component, and the amplitude of the transmission target signal a (t) is 0, + 1 in the first example, the received signal point is 0, + 1 on the I-axis. When the reference carrier wave is also placed on the I-axis, the signal points are “0 + Co” and “+ 1 + Co”, and a DC component for + Co is placed.

  In the second and third examples, if the transmission target signal b (t) is −1, +1, the reception signal point is −1, +1 on the I axis. When the reference carrier wave is also placed on the I-axis, the signal points are “−1 + Co” and “+ 1 + Co”, and the result is that a DC component for + Co is placed. When BPSK is applied, the concept is that the signal to be modulated is processed in advance by signal processing so that the reference carrier wave is also placed on the I-axis and then modulated to make it equivalent to ASK.

  In order to solve this problem, as shown in FIG. 4, it is conceivable to provide a DC component suppression unit 8407 that suppresses a DC offset component on the reception side. However, there is a problem in that variation varies from device to device, and individual adjustment is required according to the magnitude of the DC offset, and it is affected by temperature drift.

  As a method of solving this problem without providing the DC component suppression unit 8407 on the receiving side, the reference is based on a phase axis (preferably the most distant phase axis) different from the phase axis (phase axis of the modulation signal) on which transmission information is placed. It is conceivable to carry a carrier signal and send it.

  For example, in the ASK mode in which transmission information is placed only on one of the I axis and the Q axis, it is conceivable that the reference carrier signal and the modulation information are orthogonalized on the transmission side. That is, instead of performing 2-axis modulation of the I-phase signal and Q-phase signal, only one of the I-axis and Q-axis is used for signal transmission, the other is unmodulated, and the unmodulated signal is used as the reference carrier signal. Use as

  The relationship between the transmission information (modulation information) and the reference carrier signal and the I axis and Q axis may be reversed. For example, on the transmission side, the transmission information may be on the I axis side and the reference carrier signal may be on the Q axis side. Conversely, the transmission information may be on the Q axis side and the reference carrier signal may be on the I axis side. Good. The example shown in FIG. 5A shows a case where the transmission information is on the I axis side and the reference carrier signal is on the Q axis side.

  As shown in FIG. 5A (2), a frequency mixing unit 8302_I is provided for the transmission signal I-axis. The transmission target signal a (t) is supplied to the frequency mixing unit 8302_I. The reference carrier signal processing unit 8306 has a Q-axis frequency mixing unit 8302_Q for a reference carrier signal, and a 90-degree phase shift unit 8309 as a functional unit for orthogonalizing the carrier signal at the preceding stage. The phase amplitude adjustment circuit 8307 may function as the 90-degree phase shift unit 8309. A DC component Co is supplied to the frequency mixing unit 8302_Q.

  Then, on the receiving side, a reproduction carrier signal based on the output signal of the receiving side local oscillating unit 8404 is supplied to the frequency mixing unit 8402 and multiplied (synchronous detection) with the received I-axis modulation signal to thereby obtain the I-axis base. Restore the band signal. At this time, phase adjustment is performed so that the phase of the reproduction carrier signal based on the output signal of the reception-side local oscillation unit 8404 substantially matches the phase of the I-axis modulation signal. As a result, it is sufficient that the phases are substantially equal, and as described above, the phase adjustment may be performed either before or after the reception-side local oscillation unit 8404.

  Here, when the modulation signal (carrier signal) and the reference carrier signal are in an orthogonal relationship, how to obtain a reproduction carrier signal based on the output signal of the reception-side local oscillator 8404 is related to the injection amplitude. Roughly speaking, the concept of phase shift differs depending on whether injection locking in the reception-side local oscillation unit 8404 functions properly or whether the reception-side local oscillation unit 8404 operates in the amplifier mode without injection locking.

  For example, when the injection amplitude is reduced (a weak injection signal) so that the injection locking in the reception-side local oscillation unit 8404 functions properly, the output signal Vout of the reception-side local oscillation unit 8404 obtained by injection locking is used. A reproduction carrier signal is acquired based on (oscillation output signal SC). It should be noted that even though “injection amplitude is reduced (to make weak injection signal)”, if it is too weak, injection locking is lost. Therefore, an appropriate level of input is required so that injection locking functions properly. In this case, an oscillation output signal SC based on the Q-axis reference carrier signal SQ is obtained from the reception-side local oscillation unit 8404. As shown in FIG. 4A, the reception-side local oscillation is performed by the received reference carrier signal SQ and injection locking. The oscillation output signal SC output from the unit 8404 has a phase difference. Further, the Q-axis reference carrier signal that is an injection signal to the reception-side local oscillation unit 8404 has a phase difference of 90 degrees from the modulation axis (I-axis) on which the transmission target signal is placed.

  In the end, the phase shift that is adjusted by the phase amplitude adjustment unit 8406 so that the output signal of the reception-side local oscillation unit 8404 substantially matches the phase of the modulation signal SI is “θ−” in FIG. 4A. Further, the phase difference from the modulation axis on which transmission target information is placed (90 degrees in this example) is added to “φ”. As shown in FIG. 5A (3), the phase amplitude adjustment unit 8406 adjusts the phase so as to substantially match the phase of the modulation signal SI to obtain the reproduction carrier signal SR, which is supplied to the frequency mixing unit 8402. Become.

  The reproduction carrier signal SR is multiplied by the received I-axis modulation signal SI in the frequency mixing unit 8402 (synchronous detection) to restore the I-axis baseband signal. By doing so, a baseband signal having no DC offset component can be obtained.

  On the other hand, when the injection amplitude is increased (a strong injection signal is set), the reception-side local oscillation unit 8404 operates in the amplifier mode without the injection locking mode functioning. In this case, the phase amplitude adjustment unit 8406 sets the phase of the output signal of the component of the reference carrier signal when the reception-side local oscillation unit 8404 operates in the amplifier mode to the phase difference from the modulation axis on which the transmission target information is placed. What is necessary is just to phase-shift so that a part may be canceled. In the case of this example, since the transmission target information is placed on the I axis and the reference carrier signal is placed on the Q axis, the phase difference between both axes is 90 degrees.

  Therefore, as shown in FIG. 5A (4), the component of the Q-axis reference carrier signal in the output signal output from the reception-side local oscillation unit 8404 in the amplifier mode matches the phase of the I-axis modulation signal. And 90 ° phase shift to supply the frequency mixing unit 8402 as a reproduced carrier signal SR. The reproduction carrier signal SR is multiplied by the received I-axis modulation signal SI in the frequency mixing unit 8402 (synchronous detection) to restore the I-axis baseband signal. By doing so, a baseband signal having no DC offset component can be obtained.

  Since there is a phase difference of 90 degrees between the reference carrier signal SQ (= Cosin (ωt + θ) and the modulation signal SI (= a (t) cos (ωt + θ)), the phase of the reference carrier signal SQ is shifted by 90 degrees. For example, if a reference carrier wave is placed on the Q axis, the signal points become “+ 1 + jCo” and “0 + jCo”, and if only the I axis component is extracted, “0” is obtained. When the synchronous detection is performed with the output signal output in the amplifier mode from the reception-side local oscillation unit 8404 corresponding to the reference carrier signal SQ on the Q axis, only the Q axis component is obtained. Since it cannot be obtained, the I-axis component can be obtained by shifting the phase by 90 degrees in the middle.

  Therefore, as a circuit configuration of the demodulation system, there are a case where only phase adjustment is performed as shown in FIG. 5B (1) and a case where both phase and amplitude are adjusted as shown in FIG. 5B (2). When adjusting both the phase and the amplitude, either the case of performing on the injection side of the reception-side local oscillation unit 8404 or the case of performing on the oscillation output side can be adopted. Further, as shown in FIG. 5B (3), in order to adjust whether or not injection locking functions properly, the injection amplitude may be adjusted on the injection side of the reception-side local oscillation unit 8404.

[Specific example of demodulation processing in orthogonal relationship]
6 to 6C are diagrams for explaining specific examples of demodulation processing when the carrier signal and the reference carrier signal have the same frequency and the phases are orthogonal. Incidentally, a differential negative resistance oscillation circuit 8500 described later is used as the reception-side local oscillation unit 8404.

  First, FIG. 6A shows an example of a spectrum of an output signal when the reception-side local oscillation unit 8404 is in free-running oscillation. It can be seen that it oscillates at 60 GHz and a strong double harmonic is also generated. In this state, a signal Sinj including an I-axis component (modulation signal) and a Q-axis component (reference carrier signal) is injected into the reception-side local oscillation unit 8404 to simulate the behavior of the output signal Vout of the reception-side local oscillation unit 8404. .

  In the circuit shown in FIG. 5A (2), an M-sequence (2 ^ 11-1) data signal is used for the I-axis and a DC component is used for the Q-axis, and the signal Sinj up-converted to the 60 GHz band is received. Used as an injection signal to the side local oscillator 8404. FIG. 6 (2) shows the specification of the injection signal. FIG. 6A (1) shows an example of baseband I and Q signal waveforms used as injection signals, and FIG. 6A (2) shows an example of its spectrum. A current having a scale factor times the injection signal is injected into the reception-side local oscillation unit 8404 by a current source.

  6B to 6C show output signals of the reception-side local oscillation unit 8404 when the signal Sinj including the I-axis component (modulation signal) and the Q-axis component (reference carrier signal) is injected into the reception-side local oscillation unit 8404. Behavior is shown. In order to analyze the output signal Vout of the reception-side local oscillation unit 8404, as shown in FIG. 6B (1), it is down-converted into an I signal and a Q signal using a quadrature detection circuit.

  FIG. 6B (2) shows a spectrum example of the output signal Vout when the injection amplitude is set so that the injection locking in the reception-side local oscillation unit 8404 functions properly. In this example, the scale factor is set to 10 ^ -4. An example of the I signal and the Q signal after town conversion using the quadrature detection circuit shown in FIG. 6B (1) at that time is shown in FIG. 6B (3).

  Signal injection starts at 0.5 nsec, and injection locking is achieved after about 4 nsec. Thus, in the case of a weak injection signal, when the injection locking functions properly, the I-axis modulation signal component is outside the lock range Δfomax and is almost removed by the band-pass effect of the reception-side local oscillation unit 8404. I understand that.

  An oscillation output signal SC obtained by injection locking based on the Q-axis reference carrier signal SQ is adjusted so as to coincide with the phase of the I-axis modulation signal SI, and supplied to the frequency mixing unit 8402 as a reproduction carrier signal SR. By performing synchronous detection, a baseband signal having no DC offset component can be obtained.

  FIG. 6C (1) shows a spectrum example of the output signal Vout when the injection amplitude is increased so that the injection locking in the reception-side local oscillation unit 8404 does not function and operates in the amplifier mode. In this example, the scale factor is set to 5 × 10 ^ −3). An example of the I signal and the Q signal after town conversion using the quadrature detection circuit shown in FIG. 6B (1) at that time is shown in FIG. 6C (2).

  Signal injection starts at 0.5 nsec, and an output signal is obtained after about 4 nsec. Here, when attention is paid to the spectrum of the output signal Vout, the oscillation output signal is not obtained in the injection locking mode, but it is operating in the amplifier mode in which the injected signal is almost output as it is. I understand. It can be seen that when operating in the amplifier mode, a strong double harmonic is generated in addition to the fundamental wave. In this way, in the case of a strong injection signal, the injection locking mode does not function and the amplifier mode is operated, so that the I-axis modulation signal component and the Q-axis reference carrier signal component are almost output as they are. However, even in such an amplifier mode, an output signal corresponding to the Q-axis reference carrier signal component synchronized with the I-axis carrier signal for modulation generated by the transmission-side local oscillation unit 8304 is obtained.

  Accordingly, the phase of the amplifier mode output signal SA corresponding to the Q-axis reference carrier signal SQ is adjusted so as to match the phase of the I-axis modulation signal SI, and is supplied to the frequency mixing unit 8402 as the reproduction carrier signal SR. By performing synchronous detection, a baseband signal having no DC offset component can be obtained. Since the phase difference between the I-axis and the Q-axis is 90 degrees, by supplying a signal obtained by shifting the phase of the output signal SA by 90 degrees to the I-axis side to the frequency mixing unit 8402 as a reproduced carrier signal SR, synchronous detection is performed. The DC component of the baseband signal can be suppressed.

  Next, in the case of transmitting a millimeter wave signal from the first communication device 100 side to the second communication device 200 side, the transmission side (transmission side signal generation unit 110) and the reception side (reception side) when the injection locking method is adopted. A detailed example of the signal generation unit 220) will be described.

<Injection locking method: First embodiment>
7A to 7A are diagrams for explaining a first embodiment of a configuration example on the transmitter side to which the injection locking method is applied. FIG. 8 is a diagram for explaining a first embodiment of a configuration example on the receiver side to which the injection locking scheme is applied. The wireless transmission system 1A of the first embodiment is configured by a combination of the transmission-side signal generation unit 8110A of the first embodiment shown in FIGS. 7 to 7A and the reception-side signal generation unit 8220A of the first embodiment shown in FIG. The The first embodiment is configured to apply a method of controlling so that injection locking can be achieved on the receiving side.

[Sender configuration example]
FIG. 7 shows the configuration of the transmission side signal generation unit 8110A_1 (corresponding to the transmission side signal generation units 110 and 210) of the first embodiment (first example). FIG. 7A shows a configuration of the transmission side signal generation unit 8110A_2 (corresponding to the transmission side signal generation units 110 and 210) of the first embodiment (second example). In the first example, the reference “_1” is attached, and in the second example, the reference “_2” is attached. When the description is made without distinguishing both, the reference is omitted.

  The transmission-side signal generation unit 8110A of the first embodiment includes an encoding unit 8322, a multiplexer unit 8324, and a waveform shaping unit 8326 between a parallel / serial conversion unit 8114 (not shown) and a modulation function unit 8300. Providing these functional units is not essential, and may be provided when those functions are required.

  The transmission-side signal generation unit 8110A includes a controller unit 8346 that controls each functional unit. Although it is not essential to include the controller unit 8346, in various recent systems, this function often exists on a CMOS chip or a substrate. The controller unit 8346 sets encoding and multiplexing, waveform shaping setting, modulation mode setting, oscillation frequency setting, reference carrier signal phase and amplitude setting, amplification unit 8117 gain and frequency characteristic setting, antenna Has functions such as setting characteristics. Each setting information is supplied to the corresponding functional unit.

  The encoding unit 8322 performs coding processing such as error correction on the data serialized by the parallel-serial conversion unit 8114 (not shown) based on the setting information of the encoding (Encode) pattern from the controller unit 8346. At this time, the encoding unit 8322 applies DC-free encoding such as 8-9 conversion code or 8-10 conversion code as a function of the modulation target signal processing unit 8301, and there is no modulation signal component in the vicinity of the carrier frequency. In this way, it is easy to perform injection locking on the receiving side.

  The multiplexer unit 8324 packetizes the data. When the injection locking detection unit on the receiver side is configured to detect injection locking based on a correlation of known patterns, the multiplexer unit 8324 uses a known signal waveform based on the setting information of the synchronization detection packet from the controller unit 8346. Or a known data pattern (for example, pseudo-random signal: PN signal) is periodically inserted.

  The waveform shaping unit 8326 performs waveform shaping processing such as frequency characteristic correction, pre-emphasis, and band limitation based on the waveform shaping setting information from the controller unit 8346.

  The transmission side signal generation unit 8110A includes a modulation function unit 8300 having a frequency mixing unit 8302 (modulation circuit) and a transmission side local oscillation unit 8304 (transmission side oscillation unit). In addition to the modulation function unit 8300, the transmission side signal generation unit 8110A includes a reference carrier signal processing unit 8306 having a phase amplitude adjustment circuit 8307 and a signal synthesis unit 8308. In this example, the reference carrier signal processing unit 8306 uses the carrier signal itself output from the transmission-side local oscillation unit 8304 as a reference carrier signal, and adjusts the amplitude and phase of the reference carrier signal by the phase amplitude adjustment circuit 8307. The data is supplied to the synthesis unit 8308.

  Here, in the first example shown in FIG. 7, the transmission-side local oscillation unit 8304 generates a carrier signal used for modulation on the CMOS chip using a tank circuit on the CMOS chip.

  On the other hand, the second example shown in FIG. 7A is a configuration example in the case where there is a clock signal that can be used as a reference in the first communication device 100, and the modulation function unit 8300_2 performs frequency multiplication before the transmission-side local oscillation unit 8304. Part 8303 is provided. The frequency multiplier 8303 multiplies the “clock signal that can be used as a reference” supplied from a clock signal generator (not shown), and supplies the multiplied signal to the transmission-side local oscillator 8304. The transmission-side local oscillation unit 8304 of the second example is a synchronous oscillation circuit, and generates a carrier signal used for modulation in synchronization with the multiplied signal.

  The frequency mixing unit 8302 modulates the carrier signal generated by the transmission side local oscillation unit 8304 with the processed input signal from the waveform shaping unit 8326 and supplies the modulated signal to the signal synthesis unit 8308. The phase / amplitude adjustment circuit 8307 sets the phase and amplitude of the reference carrier signal to be transmitted based on the phase / amplitude setting information from the controller unit 8346.

  The signal synthesizer 8308 is provided to send the reference carrier signal to the receiving side together with the modulated signal modulated in the millimeter wave band when one antenna 8136 and 8236 are provided. When the modulation signal generated by the frequency mixing unit 8302 and the reference carrier signal generated by the reference carrier signal processing unit 8306 are transmitted by different antennas, the signal synthesis unit 8308 is not necessary.

  The signal synthesizer 8308 outputs the modulated signal modulated in the millimeter wave band by the frequency mixing unit 8302 and the phase amplitude adjustment circuit 8307 when the reference carrier signal is sent to the receiving side together with the signal modulated in the millimeter wave band. The reference carrier signal is combined and passed to the amplifying unit 8117. When only the modulation signal modulated in the millimeter wave band by the frequency mixing unit 8302 is transmitted to the receiving side, the signal synthesis unit 8308 is modulated into the millimeter wave band by the frequency mixing unit 8302 without performing the synthesis process. Only the modulation signal is passed to the amplifying unit 8117. The amplifying unit 8117 adjusts the amplitude and frequency characteristics of the transmission output of the millimeter wave signal received from the signal combining unit 8308 as necessary, and supplies the adjusted signal to the antenna 8136.

  As understood from the above description, whether or not to make the signal combining unit 8308 function when the reference carrier signal is transmitted to the receiving side together with the signal modulated in the millimeter wave band is determined by the modulation method and the frequency mixing unit. This is also related to the circuit configuration 8302. Depending on the modulation scheme and the circuit configuration of the frequency mixing unit 8302, the reference carrier signal can be sent to the receiving side together with the signal modulated in the millimeter wave band without the signal synthesizing unit 8308 functioning.

  In amplitude modulation or ASK, the frequency mixing unit 8302 may be positively changed to a carrier wave suppression type modulation circuit, and the reference carrier signal generated by the transmission side local oscillation unit 8304 may be sent together with the output. In this case, the harmonics of the carrier signal used for modulation can be used for the reference carrier signal, and the amplitudes of the modulation signal and the reference carrier signal can be adjusted separately. In other words, the amplifying unit 8117 performs gain adjustment focusing on the amplitude of the modulation signal, and at the same time, the amplitude of the reference carrier signal is also adjusted. Thus, it is possible to adjust only the amplitude of the reference carrier signal.

[Example configuration on the receiving side]
FIG. 8 shows the configuration of the reception-side signal generation unit 8220A (corresponding to the reception-side signal generation units 120 and 220) of the first embodiment. The reception-side signal generation unit 8220A of the first embodiment includes a controller unit 8446 that controls each functional unit. The reception-side signal generation unit 8220A includes a DC component suppression unit 8407 and an injection locking detection unit 8442 subsequent to the demodulation function unit 8400.

  Although it is not essential to include the controller unit 8446, like the controller unit 8346, this function is often present on a CMOS chip or a substrate in various recent systems. The controller unit 8446 sets the gain and frequency characteristics of the amplifying unit 8224, sets the phase and amplitude of the received reference carrier signal, sets the oscillation frequency, sets the modulation mode, sets the filter and equalization, codes and multiplexes Has functions such as settings. Each setting information is supplied to the corresponding functional unit.

  The demodulation function unit 8400 includes a frequency mixing unit 8402 (demodulation circuit), a reception side local oscillation unit 8404 (reception side oscillation circuit), and a phase amplitude adjustment unit 8406.

  It is also conceivable to arrange a circuit (such as a band-pass filter circuit) that extracts only the reference carrier signal component on the injection signal side to the reception-side local oscillation unit 8404 (for example, before the phase amplitude adjustment unit 8406). By doing so, the modulation signal component and the reference carrier signal component are separated from the received millimeter wave signal, and only the reference carrier signal component is supplied to the reception-side local oscillation unit 8404, thereby facilitating injection locking.

  The phase amplitude adjustment unit 8406 sets the phase and amplitude of the received reference carrier signal based on the phase / amplitude setting information from the controller unit 8446. In the figure, the phase amplitude adjustment unit 8406 is arranged on the injection signal input end side to the reception-side local oscillation unit 8404, but the phase amplitude is placed on the signal path of the reception-side local oscillation unit 8404 and the frequency mixing unit 8402. The adjustment unit 8406 may be arranged, or both may be used together.

  The DC component suppression unit 8407 suppresses unnecessary DC components (DC offset components) included in the synchronous detection signal output from the frequency mixing unit 8402. For example, when the reference carrier signal is transmitted from the transmission side to the reception side together with the modulation signal, a large DC offset component may be generated in the synchronous detection signal depending on the phase relationship between the modulation signal and the reference carrier signal. The DC component suppression unit 8407 functions to remove the DC offset component.

  Based on the information indicating the injection locking state detected by the injection locking detection unit 8442, the controller unit 8446 performs synchronization adjustment so that the demodulated carrier signal generated by the reception-side local oscillation unit 8404 is synchronized with the modulation carrier signal. The function part of the injection locking adjustment part to perform is provided. The injection locking control unit 8440 is configured by the function unit (injection locking adjustment unit) related to the injection locking adjustment of the injection locking detection unit 8442 and the controller unit 8446.

  The injection locking detection unit 8442 determines the injection locking state based on the baseband signal acquired by the frequency mixing unit 8402 and notifies the controller unit 8446 of the determination result. In the figure, the output signal of the DC component suppression unit 8407 is detected, but the input side of the DC component suppression unit 8407 may be detected.

  The “injection locked state” is whether or not the output signal (oscillation circuit output) output from the reception-side local oscillation unit 8404 is synchronized with the reference carrier signal on the transmission side. The fact that the output of the oscillation circuit and the reference carrier signal on the transmission side are synchronized is also referred to as “injection locking”.

  The reception-side signal generation unit 8220A sets the free-running oscillation frequency of the transmission-side local oscillation unit 8304, the amplitude (injection amplitude) and the phase (injection phase) of the injection signal to the reception-side local oscillation unit 8404 so that injection locking can be achieved. Control at least one. Which is controlled depends on the system configuration, and not all the elements must be controlled.

  For example, the controller unit 8446 controls the free-running oscillation frequency of the reception-side local oscillation unit 8404 in conjunction with the detection result of the injection locking detection unit 8442 so that injection locking can be achieved, and via the phase amplitude adjustment unit 8406 The injection amplitude and injection phase to the reception-side local oscillation unit 8404 are controlled.

  For example, first, a millimeter wave signal (modulated signal or reference carrier signal) transmitted from the transmission side via the millimeter wave signal transmission path 9 is amplified by the amplifying unit 8224 via the antenna 8236. Part of the amplified millimeter wave signal is injected into the reception-side local oscillation unit 8404 after the amplitude and phase are adjusted by the phase amplitude adjustment unit 8406. The frequency mixing unit 8402 converts the millimeter wave signal from the amplification unit 8224 into a baseband signal using the output signal (reproduction reference carrier signal) from the reception-side local oscillation unit 8404. A part of the converted baseband signal is input to the injection locking detection unit 8442, and information for determining whether or not the reception side local oscillation unit 8404 is synchronized with the reference carrier signal on the transmission side is the injection locking detection unit 8442. Is acquired and notified to the controller unit 8446.

  Based on the “injection synchronization state” information from the injection locking detection unit 8442 (referred to as injection locking determination information), the controller unit 8446 determines whether or not synchronization has occurred, for example, using one of the following two methods: Or they are used together.

  1) The injection locking detector 8442 correlates the restored waveform with a known signal waveform or a known data pattern, and uses the correlation result as injection locking determination information. The controller unit 8446 determines that synchronization is obtained when a strong correlation is obtained.

  2) The injection locking detector 8442 monitors (monitors) the DC component of the demodulated baseband signal, and uses the monitoring result as injection locking determination information. The controller unit 8446 determines that it is synchronized when the DC component is stabilized.

  Various methods can be considered for the mechanisms 1) and 2) described above, but the details thereof will be omitted here. In addition to the methods 1) and 2) shown here, a method for determining whether or not synchronization has occurred is also conceivable, and these can also be adopted in the present embodiment.

  If the controller unit 8446 determines that injection locking is not achieved, the carrier signal used for modulation on the transmission side and the signal output from the reception-side local oscillation unit 8404 (oscillation circuit output) according to a predetermined procedure Is changed (so that injection locking is achieved), the setting information of the oscillation frequency to the reception-side local oscillation unit 8404 and the setting information of the amplitude and phase to the phase amplitude adjustment unit 8406 are changed. Thereafter, the controller unit 8446 repeats the procedure of determining the injection locking state again until good synchronization is obtained.

  The baseband signal in which injection locking of the reception-side local oscillation unit 8404 is correctly performed and frequency conversion (synchronous detection) is performed by the frequency mixing unit 8402 is supplied to the filter processing unit 8410. The filter processing unit 8410 is provided with an equalizer 8414 in addition to the low-pass filter 8412. For example, the equalizer 8414 includes an equalizer (that is, waveform equalization) filter that adds a reduced gain to the high frequency band of the received signal in order to reduce intersymbol interference.

  A high-frequency component is removed from the baseband signal by a low-pass filter 8412, and the high-frequency component is corrected by an equalizer 8414.

  The clock recovery unit 8420 includes a symbol synchronization unit 8422, a decoding unit 8424, and a demultiplexer unit 8426. The decoding unit 8424 corresponds to the encoding unit 8322, and the demultiplexer unit 8426 corresponds to the multiplexer unit 8324, and performs a process opposite to that on the transmission side. After the symbol synchronization unit 8422 performs symbol synchronization, the clock recovery unit 8420 restores the original input signal based on the coding pattern setting information and the multiplex setting from the controller unit 8446.

  CMOS will be further miniaturized in the future, and its operating frequency will further increase. In order to realize a smaller transmission system in a higher band, it is desired to use a high carrier frequency. Since the injection locking method of this example can relax the required specification for the oscillation frequency stability, a higher carrier frequency can be easily used. As is clear from the equation (A), the reception-side local oscillation unit 8404 that oscillates by injection locking needs to have a low Q that can follow the frequency fluctuation on the transmission side. This is convenient when the entire receiving-side local oscillation unit 8404 including the tank circuit is formed on a CMOS. Of course, an oscillation circuit having the same circuit configuration as that of the reception-side local oscillation unit 8404 may be used as the transmission-side local oscillation unit 8304, and the entire transmission-side local oscillation unit 8304 including the tank circuit may be formed on the CMOS. it can.

<Injection locking method: Second embodiment>
9A to 9A are diagrams illustrating a second embodiment of a configuration example on the transmitter side to which the injection locking scheme is applied. 10A to 10A are diagrams illustrating a second embodiment of a configuration example on the receiver side to which the injection locking scheme is applied.

  The second embodiment is configured to apply a method of controlling so as to obtain injection locking by adjusting the function unit on the transmission side. Various configurations depending on what information is sent from the receiving side to the sending side, and whether the control subject is placed on the sending side or on the receiving side when adjusting the function unit on the sending side to control injection locking Can be taken. Below, only the difference with 1st Embodiment is demonstrated about two typical examples in it.

  A combination of the transmission side signal generation unit 8110B_1 of the second embodiment (first example) shown in FIG. 9 and the reception side signal generation unit 8220B_1 of the second embodiment (first example) shown in FIG. A wireless transmission system 1B_1 of the first example) is configured. A combination of the transmission side signal generation unit 8110B_2 of the second embodiment (second example) shown in FIG. 9A and the reception side signal generation unit 8220B_2 of the second embodiment (second example) shown in FIG. A wireless transmission system 1B_2 of the second example) is configured.

  The second embodiment (first example) is a configuration in which injection locking determination information is sent to the transmission side and a control subject is placed on the transmission side. Specifically, the controller unit 8446 of the reception side signal generation unit 8220B_1 sends the injection locking determination information acquired by the injection locking detection unit 8442 to the controller unit 8346 of the transmission side signal generation unit 8110B_1. The controller unit 8446 merely intervenes in the transmission of the injection locking determination information to the transmission side, and does not actually become the controlling entity. Note that the injection locking detection unit 8442 may be configured to send the injection locking determination information to the controller unit 8346 of the transmission side signal generation unit 8110B_1 without using the controller unit 8446.

  Based on the information indicating the injection locking state detected by the receiving-side injection locking detecting unit 8442, the controller unit 8346 is configured so that the demodulated carrier signal generated by the receiving-side local oscillator 8404 is synchronized with the modulated carrier signal. A function unit of an injection locking adjustment unit that performs synchronization adjustment is provided. An injection locking control unit similar to the injection locking control unit 8440 is configured by the function unit (injection locking adjustment unit) related to the injection locking adjustment of the injection locking detection unit 8442 and the controller unit 8346.

  The controller unit 8346 controls the free-running oscillation frequency of the transmission-side local oscillation unit 8304 and the transmission amplitude (transmission power) of the millimeter wave signal so that injection locking can be achieved. A method for determining whether or not synchronization is established may be the same as that for the controller unit 8446.

  When the controller unit 8346 determines that the injection locking is not established, the setting information of the oscillation frequency to the transmission side local oscillation unit 8304 and the setting of the amplitude and phase to the phase amplitude adjustment circuit 8307 are determined according to a predetermined procedure. The information is changed, and the gain setting information for the amplifying unit 8117 is changed. When the amplitude modulation or the ASK method is adopted, the amplitude of the unmodulated component of the carrier signal included in the millimeter wave signal may be adjusted by controlling the modulation degree. Thereafter, the controller unit 8346 repeats the procedure of determining the injection locking state again until good synchronization is achieved.

  On the other hand, in the second embodiment (second example), a control subject is placed on the receiving side, and a control command is sent to the transmitting side to control the transmitting side from the receiving side. Specifically, the controller unit 8446 determines whether or not synchronization is achieved based on the injection locking determination information acquired by the injection locking detection unit 8442, and determines that the injection locking is not performed. A control command for controlling the unit 8300 and the amplifying unit 8117 is sent to the transmission side. That is, the controller unit 8446 directly controls the modulation function unit 8300 and the amplification unit 8117. In other words, the controller unit 8346 makes initial settings of the oscillation frequency, the phase and amplitude of the reference carrier signal to the modulation function unit 8300, and makes initial settings of gain to the amplifier unit 8117. Change control of setting information related to synchronization is not performed.

  When the controller unit 8446 determines that the injection locking is not established, the controller unit 8446 follows the predetermined procedure and sets the oscillation frequency setting information and the phase to the transmission-side local oscillation unit 8304 in the same manner as the controller unit 8346 of the first example. The amplitude and phase setting information to the amplitude adjusting circuit 8307 is changed, and the gain setting information to the amplifying unit 8117 is changed. When the amplitude modulation or the ASK method is adopted, the amplitude of the unmodulated component of the carrier signal included in the millimeter wave signal may be adjusted by controlling the modulation degree. Thereafter, the controller unit 8446 repeats the procedure of determining the injection locking state again until good synchronization is obtained.

<Configuration example of oscillation circuit>
11A to 11A are diagrams illustrating configuration examples of oscillation circuits used as the transmission-side local oscillation unit 8304 and the reception-side local oscillation unit 8404. FIG. FIG. 11A shows an example of the circuit configuration, and FIG. 11B shows an example of the layout pattern on the CMOS of the inductor circuit. FIG. 11A is a diagram for explaining the details of a layout pattern example on the CMOS of the inductor circuit.

  The oscillation circuit shown here is a differential negative resistance oscillation circuit 8500 having a tank circuit (LC resonance circuit) composed of a general inductor and capacitor, and all the components (oscillation elements) including the tank circuit are , Formed on the same semiconductor substrate (silicon substrate).

  The differential negative resistance oscillation circuit 8500 includes a current source 8510, a negative resistance circuit 8520 configured by a differential transistor pair (transistors 8522_1 and 8522_2) having a striking configuration, and an LC circuit (inductor circuit 8532 and capacitor circuit 8534). A configured tank circuit 8530 is provided.

The sources of the transistors 8522_1 and 8522_2 are connected to the output terminal of the current source 8510 in common. The gate of the transistor 8522_1 is connected to the drain of the transistor 8522_2, and the gate of the transistor 8522_2 is connected to the drain of the transistor 8522_1, so that the transistor 8522_1 has a gate structure.

  An inductor circuit 8532 is connected between the drains of the transistors 8522_1 and 8522_2 and the power supply Vdd.

  The inductor circuit 8532 is represented by a series circuit of an inductance component 8532L_1 and a resistance component 8532R_1 on the transistor 8522_1 side and a series circuit of an inductance component 8532L_2 and a resistance component 8532R_2 on the transistor 8522_2 side. A capacitor circuit 8534 is connected between the drains of the transistors 8522_1 and 8522_2. The inductance component 8532L is an inductive component generated by the winding, and the resistance component 8532R is the loss (series resistance component).

  The inductor circuit 8532 insulates oscillation elements such as the current source 8510, the negative resistance circuit 8520, and the capacitor circuit 8534 on the same chip as the CMOS in which the transmission-side signal generation unit 8110 and the reception-side signal generation unit 8220 are formed. Arranged on the insulating layer. That is, the entire differential negative resistance oscillation circuit 8500 including the tank circuit 8530 is integrated into one chip together with the transmission side signal generation unit 8110 and the reception side signal generation unit 8220.

  The capacitor circuit 8534 is represented by a parallel circuit of a capacitor component 8534C_1 and a conductance component 8534G_1 on the transistor 8522_1 side and a parallel circuit of a capacitor component 8534C_2 and a conductance component 8534G_2 on the transistor 8522_2 side. The capacitor component 8534C uses, for example, a capacitance component generated between terminals by applying a reverse bias voltage across the diode, and a varicap diode (variable capacitance diode, varactor) or the like is used. The conductance component 8534G is a loss component of the varicap diode.

  Connection points a and b of the negative resistance circuit 8520 and the tank circuit 8530 (inductor circuit 8532 and capacitor circuit 8534) serve as signal output terminals of the differential negative resistance oscillation circuit 8500 and are connected to the frequency mixing unit 8402 by differential signals. At the same time, it serves as an input terminal for an injection signal. Incidentally, the injection signal is inputted to the connection points a and b through a current source.

  When the center frequency of the injection signal is the same as the carrier frequency of the modulation signal, the output signals at the connection points a and b (depending on the configuration, via the phase amplitude adjustment unit 8406) are used as the reproduction carrier signal to the frequency mixing unit 8402. . When N times higher harmonics of the carrier signal used for modulation are used as the reference carrier signal, a signal obtained by dividing the output signals of the connection points a and b by 1 / N times (in some configurations, the phase (Via the amplitude adjuster 8406) as the regenerative carrier signal to the frequency mixer 8402.

  In the differential negative resistance oscillation circuit 8500, when the transistors 8522_1 and 8522_2 are alternately turned on and off, a current limited by the current source 8510 flows to the drain side. Since the tank circuit 8530 (resonance circuit) is provided on the drain side, the differential negative resistance oscillation circuit 8500 has an inductor circuit 8532 and a capacitor circuit 8534 that constitute the tank circuit 8530 even when an injection signal is not supplied. Self-runs at the resonance frequency specified by the element constant of. For example, the free-running oscillation frequency of the differential negative resistance oscillation circuit 8500 can be adjusted by adjusting the reverse bias voltage of the varicap diode constituting the capacitor circuit 8534.

  In the example of the layout pattern of the inductor circuit 8532 shown in FIG. 11 (2), a substantially octagonal ring pattern is formed in a spiral shape over a plurality of layers by a metal layer pattern, thereby forming a substantially circular shape with n turns. A pair of coils is formed. For example, when the power supply Vdd side and the connection points a and b are arranged on the opposite sides of the circle, a coil having n turns and 2n layers can be obtained. One of the circular coils 8550 is represented by a series circuit of an inductance component 8532L_1 and a resistance component 8532R_1, and the other is represented by a series circuit of an inductance component 8532L_2 and a resistance component 8532R_2.

  The figure shows a case where n = 1.5. Of the wiring layers for forming the coil 8550, the layer in which the lead-out pattern of the power source Vdd is arranged is the uppermost layer (for example, the ninth wiring layer), and the connection point a , D are arranged in the lowest layer (for example, the seventh wiring layer), and one layer (for example, the eighth wiring layer) between them is used to form a 1.5-turn coil 8550_1 (inductance component 8532L_1). And a resistance component 8532R_1 in series) and a 1.5-turn coil 8550_2 (inductance component 8532L_2 and resistance component 8532R_2 in series circuit).

  As shown in FIG. 11 (2), the coils 8550_1 and 8550_2 are generally in a double spiral state (a state in which the outer wire ring pattern and the inner wire ring pattern are combined). Specifically, for example, the coil 8550_1 on the transistor 8522_1 side is half-turned around the ninth wiring layer by the outer ring pattern 8552_91 from the power supply drawing pattern of the ninth wiring layer, and the eighth contact hole 8554 Transition to the wiring layer (FIG. 11A (1)). Then, the inner wiring ring pattern 8552_81 is rotated halfway counterclockwise in the eighth wiring layer, and transitions to the seventh wiring layer in the contact hole 8555 (FIG. 11A (2)). Then, in the seventh wiring layer, the outer ring pattern 8552_71 (formed in the lower layer of the ring pattern 8552_91) is rotated halfway counterclockwise and drawn out to the connection point a (FIG. 11A (3)).

  On the other hand, the coil 8550_2 on the transistor 8522_2 side makes a half turn with the outer ring pattern 8552_92 clockwise around the ninth wiring layer from the power supply drawing pattern of the ninth wiring layer to the eighth wiring layer at the contact hole 8556. (FIG. 11A (1)). Then, in the eighth wiring layer, the inner ring pattern 8552_82 is rotated halfway clockwise, and the contact hole 8557 moves to the seventh wiring layer (FIG. 11A (2)). Then, in the seventh wiring layer, the outer ring pattern 8552_72 (formed in the lower layer of the ring pattern 8552_92) is rotated halfway clockwise and drawn out to the connection point b (FIG. 11A (3)).

  Here, when the magnetic permeability is μ, the number of turns is n, and the radius is r, the inductor value L of the inductance components 8532L_1 and 8532L_2 of the circular coil is approximately “μ · (n ^ 2) as shown in Reference Document F. ) · R ”.

  Reference F: Thomas Lee, “The Design of CMOS Radio-Frequency Integrated Circuits” (especially “4.5.1 SPIRAL INDUCTORS”, pp136-137), ISBN 0-521-83539-9

  On the other hand, the resistance value R of the resistance components 8532R_1 and 462R_2 in series with the inductance components 8532L_1 and 8532L_2 shown in FIG. 11 greatly depends on the line width W of the circular coil (metal layer pattern) shown in FIG. 11A. Since the resistance value R of the line is approximately inversely proportional to the line width W, the line width W must be increased in order to produce an inductor having a high Q value.

  In order to make a carrier wave with high stability, when trying to make an inductor having a high Q value (that is, the resistance value R of the resistance components 8532R_1 and 462R_2), the line width W becomes large, and the number of turns n that can be made with the same radius R size. Less. Conversely, if the resistance value R can be allowed to increase, the line width W can be reduced and the same inductance value L can be realized with an inductor having a small size (radius R). An injection locking method is effective for demodulating a signal transmitted by a carrier wave with a low degree of stability using a circuit having a low Q on the receiving side.

  The reason why the “small circuit” may be used is not only that the Q may be low, but also that the carrier frequency is as high as several tens of GHz by using the millimeter wave band, so that the inductor of the inductor circuit 8532 for realizing a desired impedance It is also related that the value L and the capacitance value C of the capacitor circuit 8534 can be reduced in proportion to the frequency. In addition, when the resonant tank circuit 8530 is formed with the inductor and the capacitor, if the frequency is increased, the fact that the tank circuit 8530 can be realized with a smaller inductor value and capacitance value is also a factor that can be a “small circuit”.

  From the above, by using the differential negative resistance oscillation circuit 8500 described here as the transmission-side local oscillation unit 8304 and the reception-side local oscillation unit 8404, all the oscillation elements including the tank circuit 8530 have a CMOS configuration. It can be configured as a semiconductor chip. The transmission-side local oscillation unit 8304 and the reception-side local oscillation unit 8404 can be configured without a tank circuit outside the semiconductor chip. A one-chip oscillation circuit (IC: semiconductor integrated circuit) with a built-in tank circuit is realized.

  The transmission-side local oscillation unit 8304 is combined with the other function units on the transmission side that constitute the transmission-side signal generation units 110 and 210 including the frequency mixing unit 8302, and is combined into one chip to transmit a wireless communication device (semiconductor integrated circuit) for transmission. Can be provided as The reception-side local oscillation unit 8404 is combined with other reception-side functional units constituting the reception-side signal generation units 120 and 220 including the frequency mixing unit 8402 to be integrated into a single chip for reception wireless communication devices (semiconductor integrated devices). Circuit). Further, the wireless communication device (semiconductor integrated circuit) for transmission and reception can be further integrated into one chip and provided as a wireless communication device (semiconductor integrated circuit) for bidirectional communication. A one-chip communication circuit (IC) with a built-in tank circuit is realized.

<Relationship between multi-channel and injection locking>
FIG. 12 is a diagram illustrating the relationship between multi-channeling and injection locking. As shown in FIG. 12 (1), multi-channeling is realized by using different communication frequencies for different communication transmission / reception pairs, that is, multi-channeling is realized by frequency division multiplexing. Full duplex bidirectionalization can be easily realized by using different carrier frequencies, and a plurality of semiconductor chips (that is, the transmission-side signal generation unit 110 and the reception-side signal generation unit 220) communicate independently within the housing of the imaging apparatus. Such a situation can also be realized.

  For example, as shown in FIGS. 12 (2) to 12 (4), consider a case where two transmission / reception pairs are simultaneously transmitting independently. Here, as shown in FIG. 12 (2), when the square detection method is applied, as described above, the band-pass filter for frequency selection on the reception side is used for the multi-channeling in the frequency multiplexing method. (BPF) is required. It is not easy to realize a steep bandpass filter in a small size, and a variable bandpass filter is required to change the selection frequency. Since it is affected by the time-varying frequency component (frequency variation component Δ) on the transmission side, the modulation method is limited to one that can ignore the influence of the frequency variation component Δ (for example, OOK), and the modulation signal is orthogonal. It is difficult to say that the data transmission rate is increased.

  If the receiving side does not have a carrier-synchronized PLL for miniaturization, for example, as shown in FIG. 12 (3), it is conceivable to down-convert to IF (Intermediate Frequency) and perform square detection. In this case, a signal to be received without a band-pass filter can be selected by adding a block for frequency conversion to a sufficiently high IF, but the circuit becomes complicated accordingly. Not only the frequency fluctuation component Δ on the transmission side, but also the influence of the time-varying frequency component (frequency fluctuation component Δ) in the down-conversion on the reception side. For this reason, the modulation method is limited to a method for extracting amplitude information (for example, ASK or OOK) so that the influence of the frequency variation component Δ can be ignored.

  On the other hand, as shown in FIG. 12 (4), when the injection locking method is applied, the transmission-side local oscillation circuit 304 and the reception-side local oscillation unit 8404 are completely synchronized, so various modulation methods can be easily performed. realizable. A PLL for carrier synchronization is not required, the circuit scale is small, and the reception frequency can be easily selected. In addition, since the millimeter-wave band oscillation circuit can be realized by using a tank circuit having a smaller time constant than the low frequency, the time required for injection locking can be shorter than the low frequency, and is suitable for high-speed transmission. In this manner, by applying the injection locking method, the transmission speed can be easily increased and the number of input / output terminals can be reduced as compared with signals between chips based on normal baseband signals. A small millimeter-wave antenna can be formed on the chip, and a remarkably large degree of freedom can be given to how to extract a signal from the chip. Further, since the frequency fluctuation component Δ on the transmission side is canceled by injection locking, various modulations such as phase modulation (for example, quadrature modulation) are possible.

  Even in the case of realizing multi-channel by frequency division multiplexing, the receiving side reproduces a signal synchronized with the carrier signal used for modulation on the transmitting side and performs frequency conversion by synchronous detection, so that the frequency variation Δ of the carrier signal Even if there is, the transmission signal can be restored without being affected by the influence (so-called interference). As shown in FIG. 12 (4), it is not necessary to insert a band pass filter as a frequency selection filter in the previous stage of the frequency conversion circuit (down converter).

<Transmission path structure>
[First example]
FIG. 13 is a diagram illustrating a first example of a wireless transmission path structure according to this embodiment. The transmission line structure of the first example is an application example in the case where signal transmission is performed using millimeter waves within the casing of one electronic device. As an electronic device, an example of application to an imaging device equipped with a solid-state imaging device will be described.

  The first communication device 100 is mounted on a main board on which a control circuit, an image processing circuit, and the like are mounted, and the second communication device 200 is mounted on an imaging board on which a solid-state imaging device is mounted. In FIG. 13, focusing on millimeter wave signal transmission between substrates, a schematic cross-sectional view of the imaging apparatus 500 is shown, and components not related to millimeter wave signal transmission are appropriately omitted.

  An imaging board 502 and a main board 602 are disposed in the housing 590 of the imaging apparatus 500. A solid-state imaging device 505 is mounted on the imaging substrate 502. For example, the solid-state imaging device 505 is a CCD (Charge Coupled Device), and the case where it is mounted on the imaging substrate 502 including its drive unit (horizontal driver or vertical driver) or a CMOS (Complementary Metal-oxide Semiconductor) sensor is applicable. To do.

  The first communication device 100 (semiconductor chip 103) is mounted on the main substrate 602 that performs signal transmission with the imaging substrate 502 on which the solid-state imaging device 505 is mounted, and the second communication device 200 (semiconductor chip 203) is mounted on the imaging substrate 502. Is installed. As described above, the semiconductor chips 103 and 203 are provided with the signal generation units 107 and 207 and the transmission path coupling units 108 and 208.

  Although not shown, a solid-state imaging device 505 and an imaging drive unit are mounted on the imaging substrate 502. Although not shown, an image processing engine is mounted on the main board 602. An operation unit (not shown) and various sensors are connected to the main board 602. The main board 602 can be connected to peripheral devices such as a personal computer and a printer via an external interface (not shown). For example, a power switch, setting dial, jog dial, determination switch, zoom switch, release switch, and the like are provided in the operation unit.

  The solid-state imaging device 505 and the imaging drive unit correspond to the application function unit of the LSI function unit 204 in the wireless transmission system 1. The signal generation unit 207 and the transmission path coupling unit 208 may be housed in a semiconductor chip 203 different from the solid-state imaging device 505, or may be integrated with the solid-state imaging device 505, the imaging drive unit, and the like. In the case of separate bodies, regarding signal transmission during that period (for example, between semiconductor chips), there is a concern about problems caused by transmitting signals by electric wiring, so that it is preferable to integrate them. It is assumed that the solid-state imaging device 505, the imaging drive unit, and the like are different semiconductor chips 203. The antenna 236 may be disposed outside the chip as a patch antenna, or may be formed in the chip by, for example, an inverted F type. In millimeter wave communication, since the wavelength of millimeter waves is as short as several millimeters, the antenna is small and on the order of several millimeters square, and a patch antenna can be easily installed in a narrow place such as in the imaging apparatus 500.

  The image processing engine corresponds to an application function unit of the LSI function unit 104 in the wireless transmission system 1 and accommodates an image processing unit that processes an imaging signal obtained by the solid-state imaging device 505. The signal generation unit 107 and the transmission path coupling unit 108 may be housed in a semiconductor chip 103B different from the image processing engine, or may be integrated with the image processing engine. In the case of separate bodies, regarding signal transmission during that period (for example, between semiconductor chips), there is a concern about problems caused by transmitting signals by electric wiring, so that it is preferable to integrate them. Here, it is assumed that the semiconductor chip 103 is different from the image processing engine. The antenna 136 may be disposed outside the chip as a patch antenna, or may be formed in the chip by, for example, an inverted F type.

  In the image processing engine, in addition to the image processing unit, for example, a control circuit such as a camera control unit configured by a CPU (Central Processing Unit), a storage unit (work memory, program ROM, etc.), a control signal generation unit, etc. Is also housed. The camera control unit reads a program stored in the program ROM into the work memory, and controls each unit of the imaging apparatus 500 according to the program.

  The camera control unit also controls the entire imaging apparatus 500 based on signals from the switches of the operation unit, supplies power to each unit by controlling the power supply unit, and transfers image data to and from peripheral devices via an external interface. Communication such as.

  The camera control unit also performs sequence control related to shooting. For example, the camera control unit controls the imaging operation of the solid-state imaging device 505 via a synchronization signal generation unit and an imaging drive unit. The synchronization signal generation unit generates a basic synchronization signal necessary for signal processing, and the imaging drive unit receives the synchronization signal generated by the synchronization signal generation unit and the control signal from the camera control unit, and the solid-state imaging device A detailed timing signal for driving 505 is generated.

  The image signal (imaging signal) sent from the solid-state imaging device 505 to the image processing engine may be either an analog signal or a digital signal. When the digital signal is used, regardless of whether the solid-state imaging device 505 is a CCD or a CMOS, the AD conversion unit is mounted on the imaging substrate 502 when the solid-state imaging device 505 is separate from the AD conversion unit.

  In addition to the solid-state imaging device 505, a signal generation unit 207 and a transmission path coupling unit 208 are mounted on the imaging board 502 in order to realize the wireless transmission system 1. Similarly, a signal generation unit 107 and a transmission path coupling unit 108 are mounted on the main board 602 in order to realize the wireless transmission system 1. The millimeter wave signal transmission path 9 couples between the transmission path coupling unit 208 on the imaging substrate 502 side and the transmission path coupling unit 108 on the main board 602 side. As a result, signal transmission in the millimeter wave band is bidirectionally performed between the transmission path coupling unit 208 on the imaging substrate 502 side and the transmission path coupling unit 108 on the main board 602 side.

  When unidirectional communication is acceptable, the signal generation unit 107 and the transmission line coupling unit 108 may be arranged on the transmission side, and the signal generation unit 207 and the transmission line coupling unit 208 may be arranged on the reception side. For example, if only the imaging signal acquired by the solid-state imaging device 505 is to be transmitted, the imaging board 502 side may be the transmission side and the main board 602 side may be the reception side. If only a signal for controlling the solid-state imaging device 505 (for example, a high-speed master clock signal, a control signal, or a synchronization signal) is transmitted, the main board 602 side is set as the transmission side and the imaging board 502 side is set as the reception side. That's fine.

  By performing millimeter wave communication between the two antennas 136 and 236, an image signal acquired by the solid-state imaging device 505 is put on the millimeter wave via the millimeter wave signal transmission path 9 between the antennas 136 and 236. It is transmitted to the main board 602. Various control signals for controlling the solid-state imaging device 505 are transmitted to the imaging substrate 502 by being put on millimeter waves via the millimeter wave signal transmission path 9 between the antennas 136 and 236.

  Here, the millimeter wave signal transmission path 9 may be either a form in which the antennas 136 and 236 are arranged to face each other or a form in which the antennas 136 and 236 are arranged to be shifted in the plane direction of the substrate. In the form in which the antennas 136 and 236 are arranged to face each other, for example, a patch antenna having directivity in the normal direction of the substrate may be used. In a form in which the antennas 136 and 236 are displaced in the plane direction of the substrate, for example, a dipole antenna, a Yagi-Uda antenna, an inverted F-type antenna or the like having directivity in the plane direction of the substrate may be used.

  Each of the millimeter wave signal transmission lines 9 may be a free space transmission line 9B as shown in FIG. 13 (1), but a dielectric transmission line 9A as shown in FIGS. 13 (2) and 13 (3) and FIG. It is desirable to use a hollow waveguide 9L as shown in (4) and (5).

  In the case of providing the free space transmission path 9B, when a plurality of systems of millimeter wave signal transmission paths 9 are provided close to each other, it is preferable that a structure that prevents radio wave propagation to suppress interference between the antenna pairs of each system (Millimeter wave shielding material MY) should be placed between the systems. The millimeter wave shielding material MY may be disposed on either the main substrate 602 or the imaging substrate 502 or on both. Whether or not to place the millimeter wave shielding material MY may be determined from the spatial distance between the systems and the degree of interference. Since the degree of interference is also related to transmission power, it is determined by comprehensively considering the spatial distance, transmission power, and degree of interference.

  As the dielectric transmission line 9A, for example, as shown in FIG. 13B, it is considered that the antennas 136 and 236 are connected with a soft (flexible) dielectric material such as a silicone resin. It is done. The dielectric transmission line 9A may be surrounded by a shielding material (for example, a conductor). In order to take advantage of the flexibility of the dielectric material, the shielding material should also be flexible. Although connected by the dielectric transmission line 9A, since the material is soft, it can be routed like electrical wiring.

  As another example of the dielectric transmission line 9A, as shown in FIG. 13 (3), the dielectric transmission line 9A is fixed on the antenna 136 on the main board 602, and the antenna 236 on the imaging board 502 is provided. It may be arranged at a position in contact with the dielectric transmission line 9A. Conversely, the dielectric transmission line 9A may be fixed to the imaging substrate 502 side.

  The hollow waveguide 9L may have a structure in which the periphery is surrounded by a shielding material and the inside is hollow. For example, as shown in FIG. 13 (4), the periphery is surrounded by a conductor MZ, which is an example of a shielding material, and the interior is hollow. For example, an enclosure of the conductor MZ is attached on the main board 602 so as to surround the antenna 136. The moving center of the antenna 236 on the imaging substrate 502 side is arranged at a position facing the antenna 136. Since the inside of the conductor MZ is hollow, it is not necessary to use a dielectric material, and the millimeter wave signal transmission path 9 can be easily configured at low cost.

  The enclosure of the conductor MZ may be provided on either the main substrate 602 side or the imaging substrate 502 side. In any case, the distance L between the enclosure by the conductor MZ and the imaging substrate 502 or the main substrate 602 (the length of the gap from the end of the conductor MZ to the opposite substrate) is sufficiently smaller than the wavelength of the millimeter wave. Set to. The size and shape of the shielding material (enclosure: conductor MZ) may be set to a size and a planar shape such that the opposing range of the antennas 136 and 236 exists inside the enclosure (conductor MZ). As long as this is the case, the planar shape of the conductor MZ is arbitrary, such as a circle, a triangle, or a square.

  The hollow waveguide 9L is not limited to forming an enclosure with the conductor MZ on the substrate. For example, as shown in FIG. 13 (5), a relatively thick substrate is provided with a through hole or a non-through hole, You may comprise so that the wall surface of the hole may be utilized for enclosure. In this case, the substrate functions as a shielding material. The hole may be either one of the imaging substrate 502 and the main substrate 602 or both. The side wall of the hole may or may not be covered with a conductor. In the latter case, the millimeter wave is reflected and strongly distributed in the hole depending on the relative dielectric constant ratio of the substrate and air. When penetrating the holes, the antennas 136 and 236 are preferably disposed (attached) on the back surfaces of the semiconductor chips 103 and 203. In the case of stopping the hole halfway without passing through it (making it a non-through hole), the antennas 136 and 236 may be installed at the bottom of the hole.

  The size and shape of the cross section of the hole may be set to a size and a planar shape so that the facing range of the antennas 136 and 236 exists inside the substrate side wall functioning as an enclosure. As long as this is the case, the cross-sectional shape is arbitrary such as a circle, a triangle, and a square.

  When the first communication device 100 and the second communication device 200 are arranged in a casing of one electrical device (in this example, the imaging device 500) to perform millimeter wave signal transmission, the millimeter wave signal transmission path 9 is transmitted in free space. In the case of the path 9B, there is a concern about the influence of reflection by the members in the housing. In particular, when the injection locking method is applied, the transmission power is generally higher than when the same method is not applied, and it is expected that interference and multipath problems due to reflection become obvious. On the other hand, if the millimeter-wave signal transmission path 9 having a millimeter-wave confinement structure (waveguide structure) such as the dielectric transmission path 9A or the hollow waveguide 9L is used, it is not affected by reflection by members in the casing. . In addition, the millimeter wave signal emitted from one antenna 136 can be confined in the millimeter wave signal transmission line 9 and transmitted to the other antenna 236 side, so that the waste of the emitted radio wave is reduced, so even when the injection locking method is applied. Electric power can be reduced.

[Second example]
FIG. 13A is a diagram illustrating a second example of the wireless transmission path structure according to the present embodiment. The transmission line structure of the second example is an application example in the case where signal transmission is performed by millimeter waves between electronic devices in a state where a plurality of electronic devices are integrated. For example, it is an application to signal transmission between two electronic devices when one electronic device is mounted on the other (for example, the main body side) electronic device.

  For example, a so-called IC card or memory card with a built-in central processing unit (CPU) or non-volatile storage device (for example, flash memory) is installed in the main body side electronic equipment. Some are made possible (detachable). A card type information processing apparatus which is an example of one (first) electronic device is also referred to as a “card type apparatus” below. The other (second) electronic device on the main body side is also simply referred to as an electronic device below.

  The slot structure 4A between the electronic device 101A and the memory card 201A is a structure in which the memory card 201A is attached to and detached from the electronic device 101A, and has a function of fixing means for the electronic device 101A and the memory card 201A.

  As shown in FIG. 13A (2), the slot structure 4A is configured such that the memory card 201A (the housing 290) can be inserted into and removed from the housing 190 on the electronic device 101A side. The substrate 102 is attached to one surface (outside) of the housing 190 opposite to the opening 192 by a support material 191.

  A connector on the receiving side is provided at a contact position with the terminal of the memory card 201A of the slot structure 4A. Connector signals (connector pins) are not required for signals replaced with millimeter wave transmission.

  In addition, it is conceivable to provide a connector terminal for the signal replaced with millimeter wave transmission on the electronic device 101A side (slot structure 4A). In this case, if the memory card 201 inserted in the slot structure 4A is a conventional card to which the millimeter wave transmission line structure of the second example is not applied, signal transmission can be performed by electric wiring as before.

  The electronic device 101A and the memory card 201A have a concavo-convex shape configuration as a fitting structure. Here, as shown in FIG. 13A (2), the casing 190 of the electronic apparatus 101A is provided with a cylindrical convex configuration 198A (protrusion), and as shown in FIG. 13A (1), the housing 290 of the memory card 201A. Is provided with a cylindrical concave configuration 298A (indentation). That is, as shown in FIG. 13A (3), in the housing 190, when the memory card 201A is inserted, the convex configuration 198A is provided at a portion corresponding to the position of the concave configuration 298A.

  With such a configuration, when the memory card 201A is inserted into the slot structure 4A, the memory card 201A is fixed and aligned at the same time. In addition, even if there is a backlash in the concave and convex shape fitting, the antenna 136 and 236 may be set so as not to go out of the shielding material (enclosure: conductor 144). As shown in the figure, it is not essential to have a circular shape, and any shape such as a triangle or a square is possible.

  For example, FIG. 13A (1) shows a structural example (planar perspective and sectional perspective) of the memory card 201A. The memory card 201 </ b> A includes a semiconductor chip 203 including a signal generation unit 207 (millimeter wave signal conversion unit) on one surface of the substrate 202. The semiconductor chip 203 is provided with a millimeter wave transmission / reception terminal 232 for coupling to the millimeter wave signal transmission line 9. On one surface of the substrate 202, a millimeter wave transmission path 234 and an antenna 236 (patch antenna in the figure) are formed by a substrate pattern connected to the millimeter wave transmission / reception terminal 232. The millimeter wave transmission / reception terminal 232, the millimeter wave transmission line 234, and the antenna 236 constitute a transmission line coupling unit 208.

  Since the patch antenna does not have a sharp directivity in the normal direction, the antennas 136 and 236 are not affected by the reception sensitivity even if they are arranged slightly deviated as long as the area of the overlap portion is large to some extent. In millimeter wave communication, since the wavelength of millimeter waves is as short as several millimeters, the antenna is small and is in the order of several millimeters square, and a patch antenna can be easily installed in a narrow place such as in the small memory card 201.

  When the antennas 136 and 236 are formed in the semiconductor chips 103 and 203, a smaller antenna such as an inverted F type is required. Incidentally, the inverted F-type antenna is omnidirectional, in other words, has directivity not only in the thickness (normal) direction of the substrate but also in the plane direction, and is thus coupled to the millimeter wave signal transmission line 9. It is preferable to improve the transmission efficiency by devising, for example, providing a reflection plate in the transmission line coupling units 108 and 208.

  The housing 290 is a cover for protecting the substrate 202, and at least a portion of the concave configuration 298A is made of a dielectric resin including a dielectric material having a relative permittivity capable of transmitting a millimeter wave signal. For example, a member made of an acrylic resin, a urethane resin, an epoxy resin, or the like is used as the dielectric material having the concave configuration 298A. The dielectric material of at least the concave-shaped configuration 298A of the casing 290 also forms a millimeter wave dielectric transmission path.

  In the housing 290, a concave configuration 298A is formed on the same surface as the antenna 236. The concave configuration 298A fixes the memory card 201A to the slot structure 4A and aligns the millimeter wave transmission with the millimeter wave signal transmission line 9 included in the slot structure 4A.

  On one side of the substrate 202, connection terminals 280 (signal pins) for connecting to the electronic device 101 </ b> A at predetermined locations of the housing 290 are provided at predetermined locations of the housing 290. In the case of the first embodiment, the memory card 201A partially includes a conventional terminal structure for low-speed and small-capacity signals and power supply. Since the clock signal and the plurality of data signals are subject to signal transmission by millimeter waves, the terminals are removed as shown by dotted lines in the figure.

  FIG. 13A (2) shows a structural example (planar perspective and sectional perspective) of the electronic apparatus 101A. The electronic device 101A includes a semiconductor chip 103 including a signal generation unit 107 (millimeter wave signal conversion unit) on one surface (opening 192 side) of the substrate 102. The semiconductor chip 103 is provided with a millimeter wave transmission / reception terminal 132 for coupling to the millimeter wave signal transmission line 9. On one surface of the substrate 102, a millimeter wave transmission path 134 and an antenna 136 (patch antenna in the figure) are formed by a substrate pattern connected to the millimeter wave transmission / reception terminal 132. The millimeter wave transmission / reception terminal 132, the millimeter wave transmission line 134, and the antenna 136 constitute a transmission line coupling unit 108.

  The housing 190 has an opening 192 into which the memory card 201A is inserted and removed as the slot structure 4A.

  In the case 190, when the memory card 201A is inserted into the opening 192, a millimeter wave signal transmission line 9 having a millimeter wave confinement structure (waveguide structure) is formed at a portion corresponding to the position of the concave configuration 298A. Thus, a convex configuration 198A is formed. In this example, the convex configuration 198A is configured to be a dielectric transmission line 9A by forming a dielectric waveguide 142 filled with a dielectric material in a cylindrical conductor 144. The dielectric waveguide 142 is fixedly disposed so that the center of the dielectric waveguide 142 coincides with the antenna 136 of the transmission line coupling unit 108. A dielectric waveguide 142 is provided as a structure for reinforcing the coupling between the antennas 136 and 236 in the concave-convex fitting structure.

  The provision of the dielectric waveguide 142 is not essential, and the millimeter wave signal transmission path 9 may be configured with the dielectric materials of the casings 190 and 290 being maintained. Further, instead of the dielectric transmission line 9A, the surroundings may be transformed into a hollow waveguide 9L surrounded by a shielding material and hollow inside. For example, the hollow waveguide 9L may be configured by forming the inside of the cylindrical conductor 144 in a hollow (hollow) state. Even in the hollow waveguide 9L having such a structure, since the millimeter wave is confined in the hollow waveguide 9L by the conductor 144 having an enclosure function, the millimeter wave can be efficiently transmitted with little transmission loss of the millimeter wave. Advantages such as suppression of radiation and easier EMC countermeasures can be obtained.

  Parameters such as the diameter, length, and material of the dielectric waveguide 142 are determined so that the millimeter wave signal can be efficiently transmitted. As described above, the dielectric constant is 2 to 10 (preferably 3 to 6) such as those made of acrylic resin, urethane resin, epoxy resin, silicone, polyimide, cyanoacrylate resin, etc. It is preferable to use a dielectric material having a dielectric loss tangent of about 0.00001 to 0.01 (preferably 0.00001 to 0.001). By confining the millimeter wave signal in the dielectric transmission line 9A, the transmission efficiency can be improved, and millimeter wave signal transmission can be performed without any inconvenience. In some cases, the conductor 144 may not be provided by appropriately selecting a material.

  The diameter of the conductor 144 is configured to correspond to the diameter of the concave configuration 298A of the memory card 201A. The conductor 144 also has an effect as a shielding material that suppresses external radiation of millimeter waves transmitted in the dielectric waveguide 142.

FIG. 13A (3) shows a structural example (cross-sectional perspective view) when the memory card 201A is inserted into the slot structure 4A (particularly the opening 192) of the electronic apparatus 101A. As shown in the figure, the housing 190 of the slot structure 4A has a mechanism in which the convex configuration 198A (dielectric transmission line 9A) and the concave configuration 298A come into contact with the concave and convex portions when the memory card 201A is inserted from the opening 192. It has a structure. When the concavo-convex structure is fitted, the antennas 136 and 236 face each other, and a dielectric transmission path 9A is disposed as the millimeter wave signal transmission path 9 therebetween.
With the above configuration, the memory card 201A and the slot structure 4A are fixed. In addition, the alignment of the dielectric transmission path 9A with respect to the coupling of millimeter wave transmission is realized so as to efficiently transmit a millimeter wave signal between the antennas 136 and 236.

  That is, in the electronic device 101A, the transmission path coupling unit 108 (particularly the antenna coupling unit) is disposed in the convex configuration 198A, and in the memory card 201A, the transmission path coupling unit 208 (particularly in the concave configuration 298A). Antenna coupling part) is arranged. When the unevenness is matched, the transmission path coupling units 108 and 208 are arranged so that the millimeter wave transmission characteristics are enhanced.

  With such a configuration, when the memory card 201A is attached to the slot structure 4A, it becomes possible to simultaneously fix the memory card 201A and align the millimeter wave signal transmission. In the memory card 201A, the housing 290 is sandwiched between the dielectric transmission path 9A and the antenna 236. However, since the material of the concave configuration 298A is a dielectric material, it does not significantly affect the transmission of millimeter waves. Absent. This also applies to the case where the dielectric waveguide 142 is not provided in the convex configuration 198A and is left as the dielectric material of the casing 190, and the antenna 136 is formed by the dielectric material of the casings 190 and 290. , 236, a millimeter wave signal transmission line 9 (dielectric transmission line 9A) is formed.

  According to the millimeter wave transmission line structure of the second example, when the memory card 201A is mounted in the slot structure 4A, the dielectric waveguide 142 is provided between the transmission line coupling portions 108 and 208 (particularly the antennas 136 and 236). A configuration in which the dielectric transmission line 9A is provided is employed. By confining the millimeter wave signal in the dielectric transmission line 9A, the efficiency of high-speed signal transmission can be improved.

  The idea is that the millimeter wave signal transmission line 9 is formed so that the antenna 136 and the antenna 236 face each other at a portion other than the fitting structure (convex shape configuration 198, concave shape configuration 298) of the slot structure 4A for card mounting. You can also However, in this case, there is an influence due to positional deviation. On the other hand, by providing the millimeter wave signal transmission path 9 in the fitting structure of the card mounting slot structure 4A, it is possible to reliably eliminate the influence of the positional deviation.

  In particular, in this configuration example, the millimeter wave signal transmission path 9 (dielectric transmission path 9A in this example) having a millimeter wave confinement structure (waveguide structure) is constructed using the fitting structure (slot structure 4A). The millimeter wave signal emitted from one antenna 136 can be confined in the dielectric transmission line 9A and transmitted to the other antenna 236 side without being affected by reflection by the casing or other members. For this reason, the waste of emitted radio waves is reduced, so that transmission power can be reduced even when the injection locking method is applied.

[Third example]
FIG. 13B is a diagram illustrating a third example of the wireless transmission path structure according to the present embodiment, and in particular, illustrates a modification example of the electronic device. The wireless transmission system 1 includes a portable image playback device 201K as an example of a first electronic device, and an image acquisition device 101K as an example of a second (main body side) electronic device on which the image playback device 201K is mounted. I have. In the image acquisition apparatus 101K, a mounting table 5K on which the image reproduction apparatus 201K is mounted is provided in a part of the housing 190. Instead of the mounting table 5K, the slot structure 4 may be used as in the second example. This is the same as the transmission line structure of the second example in that signal transmission is performed wirelessly in the millimeter wave band between both electronic devices when one electronic device is mounted on the other electronic device. Below, it demonstrates paying attention to difference with a 2nd example.

  The image acquisition device 101K has a substantially rectangular parallelepiped (box shape) shape and is no longer a card type. As the image acquisition device 101K, any device that acquires moving image data, for example, may be used. In the image reproduction device 201K, as an application function unit 205, a storage device that stores moving image data transmitted from the image acquisition device 101K side, or a moving image data read from the storage device and a display unit (for example, a liquid crystal display device or an organic EL device). A function unit for playing back a moving image on the display device) is provided. Structurally, it may be considered that the memory card 201A is replaced with the image reproduction device 201K, and the electronic apparatus 101A is replaced with the image acquisition device 101K.

  In the housing 190 below the mounting table 5K, for example, as in the second example of the millimeter wave transmission line structure (FIG. 13A), the semiconductor chip 103 is accommodated, and an antenna 136 is provided at a certain position. . The portion of the housing 190 facing the antenna 136 is provided with a dielectric waveguide 142 whose inner transmission path is a dielectric transmission path 9A made of a dielectric material and whose outside is surrounded by a conductor 144. Yes. It is not essential to provide the dielectric waveguide 142 (dielectric transmission path 9A), and the millimeter wave signal transmission path 9 may be configured with the dielectric material of the casing 190 as it is. These points are the same as the other structural examples described above. Note that, as described in the eighth example, a plurality of antennas 136 are provided side by side, and a millimeter wave signal for inspection is transmitted from the antenna 236 of the image reproducing device 201K prior to the actual signal transmission. A high antenna 136 may be selected.

  In the housing 290 of the image reproducing device 201K mounted on the mounting table 5K, for example, as in the second example of the millimeter wave transmission path structure (FIG. 13A), the semiconductor chip 203 is accommodated, and an antenna is located at a certain position. 236 is provided. The portion of the housing 290 that faces the antenna 236 is configured to form the millimeter wave signal transmission line 9 (dielectric transmission line 9A) by a dielectric material. These points are the same as the millimeter wave transmission line structure of the second example described above.

  With such a configuration, it is possible to perform alignment with respect to millimeter wave signal transmission of the image reproducing device 201K when the image reproducing device 201K is mounted (mounted) on the mounting table 5K. Although the casings 190 and 290 are sandwiched between the antennas 136 and 236, since they are dielectric materials, they do not significantly affect the transmission of millimeter waves.

  The millimeter wave transmission line structure of the third example adopts a wall surface abutting method instead of the concept of a fitting structure, and the antenna 136 and the antenna 236 face each other when placed so as to abut against the corner 101a of the mounting table 5K. As a result, the influence of the positional deviation can be surely eliminated.

  A configuration is adopted in which the dielectric transmission line 9A is interposed between the transmission line coupling units 108 and 208 (particularly the antennas 136 and 236) when the image reproducing device 201K is mounted at a specified position on the mounting table 5K. By confining the millimeter wave signal in the dielectric transmission line 9A, the efficiency of high-speed signal transmission can be improved. The millimeter wave signal emitted from one antenna 136 can be confined in the dielectric transmission path 9A and transmitted to the other antenna 236 side without being affected by reflection by the casing or other members. For this reason, the waste of emitted radio waves is reduced, so that transmission power can be reduced even when the injection locking method is applied.

<System configuration: first application example>
FIG. 14 is a diagram illustrating a first application example of the wireless transmission system 1 of the present embodiment. In the first application example, the above-described injection locking method is applied between the two semiconductor chips 103A and 203A formed by the CMOS process in the casing of one electronic device or between a plurality of electric devices. This is an example of signal transmission.

  The outer shape of the housing 190A on the first communication device 100A side and the housing 290A on the second communication device 200A side is not limited to a cube (a rectangular parallelepiped), but may be an ellipse even if it is a sphere, a cylinder, or a semi-column. It may be a pillar. In the case of signal transmission within one housing, for example, it may be considered that the semiconductor chip 103A and the semiconductor chip 203B are mounted on the same substrate. Alternatively, it may be considered that the housing 190A on the first communication device 100A side and the housing 290A on the second communication device 200A side are combined. In the case of signal transmission between devices in which the electronic device including the second communication device 200A is mounted on the electronic device including the first communication device 100A, the housing 190A on the first communication device 100A side and the second communication It may be considered that the housing 290A on the apparatus 200A side is in contact with the dotted line portion in the drawing.

  The casings 190A and 290A correspond to exterior (external) cases such as a digital recording / reproducing device, a terrestrial television receiver, a camera, a hard disk device, a game machine, a computer, and a wireless communication device.

  For example, in the wireless transmission system 1, in order to transmit a signal requiring high speed and large capacity such as a movie image or a computer image, the millimeter wave is set to a millimeter wave band transmission signal Sout_1 having a carrier frequency f1 of 30 GHz to 300 GHz. The signal transmission path 9_1 is transmitted.

  The millimeter-wave signal transmission path 9_1 is composed of a free space inside the casings 190A and 290A, a dielectric transmission path built inside the casing 190A, and a waveguide and / or a waveguide. And / or a microstrip line. The millimeter wave signal transmission line 9_1 may be anything as long as the millimeter wave transmission signal Sout_1 can be transmitted. The dielectric substance itself such as a resin member filled in the housings 190A and 290A also constitutes the millimeter wave signal transmission path 9_1.

  Since the millimeter wave can be easily shielded and hardly leaks to the outside, a carrier signal having a carrier frequency f1 with low stability can be used. This also leads to an increase in the degree of freedom in designing the propagation channel between the semiconductor chips 103A and 203A. For example, it is more reliable than millimeter wave signal transmission in free space by designing the sealing member (package) structure for sealing the semiconductor chips 103A and 203A and the propagation channel using a dielectric material. High-quality and good signal transmission can be performed.

  For example, the interiors of the housings 190A and 290A may be free space so that a free space transmission path may be formed between the antennas 136A and 236A. The entire interior may be made of a dielectric material such as a resin member. It may be filled. In these cases, the housings 190A and 290A are provided with a resin member in the inside of a shield case in which, for example, the outer six surfaces are surrounded by a metal plate so that the transmission signal Sout_1 in the millimeter wave band does not leak to the outside. It is desirable to be like a case coated with. The casings 190A and 290A may be a case in which the outer six surfaces are shielded by a metal member in addition to a case surrounded by a resin member. In any case, since the transmission amplitude tends to be larger when the injection locking method is applied than when the injection locking method is not applied, it is preferable to take a shielding measure in consideration of this point.

  Preferably, the inside of the housings 190A and 290A is set as a free space, and the antennas 136A and 236A are provided with a dielectric transmission line, a hollow waveguide, a waveguide structure, and the like so as to confine the millimeter wave signal in the transmission line. A millimeter-wave confinement structure (waveguide structure) having a structure for transmitting a wave signal is used. If the millimeter-wave confinement structure is used, it is possible to reliably transmit a millimeter-wave band signal between the antennas 136A and 236A without being affected by reflection from the casings 190A and 290A. In addition, since the millimeter wave signal (transmission signal Sout_1) emitted from the antenna 136A can be confined in the millimeter wave signal transmission line 9_1 and transmitted to the antenna 236A side, the transmission power can be reduced because waste can be reduced (can be eliminated). Can do. Even when the injection locking method is applied, the transmission power can be made extremely small, so that no electromagnetic induction interference (EMI) is given to the outside. Therefore, the casings 190A and 290A may omit the metal shield structure.

  The semiconductor chip 103A includes a modulation function unit 8300 (frequency mixing unit 8302, transmission-side local oscillation unit 8304) and an amplification unit 8117, and the amplification unit 8117 is connected to an antenna 136A that forms part of the transmission line coupling unit. . The semiconductor chip 103A converts (modulates) the transmission target signal SIN_1 into a millimeter wave signal and emits the transmission signal Sout_1 from the antenna 136A.

  The semiconductor chip 203A includes an amplification unit 8224, a demodulation function unit 8400 (frequency mixing unit 8402, reception-side local oscillation unit 8404), and a low-pass filter 8412. The amplification unit 8224 is an antenna that forms part of the transmission path coupling unit 208. 236A. The semiconductor chip 203A restores (demodulates) the transmission target signal SOUT_1 (corresponding to SIN_1) from the received signal Sin_1 (corresponding to Sout_1) received by the antenna 236A. That is, the semiconductor chips 103A and 203A perform signal transmission in the millimeter wave band via the millimeter wave signal transmission path 9_1 between the antennas 136A and 236A.

  Since the millimeter-wave antennas 136A and 236A have a short wavelength, it is possible to configure an ultra-small antenna element on the semiconductor chips 103A and 203A. Since the antennas 136A and 236A can be reduced in size, it is possible to give a remarkably large degree of freedom to the method of radiating the transmission signal Sout_1 from the antenna 136A and the method of extracting the reception signal Sin_1 from the antenna 236A.

  Both the transmission-side semiconductor chip 103A and the reception-side semiconductor chip 203A do not use an external tank circuit as in the conventional method, and the transmission-side local oscillation unit 8304 including the tank circuit or the reception-side local oscillation as described above. It is assumed that the entire portion 8404 is formed on the same chip. The transmission-side semiconductor chip 103A, for example, frequency-converts the carrier signal having the carrier frequency f1 generated by the transmission-side local oscillation unit 8304 into a millimeter-wave transmission signal Sout_1 by modulating the carrier signal with the ASK method based on the transmission target signal SIN_1. .

  The reception-side semiconductor chip 203A uses, for example, a millimeter wave signal (transmission signal Sout_1 = reception signal Sin_1) transmitted from the transmission-side semiconductor chip 103A as an injection signal to the reception-side local oscillation unit 8404, and is based thereon. The reception-side local oscillation unit 8404 acquires the reproduction carrier signal. The frequency mixing unit 8402 demodulates the received signal Sin_1 using the reproduced carrier signal. By passing the demodulated signal through the low-pass filter 8412, the transmission target signal SOUT_1 corresponding to the transmission target signal SIN_1 is restored.

  Since the semiconductor chip 103A in the housing 190A and the semiconductor chip 203A in the housing 290A have their arrangement positions specified (typically fixed), the positional relationship between them and the environment of the transmission channel between them Conditions (for example, reflection conditions) can be specified in advance. Therefore, it is easy to design a propagation channel between the transmission side and the reception side. In addition, when the sealing structure for sealing the transmitting side and the receiving side and the propagation channel are combined and designed using a dielectric material, good transmission with higher reliability than free space transmission becomes possible.

  The environment of the propagation channel does not change frequently, and the control for enabling the injection locking by the controller units 8346 and 8446 described above is frequently performed dynamically and adaptively as in general wireless communication. There is no need. For this reason, the overhead due to control can be reduced as compared with general wireless communication. This contributes to realizing a transmission wireless transmission system 1 that performs high-speed and large-capacity signal transmission with small size and low power consumption.

  In addition, if the wireless transmission environment is calibrated at the time of manufacture or design, and individual variations are grasped, the controller units 8346 and 8446 can make various settings so that injection locking can be established with reference to the data. It is not necessary to repeat the determination of the injection locking state and the change of various setting values in response thereto, and various settings for enabling injection locking can be simplified.

<System configuration: second application example>
FIG. 15 is a diagram illustrating a second application example of the wireless transmission system 1 according to the present embodiment. In the second application example, the above-described injection locking method is applied between the three semiconductor chips 103B, 203B_1, and 203B_2 formed by the CMOS process in the casing of one electronic device or between a plurality of electrical devices. This is an example of signal transmission in the waveband. The difference from the first application example is that signal transmission is performed on a one-to-two basis. Typically, broadcast (simultaneous) communication is performed from one transmitting-side semiconductor chip 103B to two receiving-side semiconductor chips 203B_1 and 203B_2. In the figure, there are two reception sides, but three or more may be used. The carrier frequency f2 to be used is a millimeter wave band of 30 GHz to 300 GHz. Hereinafter, differences from the first application example will be described.

  In the case of signal transmission within one housing, for example, it may be considered that the semiconductor chip 103B and the semiconductor chips 203B_1 and 203_2 are mounted on the same substrate. Alternatively, it may be considered that the housing 190B on the first communication device 100B side and the housings 290B_1 and 290B_2 on the second communication devices 200B_1 and 200B_2 side are combined. In the case of signal transmission between devices in which electronic devices having two second communication devices 200B_1 and 200B_2 are mounted on an electronic device having the first communication device 100B, a housing on the first communication device 100B side is used. It can be considered that the body 190B and the casings 290B_1 and 290B_2 on the second communication devices 200B_1 and 200B_2 side are in contact with each other at a dotted line portion in the drawing.

  The transmission-side semiconductor chip 103B, for example, frequency-converts the carrier signal having the carrier frequency f2 generated by the transmission-side local oscillation unit 8304 into a millimeter-wave transmission signal Sout_2 by modulating the carrier signal with the ASK method based on the transmission target signal SIN_2. . The transmission signal Sout_2 is supplied to the millimeter wave signal transmission line 9_2 via the antenna 136B and reaches the two antennas 236B_1 and 236B_2 on the receiving side. The reception-side semiconductor chips 203B_1 and 203B_2 use, for example, a millimeter wave signal (transmission signal Sout_2 = reception signal Sin_2) transmitted from the transmission-side semiconductor chip 103B as an injection signal to the reception-side local oscillation unit 8404, The reception-side local oscillation unit 8404 acquires a reproduction carrier signal based thereon. The frequency mixing unit 8402 demodulates the received signal Sin_2 using the reproduced carrier signal. By passing the demodulated signal through the low-pass filter 8412, the transmission target signal SOUT_2 corresponding to the transmission target signal SIN_2 is restored.

  As described above, in the second application example, the broadcast communication is realized by the millimeter wave signal transmission line 9_2 constituting the one-to-two transmission channel between the semiconductor chip 103B on the transmission side and the semiconductor chips 203B_1 and 203B_2 on the reception side. The

<System configuration: third application example>
16 to 16B are diagrams illustrating a third application example of the wireless transmission system 1 according to the present embodiment. In the third application example, N sets (N is a positive integer of 2 or more) transmitting units are arranged on the transmitting side, and M sets (M is a positive integer of 2 or more) receiving units are arranged on the receiving side. In addition, the transmission unit and the reception unit are configured to transmit using different carrier frequencies. That is, frequency division multiplex transmission is performed in which different signals are transmitted using a plurality of carrier frequencies. Below, in order to demonstrate easily, it demonstrates by the communication of 2 systems | lines using carrier frequency f1, f2.

  The third application example (No. 1) shown in FIGS. 16 to 16A is a case where both the transmitting side and the receiving side use different antennas. The configuration of the first application example and the second application example described above. This is an example in which the wireless transmission system 1 is constructed by combining these configurations. Each semiconductor chip can be regarded as either a transmission side or a reception side, and there is basically no restriction on the arrangement location of each semiconductor chip. On the other hand, the third application example (No. 2) shown in FIG. 16B is a case where both the transmitting side and the receiving side use a common antenna.

  In the third application example (part 1), the carrier frequency f1 used in the part adopting the configuration of the first application example is a millimeter wave band of 30 GHz to 300 GHz, and used in the part adopting the configuration of the second application example. The carrier frequency f2 is also a millimeter wave band of 30 GHz to 300 GHz. However, it is assumed that the carrier frequencies f1 and f2 are separated to the extent that the modulated signals do not interfere with each other. Hereinafter, differences from the first and second application examples will be described.

  In the case of signal transmission within one housing, for example, it may be considered that the semiconductor chips 103A and 103B and the semiconductor chips 203A, 203B_1, and 203B_2 are mounted on the same substrate.

  In the case of signal transmission between devices, for example, as in the third application example (part 1-1) shown in FIG. 16, the electronic device including the first communication device 100C in which the semiconductor chips 103A and 103B are accommodated. On the other hand, an electronic device including the second communication device 200C in which the semiconductor chips 203A, 203B_1, and 203_2 are accommodated is placed, and a case 190C on the first communication device 100C side and a case 290C on the second communication device 200C side are provided. What is necessary is just to consider that it is contacting in the dotted-line part in a figure.

  In addition, as in the third application example (part 1-2) illustrated in FIG. 16A, the semiconductor chips 103B and 203A are provided for the electronic apparatus including the first communication device 100C in which the semiconductor chips 103A, 203B_1, and 203B_2 are accommodated. An electronic device including the accommodated second communication device 200C is placed, and a housing 190C on the first communication device 100C side and a housing 290C on the second communication device 200C side are in contact with each other at a dotted line portion in the drawing. Think of it as something. Although not specifically described, the same applies to the third application example (part 2).

  In the third application example (part 1), the antenna between the transmission and reception is coupled by a single millimeter wave signal transmission line 9_3. Functionally, the part adopting the configuration of the first application example is the millimeter wave signal transmission line 9_1 and the first communication channel is formed, and the part adopting the configuration of the second application example is the millimeter wave signal transmission line 9_2. A second communication channel is formed. Since it is the single millimeter wave signal transmission line 9_3, for example, the radio wave of the carrier frequency f1 of the millimeter wave signal transmission line 9_1 can be transmitted to the millimeter wave signal transmission line 9_2 side, or the carrier frequency f2 of the millimeter wave signal transmission line 9_2. Can be transmitted to the millimeter wave signal transmission line 9_1 side.

  In the portion where the configuration of the first application example is adopted, signal transmission is performed in the millimeter wave band between the semiconductor chips 103A and 203A via the millimeter wave signal transmission line 9_1 using the carrier frequency f1. In the portion where the configuration of the second application example is adopted, the carrier frequency f2 (≠ f1) is used to broadcast in the millimeter wave band between the semiconductor chip 103B and the semiconductor chips 203B_1 and 203B_2 via the millimeter wave signal transmission line 9_2. Communication takes place. That is, in the third application example, one-to-one and one-to-two transmission systems are mixed. At this time, by setting different carrier frequencies f1 and f2 for each communication channel, each signal transmission is realized without being affected by interference.

  For example, as indicated by a dotted line in FIG. 16, when the semiconductor chip 203B_1 receives the transmission signal Sout_2 (= reception signal Sin_2) of the carrier frequency f2 and is injection-synchronized, the transmission signal Sout_1 of the carrier frequency f1 also arrives. Suppose that In this case, the semiconductor chip 203B_1 is not injection-synchronized with the carrier frequency f1, but is synchronously detected using the reproduced carrier signal and passed through the low-pass filter 8412 so that the transmission signal Sout_1 at the carrier frequency f1 is demodulated by the semiconductor chip 203B_1. Even if the processing is performed, the component of the transmission target signal SIN_1 is not restored. That is, even when the semiconductor chip 203B_1 is injection-locked to the carrier frequency f2, even if it receives the modulation signal of the carrier frequency f1, it is not affected by the interference of the component of the carrier frequency f1.

  Further, as indicated by a dotted line in FIG. 16, when the semiconductor chip 203A receives the transmission signal Sout_1 (= reception signal Sin_1) of the carrier frequency f1 and is injection-synchronized, the transmission signal Sout_2 of the carrier frequency f2 also arrives. Suppose that In this case, the semiconductor chip 203A is not injection-synchronized with the carrier frequency f2, but is synchronously detected using the reproduced carrier signal and passed through the low-pass filter 8412 so that the transmission signal Sout_2 of the carrier frequency f2 is demodulated by the semiconductor chip 203A. Even if the processing is performed, the component of the transmission target signal SIN_2 is not restored. That is, even if the semiconductor chip 203A receives the modulation signal of the carrier frequency f2 while being injection-synchronized with the carrier frequency f1, it is not affected by the interference of the component of the carrier frequency f2.

  In the third application example (No. 2), N sets of transmission side signal generation units 110 are accommodated in one (transmission side) semiconductor chip 103, and M sets of reception are included in the other (reception side) semiconductor chip 203. A side signal generation unit 220 is accommodated, and frequency division multiplexing is applied in the same direction from each transmission side signal generation unit 110 to each reception side signal generation unit 220 to enable simultaneous signal transmission. The transmission unit and the reception unit each apply the above-described injection locking method.

  For example, the first communication device 100C includes first and second transmission-side signal generation units 110_1 and 110_2, and the second communication device 200C includes first, second, and third reception-side signal generation units 220_1, 220_2 and 220_3 are arranged. The first transmission side signal generation unit 110_1 and the first reception side signal generation unit 220_1 use the first carrier frequency f1, and the second transmission side signal generation unit 110_1 and the second and third reception sides. It is assumed that the pair of signal generators 220_2 and 220_3 uses the second carrier frequency f2 (≠ f1).

  The millimeter wave signals of the carrier frequencies f1 and f2 generated by the transmission side signal generation units 110_1 and 110_2 are combined into one system by a coupler which is an example of the multiplexing processing unit 113, and the antenna 136 of the transmission path coupling unit 108 is connected. The millimeter-wave signal transmission path 9 is transmitted through The receiving-side antenna 236 receives the millimeter-wave signal transmitted through the millimeter-wave signal transmission path 9 and separates it into three systems by a distributor which is an example of the unification processing unit 228, and each receiving-side signal generation unit 220_1, 220_2 and 220_3.

  The reception-side signal generation unit 220_1 generates a reproduction carrier signal that is injection-locked with the carrier signal having the carrier frequency f1 used by the transmission-side signal generation unit 110_1 for modulation, and demodulates the received millimeter-wave signal having the carrier frequency f1. The reception side signal generation units 220_2 and 220_3 generate a reproduction carrier signal that is injection-synchronized with the carrier signal of the carrier frequency f2 used by the transmission side signal generation unit 110_2 for modulation, and demodulate the received millimeter wave signal of the carrier frequency f2.

  In the third application example (part 2), the frequency at which different signals are transmitted in the same direction by using two sets of carrier frequencies f1 and f2, as in the third application example (part 1). Division multiplexing transmission can be realized without causing interference problems.

<System configuration: Fourth application example>
17 to 17A are diagrams for describing a fourth application example of the wireless transmission system 1 of the present embodiment. In the fourth application example, the same number of transmitters and receivers are arranged in a pair of semiconductor chips for two-way communication, and a full duplex is used by using a different carrier frequency for each pair of transmitter and receiver. The two-way communication is performed. In the following, in order to simplify the description, the description will be made with two systems of communication using the carrier frequency f1 for one communication and using the carrier frequency f2 for communication in the opposite direction to the one. The carrier frequency f1 is a millimeter wave band of 30 GHz to 300 GHz, and the carrier frequency f2 is also a millimeter wave band of 30 GHz to 300 GHz. However, the carrier frequencies f1 and f2 are separated to the extent that the modulated signals do not interfere with each other. To do.

  A fourth application example (part 1) shown in FIG. 17 is a case where both the transmitting side and the receiving side use different antennas. On the other hand, the fourth application example (No. 2) shown in FIG. 17A is a case where each semiconductor chip for bidirectional communication uses a common antenna.

  In the case of signal transmission within one housing, for example, it may be considered that the semiconductor chips 103D and 203D are mounted on the same substrate. In the case of signal transmission between devices, for example, as shown in FIG. 17, the second communication device 200D in which the semiconductor chip 203D is accommodated in the electronic device having the first communication device 100D in which the semiconductor chip 103D is accommodated. It can be considered that the electronic device having the above is mounted, and the housing 190D on the first communication device 100D side and the housing 290D on the second communication device 200D side are in contact with each other at a dotted line portion in the drawing. Although not specifically described, the same applies to the fourth application example (part 2).

  In the fourth application example (part 1), the antennas between the two systems of transmission and reception are coupled by a single millimeter wave signal transmission line 9_4. Functionally, the millimeter wave signal transmission line 9_1 forms a first communication channel, and the millimeter wave signal transmission line 9_2 forms a second communication channel that performs transmission in the opposite direction to the first communication channel. The Since it is the single millimeter wave signal transmission line 9_4, for example, the radio wave of the carrier frequency f1 of the millimeter wave signal transmission line 9_1 can be transmitted to the millimeter wave signal transmission line 9_2 side, and the carrier frequency f2 of the millimeter wave signal transmission line 9_2 Can be transmitted to the millimeter wave signal transmission line 9_1 side.

  For example, the semiconductor chip 103D of the first communication device 100D includes a transmission-side signal generation unit 110 and a reception-side signal generation unit 120, and the semiconductor chip 203D of the second communication device 200D includes a transmission-side signal generation unit 210 and A reception side signal generation unit 220 is provided.

  The transmission-side signal generation unit 110 includes a modulation function unit 8300 (frequency mixing unit 8302, transmission-side local oscillation unit 8304) and an amplification unit 8117. The amplification unit 8117 is connected to an antenna 136_1 that forms part of the transmission line coupling unit 108. Has been. The semiconductor chip 103D (transmission side signal generation unit 110) converts (modulates) the transmission target signal SIN_1 into a millimeter wave signal and emits the transmission signal Sout_1 from the antenna 136_1.

  The reception-side signal generation unit 220 includes an amplification unit 8224, a demodulation function unit 8400 (frequency mixing unit 8402, reception-side local oscillation unit 8404), and a low-pass filter 8412. The amplification unit 8224 is a part of the transmission line coupling unit 208. Is connected to the antenna 236_2. The semiconductor chip 203D (reception-side signal generation unit 220) restores (demodulates) the transmission target signal SOUT_1 (corresponding to SIN_1) from the reception signal Sin_1 (corresponding to Sout_1) received by the antenna 236_2. That is, the semiconductor chips 103D and 203D perform signal transmission in the millimeter wave band via the millimeter wave signal transmission path 9_4 (the millimeter wave signal transmission path 9_1) between the antennas 136_1 and 236_2.

  The transmission-side signal generation unit 210 includes a modulation function unit 8300 (frequency mixing unit 8302, transmission-side local oscillation unit 8304) and an amplification unit 8117. The amplification unit 8117 is connected to an antenna 136_2 that forms part of the transmission line coupling unit 108. Has been. The semiconductor chip 203D (transmission side signal generation unit 210) converts (modulates) the transmission target signal SIN_2 into a millimeter wave signal and emits the transmission signal Sout_2 from the antenna 136_2.

  The reception-side signal generation unit 120 includes an amplification unit 8224, a demodulation function unit 8400 (frequency mixing unit 8402, reception-side local oscillation unit 8404), and a low-pass filter 8412. The amplification unit 8224 is a part of the transmission line coupling unit 208. Is connected to the antenna 236_1. The semiconductor chip 103D (reception-side signal generation unit 120) restores (demodulates) the transmission target signal SOUT_2 (corresponding to SIN_2) from the reception signal Sin_2 (corresponding to Sout_2) received by the antenna 236_1. That is, the semiconductor chips 103D and 203D perform signal transmission in the millimeter wave band via the millimeter wave signal transmission path 9_4 (the millimeter wave signal transmission path 9_2) between the antennas 136_2 and 236_1.

  Here, in order to enable full-duplex bidirectional transmission, a different frequency is assigned as a reference carrier signal for each set of a transmission unit and a reception unit that perform signal transmission. For example, the first carrier frequency f1 is used in the set of the transmission side signal generation unit 110 and the reception side signal generation unit 220, and the second carrier frequency f2 is used in the set of the transmission side signal generation unit 210 and the reception side signal generation unit 120. (≠ f1) is used. By setting different carrier frequencies f1 and f2 for each communication channel, full duplex bidirectional transmission is realized without being affected by interference.

  For example, when the reception-side signal generation unit 120 of the semiconductor chip 103D receives the transmission signal Sout_2 (= reception signal Sin_2) having the carrier frequency f2 and is injection-synchronized, the transmission-side signal generation unit 110 has the carrier frequency f1. Assume that the transmission signal Sout_1 also arrives. In this case, the reception-side signal generation unit 120 does not perform injection locking to the carrier frequency f1, but performs synchronous detection using the regenerative carrier signal and passes through the low-pass filter 8412 so that the transmission signal Sout_1 having the carrier frequency f1 is received on the reception side. Even if the signal generation unit 120 performs demodulation processing, the component of the transmission target signal SIN_1 is not restored. That is, even if the reception-side signal generation unit 120 receives the modulation signal of the carrier frequency f1 while being injection-locked to the carrier frequency f2, it is not affected by the interference of the component of the carrier frequency f1.

  Further, when the reception-side signal generation unit 220 receives the transmission signal Sout_1 (= reception signal Sin_1) of the carrier frequency f1 and is injection-synchronized, the transmission signal Sout_2 of the carrier frequency f2 is also transmitted from the transmission-side signal generation unit 210 side. Suppose it has arrived. In this case, the reception-side signal generation unit 220 does not perform injection locking to the carrier frequency f2, but performs synchronous detection using the regenerative carrier signal and passes the low-pass filter 8412, thereby receiving the transmission signal Sout_2 of the carrier frequency f2 on the reception side. Even if the signal generation unit 220 performs demodulation processing, the component of the transmission target signal SIN_2 is not restored. That is, even if the reception-side signal generation unit 220 receives the modulation signal at the carrier frequency f2 while being injection-locked to the carrier frequency f1, it is not affected by the interference of the component at the carrier frequency f2.

  Also in the fourth application example (No. 2), one transmission unit and one reception unit are arranged in the semiconductor chip for bidirectional communication. The transmission unit and the reception unit each apply the above-described injection locking method. For example, the semiconductor chip 103D of the first communication device 100D includes a transmission-side signal generation unit 110 and a reception-side signal generation unit 120, and the semiconductor chip 203D of the second communication device 200D includes a transmission-side signal generation unit 210 and A reception side signal generation unit 220 is provided.

  In order to enable full-duplex bi-directional transmission, a different frequency is assigned as a reference carrier signal for each set of transmitting unit and receiving unit that performs signal transmission. For example, the first carrier frequency f1 is used in the set of the transmission side signal generation unit 110 and the reception side signal generation unit 220, and the second carrier frequency f2 is used in the set of the transmission side signal generation unit 210 and the reception side signal generation unit 120. Assume that (≠ f1) is used.

  The millimeter wave signal of the carrier frequency f1 generated by the transmission side signal generation unit 110 of the semiconductor chip 103D is transmitted to the antenna 136 via the circulator which is an example of the antenna switching unit of the transmission path coupling unit 108, and the millimeter wave signal transmission path 9_4. Is transmitted. The semiconductor chip 203D receives the millimeter wave signal transmitted through the millimeter wave signal transmission path 9_4 by the antenna 236 and supplies it to the reception-side signal generation unit 220 via the circulator which is an example of the antenna switching unit of the transmission path coupling unit 208. . The reception-side signal generation unit 220 generates a reproduction carrier signal that is injection-locked to the carrier frequency f1 used by the transmission-side signal generation unit 110 for modulation, and demodulates the received millimeter wave signal.

  Conversely, the millimeter wave signal of the carrier frequency f2 generated by the transmission side signal generation unit 210 on the semiconductor chip 203D side is transmitted to the antenna 236 via a circulator which is an example of the antenna switching unit of the transmission path coupling unit 208, and It is transmitted to the wave signal transmission line 9_4. The semiconductor chip 103D side receives the millimeter wave signal transmitted through the millimeter wave signal transmission path 9_4 by the antenna 136 and supplies it to the reception side signal generation section 120 via the circulator which is an example of the antenna switching section of the transmission path coupling section 108. To do. The reception-side signal generation unit 120 generates a reproduction carrier signal that is injection-locked with the carrier frequency f2 used by the transmission-side signal generation unit 210 for modulation, and demodulates the received millimeter wave signal.

  In the fourth application example (part 2), in the same manner as in the fourth application example (part 1), in the application of frequency division multiplexing using the two sets of carrier frequencies f1 and f2, in the same manner, Full duplex bidirectional communication for transmitting different signals can be realized without causing interference problems.

  DESCRIPTION OF SYMBOLS 1 ... Wireless transmission system, 9 ... Millimeter wave signal transmission line, 100 ... 1st communication apparatus, 101A ... Electronic device (main body side), 101K ... Image acquisition apparatus (an example of electronic device), 102, 202 ... Substrate, 103, 203 ... Semiconductor chip, 104, 204 ... LSI functional unit, 107, 207 ... Signal generation unit, 108, 208 ... Transmission path coupling unit, 109, 209 ... Connection connector, 110, 210 ... Transmission side signal generation unit, 113, 213 ... Multiplexing processing unit 114, 214 ... Parallel serial conversion unit 115,215 ... Modulation unit 116,216 ... Frequency conversion unit 117,217 ... Amplification unit 120,220 ... Reception side signal generation unit 124,224 ... amplifiers, 125,225 ... frequency converters, 126,226 ... demodulators, 127,227 ... serial / parallel converters, 128,228 ... unification processing , 190, 290 ... housing, 200 ... second communication device, 201A ... memory card (an example of an electronic device), 201K ... an image reproduction device (an example of an electronic device), 500 ... an imaging device (an example of an electronic device), 590 ... Case, 8110 ... Transmission side signal generation unit, 8220 ... Reception side signal generation unit, 8300 ... Modulation function unit, 8301 ... Modulation target signal processing unit, 8302 ... Frequency mixing unit, 8303 ... Frequency multiplication unit, 8304 ... Transmission Side local oscillator, 8306 ... reference carrier signal processor, 8307 ... phase amplitude adjuster, 8308 ... signal synthesizer, 8346 ... controller unit (may have function of injection locking adjuster), 8400 ... demodulator function unit, 8401: Frequency separation unit, 8402: Frequency mixing unit, 8404 ... Reception-side local oscillation unit, 8406 ... Phase amplitude adjustment unit, 8407 ... DC component suppression unit, 84 0 ... injection locking controller, 8442 ... injection locking detection unit, 8446 ... (which may have a function of injection locking adjuster) controller, 8500 ... differential negative resistance oscillator circuit, 8530 ... tank circuit

Claims (27)

A communication section for transmission;
A communication unit for reception;
With
The transmission communication unit and the reception communication unit are accommodated in the same electronic device casing, or the transmission communication unit is included in the first electronic device casing. And when the communication unit for reception is housed in a housing of the second electronic device, and the first electronic device and the second electronic device are arranged and integrated at a predetermined position. Wirelessly between the communication unit for transmission and the communication unit for reception between the communication unit for transmission in the first electronic device and the communication unit for reception in the second electronic device. The wireless signal transmission path that enables the information transmission by is formed,
The transmission communication unit is a first carrier signal generation unit that generates a modulation carrier signal. The radio signal transmission path generates a modulation signal by frequency-converting a transmission target signal using the modulation carrier signal. A first frequency conversion unit for sending to the reference signal, and a reference carrier signal processing unit for obtaining a reference carrier signal that contributes to generation of the demodulation carrier signal and sending it to the wireless signal transmission line,
The reference carrier signal processing unit places the reference carrier signal on an axis having a phase different from a modulation axis on which the transmission target signal of the modulation signal output from the first frequency conversion unit is placed,
The receiving communication unit generates a demodulation carrier signal that is synchronized with the modulation carrier signal when the reference carrier signal received via the wireless signal transmission path is injected. A radio transmission system comprising: a generation unit; and a second frequency conversion unit that frequency-converts a modulation signal received via the radio signal transmission path using the demodulation carrier signal. The radio transmission system according to claim 1, wherein the second carrier signal generation unit generates the demodulation carrier signal by injecting the reference carrier signal received via the radio signal transmission path. The second carrier signal generator is
A receiving-side local oscillator that generates an output signal synchronized with the injected reference carrier signal;
The phase of the demodulation carrier signal input to the second frequency conversion unit based on the output signal generated by the reception-side local oscillation unit is the phase of the modulation signal input to the second frequency conversion unit. A phase adjustment unit that adjusts the phase to match,
The wireless transmission system according to claim 2, comprising: The phase adjustment unit, when the reception-side local oscillation unit is operating in the injection locking mode, determines the phase of the injection-locked output signal of the reception-side local oscillation unit as an injection signal to the reception-side local oscillation unit. The radio transmission system according to claim 3, wherein adjustment is performed so as to cancel out a phase difference from an output signal when injection locking is performed. A communication section for transmission;
A communication unit for reception;
With
The transmission communication unit and the reception communication unit are accommodated in the same electronic device casing, or the transmission communication unit is included in the first electronic device casing. And when the communication unit for reception is housed in a housing of the second electronic device, and the first electronic device and the second electronic device are arranged and integrated at a predetermined position. Wirelessly between the communication unit for transmission and the communication unit for reception between the communication unit for transmission in the first electronic device and the communication unit for reception in the second electronic device. The wireless signal transmission path that enables the information transmission by is formed,
The transmission communication unit is a first carrier signal generation unit that generates a modulation carrier signal. The radio signal transmission path generates a modulation signal by frequency-converting a transmission target signal using the modulation carrier signal. A first frequency conversion unit for sending to the reference signal, and a reference carrier signal processing unit for obtaining a reference carrier signal that contributes to generation of the demodulation carrier signal and sending it to the wireless signal transmission line,
The receiving communication unit generates a demodulation carrier signal that is synchronized with the modulation carrier signal when the reference carrier signal received via the wireless signal transmission path is injected. A generator, and a second frequency converter that converts the frequency of the modulated signal received via the wireless signal transmission path with the demodulation carrier signal,
The second carrier signal generator is
A receiving-side local oscillator that generates an output signal synchronized with the injected reference carrier signal;
The phase of the demodulation carrier signal input to the second frequency conversion unit based on the output signal generated by the reception-side local oscillation unit is the phase of the modulation signal input to the second frequency conversion unit. A phase adjustment unit that adjusts the phase to match,
Have
The phase adjustment unit, when the reception-side local oscillation unit is operating in an amplifier mode, outputs a phase of an output signal of a component of the reference carrier signal of the reception-side local oscillation unit as a modulation axis on which the transmission target signal is placed. And a wireless transmission system that adjusts so as to cancel out the phase difference between the reference carrier signal and the axis on which the reference carrier signal is placed. The wireless transmission system according to any one of claims 1 to 5, wherein the transmission communication unit and the reception communication unit are formed on a semiconductor substrate having a CMOS configuration. The reception communication unit includes an injection locking control unit that controls an injection voltage and a free-running oscillation frequency of the reception-side local oscillation unit so that injection locking can be achieved. The wireless transmission system described. The transmission communication unit includes a reference carrier signal processing unit that acquires a reference carrier signal that contributes to generation of the demodulation carrier signal synchronized with the modulation carrier signal, and sends the reference carrier signal to the radio signal transmission path. ,
6. The radio transmission according to claim 1, wherein the second carrier signal generation unit generates the demodulation carrier signal by injecting the modulation signal received via the radio signal transmission path. 7. system. The radio according to claim 8, wherein the reception communication unit includes a DC component suppression unit that suppresses a DC component caused by the reference carrier signal included in the demodulated signal output from the second frequency conversion unit. Transmission system. The second carrier signal generator is
A reception-side local oscillation unit that generates an output signal synchronized with the injected modulation signal;
When the reception-side local oscillating unit is operating in the injection locking mode, the phase of the injection-locked output signal of the reception-side local oscillating unit is set to the output signal when the injection-locking is performed and to the reception-side local oscillating unit. A phase adjustment unit for adjusting so as to cancel out the phase difference from the injection signal;
10. The wireless transmission system according to claim 8 or 9, comprising: The transmission communication unit includes a modulation target signal processing unit that suppresses a DC vicinity component of the transmission target signal to be modulated,
The first frequency conversion unit generates the modulation signal by frequency-converting the processed signal processed by the modulation target signal processing unit with the modulation carrier signal generated by the first carrier signal generation unit The wireless transmission system according to any one of claims 1 to 10. The wireless transmission system according to claim 11, wherein the modulation target signal processing unit performs DC-free encoding on the digital transmission target information. The communication unit for reception includes an injection locking detection unit that detects information indicating an injection locking state in the second carrier signal generation unit,
At least one of the communication unit for transmission and the communication unit for reception is generated by the second carrier signal generation unit based on information indicating the state of injection locking detected by the injection locking detection unit 13. An injection locking adjustment unit that performs synchronization adjustment so that a demodulation carrier signal is synchronized with a modulation carrier signal generated by the first carrier signal generation unit. The wireless transmission system according to item. The injection locking adjustment unit changes at least one of the amplitude of the signal injected into the second carrier signal generation unit and the frequency of the output signal at the time of free-running oscillation of the second carrier signal generation unit, The wireless transmission system according to claim 13, wherein the synchronization adjustment is performed. The injection locking adjustment unit changes the synchronization by changing at least one of a frequency of a modulation carrier signal generated by the first carrier signal generation unit and an amplitude of a signal transmitted to the radio signal transmission path. The wireless transmission system according to claim 13, wherein adjustment is performed. The wireless transmission system according to any one of claims 1 to 15, wherein the wireless signal transmission path has a structure for transmitting a wireless signal while confining the wireless signal in the transmission path. The wireless transmission system according to claim 16, wherein the wireless signal transmission path includes a waveguide. The wireless transmission system according to claim 16, wherein the wireless signal transmission path is made of a dielectric material. The carrier signal generation unit includes an oscillation circuit including a tank circuit,
The wireless transmission system according to any one of claims 1 to 18, wherein the entire oscillation circuit including the tank circuit is formed on the same semiconductor substrate. The wireless transmission system according to any one of claims 1 to 19, wherein the second frequency conversion unit restores the transmission target signal by performing the frequency conversion by synchronous detection. The transmission target signal is a baseband signal,
The radio transmission system according to any one of claims 1 to 20, wherein the first frequency conversion unit obtains a modulation signal by directly frequency-converting the baseband signal with a millimeter-wave band carrier signal. A carrier signal generation unit that generates a carrier signal in the demodulation millimeter wave band that is synchronized with the carrier signal in the modulation millimeter wave band by injecting a signal for synchronous injection received via the wireless signal transmission path. When,
A frequency converter that converts the frequency of the modulated signal in the millimeter wave band received via the wireless signal transmission path by the carrier signal in the millimeter wave band for demodulation generated by the carrier signal generator;
With
The carrier signal generation unit generates a carrier signal in the millimeter wave band for demodulation by injecting a reference carrier signal received via the wireless signal transmission path,
A receiving-side local oscillator that generates an output signal synchronized with the injected reference carrier signal;
The phase of the demodulation millimeter-wave band carrier signal input to the frequency converter based on the output signal generated by the reception-side local oscillator matches the phase of the modulation signal input to the frequency converter. A phase adjustment unit for performing phase adjustment as described above,
Have
The phase adjustment unit, when the reception-side local oscillation unit is operating in an amplifier mode, sets the phase of the output signal of the reference carrier signal component of the reception-side local oscillation unit as a modulation axis on which a transmission target signal is placed. A wireless communication apparatus that adjusts so as to cancel out a phase difference from an axis on which the reference carrier signal is placed. The carrier signal generation unit includes an oscillation circuit including a tank circuit,
The radio communication apparatus according to claim 22, wherein the entire oscillation circuit including the tank circuit and the frequency converter are formed on the same semiconductor substrate. A carrier signal generator for generating a millimeter-wave band carrier signal for modulation;
A frequency conversion unit for generating a millimeter-wave band modulation signal by frequency-converting a transmission target signal with a carrier signal for modulation generated by the carrier signal generation unit;
A reference carrier signal processing unit that acquires a reference carrier signal that contributes to generation of a demodulation carrier signal and sends it to a wireless signal transmission path;
And sending the modulated signal including a signal for synchronous injection to a wireless signal transmission path,
The wireless communication apparatus, wherein the reference carrier signal processing unit places the reference carrier signal on an axis having a phase different from a modulation axis on which the transmission target signal of the modulation signal output from the frequency converter is placed. The carrier signal generation unit includes an oscillation circuit including a tank circuit,
The radio communication apparatus according to claim 24, wherein the entire oscillation circuit including the tank circuit and the frequency conversion unit are formed on the same semiconductor substrate. Arrange the communication unit for transmission and the communication unit for reception in the housing of the electronic device,
Between the communication unit for transmission and the communication unit for reception, configure a wireless signal transmission path capable of wireless information transmission,
In the communication unit for transmission, the transmission target signal is frequency-converted with a modulation carrier signal to generate a modulation signal, and the generated modulation signal is sent to the radio signal transmission path, and the demodulation carrier signal Obtaining a reference carrier signal that contributes to the generation, and sending the obtained reference carrier signal to the radio signal transmission path on an axis having a phase different from the modulation axis on which the transmission target signal of the modulation signal is placed,
The receiving communication unit injects the reference carrier signal received via the radio signal transmission path to generate a demodulation carrier signal synchronized with the modulation carrier signal, and the radio signal transmission path A radio communication method for demodulating the transmission target signal by frequency-converting the modulated signal received via the frequency with the demodulation carrier signal. Arrange the communication unit for transmission and the communication unit for reception in the housing of the electronic device,
Between the communication unit for transmission and the communication unit for reception, configure a wireless signal transmission path capable of wireless information transmission,
In the communication unit for transmission, the transmission target signal is frequency-converted with a modulation carrier signal to generate a modulation signal, and the generated modulation signal is sent to the radio signal transmission path, and the demodulation carrier signal Obtaining a reference carrier signal that contributes to the generation, and sending the obtained reference carrier signal to the radio signal transmission path on an axis having a phase different from the modulation axis on which the transmission target signal of the modulation signal is placed,
In the communication unit for reception, the reference carrier signal received via the wireless signal transmission path is injected to generate a demodulation carrier signal synchronized with the modulation carrier signal,
Phase adjustment is performed so that the phase of the demodulation carrier signal based on the signal synchronized with the reference carrier signal generated by the reception-side local oscillation unit matches the phase of the modulation signal,
In the phase adjustment, when the reception-side local oscillation unit is operating in an amplifier mode, the phase of the component of the reference carrier signal of the reception-side local oscillation unit is changed to a modulation axis on which the transmission target signal is placed and the phase Adjust to offset the phase difference from the axis on which the reference carrier signal is placed,
A radio transmission system for demodulating the transmission target signal by frequency-converting the modulated signal received via the radio signal transmission path with the demodulation carrier signal.

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