JP2006229828A - Pulse receiver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pulse receiver capable of realizing the suppression of malfunction due to an interfering signal, quick synchronous recatching, stable synchronizing hold, and low error demodulation. <P>SOLUTION: The band limit and pulse width of a communication pulse signal received by a receiving signal 101 are changed so that an interfering wave signal 112 is suppressed by a filter 102 and the communication pulse signal is suited to demodulation in a demodulation circuit 103, and an output pass pulse signal is inputted to the demodulation circuit 103. In the demodulation circuit 103, a pulse position is extracted by a detector 104 and inputted to a correlator 107, a signal for determining a receiving signal timing is also input from a clock source 105 to the correlator 107 to perform correlation processing, a correlation discriminator 108 discriminates an error of signal timing by a signal obtained as the result of correlation processing to adjust the delay time of a delay 106, and demodulation is started after making the timing of the receiving signal to coincide with the signal timing of a receiving side apparatus. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a pulse receiving apparatus that receives a communication pulse signal used for broadband communication and the like.

  In addition to the rapid spread of wireless LAN devices represented by IEEE 802.11b, a society where a seamless network has been established by wirelessly connecting AV devices and personal computers to each other is expected. A communication method called an ultra wide band (hereinafter referred to as UWB) using a pulse-like modulation signal has been attracting attention.

  There is an urgent need to establish a technology for suppressing interference waves and realizing a high-speed data communication device at low cost.

FIG. 11 shows a configuration of a conventional pulse receiving apparatus. In a communication system using a spread spectrum technique, a control signal capable of changing a notch frequency from an interfering wave detection circuit 1104 is given to a variable notch filter 1103 so that an interfering wave is generated. A pulse receiving apparatus that suppresses is disclosed (see Patent Document 1).
Japanese Patent Laid-Open No. 9-326713

  However, in the conventional configuration, the interference wave can be suppressed. However, for the communication using the communication pulse signal by a single pulse such as UWB, the malfunction is suppressed by the interference wave and the synchronization acquisition in a short time and the stable A technique for realizing synchronization maintaining and low error demodulation in association is not disclosed.

  The present invention solves such a problem, and provides a pulse receiver that realizes suppression of malfunction due to an interference signal, synchronization acquisition in a short time, stable synchronization maintenance, and low error demodulation. Objective.

  The pulse receiving device of the present invention includes a communication pulse filter that limits a band of at least a part of a frequency component of a received communication pulse signal and changes a pulse width of the communication pulse signal, and a passing pulse signal that has passed through the communication pulse filter. And a demodulation circuit that demodulates the signal based on the pulse width.

  With this configuration, by receiving a part of the spread band of the communication pulse, the influence of the interference signal is eliminated, and the pulse width of the pulse signal demodulated by the demodulation circuit is set to an appropriate pulse width to filter the interference signal. By separating, signals that do not contain high-power level interference signals are demodulated to increase reception accuracy, and further, by limiting the band with a filter, the pulse width for demodulation processing is expanded to reduce the required accuracy for synchronization acquisition, etc. As a result, synchronization acquisition in a short time, stable synchronization maintenance, and low-error demodulation can be realized.

  The pulse receiving device of the present invention has a configuration in which the communication pulse filter is a filter that appropriately changes a frequency component to be band-limited. With this configuration, the reception band is appropriately changed depending on the presence or absence of interfering signals and optimized to reduce the effect, and the required accuracy such as synchronization acquisition is increased by widening or narrowing the pulse width for demodulation processing. Or speeding up and stabilizing the communication with high synchronization accuracy.

  In addition, the pulse receiving apparatus of the present invention has a configuration that realizes the change of the frequency component to be band-limited by changing the characteristics of the impedance variable element that constitutes the communication pulse filter. With this configuration, the pass band of the filter can be easily changed.

  In addition, the pulse receiving apparatus of the present invention has a configuration in which the change of the frequency component to be band limited is realized by switching a plurality of communication pulse filters having different frequency components to be band limited. With this configuration, the pass band of the filter can be easily changed.

  In addition, the pulse receiving device of the present invention narrows the frequency band of the passing pulse signal at the start of reception and captures synchronization with the demodulation circuit, then widens the frequency band of the passing pulse signal and establishes synchronization with the demodulating circuit. It has the composition to do. With this configuration, it is possible to suppress interference caused by a narrowband communication signal at the start of reception, perform synchronization acquisition gently with a wide pulse, and then establish high-precision synchronization with a narrow pulse to realize high-speed communication.

  In the pulse receiving apparatus of the present invention, the frequency band of the passing pulse signal is widened at the start of reception, and the demodulating circuit captures the synchronization, and then the frequency band of the passing pulse signal is narrowed and demodulated by the demodulating circuit. It has a configuration. With this configuration, a large amount of power is received at the start of reception, a signal having a large amplitude is used for acquisition of synchronization, and then the occupied band is narrowed, thereby reducing the influence from other devices including the same system.

  The pulse receiver of the present invention further includes a reception power detection unit that detects the reception power of the communication pulse signal, and when the reception power detected by the reception power detection unit is large, the frequency component to be band-limited is increased and reception is performed. When the received power detected by the power detector is small, the frequency component to be band-limited is reduced. With this configuration, when the received power is high, the pass band can be narrowed to prevent excessive input, and when the received power is low, the pass band can be widened to obtain a larger received power, thereby stabilizing the reception quality. it can.

  The pulse receiving apparatus of the present invention further includes a random number generating unit that generates a random number, and has a configuration that appropriately changes the frequency component to be band-limited based on the random number generated by the random number generating unit. With this configuration, it is possible to reduce deterioration in demodulation quality by shortening and randomizing the time during which an interference wave is input.

  In the pulse receiving device of the present invention, the demodulation circuit includes a correlation signal generation unit that generates a correlation signal for correlation processing, a correlation signal filter having characteristics correlated with the characteristics of the communication pulse filter, and a correlation signal And a correlator that correlates the passing pulse signal with the correlation signal that has passed through the filter. With this configuration, the interference wave can be more strongly suppressed.

  Furthermore, in the pulse receiving device of the present invention, the demodulation circuit distributes the delay signal from the passing pulse signal, the delay device delays the delay signal distributed by the distributor for a desired time, and the delay circuit delays the delay signal. And a delay detector that delay-detects the passing pulse signal that has passed through the distributor using the delayed signal. With this configuration, the communication pulse filter and the correlation signal filter can be used together to more strongly suppress the interference wave.

  The present invention provides a communication pulse filter that limits a band of at least a part of a frequency component of a received communication pulse signal and changes a pulse width of the communication pulse signal, and a passing pulse signal that has passed through the communication pulse filter. And receiving a part of the spread band of the communication pulse, thereby eliminating the influence of the interference signal and reducing the pulse width of the pulse signal demodulated by the demodulation circuit to an appropriate pulse width. By setting it to, the interference signal is separated by a filter, thereby demodulating a signal that does not contain a high-power level interference wave, and improving the reception accuracy. By reducing the required accuracy of synchronization acquisition, etc., it is possible to achieve synchronization acquisition in a short time, stable synchronization maintenance, and low error demodulation. It is capable of providing a pulse receiving apparatus having an effect that it is.

  Hereinafter, a pulse receiver according to an embodiment of the present invention will be described with reference to the drawings.

(Embodiment 1)
FIG. 1 is a block diagram showing a configuration of a pulse receiving apparatus according to Embodiment 1 of the present invention, a diagram showing frequency characteristics, and a diagram showing signal waveforms. In FIG. 1, the communication pulse signal received by the receiving antenna 101 is extracted by the filter 102 only with a signal in an appropriate frequency band (band limitation) and input to the demodulation circuit 103. A pulse position of the passing pulse signal (also referred to as a reception signal) input to the demodulation circuit 103 is extracted by the detector 104 and input to the correlator 107.

  The correlator 107 also receives a signal from the clock source 105 that determines the timing of the received signal, performs a correlation process, and determines a signal timing error from the resultant signal by the correlation determiner 108, and exceeds the allowable error. If there is a difference in timing, the delay time of the delay unit 106 is adjusted, and this is repeated until the timing of the received signal matches the signal timing of the receiving side device. After this timing coincides, demodulation is started at a later stage (not shown).

  Signals at various parts of the pulse receiving device will be described with reference to FIGS. FIG. 1B shows the frequency characteristics of the received power, and shows that the desired wave signal 111 and the narrowband jamming wave signal 112 exist. The frequency characteristic of the filter 102 is the filter characteristic 113, and a signal that does not include the interference wave signal 112 is input to the demodulation circuit 103 by using this. For example, when a transmission signal as shown in FIG. 1C is output from a pulse transmission device (not shown), the pulse reception device includes an interference wave signal 112 from another narrowband communication device in proximity, for example, A signal as shown in FIG. 1 (d) is received.

  In this example, since the continuous interfering wave signal 112 is added to the transmission pulse signal of FIG. 1C, the received signal waveform has a noise power increased. If this signal is demodulated as it is, a demodulation error of the signal is likely to occur, and reception performance, for example, sensitivity is deteriorated. Therefore, by extracting a signal in a band that does not include an interfering wave signal by the filter 102, a signal as shown in FIG. 1E is generated, and demodulation of the signal can be reduced by demodulating the signal. In addition, since the signal in FIG. 1E has a wider pulse width than the signal shown in FIG. 1C, the signal can be easily detected and synchronized, and the synchronization acquisition time can be shortened.

  As shown in the configuration of the above pulse receiving device, the band is limited by appropriately setting the characteristics of a filter that receives a part of the received pulse, and the received pulse is suitable for the suppression of malfunction due to an interference signal and the synchronization / demodulation processing. By setting the width, it is possible to realize a pulse receiving device that can realize synchronization acquisition in a short time, stable synchronization maintenance, and low error demodulation.

  In the above description, the configuration in which band limitation is always performed by a filter has been described. However, for example, a configuration may be used in which the presence or absence of band limitation is switched as appropriate using a changeover switch or the like. The filter type is not limited to the band pass filter (BPF), but may be a low pass filter (LPF), a high pass filter (HPF), or a notch filter.

  Moreover, although the modulation system used for communication is not described, there is no limitation by the communication system. For example, OOK (On-Off keying), BPSK (Biphase Shift keying), QPSK (Quadrature Phase Shift Keying), PPM (Pulse) (Position Modulation) or the like may be used.

  In addition, when a modulation method such as BPSK or QPSK that uses information is used, it is not a circuit that detects only the pulse amplitude described in this embodiment, and for example, a synchronous detection configuration, a delayed detection configuration, etc. are required. Needless to say. Furthermore, although the above description does not describe despreading processing as a pulse receiving device and circuit functions for realizing them, it is possible to implement a spread spectrum communication function by appropriately installing a block that realizes this. Needless to say.

(Embodiment 2)
FIG. 2 is a block diagram showing a configuration of the pulse receiving apparatus according to Embodiment 2 of the present invention. The difference from the first embodiment is that the filter can be appropriately changed with a variable band.

  In the demodulating circuit 201 of FIG. 2, the interference wave detector 202 detects the presence of the interference wave based on the output of the detector 104, and the band of the band variable filter 202 is set so as to receive a signal in a band not including the interference wave. Control to change. FIG. 3 is a diagram showing an image of band change of the band variable filter in the pulse receiving apparatus of the present embodiment. For example, the filter characteristic at the start of reception is the filter characteristic 301a, and is set to receive a band including the interference wave signal 112. Therefore, even if the passing pulse signal that has passed through the band variable filter 202 is demodulated, In the demodulation circuit 201, many demodulation errors occur. Therefore, by changing the characteristic of the variable band filter 202 to the filter characteristic 301b under the control of the interference wave detector 203, the demodulation circuit 201 can demodulate a signal having no interference wave as a passing pulse signal, and has few errors. Demodulation becomes possible.

  2 shows an example in which the filter characteristic is changed by changing the capacitance component constituting the filter. However, as shown in FIG. 4, a plurality of filters 403a to 403c having different frequency characteristics and the switches 402a and 402b are used to change the band characteristics. The variable filter 401 may be configured so that the reception band can be changed by selecting an arbitrary filter. In the present invention, including other embodiments to be described later, the variable band filter 202 is not limited to the BPF, and the variable band filter 401 is not limited to the notch filter.

  FIG. 5 is a flowchart showing the band switching operation of the band variable filter according to the present embodiment. In this example, the reception band is divided into a plurality of small bands, the filter type is BPF, and the filter band is switched to select each.

  When reception is started, the reception band is set first, for example (S501, S502), and a signal in this band is detected (S503). If a signal is detected here (Yes in S503), synchronization acquisition is started (S504). If no signal is detected (No in S503), the reception band is set to the second (S505, S502), and the signal is detected. (S503). The reception band is changed until the signal can be detected. If the signal cannot be detected even if the signal is detected in all reception bands, the signal is detected again from the first.

  When correlation processing for acquisition of synchronization is started (S504), the delay time is changed until correlation is detected (S506 to S508). After the correlation is detected (Yes in S507), the reception band is expanded one band at a time, thereby narrowing the pulse width of the reception signal and establishing synchronization with higher time accuracy (S509, S510). If correlation cannot be detected due to interference waves, noise, multipath, etc., the reception band is stopped from being widened (S511, S512), and data demodulation is started in the reception band with the best correlation.

  As shown in the configuration of the above pulse receiving apparatus, at the start of reception and thereafter, by demodulating the passing pulse signal by changing the band and pulse width for passing the communication pulse signal, suppression of malfunction due to interference signals, By performing reception pulse width control suitable for synchronization / demodulation processing, it is possible to realize a pulse receiver capable of realizing synchronization acquisition in a short time, stable synchronization maintenance, and low error demodulation.

  Although the case where the reception band at the start of reception is set to the first is described, the present invention is not limited to setting the reception band at the start of reception to the same number every time. The reception band number may be changed.

(Embodiment 3)
FIG. 6 is a flowchart showing the band switching operation of the pulse receiving apparatus according to Embodiment 3 of the present invention. The difference from Embodiment 2 is that the widest reception band is set at the start of reception, and the operation is performed to narrow the band appropriately.

  In FIG. 6, when reception starts, the number of reception bands is set to the total number (S601), and a signal in this band is detected (S602). If a signal is detected (Yes in S602), synchronization acquisition is started (S603), and if it cannot be detected (No in S602), after an appropriate time has passed (S604), the signal is detected again (S602). The signal detection is repeated until the signal can be detected. When correlation processing for acquisition of synchronization is started (S603), the delay time is changed until correlation can be detected (S605 to S607).

  After the correlation is detected (Yes in S606), the reception band is narrowed one band at a time, so that the band necessary for reception is reduced, and even if signals from other devices are received by the antenna, the effect Can be reduced (S608, S609). If the correlation cannot be detected due to the influence of interference wave, noise, multipath, etc., the reception band is narrowed and data demodulation is started in the reception band having the best correlation (S610, S611).

  As shown in the configuration of the above pulse receiver, interference is obtained by changing the band and pulse width for band limiting a part of the frequency component of the communication pulse signal at the start of reception and thereafter to obtain a passing pulse signal. It is possible to realize a pulse receiving apparatus capable of performing reception pulse width control suitable for suppression of malfunction due to signals and synchronization / demodulation processing, and realizing synchronization acquisition in a short time, stable synchronization maintenance, and low error demodulation.

  In the present invention, the passband center frequency when the number of reception bands is sequentially narrowed is not limited to the case where it changes sequentially, but may be fixed. Further, the present invention may be configured such that the number of reception bands at the start of reception can be changed by the learning function without being limited to maximize the number of reception bands at the start of reception each time.

(Embodiment 4)
FIG. 7 is a flowchart showing the band switching operation of the pulse receiving apparatus according to the fourth embodiment of the present invention. The difference from Embodiment 2 is that the widest reception band is set at the start of reception, and the operation is performed so that the band is appropriately changed in order to set the reception power to an appropriate value.

  In FIG. 7, when reception is started, the number of reception bands is set to the total number (S701, S702), and a signal in this band is detected (S703). Here, the signal level is detected (S704), and if it is an appropriate value (S704 appropriate level), synchronization acquisition is started (S705). If it exceeds the appropriate value (S704 overinput), the number of received bands is set. Decrease by 1 (S706). The reception band is reduced until the signal level reaches an appropriate value. When correlation processing for acquisition of synchronization is started (S705), the delay time is changed until correlation can be detected (S707 to S709).

  After the correlation is detected (Yes in S708), the reception band is then narrowed one band at a time, so that the band required for reception is reduced, and even if signals from other devices are received by the antenna, the effect Can be reduced (S710, S711). If the correlation cannot be detected due to the influence of interference wave, noise, multipath, etc., the reception band is narrowed and data demodulation is started in the reception band with the best correlation (S712, S713).

  As shown in the configuration of the above pulse receiver, the reception power control is performed by changing the band and the pulse width through which the received communication pulse signal passes at and after the start of reception by using a filter. By performing synchronization / demodulation processing at the power level, it is possible to realize a pulse receiver capable of realizing synchronization acquisition in a short time, stable synchronization maintenance, and low-error demodulation.

  As in the other embodiments, the present invention can change the number of reception bands at the start of reception by the learning function without limiting to the maximum number of reception bands at the start of reception every time. It may be.

(Embodiment 5)
FIG. 8 is a block diagram showing the configuration of the pulse receiving apparatus according to the fifth embodiment of the present invention. The difference from Embodiments 1 and 2 is that the band of the filter is randomly changed using an appropriate random number.

  In FIG. 8, a signal received by the receiving antenna 101 is input to the band variable filter 801, and a signal in an arbitrary band is blocked and output. In this embodiment, a trap filter is described. However, the present invention is not limited to this, and only a signal in an arbitrary band may pass. The output of the band-variable filter 801 is input to the detector 104, establishes synchronization with the output signal of the clock source 105 using the correlator 107, the correlation determiner 108, and the delay unit 106, and outputs demodulated data. Here, the band variable filter 801 is variable in band as described above, but the band is determined by the random number generator 802, and unlike other embodiments, interference wave detection, received signal level, or received pulse width. It is configured so as not to be related to

  As shown in the configuration of the above pulse receiving device, by randomly changing the band for receiving the received pulse, the influence of the interference wave, multipath, etc. depending on the frequency band is diffused and suppressed, the interference wave, By performing synchronization / demodulation processing with a received signal having a small influence such as multipath, it is possible to realize a pulse receiver capable of realizing synchronization acquisition in a short time, stable synchronization maintenance, and low error demodulation.

  In the above embodiment, the band variable filter 801 has been described as a configuration that randomly changes the band to be passed and blocked. However, it is also possible to set the band to be passed and blocked at the same time, and The same can be implemented even when the band width filter 801 changes the reception bandwidth at random.

(Embodiment 6)
FIG. 9 is a block diagram showing the configuration of the pulse receiving apparatus according to the sixth embodiment of the present invention. The difference from Embodiments 1, 2, and 5 is that the demodulation circuit is equipped with a synchronous detection function, and the waveform correlation signal is subjected to the same filter control as that of the received signal, so that a waveform correlation with a higher degree of correlation can be obtained. This is what we are doing.

  In FIG. 9, only the signal in the frequency band controlled by the band controller 907 by the band variable filter 901a is output as a passing pulse signal from the communication pulse signal received by the receiving antenna 101 and input to the waveform correlator 905. A waveform correlator 905, a waveform correlation determiner 906, a delay unit 904, and a waveform correlation signal generator 903 are circuit blocks that realize a synchronous detection function. The waveform correlation signal generated by the waveform correlation signal generator 903 and the passing pulse signal are Synchronous detection is performed by adjusting the timing to synchronize. At this time, the waveform correlation signal is subjected to band limitation by the band variable filter 901b similar to that of the pass pulse signal, thereby performing waveform conversion similar to that of the pass pulse signal, and a signal having higher correlation is output. Note that the band controller 907 controls the bands of the band variable filters 901a and 901b.

  As shown in the configuration of the above pulse receiver, when the received pulse is synchronously detected, the waveform correlation signal is also subjected to the same band conversion by performing the same band limitation as the passing pulse signal, so that a signal with higher correlation is obtained. By greatly reducing the effects of interference waves, noise, multipath, etc., and performing synchronization / demodulation processing with received signals with small effects, synchronization acquisition in a short time, stable synchronization maintenance and low A pulse receiver capable of realizing error demodulation can be realized.

  Although the above embodiment has been described using the configuration of synchronous detection, FIG. 10 shows another embodiment. FIG. 10 is a block diagram showing a configuration of a pulse receiving apparatus according to another embodiment of the present invention. The configuration of FIG. 9 is different from that of FIG. 9 in that it includes a distributor 1002 and does not have a band variable filter 901 b and a waveform correlation signal generator 903.

  In FIG. 10, the pass pulse signal, which is the output of the variable band filter 901a, is distributed to the delay signal by the distributor 1002, the delay amount at the delay device 1003 is set based on the determination result of the waveform correlation determiner 906, and the waveform correlation. By performing delay detection with the device 905, even if the band-variable filter in the demodulator circuit 1001 is not required, it can be implemented in the same manner as in FIG.

  As described above, the pulse receiving apparatus according to the present invention eliminates the influence of the interference signal by receiving a part of the spread band of the communication pulse, and sets an appropriate pulse width of the pulse signal demodulated by the demodulation circuit. By setting the width to separate the interference signal with a filter, the signal that does not contain the interference signal with a large power level is demodulated to improve the reception accuracy, and further, the band width is limited by the filter to widen the pulse width for demodulation processing. Therefore, by reducing the required accuracy of synchronization acquisition, etc., it is possible to achieve synchronization acquisition in a short time, stable synchronization maintenance and low error demodulation, and communication pulses used for broadband communication etc. It is useful as a pulse receiver for receiving signals.

The block diagram which shows the structure of the pulse receiver in Embodiment 1 of this invention, the figure which shows a frequency characteristic, and the figure which shows a signal waveform The block diagram which shows the structure of the pulse receiver in Embodiment 2 of this invention. The figure which shows the band change image of the band variable filter of the pulse receiver in Embodiment 2 of this invention. The block diagram which shows the band variable filter of the pulse receiver in Embodiment 2 of this invention Flow chart showing the operation of the pulse receiving apparatus according to the second embodiment of the present invention. Flow chart showing the operation of the pulse receiving apparatus according to the third embodiment of the present invention. The flowchart which shows operation | movement of the pulse receiver in Embodiment 4 of this invention. The block diagram which shows the structure of the pulse receiver in Embodiment 5 of this invention. Block diagram showing a configuration of a pulse receiving apparatus according to Embodiment 6 of the present invention. The block diagram which shows the structure of the pulse receiver in other embodiment of this invention. Block diagram showing the configuration of a conventional pulse receiver

Explanation of symbols

101 receiving antenna 102, 403a, 403b, 403c filter 103, 201, 902, 1001 demodulator circuit 104 detector 105 clock source 106, 904, 1003 delay unit 107 correlator 108 correlation determiner 111 desired wave signal 112 jamming wave signal 113, 301a, 301b Filter characteristics 202, 401, 801, 901a, 901b Band variable filter 203 Interference wave detector 402a, 402b Switch 802 Random number generator 903 Waveform correlation signal generator 905 Waveform correlator 906 Waveform correlation determiner 907 Band controller 1002 Distributor

Claims (10)

Based on the pulse width, a communication pulse filter that limits the band of at least part of the frequency component of the received communication pulse signal and changes the pulse width of the communication pulse signal, and a passing pulse signal that has passed through the communication pulse filter. And a demodulating circuit for demodulating. The pulse receiving device according to claim 1, wherein the communication pulse filter is a filter that appropriately changes the frequency component to be band-limited. The pulse receiving device according to claim 2, wherein the change of the frequency component for band limitation is realized by changing a characteristic of an impedance variable element constituting the communication pulse filter. 4. The pulse receiving device according to claim 2, wherein the change of the frequency component to be band-limited is realized by switching a plurality of communication pulse filters having different frequency components to be band-limited. The frequency band of the pass pulse signal is narrowed at the start of reception and synchronization is acquired by the demodulator circuit, and then the frequency band of the pass pulse signal is widened and synchronization is established by the demodulator circuit. Item 5. The pulse receiving device according to any one of Items 4 to 6. The frequency band of the pass pulse signal is widened at the start of reception, and after the synchronous acquisition is performed by the demodulator circuit, the frequency band of the pass pulse signal is narrowed and demodulated by the demodulator circuit. 5. The pulse receiving device according to any one of 4 above. A reception power detection unit that detects reception power of the communication pulse signal is further included. When the reception power detected by the reception power detection unit is large, the frequency component to be band-limited is increased and detected by the reception power detection unit. The pulse receiving device according to any one of claims 2 to 6, wherein when the received power is small, the frequency component to be band limited is reduced. 5. The pulse receiving device according to claim 2, further comprising a random number generation unit that generates a random number, wherein the change of the frequency component for band limitation is appropriately changed based on the random number generated by the random number generation unit. . The demodulation circuit includes a correlation signal generation unit that generates a correlation signal for correlation processing, a correlation signal filter having characteristics correlated with the characteristics of the communication pulse filter, and a correlation signal that has passed through the correlation signal filter. The pulse receiver according to claim 1, further comprising a correlator that performs correlation processing on the passing pulse signal. The demodulating circuit includes a distributor that distributes a delay signal from the passing pulse signal, a delay that delays the delay signal distributed by the distributor for a desired time, and a delay signal that is delayed by the delay The pulse receiving apparatus according to claim 1, further comprising: a delay detector that delay-detects a passing pulse signal that has passed through the distributor.

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