JP5353888B2 - Frequency multiplex receiver - Google Patents

Description

(Description of related applications)
The present invention is based on the priority claim of Japanese Patent Application No. 2008-232280 (filed on Sep. 10, 2008), the entire contents of which are incorporated herein by reference. Shall.
The present invention relates to a frequency multiplex receiver to which electrical signals multiplexed at a plurality of frequencies are input.

  With the development of ubiquitous networks that use weak radio wave bands typified by sensor networks, the demand for higher data rates, higher sensitivity, and lower power for wireless IP cores is increasing. Up to now, RF circuits that have been digitized for control and signal processing have been proposed. However, improvement in circuit operation speed and reduction in noise to satisfy these requirements will lead to an increase in power consumption.

  Here, in order to further reduce power, conventionally, a method has been used in which electric charges used in circuit driving are reused in a circuit that performs post-processing to reduce power. A conventional example of this method called “current reuse” described in Non-Patent Document 1 is shown in FIG.

  This conventional example relates to a reduction in power of a low-noise amplifier and a down-conversion mixer (hereinafter referred to as a mixer) used in the vicinity of the first stage of a radio reception circuit. Conventionally, the low noise amplifier and the mixer are designed as separate independent blocks, and the circuit current also flows separately between the low noise amplifier and the mixer. The operation of the mixer is generally as follows. In other words, the voltage value of the signal input from the low-noise amplifier to the mixer is converted to a current value via a transconductance amplifier, and the current value is released as appropriate according to the electrical resistance generated by the switching signal input from the outside. Alternatively, control such as narrowing is added to mix the switching signal and the mixer input signal to convert the frequency.

  Here, in FIG. 1, if the low noise amplifier 101 and the mixer transconductance amplifier 104 are vertically stacked, the circuit current flowing through the low noise amplifier 101 is reused as the circuit current of the mixer transconductance amplifier 104. The circuit current 1 (105) is processed simultaneously by the low noise amplifier 101 and the transconductance amplifier 104 of the mixer. Therefore, by reusing such current, only the circuit current 2 (107) flowing through the switching unit 106 at the subsequent stage is sufficient as the circuit current consumed by the mixer.

  However, the above technique essentially increases the efficiency of consumption of power supplied from the circuit power supply, and there is a limit that the circuit cannot obtain more power than the power supply supplied from the battery in operation.

  Since this limit is exceeded, it is conceivable to obtain power from other than the battery. A typical prior art is a wireless tag receiver disclosed in Non-Patent Document 2, and a configuration diagram is shown in FIG. The electromagnetic wave supplied from the reader / writer 201 to the wireless tag 203 is rectified from alternating current to direct current by the full-wave rectifier 204, and then stabilized and stepped up / down to a suitable quality as a circuit power source by the internal voltage control 206 and the booster 207. In addition, it is supplied as a power source for internal circuits such as the current mode demodulator 209 and the logic 210. The conversion efficiency from AC to DC here is the optimization of the element sizes of the PMOS rectifier diode 301 and the NMOS rectifier diode 302 included in the full-wave rectifier whose configuration is shown in FIG. 3, and before being input to the rectifier diode. It can be increased by suppressing the loss due to the parasitic capacitance. However, in this example, the electromagnetic wave used for data transmission / reception and the electromagnetic wave used for power supply are divided and sent in both time and frequency bands. If part of these electromagnetic waves for data transmission / reception is used as a power supply, power that was previously discarded in the form of heat energy or the like can be regenerated in the LSI to extend the battery life or achieve a complete battery-less operation. It becomes possible. In particular, a radio communication LSI receives electromagnetic waves other than the desired signal component used for actual data transmission / reception. Therefore, if the undesired electromagnetic waves are effectively used as electric power, electric power more than that supplied by the battery can be obtained.

  Patent Document 1 describes a receiving device that receives a digitally modulated electric signal and obtains a desired demodulated signal.

  Patent Document 2 describes a CATV transmission system that takes out a digital modulation signal from a transmission signal, corrects the error, and then restores the original information.

  Patent Document 3 describes an AC / DC converter that effectively reduces the ripple of DC output power by providing a band rejection filter in the subsequent stage of the full-wave rectifier circuit.

  Further, Patent Document 4 describes an RF device that distributes a received high-frequency signal to a circuit that generates power from the received signal by a distribution circuit and a circuit that demodulates the received signal after passing through a filter. ing.

International Publication No. 2006/046632 Pamphlet JP 2000-083231 A JP 2006-2111855 A JP 2007-281768 A International Publication No. 2009/038034 Pamphlet

Microwave and Wireless Components Letters, Volume 16, Issue 4, April 2006 Page (s): 206-208 International Solid Circuit Conference 2006 Proceedings No. 17.2

The entire disclosures of Patent Documents 1 to 5 and Non-Patent Documents 1 and 2 are incorporated herein by reference.
The following is an analysis of the related art according to the present invention.
The conventional wireless receiver circuit described with reference to Non-Patent Documents 1 and 2 described above has the following problems in reducing the power consumption.

  First of all, in the technique of reducing the power consumption of the radio circuit by current reuse (current reuse) described using Non-Patent Document 1, the power conversion efficiency of the amplifier is improved and the reception sensitivity is reduced due to the mixing of thermal noise. Although there is an effect of increasing the utilization efficiency of the power supplied from the battery, such as suppression, there is a limit to increasing the power efficiency. The reason is essentially to increase the consumption efficiency of the power supplied from the circuit power supply, and there is a limit that the circuit cannot obtain more power than the power supply supplied from the battery.

  Second, in the power supply in the wireless tag described using Non-Patent Document 2, the circuit can obtain more power than the power supplied from the battery compared to the case of Non-Patent Document 1, or Although it is possible to reduce the battery of the receiving circuit, there is a problem that it is difficult to increase the data transmission speed while maintaining low power operability. The reason for this is essentially a combination of diode rectification power conversion and conventional wireless reception technology. As the circuit power consumption increases as the data rate increases, the power supply side supplies power separately from the demodulation side. This is because it is necessary to improve this.

  On the other hand, as a reality in application, it is important to convert the circuit power up to the component in which the desired communication is performed to enable long-distance transmission without impairing communication quality such as signal-to-noise power ratio. . It is also important not to close the possibility of broadband communication, such as avoiding being limited to single carrier transmission by cooperating frequency multiplexed signals and power conversion. None of the above prior art documents describes a reduction in power consumption of the frequency multiplex receiver.

  In view of the above, an object of the present invention is to reduce the power consumption of a frequency multiplex receiver. In particular, the received signal multiplexed at a plurality of frequencies is intended to reduce the power without missing the necessary information.

  A frequency multiplex receiver according to one aspect of the present invention is a frequency multiplex receiver to which an electrical signal multiplexed at a plurality of frequencies is input, and the first filter and a frequency different from the first filter. A second filter having characteristics, a receiving unit for extracting demodulated data from the input electric signal, and AC / DC conversion for converting the input electric signal into a DC signal to obtain power necessary for circuit operation An operation of inputting a first frequency that has passed through the first or second filter out of the plurality of frequencies to the receiving unit and extracting demodulated data, and converting the first frequency to the alternating current An operation for obtaining power by inputting to the DC converter is performed in a time division manner, and in parallel with the time division operation, a second of the plurality of frequencies that has passed through the second or first filter. Receiving frequency Wherein the operation of taking out the input demodulated data, to perform in the time division operation and obtain power input the second frequency to the AC-DC converter unit to.

  A frequency multiplex receiver according to another aspect of the present invention is a frequency multiplex receiver to which electrical signals multiplexed at a plurality of frequencies are input, and each of the plurality of frequencies is input from an input electrical signal. A band-pass filter that selects and passes a corresponding frequency; and a radio reception unit that performs demodulation from a signal that has passed through the band-pass filter, and the band-pass filter does not perform demodulation in the radio reception unit A band-pass filter / AC / DC converter that functions as an AC / DC converter that converts an input electrical signal into a DC signal to obtain power required for circuit operation, the wireless receiver, and a band-pass filter / AC DC A conversion unit is provided for each of the plurality of frequencies.

  According to still another aspect of the present invention, there is provided a method of operating a frequency multiplex receiver that receives an electric signal multiplexed at a plurality of frequencies and demodulates a signal of each frequency component, The frequency multiplexing receiver includes a first filter, a second filter having a frequency characteristic different from that of the first filter, a receiving unit for extracting demodulated data from the input electric signal, and the input An AC / DC converter for converting an electrical signal into a DC signal and obtaining electric power necessary for circuit operation, and among the plurality of frequencies, a first frequency that has passed through the first or second filter The operation of inputting the demodulated data input to the receiving unit and the operation of obtaining the power by inputting the first frequency to the AC / DC conversion unit are performed in a time division manner, and in parallel with the time division operation, Multiple laps Among the numbers, the second frequency that has passed through the second or first filter is input to the receiving unit to extract the demodulated data, and the second frequency is input to the AC / DC converting unit to obtain power. The operation is performed in a time-sharing manner.

  According to the present invention, it is possible to reduce the power consumption of a frequency multiplexing receiver. The reason is that, among received signals multiplexed at a plurality of frequencies, a received signal having a frequency not used for the demodulation operation can be used as power. In addition, since the frequency used for the demodulation operation and the frequency used as power can be switched in a time-sharing manner, low power can be realized without missing the reception of necessary information.

It is a circuit diagram which shows the conventional electric current reuse technique. It is a block diagram of the conventional wireless tag receiver. It is a block diagram of the conventional full wave rectifier contained in a wireless tag receiver. 1 is a block diagram of a frequency multiplexing receiver according to an embodiment of the present invention. FIG. It is an operation | movement diagram of the band variable filter by one Example of this invention. FIG. 4 is a block diagram of a frequency multiplexing receiver according to another embodiment of the present invention. It is a figure explaining switching of the function of the band pass filter and alternating current direct current | flow converter in another Example of this invention. FIG. 6 is an operation diagram according to another embodiment of the present invention. FIG. 6 is an operation diagram according to still another embodiment of the present invention. FIG. 4 is a more general block diagram of a frequency multiplex receiver according to another embodiment of the present invention.

  Embodiments of the present invention will be described with reference to the drawings as necessary.

  A frequency multiplex receiver according to an embodiment of the present invention is a frequency multiplex receiver to which electrical signals multiplexed at a plurality of frequencies are input, as shown in FIG. 4 or FIG. One filter (401, 601), a second filter (402, 602) having a frequency characteristic different from that of the first filter, and a receiving unit (403, 603) for extracting demodulated data from the input electric signal 604) and an AC / DC converter (405, 601 and 602) for converting the input electric signal into a DC signal and obtaining electric power necessary for circuit operation. An operation for inputting the first frequency (for example, f1 in FIGS. 5, 8, and 9) that has passed through the first or second filter to extract the demodulated data (first half of FIGS. 5 and 8, data symbol period in FIG. 9) 2, 3) and the first The operation of obtaining the power by inputting the wave number (for example, f1) to the AC / DC converter (the second half of FIGS. 5 and 8 and the data symbol period 1 of FIG. 9) is performed in a time division manner and in parallel with the time division operation. Then, among the plurality of frequencies, the second frequency (for example, f2 in FIGS. 5, 8, and 9) that has passed through the second or first filter is input to the receiving unit and the demodulated data is extracted (FIG. 5). The second half, the first half of FIG. 8, the data symbol period 3 of FIG. 9, and the operation of obtaining the power by inputting the second frequency to the AC / DC converter (the first half of FIG. 5, the second half of FIG. 8, the data symbol of FIG. 9). Periods 1 and 2) are performed in a time-sharing manner.

  In addition, as shown in FIG. 4, in the frequency multiplex receiver according to the embodiment of the present invention, the output of the first filter 401 is connected to the input of the receiving unit 403, and one frequency selected from a plurality of frequencies is selected. The second filter 402 may be a band variable blocking filter whose output is connected to the AC / DC converter 405 and blocks one selected frequency.

  In addition, as shown in FIG. 5, the frequency division multiplex receiver according to the embodiment of the present invention passes the frequency band of the first filter 401 upon completion of demodulation of the first frequency that has passed through the first filter 401. Is switched to the second frequency f2, the blocking frequency band of the second filter 402 is switched to the second frequency f2, and the second frequency is demodulated. A plurality of frequencies may be demodulated.

  That is, even if the reception frequency of the frequency multiplex receiver is 3 or more, the first filter 401 and the receiving unit 403 perform demodulation of one selected frequency, and the second filter for the other frequency components. Electric power can be obtained by 402 and the AC / DC converter 405.

  In addition, as shown in FIG. 6, in the frequency multiplex receiver according to the embodiment of the present invention, the AC / DC conversion unit includes a first AC / DC conversion unit 601 and a second filter that switch functions in a time division manner with the first filter. And a second AC / DC converter 602 that switches functions in a time-sharing manner, and the receiver is connected to the first receiver 603 connected to the output of the first filter and the output of the second filter. And the second receiving unit 604. When the first receiving unit 603 does not perform demodulation, the first filter 601 functions as a first AC / DC converting unit, and the second receiving unit 604 performs demodulation. When not performed, the second filter 602 may function as a second AC / DC converter.

  Further, in the frequency multiplexing receiver of one embodiment of the present invention, as shown in FIGS. 6 and 8, the first filter 601 is a band-pass filter / AC / DC converter of the first frequency f1, The second filter 602 may be a band-pass filter / AC / DC converter of the second frequency f2.

  In addition, as shown in FIG. 10, the frequency multiplex receiver according to an embodiment of the present invention is a frequency multiplex receiver to which electric signals multiplexed at a plurality of frequencies are input. Then, a band pass filter (601, 602, 605) that selects and passes a corresponding frequency from the input electric signal, and a radio receiver (603, 604, 606) that demodulates the signal that has passed through the band pass filter. The band-pass filters (601, 602, 605) convert electric signals inputted when the radio receivers (603, 604, 606) are not demodulated into DC signals, and are necessary for circuit operation. A band-pass filter / AC / DC converter (601, 602, 605) that functions as an AC / DC converter that obtains a wireless receiver and a band-pass filter / AC / DC converter When, or may be a provided for a plurality of frequencies each frequency.

  Furthermore, as shown in FIG. 7, the frequency multiplex receiver according to the embodiment of the present invention is configured so that each band pass filter / AC / DC converter (601, 602, 605 in FIGS. 6 and 10) is one of the drain sources. Includes a MOS transistor (701, 704) whose input terminal 408 is connected to the output terminal, and a capacitive element (703, 705) connected between the output terminal and a fixed potential, as a band-pass filter. When functioning, the gate of the MOS transistor may be connected to the sampling clock, and when functioning as an AC / DC converter, the gate of the MOS transistor may be connected to the input terminal 408.

  In addition, as shown in FIG. 8, the frequency multiplex receiver according to the embodiment of the present invention has each bandpass filter / AC / DC converter (601, 602, 605 in FIG. 6 and FIG. 10) corresponding frequency components. As soon as the demodulation is completed, the function may be switched to the AC / DC converter within the data symbol period.

  Further, in the frequency multiplexing receiver according to the embodiment of the present invention, as shown in FIG. 9, each band pass filter / AC / DC converter (601, 602, 605 in FIGS. 6 and 10) switches the data symbol period. As a minimum unit, a band pass filter function and an AC / DC conversion function may be arbitrarily switched to perform a demodulation operation or a power regeneration operation.

  In addition, as shown in FIGS. 4 to 6 and FIGS. 8 to 10, the operation method of the frequency multiplex receiver according to the embodiment of the present invention is to input an electrical signal multiplexed at a plurality of frequencies and to receive a signal of each frequency component. Of the first filter (401, 601) and the second filter (402, 602) having a frequency characteristic different from that of the first filter. ), Receiving units (403, 603, 604, 606) for extracting demodulated data from the input electric signal, and AC for converting the input electric signal to a DC signal and obtaining electric power necessary for circuit operation DC converters (405, 601, 602, 605), among which a first frequency f1 that has passed through the first or second filter is input to a receiver (403, 603) and demodulated. Collecting data 5 (first half of FIG. 5, FIG. 8, FIG. 9) data symbol period 2 and the operation of inputting the first frequency f1 to the AC / DC converter (405, 601) to obtain power in a time-sharing manner, and In parallel with the time division operation, the second frequency f2 that has passed through the second or first filter out of a plurality of frequencies is input to the receiving unit (403, 603) and demodulated data (for example, 404) is extracted. The operation of obtaining power by inputting the second frequency f2 to the AC / DC converter (405, 602) may be performed in a time-sharing manner.

  Hereinafter, it will be described in detail with reference to the drawings in accordance with embodiments.

  FIG. 4 is a block diagram showing the configuration of the frequency multiplexing receiver according to the first embodiment. First, a frequency multiplexed signal received in wireless communication is simultaneously input from a signal input terminal 408 to a band variable filter A (401) and a band variable filter B (402) placed in parallel. The signal in the frequency band transmitted through the band-variable filter A (401) is sent to the wireless reception unit 403, and the wireless reception unit 403 outputs a digital signal as demodulated data 404. On the other hand, the signal in the frequency band transmitted through the band-variable filter B (402) is sent to the AC / DC converter 405 and converted into electric power. The electric power obtained here is sent to the circuit power supply 407 together with the electric power supplied from the battery 406. Electric power is supplied from the circuit power source 407 to the wireless reception unit 403, the variable band filter A (401), the variable band filter B (402), and the like.

  As a feature of this configuration, a variable band filter A (401) and a radio receiving unit 403, which are blocks for demodulating a radio signal into digital data, a variable band filter B (402) and an AC / DC converting unit for converting a radio signal into electric power. 405, and there is only one radio reception unit regardless of frequency multiplicity.

  Next, with reference to FIG. 5 in addition to the configuration example of FIG. 4, the operation of the frequency multiplex receiver with power regeneration of this embodiment will be described in detail. Here, a radio signal as an electromagnetic wave flying in space is treated as a signal after being converted into an electric signal by an antenna or the like. Here, it is assumed that a signal in which two frequencies f1 and f2 are multiplexed is handled, and that data 1 is loaded on f1, and data 2 is loaded on f2, respectively. Here, in order to simplify the description, the frequency multiplicity is only two, f1 and f2, but this does not limit the number of multiplicity of the present invention.

  The signals multiplexed by the above f1 and f2 are first inputted simultaneously to both the band variable filters A (401) and B (402) and subjected to processing according to the respective filter characteristics. FIG. 5 shows the characteristics of the band-variable filters A and B at each stage of operation. The characteristics of the band-variable filter A and the band-variable filter B at the initial stage of operation are shown on the left side of FIG. That is, at this stage, the band-variable filter A transmits with low impedance and loss with respect to f1, but appears as high impedance with respect to f2. On the other hand, the band-variable filter B has a low impedance with respect to f2, but is viewed as a high impedance with respect to f1. As a result, the component f1 is mainly input to the wireless reception unit 403, and the component f2 is mainly input to the AC / DC converter 405. Since there is a low-impedance escape path for each of f1 and f2, components that are converted into heat energy and lost due to signal degradation or heat dissipation are suppressed.

  Here, the characteristic required for the variable band filter A is that if f2 is blocked and only f1 is passed through with low loss and output to the radio receiver, the desired data 1 can be demodulated. This is a band-pass filter type that selectively passes the band. On the other hand, although it is a characteristic required for the band variable filter B, it becomes a band stop type that blocks only the passage of f1. The reason is that if f1 is passed here, the component of f1 converted as electric power is generated, and the component of f1 flowing to the band variable filter A is reduced accordingly.

  As a result, the signal-to-noise power ratio of the data 1 when demodulated by the radio reception unit is reduced, leading to degradation of demodulation characteristics. Further, except for f1, all the bands should be passed by the band variable filter B. In addition to frequency multiplexed signals such as f1 and f2, the side that receives the radio signal also receives interference waves flying from different standards and different terminals at the same time, so all energy from electromagnetic waves that can be converted to power should be collected. Because. Here, since the power of the interference wave reaches 1000 times the desired wave power in some cases, it has never exceeded the power regeneration, but such a useful interference wave does not always come and communication. Depending on the environment, the expected power reduction may not be achieved. However, in the case of frequency multiplex transmission, in addition to the signal to be demodulated, a plurality of electromagnetic waves having the same strength always come in, so stable power regeneration can be expected. By the operation shown here, in the prior art, such unnecessary components in frequency multiplexing and the like are removed by a filter and converted to thermal noise. For this reason, the proposed technology of the present invention makes it possible to convert the energy that has been irreversibly dissipated out of the LSI as heat into a form that can be used in the circuit without impairing the communication quality such as the data rate. It turns out that it is.

  Thereafter, the component f1 output from the band variable filter A is input to a radio reception unit having the same configuration as that of the conventional radio reception technology and demodulated into digital data.

  Here, the radio reception unit needs to output the digital data after being demodulated in half the data symbol period. The specific circuit operation for completing demodulation in half the time within the data symbol period follows the example shown in Patent Document 1 or Patent Document 5 described in the background art.

  In parallel, components other than f1, mainly f2, output from the band-variable filter B are converted from electromagnetic waves to DC power that can be used as a circuit power supply by AC / DC conversion. The AC / DC conversion used in this configuration undergoes full-wave rectification by the PMOS rectifier diode 301 and the NMOS rectifier diode 302 in FIG. 3, smoothing by the decoupling capacitor (positive) 303 and decoupling capacitor (negative) 304, and low impedance The conventional configuration may be used up to the stable output of power. However, depending on the communication state, the power that receives power regeneration by this AC / DC conversion may be insufficient as the circuit supply power, so the power supplied by the battery is also used as the circuit power supply. After receiving the step-up / step-down / stabilization processing necessary for circuit operation with this circuit power supply, the circuit power is sent to a portion requiring power supply, such as band-variable filter A, band-variable filter B, and radio demodulator.

  After the series of processes described above continues, after half the time of the data symbol period has passed, the characteristics of the band variable filter A and the band variable filter B are switched as shown on the right side of FIG. By this switching, f2 flows through the wireless reception unit, and components other than f2, mainly f1, flow through the AC / DC conversion. As a result, the frequency component f2 provided to the circuit power supply as the DC power supply before the switching is demodulated and the data 2 can be acquired. Also, since the data f1 has already been taken out before switching, it will be supplied to the circuit power supply after AC / DC conversion. This switching only replaces the processing received at each of f1 and f2, and there is no change in the operation itself such as data demodulation and power extraction. In FIG. 4, the circuit power source combined with the band-variable filter B and AC / DC conversion and the battery flows the power, and the data flows from the band-variable filter A to the wireless receiver.

  Next, the effect of the present embodiment will be described. According to the present embodiment, the power processing including the AC / DC conversion from the band variable filter B and the data processing from the band variable filter A to the wireless reception unit are distinguished. For this reason, in the above description of the operation, the frequency multiplicity is only two. However, even if the frequency multiplicity sequentially increases to 3, 4, no substantial difference occurs in the circuit. Therefore, this embodiment is effective when it is necessary to improve the data rate while suppressing an increase in circuit area.

  However, if the frequency multiplicity is N, the time taken to demodulate one subcarrier is a data symbol period / N, and the energy per bit and the signal-to-noise power ratio derived therefrom are reduced. For this reason, when the demand for transmitting a radio signal over a long distance is stronger than the demand for suppressing LSI cost, it is desirable to adopt the form of Example 2 described later.

  FIG. 6 is a block diagram of a frequency multiplexing receiver according to the second embodiment. Here, only the configuration different from that of the first embodiment will be described. In FIG. 6, the difference from the embodiment 1 is that the variable band filter and the AC / DC conversion function are shared in one circuit to be a band-pass filter / AC / DC converter, and this filter and the radio reception The same number of frequency multiplicity units are placed, and the band pass filter / AC / DC converter 1 (601), the band pass filter / AC / DC converter 2 (602), the radio receiver 1 (603), and the radio receiver This is a point designated as part 2 (604).

  FIG. 7 shows an example of the configuration when the band-pass filter / AC / DC converter is realized by a circuit. When a band selection filter is configured as a sampling circuit, a sampling clock 702 is input to an NMOS gate 701 as a sampling switch, and a discrete processing filter is formed according to a timing relationship defined by the clock. The value is held in the sampling capacitor 703. Next, the rectifier diode 704 can be formed by changing the connection of the NMOS gate as the sampling switch so as to be short-circuited with one of the NMOS source and drain instead of the sampling clock. The sampling capacitor 703 during the filter operation is a decoupling capacitor 705 that follows the rectifier diode 704. As described above, in the circuit composed of the NMOS and the capacitor, the two functions of the discrete processing filter and the AC / DC conversion can be easily switched by switching the NMOS gate connection destination.

  In FIG. 6, as in FIG. 4 of the first embodiment, the frequency multiplicity is assumed to be 2 in order to simplify the explanation, but this does not limit the number of multiplicity that can be realized.

  Next, the operation of the second embodiment will be described. Here, operations different from those of the first embodiment will be described with reference to FIGS. 6 and 8 together. Also in the second embodiment, the signals multiplexed by f1 and f2 are simultaneously input to the band pass filter / AC / DC converters 601 and 602, respectively, and are subjected to processing corresponding to the filter characteristics. However, at the initial stage of this operation, each filter has a band-pass filter characteristic, and the band-pass filter 601 transmits only f1 and the band-pass filter 602 transmits only f2. The f1 that has passed through the filter 601 is sent to the radio receiving unit 1, and the f2 that has passed through the filter 602 is sent to the radio receiving unit 2 to obtain demodulated data 1 and 2, respectively. In the first embodiment, it is divided into a filter that extracts f1 that performs demodulation and a filter that extracts other than f1 that performs power extraction, and the data demodulation and power conversion in the subsequent stage are performed in parallel. The embodiment is different in that data demodulation is first completed for both f1 and f2 at the beginning of the operation. This operation phase is continued until data demodulation is completed with a desired demodulation quality, and this period is not limited by the frequency multiplicity. This is different from the first embodiment in which data demodulation needs to be completed between data symbol periods / frequency multiplicity.

  As soon as the above data demodulation is completed, the functions of the band pass filter / AC / DC converters 601 and 602 are switched to a rectifier diode and a decoupling capacitor as shown in FIG. At this time, the outputs of the band pass filter / AC / DC converters 601 and 602 are also switched from the wireless receivers 1 and 2 to the circuit power supply.

  From the above, although there is a difference in operation in the first embodiment in which data demodulation and power conversion are performed in parallel and in the present embodiment in which power conversion is performed after data demodulation is completed in all subcarriers, The point that the energy that was thrown away is converted into DC power and used as circuit power is the same as in the first embodiment.

  FIG. 6 shows a block diagram when the frequency multiplicity is 2, but FIG. 10 shows a block diagram of a general configuration when the frequency multiplicity is 3 or more for reference. As shown in FIG. 10, when the frequency multiplicity is 3 or more, the number of band-pass filters and AC / DC converters connected in parallel and the number of radio communication units are set in accordance with the number (n) of the frequency multiplicity. Increase it. Each band-pass filter / AC / DC converter unit functions as a band-pass filter when demodulation of received data is necessary, and functions as an AC / DC converter unit when demodulation of received data is not required to supply power. As a result, the frequency multiplex receiver can achieve low power consumption as a whole without missing necessary information.

  In the description of the operation of the second embodiment, the data demodulation and power conversion on the receiving side are switched in one data symbol period. That is, on the transmission side, there is a premise that there is no change in assigning data 1 and data 2 to f1 and f2 throughout the entire communication period without changing the data transmission method according to the communication environment. Here, if the type of data to be allocated to f1 and f2 is adaptively changed on the transmission side according to the communication environment and the remaining battery level, more detailed power optimization can be achieved by taking advantage of the characteristics of frequency multiplex transmission. . The specific operation of the third embodiment is shown in the operation diagram of FIG. The circuit configuration of the third embodiment is the same as the circuit configuration of the second embodiment shown in FIG. The difference between the second embodiment and the third embodiment is only a difference in operation switching between data demodulation and power conversion for each frequency.

  In the third embodiment, as shown in FIG. 9, first, at the start of communication, an electromagnetic wave that is not subjected to data modulation for each of f1 and f2 is skipped from the transmission side. In this case, since neither f1 nor f2 contributes to actual data communication, the receiving side performs AC / DC conversion for each of the band-pass filter / AC / DC converters 1 and 2 to extract electric power from the electromagnetic wave, and from the battery. A circuit power supply is combined with the supplied power. This operation is continued in the data symbol period 1.

  Next, in the data symbol period 2, the transmission side modulates f1 so that data 1 is carried. Thus, f2 does not change that it contributes to power supply but not data communication, but f1 finishes the role of power supply and contributes to data communication. In this case, the band pass filter / AC / DC converter 1 performs the AC / DC conversion in the same manner as the data symbol period 1 and supplies power to the circuit power source. .

  Next, in the data symbol period 3, the transmission side also modulates f2 so that data 2 is carried. As a result, f2 also finishes the role of power supply and contributes to data communication. In this case, the band pass filter / AC / DC converter 1 is output to the radio receiver 1 and the band pass filter / AC / DC converter 2 is output to the radio receiver 2 to obtain demodulated data 1 and demodulated data 2, respectively.

  With this operation, in the situation where the communication has just started and the amount of power regeneration is small, and the power in the circuit other than the battery is insufficient, only the subcarrier that skips the power is sent, and the power regeneration occurs after the communication time has elapsed. As the amount increases, it is possible to gradually reduce the ratio of subcarriers that dedicate power to increase the number of subcarriers subjected to data modulation.

  If this operation is extended, it is possible to embed not only a communication subcarrier modulated in frequency multiplexing communication but also a subcarrier for power transmission. In this case, the ratio between the communication subcarrier and the power transmission subcarrier can be changed in a scalable manner in accordance with the transmission state and the power supply amount of the wireless device. For example, when starting communication, a number of subcarriers for power transmission that are not subjected to data modulation are arranged, and if charge is accumulated over time, the communication subcarriers are increased to increase data transmission / reception Embedded power transmission becomes possible.

  Also, instead of deciding the ratio of communication subcarriers and power transmission subcarriers uniformly, if you want to increase the amount of power regeneration even when flying over long distances, increase the ratio of power transmission subcarriers. It is also possible to decide adaptively according to the situation.

  Next, unique effects when the circuit configurations of the second and third embodiments are adopted will be described. Compared with the circuit configuration of the first embodiment, the LSI cost is increased in that the same number of band-pass filters / AC / DC converters and radio receivers as the frequency multiplicity are prepared. On the other hand, since the data demodulation period can be taken regardless of the frequency multiplicity, it is not necessary to sacrifice the signal-to-noise power ratio. For this reason, it is effective when a long wireless transmission distance is desired.

  As described in the above embodiments, according to the disclosure of the present invention, low power operability that cannot be achieved by a wireless receiver having a conventional configuration can be obtained. The reason for this is that the received interference wave or frequency-multiplexed component is conventionally converted into thermal energy by a filter circuit and incorporated into the signal-to-noise ratio required for communication as noise, or dissipated outside the LSI. This is because, in the present invention, it is converted into a form that can be used as a circuit power supply by AC → DC conversion, and can be used in a circuit without being discarded.

  Furthermore, according to the disclosure of the present invention, it is possible to change communication power consumption and transmission rate in a scalable manner by making use of frequency multiplexing transmission. The reason is that in frequency multiplex transmission, a plurality of subcarriers are always flying from the transmission side, and if some of them are allocated for communication and the rest are allocated for power transmission without data, their ratio This is because the supply power and transmission rate are determined by the above. Furthermore, it is easy to change the ratio in a scalable manner according to the transmission state and the remaining battery capacity of the chip.

The present invention has been described with reference to the embodiments. However, the present invention is not limited to the configurations of the above embodiments, and various modifications that can be made by those skilled in the art within the scope of the present invention. Of course, modifications are included.
Within the scope of the entire disclosure (including claims) of the present invention, the embodiments and examples can be changed and adjusted based on the basic technical concept. Further, various combinations or selections of various disclosed elements are possible within the scope of the claims of the present invention (claims).

101: Low noise amplifier 102: Low noise amplifier input 103: Low noise amplifier output 104: Mixer (transconductance amplifier)
105: Circuit current 1
106: Mixer (switching unit)
107: Circuit current 2
108: switch signal 109: mixer output 201: reader / writer 203: wireless tag 204: full-wave rectifier 205: protection circuit 206: internal voltage control 207: booster 208: nonvolatile memory 209: current mode demodulator 210: logic 211: Voltage controlled oscillator 212: Modulator 301: PMOS rectifier diode 302: NMOS rectifier diode 303: Decoupling capacitance (positive)
304: Decoupling capacity (negative)
401: Band-variable filter A
402: Band-variable filter B
403: Wireless receiver 404: Demodulated data 405: AC / DC converter 406: Battery 407: Circuit power supply 408: Signal input terminal 601: Band pass filter / AC / DC converter 1
602: Band pass filter and AC / DC converter 2
603: Wireless receiver 1
604: Radio receiver 2
605: Band pass filter and AC / DC converter n
606: Radio receiver n
701: Sampling switch 702: Sampling clock 703: Sampling capacity 704: Rectifier diode 705: Decoupling capacity

Claims (11)

A frequency multiplex receiver to which electrical signals multiplexed at a plurality of frequencies are input,
A first filter;
A second filter having a frequency characteristic different from that of the first filter;
A receiving unit for extracting demodulated data from the input electrical signal;
An AC / DC converter for converting the input electric signal into a DC signal to obtain electric power necessary for circuit operation;
With
Of the plurality of frequencies, an operation of inputting a first frequency that has passed through the first or second filter to the receiving unit to extract demodulated data, and inputting the first frequency to the AC / DC converting unit. The operation for obtaining power is performed in a time-sharing manner, and in parallel with the time-sharing operation,
Of the plurality of frequencies, the second frequency that has passed through the second or first filter is input to the receiving unit and the demodulated data is extracted, and the second frequency is input to the AC / DC converting unit. A frequency multiplexing receiver characterized in that the operation of obtaining power is performed in a time division manner. The first filter is a band-variable pass filter whose output is connected to the input of the receiving unit and passes one frequency selected from the plurality of frequencies,
2. The frequency multiplex receiver according to claim 1, wherein the second filter is a band variable blocking filter whose output is connected to the AC / DC converter and blocks the selected one frequency. 3.   Upon completion of demodulation of the first frequency that has passed through the first filter, the pass frequency band of the first filter is switched to the second frequency, and the stop frequency band of the second filter is switched to the second frequency. 3. The frequency multiplex receiver according to claim 2, wherein the second frequency is demodulated, the frequency bands are sequentially switched, and the plurality of frequencies are demodulated within a data symbol period. The AC / DC converter includes a first AC / DC converter that switches functions in time division with the first filter, and a second AC / DC converter that switches functions in time division with the second filter. Prepared,
The receiving unit includes a first receiving unit connected to the output of the first filter, and a second receiving unit connected to the output of the second filter,
When the first receiver does not perform demodulation, the first filter functions as the first AC / DC converter,
The frequency multiplex receiver according to claim 1, wherein the second filter functions as the second AC / DC converter when the second receiver does not perform demodulation.   The first filter is a band-pass filter / AC / DC converter of the first frequency, and the second filter is a band-pass filter / AC / DC converter of the second frequency. 4. The frequency multiplexing receiver according to item 4. A frequency multiplex receiver to which electrical signals multiplexed at a plurality of frequencies are input,
For each of the plurality of frequencies,
A bandpass filter that selects and passes the corresponding frequency from the input electrical signal;
A radio receiver that demodulates the signal that has passed through the bandpass filter;
The bandpass filter functions as an AC / DC converter that converts an electric signal input to a DC signal when the radio receiver does not perform demodulation and obtains power necessary for circuit operation. A direct current converter,
A frequency division multiplex receiver, wherein the wireless receiver and a band-pass filter / AC / DC converter are provided for each of the plurality of frequencies.   Each of the band pass filters and AC / DC converters includes a MOS transistor in which one of drain sources is connected to an input terminal and the other to an output terminal, and a capacitive element connected between the output terminal and a fixed potential, The gate of the MOS transistor is connected to a sampling clock when functioning as a band-pass filter, and the gate of the MOS transistor is connected to the input terminal when functioning as an AC / DC converter. Item 7. The frequency multiplexing receiver according to item 5 or 6.   8. The function of each of the band pass filters and AC / DC converters is switched to the AC / DC converter within a data symbol period upon completion of demodulation of the corresponding frequency component. Frequency multiplex receiver.   Each of the band pass filters and AC / DC converters can perform a demodulation operation or a power regeneration operation by arbitrarily switching between a band pass filter function and an AC / DC conversion function using a data symbol period as a minimum unit for switching. The frequency multiplex receiver according to any one of claims 5 to 7.   Among the band pass filters / AC / DC converters, at least some of the band pass filters / AC / DC converters are configured to function as AC / DC converters at the start of reception. The frequency multiplex receiver according to claim 9. An operation method of a frequency multiplex receiver that receives an electric signal multiplexed at a plurality of frequencies and demodulates a signal of each frequency component,
The frequency multiplex receiver is:
A first filter;
A second filter having a frequency characteristic different from that of the first filter;
A receiving unit for extracting demodulated data from the input electrical signal;
An AC / DC converter for converting the input electric signal into a DC signal to obtain electric power necessary for circuit operation;
With
Of the plurality of frequencies, an operation of inputting a first frequency that has passed through the first or second filter to the receiving unit to extract demodulated data, and inputting the first frequency to the AC / DC converting unit. The operation for obtaining power is performed in a time-sharing manner, and in parallel with the time-sharing operation,
Of the plurality of frequencies, the second frequency that has passed through the second or first filter is input to the receiving unit and the demodulated data is extracted, and the second frequency is input to the AC / DC converting unit. A method of operating a frequency multiplex receiver, characterized in that the operation of obtaining power is performed in a time division manner.

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