JP5642863B1 - COMMUNICATION DEVICE, COMMUNICATION METHOD, BAND DIVISION CIRCUIT, AND BAND SYNTHESIS CIRCUIT - Google Patents

Abstract

An object of the present invention is to prevent the occurrence of intersymbol interference resulting from the division of a band dispersion adapter and to improve signal transmission characteristics. A division filter that divides a sub-modulation signal having the lowest frequency and a sub-modulation signal having the highest frequency among a plurality of division filters of the band division circuit has a filter coefficient that retains frequency characteristics of a transition region of the modulation signal. Among the plurality of extraction filters of the band synthesis circuit, the extraction filter for extracting the submodulation signal with the lowest frequency and the submodulation signal with the highest frequency is a filter coefficient that holds the frequency characteristics of the transition region of the received signal. The modulation signal having the root roll-off characteristic is input from the band synthesis circuit to the reception circuit, and the modulation signal having the full roll-off characteristic is demodulated by the demodulator. [Selection] Figure 1

Description

  The present invention relates to a communication apparatus used for wireless communication or wired communication, in which a plurality of different users effectively use a limited frequency band, and a signal transmitted by dividing the frequency band from the transmission apparatus is received by the reception apparatus. The present invention relates to a communication apparatus, a communication method, a band dividing circuit, and a band synthesizing circuit that perform band demodulation and demodulation processing.

FIG. 7 shows a configuration example of a conventional communication device (see Non-Patent Document 1). FIG. 7A shows a transmitting apparatus, and FIG. 7B shows a receiving apparatus.
In FIG. 7 (a), the transmission apparatus includes a modulator 1, a root roll-off filter 2, and a band dividing circuit 10. The modulator 1 modulates the data signal to be transmitted by a modulation method such as QPSK, and inputs the modulated signal whose waveform is shaped via the root roll-off filter 2 to the band dividing circuit 10.

The band division circuit 10 includes a series-parallel conversion circuit 12, an FFT (Fast Fourier Transform) circuit 13, division filters 14 _{1 to} 14 _N (N is an integer of 2 or more), a frequency shifter 15 ₁ to 15 _N , an addition circuit 16, and an IFFT. (Fast Inverse Fourier Transform) A circuit 17, a parallel-serial converter circuit 18, and a D / A converter 19 are provided, and the band of the modulation signal is divided into N parts and distributed and transmitted on the frequency axis. An example of dividing the modulation signal band into three (N = 3) is shown in FIG.

The modulation signal input to the band dividing circuit 10 is serial-parallel converted and fast Fourier transformed by the FFT circuit 13 to convert the time domain signal to the frequency domain signal (FIG. 8 (a)). The division filters 14 _{1 to} 14 _N multiply the modulated signal converted into the frequency domain by a filter coefficient for dividing the signal band indicated by the broken line in FIG. Generate a signal. The frequency shifters 15 ₁ to 15 _N disperse and arrange the sub-modulated signals in a desired band on the frequency axis, and add them by the adder circuit 16 to generate sub-modulated signals that are distributed and arranged (FIG. 8 ( c)). The sub-modulated signal after the distributed arrangement is converted from a frequency domain signal to a time domain signal by high-speed inverse Fourier transform in the IFFT circuit 17, and converted into a transmission signal by parallel-serial conversion and D / A conversion.

In FIG. 7 (b), the receiving device includes a band synthesis circuit 20 and a demodulator 6. The band synthesis circuit 20 includes an A / D converter 21, a serial-parallel conversion circuit 22, an FFT circuit 23, extraction filters 24 _{1 to} 24 _N , frequency shifters 25 _{1 to} 25 _N , an adder circuit 26, an IFFT circuit 27, and parallel-serial conversion. A circuit 28 is provided, and a sub-modulated signal whose band is divided into N is synthesized with a modulated signal before division and demodulated. An example of synthesizing a modulation signal whose band is divided into three (N = 3) is shown in FIG.

The received signal input to the band synthesizing circuit 20 is A / D converted and serial / parallel converted, and fast Fourier transformed by the FFT circuit 23 to convert the time domain signal to the frequency domain received signal (FIG. 9A). . Each of the extraction filters 24 _{1 to} 24 _N multiplies the reception signal converted into the frequency domain by a filter coefficient indicated by a broken line in FIG. Is extracted (FIG. 9 (c)). The frequency shifters 25 _{1 to} 25 _N return the extracted sub-modulated signal to the band before being frequency-shifted on the transmission side, and add it by the adding circuit 26 to generate a synthesized modulated signal (FIG. 9 ( d)). The combined modulation signal is converted from a frequency domain signal to a time domain signal by high-speed inverse Fourier transform in the IFFT circuit 27, and is subjected to parallel-serial conversion and output. The demodulator 6 demodulates the modulation signal output from the band synthesis circuit 20 and restores the data signal transmitted from the transmission device.

  By using such a transmission device and reception device, each sub-modulation signal generated by dividing the occupied band of the modulation signal can be distributed and distributed at arbitrary locations on the frequency axis, so that it is discontinuous among different users. It is possible to effectively use a vacant frequency band.

Abe, Yamashita, Kobayashi: "Proposal of spectrum-editing band-dispersed transmission to achieve high frequency utilization efficiency" IEICE Tech. Reports SAT2009-48, Dec 2009. Abe, Yamashita, Nakahira, Kobayashi: “Examination of frequency utilization efficiency improvement of existing satellite communication earth station by spectrum editing type band dispersion transmission” IEICE Technical Report SAT2010-67, Oct 2010.

On the transmission side, as shown in FIG. 8 (c), the filter coefficients of the division filters 14 _{1 to} 14 _N are designed so that each divided sub-modulated signal has a root roll-off characteristic. The characteristics of the division filters 14 ₁ and 14 _N are spectrum-edited asymmetrically.

When the roll-off rate of the single carrier modulation signal shown in FIG. 8A is α and the roll-off rate of the sub-modulation signal after division is β, the filters of the division filters 14 _{1 to} 14 _N shown in FIG. The coefficient Hd _k (f) is expressed by the following equation.

ここで、ｆは周波数、ｆ_{c k} は分割後のサブ変調信号ｋの中心周波数、Ｂはロールオフフィルタの半値幅、Ｂ_k はサブ変調信号ｋの半値幅である。また、ルートロールオフ関数Ｈ(α,ｆ,Ｂ)は、次式で表される。

Where f is the frequency and f _{c k} is the center frequency of the divided sub-modulation signal k, B is the half-value width of the roll-off filter, and B _k is the half-value width of the sub-modulation signal k. The root roll-off function H (α, f, B) is expressed by the following equation.

On the receiving side, as shown in FIG. 9 (a), for the sub-modulated signal having the root roll-off characteristic with the roll-off rate β, as the extraction filters 24 _{1 to} 24 _N , the root roll-off with the same roll-off rate β is obtained. The filter is multiplied (FIG. 9 (b)). As a result, as shown in FIG. 9 (c), the extracted sub-modulated signal has a full roll-off characteristic with a roll-off rate β.

  Each extracted sub-modulated signal is frequency-shifted to the band before division and synthesized. At this time, because the frequency is reduced by 6 dB in the adjacent sub-modulated signal, that is, the frequencies corresponding to the cutoff frequency in the filter characteristics of the extraction filter are combined, as shown in FIG. A single carrier modulation signal having a full roll-off characteristic is obtained. Since this signal has a full roll-off characteristic, no intersymbol interference occurs, so that it can be demodulated by the demodulator 6 as it is.

  Here, only the band dividing circuit 10 and the band synthesizing circuit 20 shown in FIG. 7 are taken out, and this is used as a “band distribution adapter” to constitute a wireless communication system as shown in FIG. 10 (Non-Patent Document 2). That is, the wireless station A and the wireless station B insert a band dispersion adapter between the existing modem that transmits and receives an existing single carrier modulation signal and the antenna, and divide the output signal of the existing modem on the frequency axis by the band dispersion adapter. In addition, the frequency utilization efficiency is improved by distributing and arranging the unused bands.

FIG. 11 shows a circuit configuration example of an existing modem and a bandwidth distribution adapter.
In FIG. 11, the transmission circuit of the existing modem is composed of a modulator 1, a root roll-off filter 2, and a D / A converter 3, and generates and outputs a band-limited single carrier modulation signal. The band dividing circuit 10 of the band distribution adapter has a configuration in which an A / D converter 11 is added to the configuration shown in FIG. 7A, and performs A / D conversion and serial-parallel conversion on the output signal of the transmission circuit, and an FFT circuit. 13 converts the signal from the time domain to the frequency domain, generates a plurality of sub-modulated signals having root roll-off characteristics by the division filters 14 _{1 to} 14 _N, and distributes them in the unused band by the frequency shifters 15 ₁ to 15 _N The IFFT circuit 17 converts the signal into a time domain signal, performs parallel-serial conversion and D / A conversion, and outputs a transmission signal.

The band synthesizing circuit 20 of the band distribution adapter has a configuration in which a D / A converter 29 is added to the configuration shown in FIG. 7 (b), receives a received signal, performs A / D conversion and serial-parallel conversion, and an FFT circuit. 23, a signal in the time domain is converted into a signal in the frequency domain, sub-modulated signals having full roll-off characteristics are extracted by the extraction filters 24 _{1 to} 24 _N , and shifted to the band before the division by the frequency shifters 25 _{1 to} 25 _N , Synthesize. The synthesized signal is a single carrier modulation signal having a full roll-off characteristic. This is converted into a signal in the time domain by the IFFT circuit 27, subjected to parallel-serial conversion and D / A conversion, and input to the receiving circuit of the existing modem.

  The reception circuit of the existing modem includes an A / D converter 4, a root roll-off filter 5 and a demodulator 6. The output signal of the band synthesis circuit 20 is A / D converted and multiplied by the root roll-off filter 5. Demodulated by the demodulator 6. However, the output signal of the band synthesizing circuit 20 already has a full roll-off characteristic as shown in FIG. 9 (d) or FIG. 12 (d). For this reason, as shown in FIGS. 12E and 12F, if the root roll-off filter 5 is further multiplied in the receiving circuit, the roll-off characteristic is not satisfied, and intersymbol interference occurs. Therefore, there is a problem that the signal transmission characteristics deteriorate.

  An object of the present invention is to provide a communication device, a communication method, a band dividing circuit, and a band synthesizing circuit that can prevent the occurrence of intersymbol interference due to the division of the band dispersion adapter and improve the signal transmission characteristics. .

According to a first aspect of the present invention, an opposing radio station includes a modem having a transmission circuit and a reception circuit, and a band distribution adapter having a band dividing circuit connected to the transmission circuit and a band synthesis circuit connected to the reception circuit. The band division circuit includes a plurality of division filters that generate sub-modulation signals divided into a plurality of bands on the frequency axis from the modulation signal input from the transmission circuit , and each sub-modulation signal is placed at an arbitrary location on the frequency axis. The transmission signal is distributed and the band synthesis circuit is equipped with multiple extraction filters that extract each sub-modulated signal from the received signal that received the transmission signal of the opposite radio station, and the band of each sub-modulated signal is distributed outputting a modulated signal by combining back to the previous band to the receiving circuit, the receiving circuit is input to the demodulator a modulated signal outputted from the band combining circuit via the Le chromatography trawl off filter In the communication device configured to adjust, the division filter that divides the sub-modulation signal of the lowest frequency and the sub-modulation signal of the highest frequency among the plurality of division filters of the band division circuit has the frequency characteristics of the transition region of the modulation signal, respectively. It has a filter coefficient for holding, and a broad wide-band filter than the bandwidth of the asymmetric filter or said sub modulation signal of the filter coefficient is asymmetric, among the plurality of extraction filter band synthesizing circuit, sub-modulation signal and the lowest frequency extracting filter for extracting a sub-modulation signal of the highest frequency have a filter coefficient for holding the frequency characteristic of the transition band of the respective received signals, and the filter coefficient is wider than the bandwidth of the asymmetric filter or said sub modulation signal asymmetrical a wide-band filter, a modulation signal having a root roll-off characteristic from the band combining circuit Enter the root roll-off filter signal circuit, which demodulates the input to the demodulator to generate a modulated signal having a full Ruroruofu characteristics.

According to a second aspect of the present invention, an opposing radio station includes a modem having a transmission circuit and a reception circuit, and a band distribution adapter having a band dividing circuit connected to the transmission circuit and a band synthesis circuit connected to the reception circuit. The modulation signal is input from the transmission circuit to the band division circuit, and the band division circuit generates a sub modulation signal divided into a plurality of bands on the frequency axis from the modulation signal by a plurality of division filters, and the frequency of each sub modulation signal is generated. A transmission signal distributed at an arbitrary location on the axis is output, and the band synthesis circuit extracts each sub-modulated signal from the reception signal that has received the transmission signal of the opposite radio station by a plurality of extraction filters , outputting a modulated signal band synthesized back to the band before distributed modulated signal, the receiver circuit is input to a demodulator modulated signal outputted from the band combining circuit via the Le chromatography trawl off filter Among the plurality of division filters of the band division circuit, the division filter that divides the sub-modulation signal with the lowest frequency and the sub-modulation signal with the highest frequency holds the frequency characteristics of the transition region of the modulation signal, respectively. A filter coefficient having a left-right asymmetric filter coefficient or a filter coefficient that is wider than the bandwidth of the sub-modulation signal, and having the lowest frequency sub-modulation signal and the highest frequency of the plurality of extraction filters of the band synthesis circuit Each extraction filter that extracts a sub-modulated signal has a filter coefficient that retains the frequency characteristics of the transition region of the received signal, and has a filter coefficient that is asymmetrical to the left or right , or a filter coefficient that is wider than the bandwidth of the sub-modulated signal. , root roll-off filter of the receiving circuit a modulated signal having a root roll-off characteristic from the band combining circuit Type, demodulates input to the demodulator to generate a modulated signal having a full Ruroruofu characteristics.

A third invention includes a modem having a transmission circuit and a reception circuit, and a band distribution adapter having a band dividing circuit connected to the transmission circuit and a band synthesizing circuit connected to the reception circuit, in a radio station facing each other. The band division circuit includes a plurality of division filters that generate sub-modulation signals divided into a plurality of bands on the frequency axis from the modulation signal input from the transmission circuit , and each sub-modulation signal is placed at an arbitrary location on the frequency axis. The transmission signal is distributed and the band synthesis circuit is equipped with multiple extraction filters that extract each sub-modulated signal from the received signal that received the transmission signal of the opposite radio station, and the band of each sub-modulated signal is distributed outputting a modulated signal by combining back to the previous band, the reception circuit is configured to demodulate the input to the demodulator via a modulated signal outputted from the band combining circuit Le chromatography trawl off filter In the band dividing circuit of the communication apparatus, among the plurality of division filters, the division filter that divides the sub-modulation signal with the lowest frequency and the sub-modulation signal with the highest frequency is a filter that holds the frequency characteristics of the transition region of the modulation signal, respectively. It has a coefficient, and the filter coefficient is wider broadband filter than the bandwidth of the asymmetric filter or said sub modulation signal asymmetrical.

According to a fourth aspect of the present invention, in the band synthesizing circuit of the communication apparatus including the band dividing circuit according to the third aspect of the present invention, the extraction filter for extracting the lowest frequency sub-modulated signal and the highest frequency sub-modulated signal among the plurality of extraction filters is , have a filter coefficient for holding the frequency characteristic of the transition band of the respective received signals, and a broad wide-band filter than the bandwidth of the asymmetric filter or said sub modulation signal of the filter coefficients is asymmetrical, root roll-off from the band combining circuit It receives the modulation signal having the characteristics on the root roll-off filter of the reception circuit, and demodulates input to the demodulator to generate a modulation signal having a full Ruroruofu characteristics.

  According to the present invention, a transmission-side band dividing circuit divides a modulation signal output from a transmission device such as an existing modem into a plurality of sub-modulation signals, and distributes them on the frequency axis for transmission. In the reception side band synthesis circuit, a modulated signal extracted from the received signal and synthesized is input to a receiving apparatus such as an existing modem. In such a configuration, by using a filter coefficient that retains the frequency characteristics of the transition region of the signal before division at the time of division and extraction, a modulation signal having a root roll-off characteristic is input from the band synthesis circuit to the reception circuit and demodulated. The demodulator can demodulate the modulated signal having the full roll-off characteristic, prevent the occurrence of intersymbol interference, and improve the transmission characteristic.

  Further, the band dividing circuit and the band synthesizing circuit can be used as a band distribution adapter by being connected to a transmission circuit and a reception circuit of an existing modem.

It is a figure which shows the structure of Example 1 of the communication apparatus of this invention. It is a figure which shows the example of a band division in the band division circuit 10A of Example 1. FIG. It is a figure which shows the band synthetic | combination example in 20 A of band synthetic | combination circuits of Example 1. FIG. It is a figure which shows the structure of Example 2 of the communication apparatus of this invention. It is a figure which shows the example of a band division in the band division circuit 10B of Example 2. FIG. It is a figure which shows the band synthesis example in the band synthesis circuit 20B of Example 2. FIG. It is a figure which shows the structural example of the conventional communication apparatus. It is a figure which shows the example of a band division in the conventional band division circuit. It is a figure which shows the band synthetic | combination example in the conventional band synthetic | combination circuit 20. FIG. It is a figure which shows the structural example of the radio | wireless communications system using a band dispersion | distribution adapter. It is a figure which shows the circuit structural example of the existing modem and a band distribution adapter. It is a figure which shows the example of a band synthesis in the existing modem and a band distribution adapter.

FIG. 1 shows a configuration of a communication apparatus according to a first embodiment of the present invention.
In FIG. 1, the bandwidth distribution adapter of the communication apparatus according to the first embodiment includes a band division circuit 10A connected to a transmission circuit of an existing modem and a band synthesis circuit 20A connected to a reception circuit of the existing modem.

In the band dividing circuit 10A, the low frequency side and high frequency side dividing filters 14 ₁ and 14 _N of the band dividing circuit 10 of the band distribution adapter shown in FIG. 11 are replaced with transition band preserving type dividing filters 14A ₁ and 14A _N. Others have the same configuration. The band synthesis circuit 20A replaces the extraction filters 24 ₁ and 24 _N on the low frequency side and the high frequency side of the band synthesis circuit 20 of the band dispersion adapter shown in FIG. 11 with the transition band preserving type extraction filters 24A ₁ and 24A _N. Others have the same configuration.

The filter coefficients of the transition region preserving division filters 14A ₁ and 14A _N and the transition region preserving extraction filters 24A ₁ and 24A _N are left-right asymmetric or filter coefficients having a frequency characteristic wider than the bandwidth of the sub-modulation signal. Thus, the characteristics of the transition region of the single carrier modulation signal output from the transmission circuit of the existing modem are maintained, and the division and synthesis of the single carrier modulation signal are realized.

The band division circuit 10A performs A / D conversion and serial / parallel conversion on the single carrier modulation signal output from the transmission circuit of the existing modem, and converts the signal from the time domain to the frequency domain by the FFT circuit 13, and performs the transition area preserving division The signals are divided into a plurality of sub-modulated signals by the filters 14A ₁ and 14A _N and the division filters 14 _{2 to} 14 _N−1 .

An example in which the modulation signal band is divided into three (N = 3) is shown in FIG. Here, due to the transition band preserving division filters 14A ₁ and 14A ₃ , one sub-modulation signal on the low frequency side and the high frequency side is left-right asymmetric, or a filter coefficient having a frequency characteristic wider than the bandwidth of the sub-modulation signal. Is divided by a filter having That is, the low-frequency-side transition region preserving division filter 14A ₁ is a filter coefficient that passes the frequency characteristics of the transition region of the single carrier modulation signal as it is. For example, as shown in FIG. 2 (b1), the left half is an asymmetric filter that is a rectangular filter, or as shown in FIG. 2 (b2), it is a broadband filter having a transition band as a pass band. The filter coefficients in FIG. 2 (b2) may be left-right symmetric or left-right asymmetric.

Similarly, the transition region preserving division filter 14A ₃ on the high frequency side is a filter coefficient that passes the frequency characteristic of the transition region of the single carrier modulation signal as it is. For example, as shown in FIGS. 2 (b1) and 2 (b2), the right half is an asymmetric filter that is a rectangular filter or a broadband filter.

The low-frequency side and high-frequency side sub-modulated signals divided by the transition band preserving division filters 14A ₁ and 14A ₃ have different left and right roll-off rates as shown in FIG. The division filters 14 ₂ (˜14 _N-1 ) other than the left end and the right end are symmetric root roll-off filters.

The sub-modulated signals generated by these division filters are shifted to an unused band on the frequency axis by the frequency shifters 15 ₁ to 15 _N , converted into a signal on one frequency axis by the adder circuit 16, and then the IFFT circuit In 17, the signal is converted into a signal in the time domain, serial-parallel converted and D / A converted, and transmitted.

The same applies to the band synthesizing circuit 20A. The received signal is A / D converted and serial-parallel converted, converted from a time domain signal to a frequency domain signal by the FFT 23, and the transition area preserving extraction filters 24A ₁ and 24A _N and the extraction filter 24 _A plurality of sub-modulated signals are extracted from _{2 to} 24 _N-1 .

An example in which the modulation signal band is divided into three (N = 3) is shown in FIG. Here, by the transition band preserving extraction filters 24A ₁ and 24A ₃ , one sub-modulation signal on the low frequency side and the high frequency side has a left-right asymmetrical filter coefficient having a frequency characteristic wider than the bandwidth of the sub-modulation signal. Is extracted with a filter having That is, the transition zone preserving extraction filter 24A ₁ of the low frequency side, and as filter coefficients to pass a frequency characteristic of the transition band of the received signal. For example, as shown in FIG. 3 (b1), the left half is an asymmetric filter that is a rectangular filter, or as shown in FIG. 3 (b2), it is a broadband filter having a transition band as a pass band. The filter coefficients in FIG. 3 (b2) may be left-right symmetric or left-right asymmetric.

Similarly, the transition band preserving extraction filter 24A ₃ of the high-frequency side, and as filter coefficients to pass a frequency characteristic of the transition band of the received signal. For example, as shown in FIGS. 3 (b1) and 3 (b2), the right half is an asymmetric filter that is a rectangular filter or a broadband filter.

The low-frequency side and high-frequency side sub-modulated signals extracted by the transition band preserving type extraction filters 24A ₁ and 24A ₃ have different left and right roll-off rates as shown in FIG. The extraction filters 24 ₂ (˜24 _N−1 ) other than the left end and the right end are symmetric root roll-off filters.

The sub-modulated signals generated by these extraction filters are shifted to the band before division by the frequency shifters 25 _{1 to} 25 _N and synthesized by the adder circuit 26. This is converted into a signal in the time domain by the IFFT circuit 27, and serial-parallel conversion and D / A conversion are performed. As a result, a single carrier modulation signal having a root roll-off characteristic is generated (FIG. 3 (d)). This is input to the receiving circuit of the existing modem.

  As described above, the output signal of the band synthesizing circuit 20A of the band dispersion adapter has the root roll-off characteristic, so that the modulation signal having the full roll-off characteristic is obtained by multiplying the root roll-off filter 5 by the receiving circuit of the existing modem. (FIGS. 3E and 3F), it is possible to prevent the occurrence of intersymbol interference and improve the transmission characteristics.

FIG. 4 shows the configuration of a second embodiment of the communication apparatus of the present invention.
In FIG. 4, the band distribution adapter of the communication apparatus according to the second embodiment includes a band division circuit 10B connected to a transmission circuit of an existing modem and a band synthesis circuit 20B connected to a reception circuit of the existing modem.

The band dividing circuit 10B uses the dividing filters 14 _{2 to} 14 _N-1 of the band dividing circuit 10A according to the first embodiment shown in FIG. 1 as asymmetric dividing filters 14B _{2 to} 14B _N− whose filter coefficients (roll-off rates) are asymmetrical. The configuration is the same except that it is replaced with ₁ . Other band synthesizing circuit 20B is the extraction filter 24 ₂ to 24 _N-1 of the first embodiment shown in FIG. 1, the filter coefficients (roll-off rate) was replaced with asymmetric extraction filter 24B ₂ ~24B _N-1 asymmetrical Has the same configuration.

The filter coefficients of the transition region preserving division filters 14A ₁ and 14A _N and the transition region preserving extraction filters 24A ₁ and 24A _N are asymmetrical to the left or right, or a frequency characteristic wider than the bandwidth of the submodulation signal. By using the filter coefficient having the above, the characteristics of the transition region of the single carrier modulation signal output from the transmission circuit of the existing modem are maintained, and the division and synthesis of the single carrier modulation signal are realized. However, the asymmetric division filters 14B ₂ and 14B _N−1 adjacent to the transition region preserving division filters 14A ₁ and 14A _N , respectively, and the asymmetric extraction filters 24B ₂ and adjacent to the transition region preserving extraction filters 24A ₁ and 24A _N , respectively. 24B _N-1 has the following restrictions.

Examples of dividing the modulation signal band into three (N = 3) are shown in FIGS.
As shown in FIGS. 5 (b1) and 5 (b2), the filter coefficient in the transition region (right end) on the high frequency side of the transition region preserving division filter 14A ₁ on the low frequency side and the low coefficient of the adjacent asymmetric division filter 14B ₂ are shown. It is assumed that the filter coefficients in the frequency side transition region (left end) are generated with a line-symmetric relationship, that is, with the same roll-off rate. The same applies to the asymmetric splitting filter 14B ₂ adjacent to the transition zone preserving splitting filter 14A ₃ of the high frequency side.

FIG 6 (b1), as shown in (b2), the filter coefficient of the transition band preserving extract the high-frequency side of the transition band of the filter 24A ₁ of the low frequency side (right end) of the adjacent asymmetric extraction filter 24B ₂ Low It is assumed that the filter coefficients in the frequency side transition region (left end) are generated with a line-symmetric relationship, that is, with the same roll-off rate. The same applies to asymmetric extraction filter 24B ₂ adjacent to the transition zone preserving extraction filter 24A ₃ of the high frequency side.

  The filter coefficient of each division filter of the band synthesis circuit 20B needs to have the same filter coefficient as that of the division filter that generates the transition band in the transmission-side band division circuit 10B, that is, the roll-off rate must be the same. .

DESCRIPTION OF SYMBOLS 1 Modulator 2 Root roll-off filter 3 D / A converter 4 A / D converter 5 Root roll-off filter 6 Demodulator 10, 10A, 10B Band division circuit 11 A / D converter 12 Serial-parallel conversion circuit 13 FFT ( Fast Fourier transform) circuit 14 _{1 to} 14 _N division filter 14A ₁ , 14A _N transition band preserving division filter 14B _{2 to} 14B _N-1 asymmetric division filter 15 ₁ to 15 _N frequency shifter 16 addition circuit 17 IFFT (fast inverse Fourier transform) ) Circuit 18 Parallel-serial conversion circuit 19 D / A converter 20, 20A, 20B Band synthesis circuit 21 A / D converter 22 Series-parallel conversion circuit 23 FFT (Fast Fourier Transform) circuit 24 _{1 to} 24 _N extraction filter 24A ₁ , 24A _N transition region preserving extraction filter 24B _{2 to} 24B _N-1 asymmetric extraction filter 25 _{1 to} 25 _N frequency shifter 2 6 Adder Circuit 27 IFFT (Fast Inverse Fourier Transform) Circuit 28 Parallel Serial Converter 29 D / A Converter

Claims (4)

A radio station facing the modem includes a modem having a transmission circuit and a reception circuit, and a band distribution adapter having a band dividing circuit connected to the transmission circuit and a band synthesis circuit connected to the reception circuit,
The band division circuit includes a plurality of division filters that generate sub-modulation signals that are divided into a plurality of bands on the frequency axis from the modulation signal input from the transmission circuit , and each sub-modulation signal is arbitrarily placed on the frequency axis. Output transmission signals distributed in
The band synthesizing circuit includes a plurality of extraction filters that extract the sub-modulated signals from the received signal that has received the transmission signal of the opposing radio station, and sets the bands of the sub-modulated signals to the bands before the distributed arrangement. The modulated signal synthesized by returning is output to the receiving circuit ,
The receiving circuit is a communication device is configured to demodulate the input to the demodulator via the Le chromatography trawl-off filter a modulated signal outputted from said band combining circuit,
Among the plurality of division filter of the band-splitting circuit, dividing filter for dividing the sub-modulation signal of sub-modulation signal and the maximum frequency of the lowest frequency is to have a filter coefficient for holding the frequency characteristic of the transition band of each of the modulated signal , And a wideband filter whose filter coefficient is asymmetrical left / right or wider than the bandwidth of the sub-modulated signal,
Of the plurality of extraction filters of the band synthesis circuit, the extraction filter for extracting the sub-modulation signal of the lowest frequency and the sub-modulation signal of the highest frequency has a filter coefficient that holds the frequency characteristics of the transition region of the received signal, respectively. Yes and, and a broad wide-band filter than the bandwidth of the asymmetric filter or said sub modulation signal of the filter coefficients are asymmetrical,
Wherein a modulated signal having a root roll-off characteristic from the band combining circuit is input to the root roll-off filter of the reception circuit, and demodulates input to the demodulator to generate a modulated signal having a full Ruroruofu characteristics A communication device. A radio station facing the modem includes a modem having a transmission circuit and a reception circuit, and a band distribution adapter having a band dividing circuit connected to the transmission circuit and a band synthesis circuit connected to the reception circuit,
It receives the modulation signal to the band-splitting circuit from the transmission circuit,
The band dividing circuit generates a sub modulation signal that is divided into a plurality of bands on the frequency axis from the modulation signal by a plurality of division filters, and a transmission signal in which each sub modulation signal is dispersedly arranged at an arbitrary place on the frequency axis Output
The band combining circuit from the received signal which has received the transmission signal of the radio station to the opposed, extracts before Stories each sub-modulated signals in a plurality of extraction filters, the bandwidth before the distributed bandwidth of each sub-modulated signal To output the combined modulation signal
The receiving circuit is a communication method of demodulating by inputting a modulation signal outputted from said band combining circuit to the demodulator via the Le chromatography trawl-off filter,
Of the plurality of division filters of the band division circuit, the division filter that divides the sub-modulation signal having the lowest frequency and the sub-modulation signal having the highest frequency each has a filter coefficient that holds the frequency characteristics of the transition region of the modulation signal. And a filter coefficient that is wider than the bandwidth of the left-right asymmetric filter coefficient or the sub-modulated signal,
Of the plurality of extraction filters of the band synthesis circuit, the extraction filter for extracting the sub-modulation signal of the lowest frequency and the sub-modulation signal of the highest frequency has a filter coefficient that holds the frequency characteristics of the transition region of the received signal, respectively. And having a filter coefficient that is wider than the bandwidth of the left-right asymmetric filter coefficient or the sub-modulated signal,
Wherein a modulated signal having a root roll-off characteristic from the band combining circuit is input to the root roll-off filter of the reception circuit, and demodulates input to the demodulator to generate a modulated signal having a full Ruroruofu characteristics Communication method. A radio station facing the modem includes a modem having a transmission circuit and a reception circuit, and a band distribution adapter having a band dividing circuit connected to the transmission circuit and a band synthesis circuit connected to the reception circuit,
The band division circuit includes a plurality of division filters that generate sub-modulation signals that are divided into a plurality of bands on the frequency axis from the modulation signal input from the transmission circuit , and each sub-modulation signal is arbitrarily placed on the frequency axis. Output transmission signals distributed in
The band synthesizing circuit includes a plurality of extraction filters that extract the sub-modulated signals from the received signal that has received the transmission signal of the opposing radio station, and sets the bands of the sub-modulated signals to the bands before the distributed arrangement. outputting a modulated signal by combining back,
The receiving circuit in the band division circuit of the band-modulated signal outputted from the combining circuit via the Le chromatography trawl-off filter is configured to demodulate the input to the demodulator communication device,
Among the plurality of division filter, dividing filter for dividing the sub-modulation signal of sub-modulation signal and the maximum frequency of the lowest frequency is to have a filter coefficient for holding the frequency characteristic of the transition band of each of said modulated signal, and filter coefficients Is a left-right asymmetric filter or a wideband filter wider than the bandwidth of the sub-modulated signal . In the band synthesizing circuit of the communication device including the band dividing circuit according to claim 3,
Among the plurality of extraction filters, extracting filter for extracting a sub-modulation signal of the sub-modulation signal and the maximum frequency of the lowest frequency is to have a filter coefficient for holding the frequency characteristic of the transition band of the respective said received signals, and A wideband filter having a filter coefficient wider than the bandwidth of the submodulated signal
Wherein a modulated signal having a root roll-off characteristic from the band combining circuit is input to the root roll-off filter of the reception circuit, and demodulates input to the demodulator to generate a modulated signal having a full Ruroruofu characteristics A band synthesis circuit.

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