JP5587487B1 - Receiving apparatus and receiving method - Google Patents

Abstract

To prevent clipping of a received signal, appropriately operate a subsequent spectrum equalization process, and reduce an error rate of a demodulated signal.
An AGC circuit that corresponds to a finite dynamic range of A / D conversion, reduces the clip area according to control information that determines the size of the clip area of a band-synthesized signal, and is necessary for spectrum equalization processing Further, the gain adjustment of the amplitude control circuit is performed, and further, the first demodulation circuit and the second demodulation circuit are controlled to degenerate the reference signal point whose position has been changed by the gain adjustment.
[Selection] Figure 1

Description

  The present invention divides a modulated signal from a transmitting device into a plurality of sub-spectrums, receives signals transmitted by being distributed in vacant bands, and band-synthesizes and demodulates the sub-spectrums extracted from the signals. The present invention relates to a receiving apparatus and a receiving method for receiving a signal transmitted by removing a partial band of a sub-spectrum and performing a demodulation process in a transmission system.

  In wireless communication and wired communication, improvement in frequency band utilization efficiency is required as demand increases. In order to improve the utilization efficiency of the frequency band, the spectrum of the modulated signal is divided into a plurality of sub-spectrums from the transmitting device, further distributed in the vacant band and transmitted, and the receiving device receives the plurality of sub-spectrums. There is a band dispersion transmission technique for performing band synthesis and demodulating the original modulated signal. In this technique, unused bandwidths scattered on the frequency axis can be used to reduce unused bandwidths. Furthermore, by deleting a part of the spectrum band in the transmission apparatus, the total occupied bandwidth of the signal can be reduced and the frequency band utilization efficiency can be improved (Non-Patent Documents 1 and 2).

FIG. 3 shows a configuration example of a conventional transmission apparatus.
In FIG. 3, the transmission device includes a modulation circuit 51, a transmission filter bank 52, and a D / A converter 61. The modulation circuit 51 modulates a data signal to be transmitted by a modulation method such as QPSK, and inputs the waveform-shaped modulation signal to the transmission filter bank 52.

  The transmission filter bank 52 includes a serial-parallel conversion circuit 53, an FFT (Fast Fourier Transform) circuit 54, a division circuit 55, N switches (N is an integer of 2 or more), switches 56-1 to 56-N, N The frequency shifters 57-1 to 57-N, the adder circuit 58, the IFFT (Inverse Fast Fourier Transform) circuit 59, and the parallel-serial converter circuit 60 are provided, and the modulation signal band is divided into N sub-spectrums. It is the structure which transmits by dividing | segmenting. FIG. 5 shows an example of dividing the modulation signal band into two (N = 2).

  The serial / parallel conversion circuit 53 of the transmission filter bank 52 performs serial / parallel conversion on the modulation signal, and fast Fourier transforms the FFT circuit 54 to convert the signal in the time domain into the signal in the frequency domain. The dividing circuit 55 multiplies the modulated signal converted into the frequency domain by a coefficient for dividing the signal band indicated by the broken line in FIG. 5A into N, and the N sub-spectrum 1 shown in FIG. ~ N are generated. The frequency shifters 57-1 to 57-N perform a frequency shift operation for distributing and arranging the N sub-spectrums in the vacant bands on the frequency axis, and adding them by the adding circuit 58, the result shown in FIG. A sub-spectrum distributed as shown is generated. The sub-spectrum after the distributed arrangement is converted from a frequency domain signal to a time domain signal by fast inverse Fourier transform in the IFFT circuit 59, and parallel-serial converted by the parallel-serial conversion circuit 60 and output. Further, the output signal of the transmission filter bank 52 is converted into an analog signal by the D / A converter 61 and transmitted.

  At this time, for the band to be partially deleted, before inputting to the frequency shifters 57-1 to 57-N, the switches 56-1 to 56-N corresponding to the sub-spectrum to be deleted are opened (OFF). To interrupt signal transmission. As a result, no signal component is arranged in the band, and transmission is performed with a part of the spectrum removed, so that the frequency band required for transmission can be reduced.

FIG. 4 shows a configuration example of a conventional receiving apparatus.
In FIG. 4, the receiving apparatus includes an A / D converter 71, a reception filter bank 72, and a demodulation circuit 81. The reception filter bank 72 includes a serial-parallel conversion circuit 73, an FFT circuit 74, an extraction circuit 75, N frequency shifters 76-1 to 76-N, a distortion compensation circuit 77, an addition circuit 78, an IFFT circuit 79, and a parallel-serial conversion circuit. 80, and a signal obtained by synthesizing a signal whose band is divided into N into a signal before division. An example of synthesizing a signal whose band is divided into two (N = 2) is shown in FIG.

  The A / D converter 71 of the receiving apparatus converts the received signal into a digital signal and inputs it to the reception filter bank 72. The serial / parallel conversion circuit 73 of the reception filter bank 72 performs serial / parallel conversion on the received signal, and fast Fourier transforms the FFT circuit 74 to convert the time domain signal into the frequency domain received signal. The extraction circuit 75 multiplies the received signal converted into the frequency domain by a filter coefficient indicated by a broken line in FIG. 6A, and extracts sub-spectrum 1 to N frequency-shifted on the transmission side. As shown in FIG. 6B, the frequency shifters 76-1 to 76 -N return the extracted sub-spectrums 1 to N to the bands before being frequency-shifted by the transmission device, and add them by the adder circuit 78. By combining them, a band-synthesized modulated signal shown in FIG. 6 (c) is generated. This band-synthesized modulation signal is converted from a frequency domain signal to a time domain signal by fast inverse Fourier transform in IFFT circuit 79, and parallel-serial conversion circuit 80 performs parallel-serial conversion and outputs the result. The demodulation circuit 81 demodulates the modulation signal output from the reception filter bank 72 and restores the data signal transmitted from the transmission device.

  At this time, with respect to the band from which the spectrum is removed by the transmission device, the signal of the band is not received by the reception device. Therefore, some compensation processing is required. For example, there may be a noise component not only having no signal component in this band but also causing deterioration in reception characteristics. Therefore, the distortion compensation circuit 77 outputs the received signal as it is in the band in which the signal is transmitted in the transmission apparatus, and performs compensation so that “0” is output in the band from which the signal is removed in the transmission apparatus. As a result, the noise component in the band from which the signal is removed in the transmission apparatus is removed, and the reception characteristics can be improved.

  As described above, between the transmitting device and the receiving device, the occupied band of the transmission signal is divided, each generated sub-spectrum is distributed and arranged at any location on the frequency axis, and some bands are deleted Then transmitted. Therefore, it is possible to effectively use discontinuous free bands and the like, reduce the total occupied bandwidth of signals, and improve the efficiency of using frequency bands.

  By the way, if distortion compensation is performed by inputting “0” in the band from which the signal is removed in the transmission apparatus, the noise component in this band is removed, but the spectrum in which this band is missing on the spectrum. It becomes. Therefore, since the error rate when the signal is demodulated becomes high, methods shown in Patent Document 1 and Non-Patent Document 2 are considered as methods for improving this.

  In this method, a received signal after band synthesis having a spectrum with a partial band missing is temporarily demodulated, and a transmission signal replica is generated by re-encoding and re-modulating based on the obtained received bit string. Then, it is decomposed into sub-spectrum replicas by the same band division filter as that of the transmission device, and a sub-spectrum replica corresponding to the sub-spectrum deleted in the transmission device is generated, and spectrum equalization is performed by adding to the received signal after band synthesis. This is to improve the error rate of the demodulated signal.

FIG. 7 shows a configuration example of a receiving apparatus based on Patent Document 1.
In FIG. 7, the receiving apparatus includes an AGC circuit 11, an A / D converter 12, a first serial-parallel conversion circuit 13, a first FFT circuit 14, an extraction circuit 15, a frequency shifter 16, an amplitude / phase control circuit 17, an addition circuit 18, First IFFT circuit 19, first parallel / serial conversion circuit 20, first demodulation circuit 21, first error correction decoding circuit 22, transmission signal replica generation circuit 23, second serial / parallel conversion circuit 24, second FFT circuit 25, amplitude control circuit 26, a dividing circuit 27, a reception buffer 28, a combining circuit 29, a second IFFT circuit 30, a second parallel / serial conversion circuit 31, a second demodulation circuit 32, and a second error correction decoding circuit 33.

  The A / D converter 12 to the first demodulation circuit 21 perform a process of restoring the data signal transmitted from the transmission device, similarly to the conventional reception device shown in FIG. The frequency shifter 16 and the amplitude / phase control circuit 17 have configurations corresponding to N sub-spectrums, but only one of them is shown here. The amplitude phase control circuit 17 detects the phase of the transition region of the adjacent sub-spectrum before synthesizing the sub-spectrum frequency-shifted by the frequency shifter 16 by the adder circuit 18 and calculates the relative phase difference and amplitude difference between the sub-spectrums. Perform correction processing. Although the distortion compensation circuit 77 shown in FIG. 4 is omitted, the addition circuit 18 performs distortion compensation by inputting “0” in order to remove a noise component in a band from which a signal has been removed in the transmission device. Processing is performed.

  The band-combined signal output from the adder circuit 18 is branched and stored in the reception buffer 28, converted into a time domain signal by the first IFFT circuit 19, and further converted by the first parallel / serial converter circuit 20. 1 Input to demodulator circuit 21. The first demodulation circuit 21 and the first error correction decoding circuit 22 perform temporary demodulation, and a transmission signal replica generation circuit 23 generates a transmission signal replica using the obtained temporary decoding sequence. The transmission signal replica generation circuit 23 includes, for example, a re-encoding circuit and a re-modulation circuit that use the same parameters as those of the transmission device. In addition, when a soft decision is used for provisional decoding, a replica signal is directly generated. A soft output replica may be substituted.

  The second serial / parallel conversion circuit 24 performs serial / parallel conversion on the transmission signal replica generated by the transmission signal replica generation circuit 23. The second FFT circuit 25 converts the transmission signal replica subjected to serial-parallel conversion from a time domain signal to a frequency domain signal and inputs the signal to the amplitude control circuit 26. The amplitude control circuit 26 receives the amplitude control value from the amplitude / phase control circuit 17 as control information, and adjusts the amplitude of the transmission signal replica based on this information. The transmission signal replica whose amplitude is adjusted is input to the dividing circuit 25, and only the sub-spectrum replica corresponding to the sub-spectrum deleted by the transmitting device is divided.

  The synthesizing circuit 29 adds the band synthesized signal (received signal spectrum) accumulated in the receiving buffer 28 and the amplitude-adjusted sub-spectrum replica in the frequency domain, and inputs them to the second IFFT circuit 30 for spectrum equalization. After being converted into a time domain signal as a received signal, it is input to the second demodulation circuit 32 via the second parallel-serial conversion circuit 31. The second demodulation circuit 32 and the second error correction decoding circuit 33 demodulate and decode the spectrum equalized reception signal to restore the reception data.

JP 2013-126088 A

Abe et al., "Proposal of blind type phase compensation method in band dispersion transmission and basic characteristic evaluation", IEICE technical report, SAT2011-35, Satellite communication, vol.111, no.179, pp.105-110, August 18, 2011 Masuno et al., “Proposal of waveform equalization using sub-spectrum replica in spectrum-suppressed transmission”, IEICE General Conference Proceedings 2011, B-3-9, p.290, February 28, 2011 Masuno et al., "Experimental verification of self-spectrum regeneration equalization effect in spectrum compression transmission", IEICE Technical Report, SAT2013-27, vol.113, no.193, pp.31-36, 2013 8 Moon

  In the receiving apparatus shown in FIG. 7, the amplitude / phase control circuit 17 is configured to control the phase and amplitude of the subspectrum based on the transmission path estimation. However, in a practical implementation, the A / D converter 12 having a finite dynamic range is used. Therefore, it is desirable to perform amplitude adjustment (AGC: Auto Gain Control) in the AGC circuit 11. This is because the waveform is prevented from being distorted by the influence of a quantization error, a nonlinear effect due to saturation, or the like by adjusting the amplitude in advance in the analog region before the A / D conversion. In general, gain adjustment can be performed so that each signal point (constellation) of the received signal on the IQ plane matches each signal point of the transmission signal generated with normalized power (a constant value such as 1). On the other hand, it is known that if spectrum-suppressed transmission is performed, the IQ constellation is greatly distorted and the dynamic range of the amplitude is expanded due to the effect of intersymbol interference caused by the loss of some frequency bands. (Non-patent Document 3).

  FIG. 8 (a) shows an example of IQ constellation of a QPSK modulated signal without spectrum suppression. Here, transmission signal points with respect to the dynamic range of the A / D changer 12 are shown, and noise is ignored for simplicity. FIG. 8B simulates an IQ constellation of a QPSK modulation signal in which intersymbol interference occurs due to spectrum suppression. In this case, if the center of the reception signal point is made to coincide with the transmission signal point (FIG. 8 (a)), some reception signal points exceed the dynamic range that can be expressed by the A / D converter 12, and are clipped. Will be. However, in this example, there is usually no problem because clipping does not affect the determination of the four signal points used in QPSK.

  However, in the receiving apparatus shown in FIG. 7, when spectrum equalization processing is performed in the synthesis circuit 29, a new received signal obtained by linearly synthesizing the sub-spectrum replica with the band-synthesized signal is transmitted by the second demodulation circuit 32. Demodulate. At this time, if the band-synthesized signal is distorted by clipping as shown in FIG. 8 (b), linear synthesis is not established, and there is a problem that spectrum equalization processing does not work. Therefore, as shown in FIG. 9, it is necessary to adjust the gain of the AGC circuit 11 so that a signal distorted by the influence of intersymbol interference falls within the dynamic range of the A / D converter 12.

  An object of the present invention is to provide a receiving apparatus and a receiving method that can prevent clipping of a received signal, appropriately operate a subsequent spectrum equalization process, and reduce an error rate of a demodulated signal.

In the first invention, a transmission device divides a transmission signal into a plurality of sub-spectrums and disperses them on the frequency axis, removes a part of the band, receives the transmitted signal, and receives the signal. A / D conversion is performed on the signal whose amplitude is automatically adjusted by the AGC circuit with a finite dynamic range, each sub-spectrum distributed on the frequency axis is extracted, and the signal obtained by performing band synthesis by returning to the frequency band before the dispersion is demodulated. in the receiving method of a step 1 for tentatively demodulated band synthesized signal in the first demodulation circuit, and step 2 to generate a transmission signal replica by remodulate tentatively demodulated signals, generated in step 2 and step 3 for generating a sub-spectrum replica by dividing a sub-spectrum of partially been removed by the transmitting apparatus from the transmission signal replica band, an amplitude control circuit, step Controlling the amplitude of the generated sub-spectrum replica, OR migration by controlling the amplitude of the generated transmission signal replica to the process of step 3, or in Step 3, Step 4 to generate a sub-spectrum replica is amplitude controlled Then, the band synthesized signal and the sub-spectrum replica whose amplitude is controlled in step 4 are synthesized to perform spectrum equalization processing, and the obtained signal is demodulated by the second demodulator circuit in step 5 ; The gain of the AGC circuit and the amplitude control circuit required for the spectrum equalization process in step 5 is reduced and the clip area is reduced in accordance with control information for determining the size of the clip area of the band synthesized signal corresponding to the finite dynamic range. Adjust the position of the first demodulator circuit and the second demodulator circuit by adjusting the gain. And a step 6 which performs control to degenerate the reference signal point changed.

  In the receiving method of the first invention, the control information is at least one of a band compression rate, a modulation scheme, an error correction coding scheme, and a coding rate in spectrum suppression transmission.

According to a second aspect of the invention, a transmission signal is divided into a plurality of sub-spectrums by a transmission device and distributed on the frequency axis, a signal transmitted by removing a part of the band is received, and the signal is received by an AGC circuit. A receiving device that performs A / D conversion on a signal with automatic amplitude adjustment in a finite dynamic range, extracts each sub-spectrum dispersedly arranged on the frequency axis, and demodulates the band-synthesized signal by returning to the frequency band before the dispersed arrangement The first demodulating circuit for temporarily demodulating the band-synthesized signal, the transmission signal replica generating means for generating the transmission signal replica by remodulating the temporarily demodulated signal, and the transmission signal replica generating means Sub-spectrum replica generation means for generating a sub-spectrum replica by dividing a sub-spectrum of a partial band removed from a transmission signal replica by a transmission device To control the amplitude of the sub-spectrum replica generated by the sub-spectrum replica Type or generation means or sub-spectrum replica generating means controls the amplitude of the transmission signal replica generated by the transmission signal replica generating means, amplitude control An amplitude control circuit that generates a sub-spectrum replica , a synthesis circuit that performs spectrum equalization processing by synthesizing a band-synthesized signal and a sub-spectrum replica that is amplitude-controlled by the amplitude control circuit, and spectrum equalization by the synthesis circuit A second demodulating circuit that demodulates the processed received signal and a finite dynamic range of A / D conversion, and the clip area is reduced according to control information that determines the size of the clip area of the band synthesized signal. AGC circuits and amplitude required spectrum equalization of the synthesis circuit with Adjusts the gain of the control circuit, comprising further to the first demodulator circuit and a second demodulation circuit, an AGC correction circuit for performing control to degenerate the reference signal point position by the gain adjustment is changed.

  In the receiving apparatus of the second invention, the control information input to the AGC correction circuit is at least one of a band compression rate, a modulation method, an error correction coding method, and a coding rate in spectrum suppression transmission.

  The present invention prevents the clipping of the received signal by adjusting the gain of the AGC circuit, and can appropriately operate the spectrum equalization process by applying the same offset to the transmission signal replica. Further, in the first demodulation circuit and the second demodulation circuit, the error rate of the demodulated signal can be reduced by degenerating the reference signal point whose position has been changed by gain adjustment and performing signal determination and likelihood calculation.

It is a figure which shows the Example structure of the receiver of this invention. It is a figure which shows the relationship between a zone | band compression rate and an AGC gain correction value. It is a figure which shows the structural example of the conventional transmitter. It is a figure which shows the structural example of the conventional receiver. It is a figure explaining the band division | segmentation in a transmitter. It is a figure explaining the zone | band synthesis | combination in a receiver. FIG. 11 is a diagram illustrating a configuration example of a receiving device based on Patent Literature 1. It is a figure which shows IQ constellation of a QPSK modulation signal. It is a figure which shows the subject in a spectrum equalization process.

FIG. 1 shows a configuration of an embodiment of a receiving apparatus according to the present invention.
In FIG. 1, the receiving apparatus of the present embodiment is similar to the receiving apparatus of FIG. 7 in that the AGC circuit 11, the A / D converter 12, the first series-parallel converting circuit 13, the first FFT circuit 14, the extracting circuit 15, the frequency Shifter 16, adder circuit 18, first IFFT circuit 19, first parallel-serial converter circuit 20, first demodulator circuit 21, first error correction decoding circuit 22, transmission signal replica generation circuit 23, second serial-parallel converter circuit 24, second 2 FFT circuit 25, amplitude control circuit 26, division circuit 27, reception buffer 28, synthesis circuit 29, second IFFT circuit 30, second parallel-serial conversion circuit 31, second demodulation circuit 32, second error correction decoding circuit 33, Instead of the amplitude / phase control circuit 17, a phase control circuit 42 that performs only phase control between sub-spectrums is provided. The amplitude adjustment for the first demodulator circuit 21 is performed by the AGC circuit 11 provided in front of the A / D converter 12. Further, the amplitude control circuit 26 of the present embodiment shows an example in which the amplitude control circuit 26 is disposed between the second FFT circuit 25 and the dividing circuit 27. However, the amplitude control circuit 26 may be present between the transmission signal replica generation circuit 23 and the synthesis circuit 29. May be.

  The feature of the present embodiment is that an AGC correction circuit 41 that controls the AGC circuit 11, the amplitude control circuit 26, the first demodulation circuit 21 and the second demodulation circuit 32 is provided.

  In the transmitter, when a part of the transmission signal spectrum is deleted by spectrum-suppressed transmission to reduce the occupied bandwidth, the bandwidth compression ratio, which is the ratio of the occupied bandwidth after deletion to the occupied bandwidth before deletion, is Determined. The AGC correction circuit 41 calculates a gain correction value according to the band compression rate, and offsets the AGC gain in the negative direction with respect to the AGC circuit 11 in order to prevent clipping of the received signal. Further, the AGC correction circuit 41 applies the same offset to the transmission signal replica generated with the normalized power inside the receiving apparatus, and performs gain control on the amplitude control circuit 26. As a result, the amplitude of the sub-spectrum replica is adjusted in accordance with the band-synthesized signal output from the adder circuit 18, so that the spectrum equalization process can be appropriately operated in the synthesis circuit 29.

  Further, due to the signal point degeneration caused by the gain adjustment of the AGC circuit 11 and the amplitude control circuit 26, the reference signal point position is changed from the position of x to the position of ● as shown in FIG. Reference signal point position change control is performed on the first demodulation circuit 21 and the second demodulation circuit 32. As a result, the first demodulation circuit 21 and the second demodulation circuit 32 can perform signal determination and likelihood calculation by degenerating reference signal points whose positions have been changed by gain adjustment, and reduce the error rate of the demodulated signal. be able to.

  The bandwidth compression rate may be notified from the transmission device to the reception device via a control line or the like, or the AGC correction circuit 41 of the transmission device and the reception device operates according to a preset bandwidth compression rate. Good.

  In addition, the AGC gain correction value for the band compression rate can be uniquely calculated by using an AGC correction table as shown in FIG. 2, for example. It also varies depending on the coding method and coding rate. The influence of intersymbol interference increases as (1) the modulation multi-level number increases, (2) the encoding scheme with lower error correction capability, (3) the encoding rate increases, and FIG. This is because the clip area indicated by is enlarged. Therefore, the AGC correction circuit 41 may calculate the AGC gain correction value according to the modulation method, the error correction coding method, and the coding rate without being limited to the band compression rate, and may perform the degeneration control of the reference signal point.

DESCRIPTION OF SYMBOLS 11 AGC circuit 12 A / D converter 13 1st serial-parallel conversion circuit 14 1st FFT circuit 15 Extraction circuit 16 Frequency shifter 17 Amplitude phase control circuit 18 Adder circuit 19 1st IFFT circuit 20 1st parallel-serial conversion circuit 21 1st demodulation circuit 22 first error correction decoding circuit 23 transmission signal replica generation circuit 24 second serial-parallel conversion circuit 25 second FFT circuit 26 amplitude control circuit 27 division circuit 28 reception buffer 29 synthesis circuit 30 second IFFT circuit 31 second parallel-serial conversion circuit 32 second 2 demodulation circuit 33 second error correction decoding circuit 41 AGC correction circuit 42 phase control circuit

Claims (4)

The transmission device divides the transmission signal into multiple sub-spectrums, distributes them on the frequency axis, removes some of the bands, receives the transmitted signal at the reception device, and automatically adjusts the amplitude of the signal by the AGC circuit In a receiving method of performing A / D conversion on a finite dynamic range, extracting each of the sub-spectrums distributed on the frequency axis, and demodulating the band-synthesized signal by returning to the frequency band before the distributed arrangement,
Step 1 for temporarily demodulating the band-synthesized signal with a first demodulation circuit;
Step 2 to generate a transmission signal replica by re modulating the tentatively demodulated signal,
And Step 3 for generating a sub-spectrum replica by dividing a sub-spectrum of the transmission part band removed by the device from the transmission signal replica generated by the step 2,
The amplitude control circuit controls the amplitude of the transmission signal replica generated in step 2 and shifts to the processing in step 3 or controls the amplitude of the sub-spectrum replica generated in step 3 to control the amplitude. and step 4 of creating the sub-spectrum replica that is,
And Step 5 performs spectrum equalization by combining sub-spectrum replica is amplitude controlled, demodulates the resultant signal by the second demodulation circuit in the step 4 and the band combined signal,
Corresponding to the finite dynamic range of the A / D conversion, the clip area is reduced according to control information for determining the size of the clip area of the band-synthesized signal, and necessary for the spectrum equalization processing in step 5 It adjusts the gain of the AGC circuit and the amplitude control circuit, with respect to further the first demodulator and the second demodulator circuit, and a step 6 which performs control to degenerate the reference signal point position is changed by the gain adjustment A receiving method comprising: The reception method according to claim 1,
The reception method according to claim 1, wherein the control information is at least one of a band compression rate, a modulation scheme, an error correction coding scheme, and a coding rate in spectrum suppression transmission. A transmission device divides a transmission signal into a plurality of sub-spectrums, disperses and arranges them on the frequency axis, receives a signal transmitted by removing a part of the band, and a signal obtained by automatically adjusting the amplitude of the signal by an AGC circuit. In a receiving apparatus that performs A / D conversion with a finite dynamic range, extracts each of the sub-spectrums distributed and arranged on the frequency axis, and demodulates a band-combined signal by returning to the frequency band before the distributed arrangement.
A first demodulating circuit for temporarily demodulating the band-synthesized signal;
Transmission signal replica generation means for generating a transmission signal replica by remodulating the temporarily demodulated signal;
Sub-spectrum replica generation means for generating a sub-spectrum replica by dividing a sub-spectrum of a partial band removed by the transmission device from the transmission signal replica generated by the transmission signal replica generation means;
Control the amplitude of the transmission signal replica generated by the transmission signal replica generation means and input to the sub-spectrum replica generation means , or control the amplitude of the sub-spectrum replica generated by the sub-spectrum replica generation means , An amplitude control circuit for generating an amplitude-controlled sub-spectrum replica ;
A synthesis circuit for performing spectrum equalization processing by synthesizing the band-synthesized signal and a sub-spectrum replica whose amplitude is controlled by the amplitude control circuit;
A second demodulating circuit for demodulating the received signal spectrum-equalized by the combining circuit;
Corresponding to the finite dynamic range of the A / D conversion, the clip area is reduced according to control information for determining the size of the clip area of the band synthesized signal, and necessary for spectrum equalization processing of the synthesis circuit. An AGC correction circuit that performs gain adjustment of the AGC circuit and the amplitude control circuit, and further controls the first demodulation circuit and the second demodulation circuit to degenerate a reference signal point whose position has been changed by the gain adjustment; A receiving apparatus comprising: The receiving apparatus according to claim 3,
The receiving apparatus, wherein the control information input to the AGC correction circuit is at least one of a band compression rate, a modulation method, an error correction coding method, and a coding rate in spectrum suppression transmission.

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