JP4907423B2 - Transmitter - Google Patents

Description

The present invention relates to transmission equipment, about the particular transmission equipment which performs radio communication.

In recent years, the demand for mobile communication services such as mobile phones is rapidly increasing, and the importance of wireless communication technology is increasing in the advanced information society.
As a basic method of wireless communication, on the transmitter side, an IF (Intermediate Frequency) signal modulated by information is mixed with a local oscillation signal oscillated from a local oscillator to increase the frequency, and RF (Radio) Frequency) signal is generated and transmitted from the antenna.

  On the receiver side, the RF signal received by the antenna is mixed with the local oscillation signal oscillated from the local oscillator and returned to the IF signal again. In this case, it is a premise of communication that the local signals used by the transmitter and the receiver have the same frequency.

  FIG. 17 is a diagram showing a conventional wireless communication system. The wireless communication system 300 includes a transmitter 600 and a receiver 700. The transmitter 600 includes a mixer 601, a local oscillator 602, an amplifier 603, and an antenna 604, and the receiver 700 includes an antenna 704, an amplifier 703, a mixer 701, and a local oscillator 702.

For the transmitter 600, the mixer 601 multiplies the input IF signal IF _in (modulated wave of frequency f _IF ) by the local oscillation signal Loa (frequency f _L ) oscillated from the local oscillator 602, and the frequency f _RF. An RF signal of (= f _IF + f _L ) is output. Then, after being amplified by the amplifier 603, it is emitted from the antenna 604 into the air as radio waves.

The receiver 700 receives the RF signal transmitted from the transmitter 600 by the antenna 704 and amplifies it by the amplifier 703. The mixer 701 multiplies the amplified signal and a local oscillation signal Lob (the same frequency f _{L as that} on the transmission side) oscillated from the local oscillator 702, and a frequency f _IF (= f _RF −f _L = (f _IF + F _L ) −f _L ) IF signal IF _out .

Thus, in order for the IF signal IF _out output from the mixer 701 to be the same signal as the IF _in sent from the transmitter 600 and communication be established, local oscillators possessed by the transmitter 600 and the receiver 700 respectively. The condition is that the frequencies of the local signals Loa and Lob of 602 and 702 match. For this reason, a highly stable and low phase noise oscillator to which a PLL (Phase-Locked Loop) circuit or the like is added is often used as the local oscillator.

  On the other hand, in the field of wireless communication in recent years, the application of the millimeter wave band (frequency range from 30 GHz to 300 GHz) and a slightly lower quasi-millimeter wave band has attracted attention. In particular, in order to realize advanced wireless short-range communication represented by ITS (Intelligent Transport Systems) such as inter-vehicle communication and wireless LAN, it is possible to widen the bandwidth (capable of large-capacity communication). The use of the millimeter wave band, which is almost unused, is considered promising. In addition, there are many calls for downsizing and cost reduction of consumer devices that perform such millimeter-wave band wireless communication.

  However, in the conventional wireless communication system 300 as described above, a local oscillator having a local oscillation signal up to about 3 GHz can secure the stability necessary for communication relatively easily. When the transmitter and the receiver to be performed are targeted, there is a problem that it is difficult to always stably operate the local oscillation signal in the millimeter wave frequency domain with high accuracy.

  That is, it is difficult to develop a frequency divider and phase comparator for configuring a PLL circuit added to an oscillator (VCO: Voltage Controlled Oscillator) exceeding 30 GHz. There is currently no small, inexpensive, and highly accurate VCO.

  Further, even if a signal source that is stably oscillated at about several GHz is controlled to be raised to a desired frequency by a multiplier, there is a problem that phase noise increases and normal communication cannot be realized.

The present invention has been made in view of these points, and an object thereof is to provide a transmission apparatus that performs highly accurate and highly stable wireless communication .

To solve the above SL problems, as shown in FIG. 1, the transmitter 10 and the receiver 20 is provided. Here, the transmitting apparatus 10 mixes the first signal wave that is an information signal and the second signal wave that is an unmodulated wave with a carrier wave signal, and the first signal wave and the second signal wave are mixed at a radio frequency. Send. The second signal wave has a different frequency from the first signal wave. The receiving device 20 mixes the radio frequencies of the first signal wave and the second signal wave. On the receiving device 20 side, the Δf component including the frequency shift and phase noise included in the radio frequency is canceled out, and the unstable component on the transmitting device 10 side is removed to extract information.

  The transmission apparatus of the present invention includes a transmission mixer that mixes a first signal wave modulated by an information signal and a second signal wave that is an unmodulated wave with a carrier wave signal, and the first signal wave and the second signal Waves are transmitted at a radio frequency. Thereby, highly accurate and highly stable wireless communication can be performed.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a principle diagram of a transmission device and a reception device (wireless communication system). As shown in the figure, on the transmitting apparatus 10 side, a first signal wave that is an information signal and a second signal wave that is an unmodulated wave are mixed with a carrier wave signal. As a result, the first signal wave and the second signal wave are transmitted at radio frequencies, and each radio frequency includes Δf. Δf represents an unstable part of the frequency including frequency shift and phase noise. In the receiving device 20, by mixing the radio frequencies of the first signal wave and the second signal wave, the Δf component is canceled and the unstable component on the transmitting device 10 side is removed.

  In this figure, the component demodulated by the receiving device 20 is s1-s2, but the second signal wave s2 is an unmodulated wave, so that it is easy to correct on the receiving device 20 side. For example, an oscillator corresponding to s2 may be used.

  In this way, the first signal wave and the second signal wave (unmodulated) are each mixed by the carrier wave, and on the receiving side, the radio signal waves of the first signal wave and the second signal wave are mixed to extract the difference component. It is a configuration. Therefore, on the receiving side, the frequency difference component extracted by the mixing only shows a difference from the known second signal wave, so that the user can use this as it is (or the second signal). It is also possible to reproduce the first signal wave by a method other than mixing with the wave).

Next, the configuration and operation will be described in detail. FIG. 2 is a configuration diagram of a transmission device and a reception device (wireless communication system). A modulation signal IF1 having a first intermediate frequency (= f _IF1 ) including transmission information is input to the first terminal 11a to the transmission device 10. The second terminal 11b receives a sine wave signal IF2 having a constant period of the second intermediate frequency (= f _IF2 ).

The transmitting local oscillator 12 oscillates a transmitting station originating signal Lo1. The transmission mixer 13 mixes the modulation signal IF1 and the sine wave signal IF2 with the transmission station-generated signal Lo1 and up-converts the signal to the RF band to generate radio frequency signals RF1 (= frequency f _RF1 ) and RF2 (= frequency f _RF2 ). Two signals are generated. The arithmetic expression is expressed by the following expressions (1a) and (1b).

  The transmission amplifier 14 amplifies these radio frequency signals RF1 and RF2. The amplified radio frequency signals RF1 and RF2 are emitted from the transmission antenna 15 as two radio waves.

The reception antenna 25 receives two radio waves from the reception device 20, and the reception amplifier 24 amplifies the received signal.
The reception local oscillator 22 oscillates a reception local signal Lo2 having the same frequency (= f _IF2 ) as the second intermediate frequency of the sine wave signal IF2 used in the transmission device 10. The receiving mixer 23 mixes the radio frequency signals RF1 and RF2 amplified by the receiving amplifier 24 with the receiving station-generated signal Lo2, down-converts it, and reproduces the modulated signal IF1 including transmission information.

  In this example, the intermediate frequency signal is mixed with the carrier wave, but the intermediate frequency signal (the original signal (= baseband signal) mixed with the intermediate frequency signal) is not a baseband signal. You may use it.

  Next, the operation (wireless communication method) will be described in detail. In the following, millimeter wave wireless communication (that is, on the transmitting side, the local frequency signal in the millimeter wave frequency unit is mixed with the IF signal of the intermediate frequency including the information, and the radio wave in the RF band is transmitted. It is assumed that the present invention is applied to (demodulated wireless communication).

With respect to the transmission apparatus 10, the transmission local oscillator 12 is an oscillator that oscillates a transmission local signal Lo1 in the millimeter wave band (= f _Lo ). The transmission local oscillator 12 need not be stabilized with PLL or the like.

Therefore, the actual frequency component of the transmitting station originating signal Lo1 is f _LO ± Δf. Δf represents an unstable portion of the frequency including frequency deviation, phase noise, and the like (the frequency unstable portion Δf is output to a high-frequency oscillator that is not subjected to stabilization control).

Furthermore, through each of the terminals of the first terminal 11a and second terminal 11b, and the modulation signal IF1 of the intermediate frequency f _IF1, and the sine wave signal IF2 intermediate frequency f _IF2 is input. Thereafter, the transmission mixer 13 multiplies each of the modulation signal IF1 and the sine wave signal IF2 by the transmission station originating signal Lo1.

Then, from the transmission mixer 13, a radio frequency signal RF2 radio frequency signals RF1 and the radio frequency f _RF2 radio frequency f _RF1 is output. The frequencies f _RF1 and f _RF2 are expressed by the following equations.
f _RF1 = f _IF1 + f _LO ± Δf (1a)
f _RF2 = f _IF2 + f _LO ± Δf (1b)
Thereafter, the radio frequency signals RF <b> 1 and RF <b> 2 are amplified by the transmission amplifier 14 and emitted as radio waves through the transmission antenna 15. Here, the output from the transmission mixer 13 is actually an image signal and a leakage signal from the transmission local oscillator 12 in addition to the radio frequency signals RF1 and RF2 described above. Depending on the feature, it can be easily excluded by a bandpass filter (described later in FIG. 5).

On the other hand, the radio frequency signals RF <b> 1 and RF <b> 2 are received by the receiving antenna 25 and amplified by the receiving amplifier 24 with respect to the receiving device 20. The receiving local oscillator 22 oscillates a receiving station originating signal Lo2 having the same frequency (= f _IF2 ) as the sine wave signal IF2. Thus, the receiving device 20 does not require a millimeter-wave band local oscillator and is provided with a low-frequency oscillator.

The receiving mixer 23 mixes the receiving station originating signal Lo2 with the radio frequency signals RF1 and RF2. Then, a signal having a frequency component of (f _RF1 −f _RF2 + f _IF2 ) is output from the reception mixer 23. This frequency component is
f _RF1 −f _RF2 + f _IF2 = (f _IF1 + f _LO ± Δf) − (f _IF2 + f _LO ± Δf)
+ F _IF2
= _{FIF1- fIF2} + _fIF2
= F _IF1 (2)
It becomes. As can be seen from the equation (2), Δf which is included in the transmission station originating signal Lo1 of the transmission device 10 and hinders communication is excluded. Further, it is seen that only the modulated signal IF1 (= f _IF1 ) including the transmission information is output from the reception mixer 23 because it is multiplied by the reception station originating signal Lo2 signal of the frequency f _IF2 .

  Thus, in addition to the IF signal including the transmission information, an IF signal serving as a reference signal is further added to perform communication control, thereby realizing efficient millimeter-wave band wireless communication. Therefore, it is not necessary to pursue the high stability that has been required for millimeter-wave band oscillators until now, and the circuit can be simplified and the cost can be reduced.

  In the above description, a single first terminal 11a is provided and a modulated signal including one piece of transmission information is transmitted. However, a plurality of pieces of transmission information may be transmitted by providing a plurality of first terminals. it can.

  For example, two first terminals 11a-1 and 11a-2 are provided, the first terminal 11a-1 receives the modulation signal IF1-1 including audio information, and the first terminal 11a-2 receives image information. The modulated signal IF1-2 is received. Then, by applying the control described above to each of the modulation signals IF1-1 and IF1-2, transmission control of two pieces of transmission information can be performed.

  Next, the difference between the present invention and the prior art will be described. In the present invention, a technique is used in which a signal of two waves is transmitted from the transmission side and the two waves are added on the reception side. A similar technique is reported in "A Study on Millimeter-wave Communication System Using Self-Heterodyne Detection" 1999 IEICE Communication Society, B-5-135.

FIG. 3 is a diagram showing the configuration of the prior art. (A) is the transmitter 400, and (B) is the receiver 500. The conventional self-heterodyne detection method up- _converts a modulation signal IFa having an intermediate frequency (= f _IFa ) with respect to a transmitter 400 using a local oscillation signal having a high frequency f _L oscillated from a local oscillator 402. The signal RFa is output and emitted from the antenna (vertically polarized wave) 404a through the filter 403. At the same time, a carrier wave (hereinafter, a leak signal of the local oscillator signal is referred to as a carrier wave) La, which is a part of the local oscillator signal, is emitted from an antenna (horizontal polarization) 404b having orthogonal polarization.

  On the other hand, after receiving radio waves with the antenna 500 (vertically polarized wave) 504a and antenna (horizontal polarized wave) 504b whose polarizations are orthogonal to each other, the receiver 500 receives amplifiers 505a and 505b, a filter 503a, The signal passes through 503b and is input to the mixer 501. The mixer 501 outputs the frequency component of the difference component between the two input signals by multiplying the two input signals (the radio frequency signal RFa and the carrier wave La). Thereby, the original modulation signal IFa can be obtained.

  Here, the receiver 500 does not need a millimeter wave band oscillator. Further, it is proposed that the phase noise (corresponding to Δf described above) due to the local oscillation signal is removed because the carrier La, which is a leak signal of the local oscillation signal used in the transmitter 400, is down-converted by the mixer 501. ing. However, there is a problem that it is difficult to realize such a conventional technology as a low-priced and compact product in the following points.

In general, when an IF signal (= f _IF ) is up-converted by a local oscillator signal (= f _Lo ) by a mixer, a signal output from the mixer leaks from an RF signal (= f _IF + f _Lo ) and a local oscillator. A carrier wave (= f _Lo ) and an image signal (= f _Lo −f _IF ) are output.

  In the prior art system, it is necessary to emit the carrier wave and the RF signal from the antenna and not the image signal. As a typical method for not emitting the image signal, blocking by a filter is performed.

  FIG. 4 is a diagram showing a frequency arrangement image of the prior art. The vertical axis represents signal intensity, and the horizontal axis represents frequency. Here, the 60 GHz band that allows the most occupied band in the millimeter wave band (the 60 GHz band has physical characteristics in which interference is unlikely to occur, and is expected to be used by various wireless systems with large capacity and low cost. For example, the RF band per channel is defined as 2.5 GHz by the Radio Law.

  Therefore, when the conventional technology is applied to 60 GHz band wireless communication, two waves of the carrier wave La and the radio frequency signal RFa are transmitted. Therefore, the carrier wave La and the radio frequency signal RFa are included in the RF bandwidth of 2.5 GHz. I have to put it in. In this case, an image signal of the radio frequency signal RFa appears at a symmetrical position with respect to the carrier wave La that is a local oscillation signal.

  For example, when the modulation signal IFa is transmitted by a local oscillation signal having a frequency of 59.0 GHz, the intermediate frequency of the modulation signal IFa must be 2.5 GHz or less. Accordingly, when the modulation signal IFa of 2.45 GHz is used, the RF band between the carrier wave La and the radio frequency signal RFa is a 2.5 GHz band between 59.0 GHz and 61.5 GHz. In this case, the image signal appears between 56.5 GHz and 58.95 GHz.

  In the prior art, since the carrier wave La is included in the RF band, an image signal appears at a position very close to the RF band as shown in the figure. Therefore, in order to remove this image signal, it is essential to use a waveguide filter with good characteristics. However, the waveguide filter is expensive and large, and therefore, the conventional technology is reduced in price and size. For example, it is difficult to realize as a product such as a semiconductor device.

  FIG. 5 is a diagram showing an arrangement image of frequencies according to the present invention. The vertical axis represents signal intensity, and the horizontal axis represents frequency. In the present invention, two waves of the radio frequency signals RF1 and RF2 are included in the RF band of 2.5 GHz.

  For example, in the case of transmitting a transmission station signal Lo1 having a frequency of 59.0 GHz, a sine wave signal IF2 having an intermediate frequency of 4 GHz, and a modulation signal IF1 having an intermediate frequency of 5.1 GHz, the radio frequency signal RF2 and the radio frequency signal RF1 The RF band in between is a 2.5 GHz band between 63.0 GHz and 65.5 GHz. In this case, the image signal appears between 52.5 GHz and 55.0 GHz.

  In the present invention, the position of the transmission station originating signal Lo1 used when performing up-conversion can be arranged at a position away from the RF band. Then, the image signals of the radio frequency signals RF1 and RF2 and the carrier wave that is the leakage signal of the transmission station Lo1 appearing symmetrically with respect to the transmission station oscillation signal Lo1 are also separated from the RF band in which the actual signal is transmitted. (In the figure, the local oscillation signal and the RF band are separated by 4 GHz as an example, but can be separated further).

  For this reason, these image signals and carrier waves can be suppressed by a band-pass filter having normal characteristics. For example, by using a planar filter realized by a planar circuit on a dielectric substrate, it is possible to sufficiently remove these carrier waves and image signals.

  Therefore, by applying the transmission device of the present invention to millimeter-wave band wireless communication such as 60 GHz, an expensive and large filter such as a waveguide filter is not required, and it is miniaturized with high accuracy and low cost. Product can be realized.

  Next, the operation will be described using specific numerical values. FIG. 6 is a diagram illustrating a configuration of the transmission apparatus according to the first embodiment. The transmission apparatus 10-1 includes a first terminal 11a, a second terminal 11b, a transmission local oscillator 12, a transmission mixer 13, a transmission filter 16, a transmission amplifier 14, and a transmission antenna 15.

  Here, the transmission local oscillator 12, the transmission mixer 13, and the transmission amplifier 14 are configured by an MMIC (Microwave Monolithic IC) made on the same substrate. The transmission filter 16 is a flat filter made by forming a conductive film on a ceramic substrate, and the transmission antenna 15 is a flat antenna made by forming a conductive film on a quartz substrate. The first terminal 11a and the second terminal 11b correspond to external terminals.

A 156 Mbps, 4PSK modulated signal IF1 (f _IF1 = 5.1 GHz) is input to the transmission device 10-1 through the first terminal 11a. Further, a sine wave signal IF2 (f _IF2 = 4.0 GHz) is input from the second terminal 11b.

The transmission local oscillator 12 oscillates a transmission local signal Lo1 (f _Lo1 = 56.0 ± Δf _T GHz) (since the transmission local oscillator 12 is not subjected to frequency stabilization such as PLL, the frequency of Δf _T It has a fluctuation component). Then, the transmission mixer 13 mixes the modulation signal IF1, the sine wave signal IF2, and the transmission station originating signal Lo1.

The mixed radio frequency signal becomes a radio frequency signal RF1 (f _RF1 = 61.1 ± Δf _T GHz) and a radio frequency signal RF2 (f _RF2 = 60.0 ± Δf _T GHz). At the same time, a carrier wave that is a leakage signal of the two image signal waves (50.9 ± Δf _T GHz, 52.0 ± Δf _T GHz) and the transmitting station originating signal Lo1 is output.

  These image signal and carrier wave are sufficiently suppressed by the transmission filter 16 as described above with reference to FIG. The transmission amplifier 14 amplifies the output signal from the transmission filter 16 to, for example, 10 dBm. The transmission antenna 15 emits the amplified radio frequency signals RF1 and RF2 into the air.

  FIG. 7 is a diagram illustrating the configuration of the receiving apparatus according to the first embodiment. The reception device 20-1 includes a reception antenna 25, a reception amplifier (LNA: Low Noise Amplifier) 24, a reception mixer 23, and a reception local oscillator 22.

  Here, the reception local oscillator 22, the reception mixer 23, and the reception amplifier 24 are configured by MMICs formed on the same substrate. The receiving antenna 25 is a planar antenna made by forming a conductive film on a quartz substrate.

For the receiving device 20-1, the radio frequency signals RF 1 and RF 2 are received by the receiving antenna 25 and amplified by the receiving amplifier 24. The reception local oscillator 22 oscillates a reception local signal Lo2 (f _Lo2 = f _IF2 = 4.0 GHz) having the same frequency as the sine wave signal IF2 on the transmission side.

The receiving mixer 23 mixes the radio frequency signals RF1 and RF2 and the receiving station originating signal Lo2. The calculation formula is shown below.
RF1−RF2 + Lo2 = f _RF1 −f _RF2 + f _Lo2
= (61.1 ± Δf _T ) − (60.0 ± Δf _T ) +4.0
= 5.1 GHz (= f _IF1 ) (3)
Therefore, the information of the original modulation signal IF1 (156 Mbps, 4PSK) is output from the reception mixer 23.

Next, a second embodiment will be described. FIG. 8 is a diagram illustrating the configuration of the receiving apparatus according to the second embodiment. Since the transmission apparatus has the same configuration as that of the first embodiment, description thereof is omitted.
The receiving device 20-2 according to the second embodiment includes a receiving antenna 25, a receiving amplifier 24, a difference component detection mixer 26, a receiving mixer 23, and a receiving local oscillator 22.

  Radio frequency signals RF1 and RF2 input from the reception antenna 25 are amplified by the reception amplifier 24 and input to the difference component detection mixer 26. The difference component detection mixer 26 detects and outputs the difference components of the radio frequency signals RF1 and RF2, as shown in the following equation (4).

_{RF1-RF2 = f RF1 -f RF2} = (61.1 ± Δf T) - (60.0 ± Δf T)
= 1.1GHz (4)
As can be seen from Equation (4), the frequency fluctuation component Δf _T due to the transmission local oscillator 12 on the transmission side is first removed by the difference component detection mixer 26. Thereafter, the output signal of the difference component detection mixer 26 is input to the reception mixer 23, and is up-converted by a signal from the reception-station-derived signal Lo2 having the same frequency as that of the sine wave signal IF2 on the transmission side. IF1 (156 Mbps, 4PSK) is output. As described above, in the second embodiment, the processing load is distributed by further mixing after dropping to a low frequency.

Next, a third embodiment will be described. FIG. 9 is a diagram illustrating a configuration of a receiving apparatus according to the third embodiment. Since the transmission apparatus has the same configuration as that of the first embodiment, description thereof is omitted.
The receiving apparatus 20-3 of the third embodiment includes a receiving antenna 25, a receiving amplifier 24, a difference component detecting mixer 26, a receiving mixer 23, a receiving local oscillator 22, a level detecting means 27a, a gain adjusting means (auto gain controller). 27b.

  Radio frequency signals RF1 and RF2 input from the reception antenna 25 are amplified by the reception amplifier 24 and input to the difference component detection mixer 26. On the other hand, in the third embodiment, the level detection means 27a detects the level of the output signal from the reception amplifier 24 and transmits the detection signal to the gain adjustment means 27b.

  Then, the gain adjusting unit 27b adjusts the output gain of the reception amplifier 24 based on this detection signal so that the mixing conversion efficiency of the difference component detection mixer 26 is maximized. By performing such control, it is possible to realize more accurate processing. Since the output from the difference component detection mixer 26 is the same as that of the second embodiment, the description thereof is omitted.

  In the second and third embodiments, the post-processing of the difference component detection mixer 26 is mixed to generate the intermediate frequency modulation signal IF1 as the output of the receiver 20-3. The difference component (1.1 GHz) detected in step 1 includes information, and this may be used as the output of the receiving device 20-3 as it is.

Next, a fourth embodiment will be described. FIG. 10 is a diagram illustrating a configuration of a receiving apparatus according to the fourth embodiment. Since the transmission apparatus has the same configuration as that of the first embodiment, description thereof is omitted.
The receiving device 20-4 of the fourth embodiment includes a receiving antenna 25, a receiving amplifier 24, a pre-stage side frequency converting means 28, a receiving filter 29, a receiving mixer 23, and a receiving local oscillator 22. The pre-stage side frequency conversion means 28 includes a pre-stage mixer 28a and a conversion local oscillator 28b.

The radio frequency signals RF1 and RF2 input from the receiving antenna 25 are amplified by the receiving amplifier 24. The conversion local oscillator 28b oscillates a local oscillation signal having the same frequency of 56.0 GHz as the transmission local oscillator 12 on the transmission side. However, since stabilization is not performed by the PLL, the oscillation frequency f _Lo3 of the local oscillation signal _Lo3 is 56.0 ± Δf _R (Δf _R is a frequency fluctuation component of the conversion local oscillator 28b).

The front-stage mixer 28a mixes the radio frequency signals RF1 and RF2 and the local oscillation signal Lo3 and outputs down-converted signals of 5.1 ± Δf _T ± Δf _R GHz and 4.0 ± Δf _T ± Δf _R GHz. appear. The conversion local oscillator 28b generates constant power that maximizes the mixing conversion efficiency of the front-stage mixer 28a.

Thereafter, after the unnecessary wave is suppressed by the reception filter 29, the reception mixer 23 transmits the signal of 5.1 ± Δf _T ± Δf _R GHz, the signal of 4.0 ± Δf _T ± Δf _R GHz, and the reception station transmission. Mix with Lo2. The arithmetic expression is shown in the following expression (5).

(5.1 ± Δf _T ± Δf _R ) − (4.0 ± Δf _T ± Δf _R ) + f _IF2
= 1.1 + 4.0 = 5.1 GHz (5)
As a result, the information of the modulation signal IF1 (156 Mbps, 4PSK) is output from the reception mixer 23.

  Next, a fifth embodiment will be described. FIG. 11 is a diagram illustrating the configuration of the transmission apparatus according to the fifth embodiment. The transmission device 10-5 includes a first terminal 11a, a transmission local oscillator 12a, a first transmission mixer 13a, a second transmission mixer 13b, a transmission local oscillator 12b, a transmission filter 16, a transmission amplifier 14, and a transmission antenna 15. The

The transmitting local oscillator 12a oscillates a local oscillation signal _{IF2 of} 4.0 GHz (= f _IF2 ). Also, a 156 Mbps, 4PSK modulation signal IF1 (f _IF1 = 1.1 GHz) is input from the first terminal 11a. The first transmission mixer 13a mixes the modulation signal IF1 and the local oscillation signal IF2, and generates an intermediate frequency signal IF1a up-converted to 5.1 GHz.

The transmission local oscillator 12b oscillates a transmission local signal Lo1 (f _Lo1 = 56.0 ± Δf _T GHz) (since the transmission local oscillator 12 is not subjected to frequency stabilization such as PLL, the frequency of Δf _T It has a fluctuation component). Then, the second transmission mixer 13b mixes the intermediate frequency signal IF1a, the local oscillation signal IF2, and the transmission local oscillation signal Lo1.

The mixed radio frequency signal becomes a radio frequency signal RF1 (f _RF1 = 61.1 ± Δf _T GHz) and a radio frequency signal RF2 (f _RF2 = 60.0 ± Δf _T GHz). At the same time, a carrier wave that is a leakage signal of the two image signal waves (50.9 ± Δf _T GHz, 52.0 ± Δf _T GHz) and the transmitting station originating signal Lo1 is output.

  These image signals and carrier waves are sufficiently suppressed by the transmission filter 16. The transmission amplifier 14 amplifies the output signal from the transmission filter 16. The transmission antenna 15 emits the amplified radio frequency signals RF1 and RF2 into the air.

FIG. 12 is a diagram illustrating the configuration of the receiving apparatus according to the fifth embodiment. The reception device 20-5 includes a reception antenna 25, a reception amplifier 24, and a reception mixer 23.
The radio frequency signals RF1 and RF2 are received by the reception antenna 25 and amplified by the reception amplifier 24. The reception mixer 23 mixes the radio frequency signals RF1 and RF2. The arithmetic expression is the same as the above expression (4). Therefore, the frequency fluctuation component Δf _T of the transmission device 10-5 is canceled by the reception device 20-5. Then, a modulation signal IF1 (156 Mbps, 4PSK) having an intermediate frequency of 1.1 GHz is output from the reception mixer 23.

  As described above, in the fifth embodiment, the first terminal 11a receives the modulation signal having the same intermediate frequency as the frequency difference value of the two radio frequency signals to be emitted as the modulation signal including the transmission information. . In the above example, a modulation signal having a frequency difference value 1.1 GHz (= 61.1-60.0) between the radio frequency signals RF1 and RF2 is received.

  The modulation signal is frequency-converted at a low frequency and then frequency-converted at a millimeter wave high frequency. By configuring the transmission apparatus in such a configuration, when mixing is performed on the reception side, the difference component of the radio frequency signal outputs the intermediate frequency of the original modulation signal as it is. This eliminates the need for a local oscillator in the receiving apparatus.

Here, as described above, a signal obtained by detecting (calculating) a frequency difference component between the first signal wave and the second signal wave output from the transmission apparatus is handled as a demodulated signal.
Therefore, in order to selectively demodulate radio communication waves from a plurality of different transmission devices, the frequency difference between the first signal wave and the second signal wave needs to be different in each transmission device (frequency Corresponding to the information channel).

  For this reason, the transmission device 10 has a frequency variable function that makes the frequency difference between the first signal wave and the second signal wave variable (for example, a plurality of second terminals 11b are provided and the frequency is switched by switching control). Is installed. As a result, interference can be prevented.

  In the above description, the second signal wave is a sine wave, but a rectangular wave can also be used. When the second signal wave is a rectangular wave, a component corresponding to the difference between the sine wave and the rectangular wave when the receiving apparatus mixes and demodulates the radio frequency component of the first signal wave and the radio frequency component of the second signal wave However, the distortion occurs when mixing with the first signal wave component. If the rectangular wave component is known in the receiving apparatus, this distortion can be corrected.

  That is, when the modulated wave and the rectangular wave are mixed with the carrier wave on the transmission side, the spectrum is broadened by the Fourier transform component of the rectangular wave. For this reason, the receiving side performs mixing with a rectangular wave synchronized with the transmitting side, returns the spread spectrum to the original spectrum, takes the difference component, and restores the modulated signal.

  In this case, instead of mixing using PN codes such as spread spectrum communication, it is only necessary to match the rising or falling of the rectangular wave on the transmitting side and the receiving side, so that synchronization can be easily performed. It can be carried out.

  Further, the second signal wave may have substantially the same frequency as the first signal wave. When the first signal wave and the second signal wave have substantially the same frequency, the radio signal wave is obtained by mixing a carrier wave with a synthesized wave of the first signal wave and the second signal wave (note that the second signal wave is the second signal wave). When the signal wave is a sine wave, the center frequency of the band is distorted by a sine wave component. When the signal wave is a rectangular wave, the band is spread and spread, but these can be removed by the receiving device. ).

  In the above description, the first signal wave is mixed with the carrier frequency using a baseband signal, which is a band of the information signal, once converted into an intermediate frequency signal. This mixing is performed on the baseband signal. You may go as it is. In that case, the second signal wave may also be set to a predetermined band other than the intermediate frequency.

  Furthermore, the transmission apparatus of the present invention can transmit a multiwave signal (for example, a TV signal). For example, a TV signal received by an external antenna or the like is retransmitted by the transmission apparatus of the present invention, so that the TV signal can be supplied wirelessly to a TV receiver (TV receiver in which the receiving apparatus is installed). it can. This makes it possible to place the TV receiver anywhere in the home and eliminates the need for commonly used home antenna wiring.

  Next, module configurations of the transmission device 10 and the reception device 20 will be described. FIG. 13 is a diagram showing an overview of a semiconductor device. The transmission device 10a is a semiconductor device in which circuit elements of the transmission device 10 are integrated on the same substrate. In addition, a radio wave transmission window 10a-1 that emits radio waves from a built-in planar antenna is provided.

  The receiving device 20a is a semiconductor device in which circuit elements of the receiving device 20 are integrated on the same substrate. In addition, a radio wave receiving window 20a-1 for receiving radio waves with a built-in planar antenna is provided.

  Here, the modulation signal IF1 is input from the input pin Pin1 of the transmission device 10a, and the sine wave signal IF2 is input from the input pin Pin2. Then, the internally processed millimeter wave band radio wave is emitted from the radio wave transmission window 10a-1 into the air. The receiving device 20a receives millimeter wave radio waves through the radio wave receiving window 20a-1. Then, after the internal processing, the transmitted original modulation signal IF1 is output from the output pin Pout.

  FIG. 14 is a diagram showing the structure of a semiconductor device. In a semiconductor device (transmitting device 10a or receiving device 20a) 1a, an antenna element substrate 3 and a semiconductor circuit 4 are formed on a substrate 5 provided with external pins. An antenna element (planar antenna) 2 is formed on the antenna element substrate 3. The semiconductor circuit 4 is a semiconductor circuit element that drives and processes a millimeter-wave band signal, and is connected to the antenna element 2.

  On the other hand, a conductive package 6 is attached to the substrate 5 so as to hermetically seal the antenna element 2 and the semiconductor circuit 4. Further, a non-conductive radio wave window 7 is provided in a region facing the antenna element 2 of the package 6.

  Next, application examples of the present invention will be described. 15 and 16 are diagrams showing application examples. FIG. 15 shows an application example to a wireless LAN. A server 104, a printer 105, a digital multifunction telephone 106, and an inter-building communication unit 108 are connected to the wireless LAN card 107 with respect to the wireless LAN 100. The personal computers 101 to 103 are connected to the wireless LAN card 107 wirelessly.

  The personal computers 101 to 103, the wireless LAN card 107, and the inter-bill communication unit 108 include, for example, a transmission device 10 and a reception device 20 for performing millimeter-wave band wireless communication in the 60 GHz band.

  The wireless LAN card 107 is a network interface card for wirelessly connecting the personal computers 101 to 103 to the LAN. The inter-building communication unit 108 is an outdoor wireless unit that connects LANs installed in remote buildings by high-speed communication.

  FIG. 16 shows an application example to an inter-vehicle communication system. A radio communication device 200a including the transmission device 10 and the reception device 20 is attached to the inter-vehicle communication system 200 before and after the vehicle. The radio communication device 200a performs control for maintaining an appropriate inter-vehicle distance, control for transmitting danger information to the vehicles before and after traveling, and the like.

  As described above, the wireless system using the transmission apparatus of the present invention is a millimeter-wave band wireless communication, for example, a high-speed wireless LAN connecting indoors such as homes and offices, between buildings, and safe driving support. It can be applied to an inter-vehicle communication system for

  As described above, the transmission apparatus 10 of the present invention includes a transmission mixer that mixes a first signal wave modulated by an information signal, a second signal wave that is an unmodulated wave, and a carrier wave signal, and the first mixer. The signal wave and the second signal wave are transmitted at a radio frequency, and the receiving device 20 includes a reception mixer that mixes the radio frequency signals of the first signal wave and the second signal wave, and demodulates the frequency difference. .

  As a result, the frequency fluctuation of the local oscillator on the transmission side does not affect the reception side, so high-precision wireless communication can be performed even if the accuracy (stability and phase noise) of the local oscillator on the transmission side is low. .

  In addition, the receiving device 20 does not require a (high accuracy) oscillator that reproduces the local oscillator on the transmission side. Since this is not related to the frequency to be handled, it is also effective for wireless communication at a frequency lower than the millimeter wave band.

  Further, in the transmitter of the present invention, the local oscillation signal is arranged at a position distant from the transmission band and the two-wave signal is transmitted. Therefore, a large filter such as a waveguide filter is used for the image wave or the carrier wave. Even if it is not used, it can be suppressed by a normal band-pass filter, and the circuit can be simplified and the cost can be reduced.

  Although the above description has focused on the application to the millimeter wave band, the wireless system to which the present invention is applied does not depend on the frequency band used, and is widely applied to wireless communications other than the millimeter wave band. Is possible.

  Moreover, although it was mentioned that a stable VCO in the millimeter wave band is difficult as a problem to be solved, a wireless system using the transmission device of the present invention can exhibit an effect even when a stable oscillator is used. . That is, even when a stable oscillator such as a PLL can be mounted on the transmitter or the receiver, the same oscillator cannot be prepared by the transmitter and the receiver.

  Therefore, the radio signal wave to be transmitted often includes components that are difficult to reproduce on the receiver side, such as inherent fluctuation components, but it is transmitted by adopting the radio system using the transmission device of the present invention. Since the fluctuation component contained in the wireless signal wave is removed, even in such a case, the effect can be exhibited by adopting the present invention.

It is a principle figure of a transmitter and a receiver. It is a block diagram of a transmitter and a receiver. It is a figure which shows the structure of a prior art. (A) is a transmitter and (B) is a receiver. It is a figure which shows the arrangement image of the frequency of a prior art. It is a figure which shows the arrangement | positioning image of the frequency of this invention. It is a figure which shows the structure of the transmitter of 1st Embodiment. It is a figure which shows the structure of the receiver of 1st Embodiment. It is a figure which shows the structure of the receiver of 2nd Embodiment. It is a figure which shows the structure of the receiver of 3rd Embodiment. It is a figure which shows the structure of the receiver of 4th Embodiment. It is a figure which shows the structure of the transmitter of 5th Embodiment. It is a figure which shows the structure of the receiver of 5th Embodiment. It is a figure which shows the external appearance of a semiconductor device. It is a figure which shows the structure of a semiconductor device. It is a figure which shows the example of application. It is a figure which shows the example of application. It is a figure which shows the conventional radio | wireless communications system.

Explanation of symbols

10 transmitting device 20 receiving device

Claims (12)

A transmission device for realizing down-conversion of a first radio frequency signal and a second radio frequency signal by mixing on a receiving side,
A first signal wave modulated by an information signal and a second signal wave that is an unmodulated wave are input, and each of the first signal wave and the second signal wave is mixed with a carrier signal of a transmission radio frequency. One transmission mixer
Upconverting the first signal wave and the second signal wave to the transmission radio frequency, and transmitting the first radio wave signal and the second radio frequency signal, respectively,
The second signal wave is different in frequency from the first signal wave.
A transmission apparatus characterized by the above.   The transmission apparatus according to claim 1, wherein the second signal wave is a sine wave signal.   The transmitting apparatus according to claim 1, wherein the second signal wave is a rectangular wave signal.   The transmission apparatus according to claim 1, wherein the transmission mixer mixes each of the first signal wave and the second signal wave having different frequencies with the carrier signal.   The transmission apparatus according to claim 1, further comprising a filter that removes unnecessary components other than the components of the first radio frequency signal and the second radio frequency signal from the mixed signal.   The transmission apparatus according to claim 1, further comprising a transmission amplifier that amplifies the mixed signal.   The transmission apparatus according to claim 6, wherein the transmission mixer and the transmission amplifier are integrated on the same semiconductor chip.   The transmission apparatus according to claim 1, further comprising an antenna that emits a mixed signal.   The transmission apparatus according to claim 1, further comprising a transmission local oscillator that generates a carrier signal of the transmission radio frequency.   10. The transmission apparatus according to claim 9, wherein the transmission mixer and the transmission local oscillator are integrated on the same semiconductor chip.   The transmission apparatus according to claim 1, wherein the first signal wave is generated by mixing an information signal with an intermediate frequency signal. A transmission device for realizing down-conversion of a first radio frequency signal and a second radio frequency signal by mixing on a receiving side,
A first signal wave that is a baseband signal and a second signal wave that is an unmodulated wave are input, and each of the first signal wave and the second signal wave is mixed with a carrier signal having a transmission radio frequency. With one transmission mixer,
Upconverting the first signal wave and the second signal wave to the transmission radio frequency, and transmitting the first radio wave signal and the second radio frequency signal, respectively,
The second signal wave is different in frequency from the first signal wave.
A transmission apparatus characterized by the above.

Images