JP2012209667A - Frequency conversion device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce costs by flexibly meeting users' requests.SOLUTION: An input signal x(t) input into a signal division section 21 is divided into a plurality of adjacent band signals having a narrower signal bandwidth before being fed to a frequency conversion/combination processing section 25. The frequency conversion/combination processing section 25 includes: a plurality of modules 31 each integrally having a band signal input terminal 31a, a frequency conversion circuit 32, an A/D converter 33, a correction processing circuit 34, a combination signal input terminal 31d, a combination circuit 35 and a combination signal output terminal 31e; module holding means 40 for holding the plurality of modules 31 removable in a device; band signal connection means 41 for connecting the modules 31 thus held to the signal division section 21; and combination signal connection means 43 for connecting the combination signal output terminal 31e and the combination signal input terminal 31d sequentially between the different modules 31 thus held and outputting a full band combination signal from the final stage module 31.

Description

  The present invention reduces distortion due to instantaneous power of a wideband signal in a frequency converter used when performing waveform analysis and spectrum analysis of a high-frequency and wideband analog signal used in mobile communication, for example, with a digital analysis device. And a technique for realizing a wide dynamic range with a wide bandwidth.

  For example, a radio signal used in mobile communication is a modulated wave having a wide frequency band of several GHz or higher and several tens of MHz or higher. Conventionally, an analog spectrum analyzer has been used as an apparatus for performing such high-frequency and wideband signal analysis, for example, spectrum analysis.

  An analog spectrum analyzer has a configuration in which an analog signal to be measured is input to a mixer and mixed with a local signal, and the difference frequency component is extracted by a narrow-band filter. The frequency of the local signal is swept over a wide band. In general, the level of each frequency component included in the input analog signal is detected.

  However, when the analog signal to be measured is a broadband modulated wave as described above, the peak power to average power ratio becomes very large, and all the power is input to the mixer. This results in cross-modulation distortion exceeding the normal operating range, and errors in the measurement results.

  In order to prevent this, an attenuator is usually provided in front of the mixer to attenuate the peak power of the input signal so that it falls within the proper range, but this attenuator also reduces the average power level. There is a problem that the S / N of the signal is lowered and the measurement dynamic range is narrowed.

  In addition, as a method for solving the above problem, a filter selection method in which a plurality of filters having different bands can be selected at the front stage of the mixer and the front stage filter is selected according to the frequency of the local signal to the mixer, There is a tracking method in which a variable frequency type filter is provided at the front stage of the mixer, and the frequency of the filter changes following the frequency of the local signal.

  However, in any method, since the spectrum information of the input signal is obtained by sweeping the local signal, in principle, real time measurement cannot be performed.

  As an effective technique for solving this problem, a broadband input signal in a high frequency band is demultiplexed into a plurality of band signals, and the frequency conversion processing to the intermediate frequency band is performed on the signals in each band. Each signal converted to the intermediate frequency band is A / D converted into a digital signal sequence, and is further caused by a slight difference in signal path for each band, a slight sampling timing shift in A / D conversion, and the like. It has been proposed to convert real-time spectrum information of a wideband input signal in a high frequency band to a lower frequency band that is easy to digitally process with a high dynamic range by performing a multiplexing process after correcting the interband error. (Patent Document 1).

JP 2009-246958 A

  In the case of actually configuring the frequency conversion device having the above configuration, conventionally, a signal demultiplexing unit that demultiplexes an input signal into a plurality of band signals, a band signal divided into a plurality of series is converted into an intermediate frequency band, and A A frequency conversion unit that performs / D conversion, a correction processing unit that performs correction processing, and a multiplexing processing unit are provided, and the signals are sequentially passed between these units.

  However, when the apparatus is configured by unitizing the circuits in units of processing types and connecting them, the following problems occur.

  As the bandwidth of the target signal increases, the number of demultiplexes increases, and not only the signal demultiplexing unit, but all subsequent units must be changed, and eventually, of the signals that can be analyzed. Each unit must be configured in accordance with the bandwidth of the widest signal, and includes a circuit unnecessary for a user who targets only a narrow-band signal, resulting in high cost.

  In addition, even if there is an abnormality in signal processing in a specific band, it will be repaired by exchanging the entire unit at the abnormal part, and if the number of demultiplexing is large, the part fee for each unit is also expensive. This will cause more damage to the user than necessary.

  The present invention provides a frequency converter that solves this problem, can flexibly respond to user requests, saves unnecessary costs, and does not cause unnecessary damage to the user during maintenance such as repairs. It is an object.

In order to achieve the above object, the frequency conversion device according to claim 1 of the present invention provides:
A signal demultiplexing unit (21) for demultiplexing an input signal in a high frequency band into a plurality of adjacent band signals having a narrower width than the band of the input signal, and outputting each band signal from a plurality of output terminals (24), respectively. When,
Each band signal is subjected to frequency conversion processing to an intermediate frequency band, each signal converted to the intermediate frequency band is subjected to A / D conversion, and error correction processing caused by band demultiplexing is performed. A frequency converting / combining processing unit (25) for combining the input signals, and converting the input signal into a signal of a lower frequency band,
The frequency conversion / combining processing unit
A band signal input terminal (31a) for inputting the band signal, a frequency conversion circuit (32) for frequency-converting the band signal input to the band signal input terminal to a predetermined intermediate frequency band, and an output signal of the frequency conversion circuit A / D converter (33) that samples the signal and converts it into a digital signal sequence, and a correction that performs a correction process for errors caused by band demultiplexing on the digital signal sequence output from the A / D converter A processing circuit (34), a combined signal input terminal (31d) for inputting a combined signal, and a signal for combining the signal corrected by the correction processing circuit and the signal input to the combined signal input terminal A plurality of frequency conversion / combination processing modules (31) integrated with a wave circuit (35) and a combined signal output terminal (31e) for outputting a combined signal combined by the combining circuit )When,
Module holding means (40) for holding the plurality of frequency conversion / multiplexing processing modules in the apparatus in a detachable state;
A connector is connected between each band signal input terminal of each of the plurality of frequency conversion / multiplexing processing modules held by the module holding means and each output terminal of the signal branching unit, and each band signal is sent to each Band signal connection means (41) to be given to the frequency conversion / multiplexing module;
For the plurality of frequency conversion / multiplexing processing modules held in the module holding means, the connectors between the combined signal output terminal and the combined signal input terminal are sequentially connected between different modules, and the final stage It is characterized by comprising combining signal connecting means (43) for outputting combined signals for all bands from the combined signal output terminal of the combining circuit of the frequency conversion / combining processing module.

Moreover, the frequency converter of Claim 2 of this invention is the frequency converter of Claim 1,
The frequency of the local signal used by the frequency conversion circuit of each of the frequency conversion / multiplexing processing modules is equal, and the center of each intermediate frequency band is equal to the difference between the center frequencies of a plurality of adjacent bands of the signal demultiplexing unit. It is characterized by having.

The frequency converter according to claim 3 of the present invention is the frequency converter according to claim 1,
The frequency of the local signal used by the frequency conversion circuit of each frequency conversion / multiplexing processing module has a difference equal to the difference between the center frequencies of a plurality of adjacent bands of the signal demultiplexing unit, While converting the signal to a common intermediate frequency band,
A frequency shift circuit that gives a difference equal to a difference between center frequencies of a plurality of adjacent bands of the signal demultiplexing unit to signals input to the multiplexing circuit of each of the frequency conversion / multiplexing processing modules ( 38)
A synchronization circuit (39) for compensating for a phase error between bands caused by a difference in frequency of a local signal used by the frequency conversion circuit of each frequency conversion / combination processing module by phase correction of the local signal of the frequency shift circuit; It is provided.

  With this configuration, the frequency conversion device of the present invention is equipped with a frequency conversion / combination processing module for the bandwidth required by the user in the device, and a connector between the signal branching unit and each module. By connecting, an apparatus can be constructed without incurring unnecessary costs.

  In addition, since the hardware configuration of each frequency conversion / combining processing module may be the same, the design cost can be reduced, and the frequency conversion processing module is independent for each band, so there is an abnormality in a specific band. In such a case, it is sufficient to replace only the module of the band with a normal one, and the repair cost can be reduced when the band is large.

Overall configuration diagram of an embodiment of the present invention Spectrum diagram for explaining the operation of band demultiplexing and multiplexing of the embodiment The figure which shows the structural example of the frequency converter circuit of embodiment. Diagram for explaining delay processing before multiplexing Diagram showing an example of the structure of the device Configuration diagram of another embodiment of the present invention Spectrum diagram for explaining the operation of band demultiplexing and multiplexing of another embodiment

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is an overall configuration diagram of a frequency conversion device 20 to which the present invention is applied.

  The frequency conversion device 20 includes a signal demultiplexing unit 21, a frequency conversion / synthesis processing unit 25, and a control unit 50.

The signal demultiplexing unit 21 receives a wide-band input signal x (t) in a high-frequency band at an input terminal 22 and a plurality of M adjacent band-pass filters having a narrower width than the band of the input signal x (t) ( BPF) 23 ₁ to 23 _M are input, demultiplexed into band signals x ₁ (t) to x _M (t), and output from a plurality of band signal output terminals 24 _{1 to} 24 _M , respectively.

As shown in FIG. 2A, the bandpass filters 23 ₁ to 23 _M have predetermined frequency regions f _{0 to} f ₀ + f _BW (for example, f ₀ = 2 GHz, f) in which a signal to be converted may exist. _BW = 100 MHz) is divided into M equal frequency widths f _W = f _BW / M (for example, 100/10 = 10 MHz when M = 10), and the divided signal x ₁ (t) in each band ~ X _M (t) are selectively extracted and output. Here, the plurality M is arbitrary, and may be determined according to the processing capability of frequency conversion, which will be described later, or the user's request.

Here, when the center frequency of the bandpass filter ₂₃ 1 ~ 23 _M and _fc 1 _{~fc M,} the pass band of the band-pass filters ₂₃ 1 ~ 23 _M from the relationship, _{respectively, fc 1 ± f W / 2} , fc ₂ ± f _W / 2,... fc _M ± f _W / 2.

  The configuration of the signal demultiplexing unit 21 is not limited to a structure in which a plurality of bandpass filters having different passbands are simply connected in parallel as shown in the figure, and the above-mentioned Patent Document 1 (Japanese Patent Laid-Open No. 2009-246958). Various configurations shown in FIG. 7 to FIG.

The frequency converting / synthesizing unit 25 includes a signal generating unit 26, a plurality of frequency converting / combining processing modules (hereinafter simply referred to as modules) 31 _{1 to} 31 _M , a module holding unit 40, a band signal connecting unit 41, and a conversion unit. The signal connecting means 42 and the combined signal connecting means 43 are configured.

  The signal generator 26 generates a local signal L phase-synchronized with a reference signal R having a predetermined frequency (for example, 10 MHz, 1 MHz, 100 kHz, etc.), and outputs the local signal L from the local signal output terminal 26a. The clock signal generator 28 generates a sampling clock signal C phase-synchronized with R and outputs it from a clock signal output terminal 26b.

  Each module 31 includes a band signal input to a band signal input terminal 31a, a local signal input terminal 31b, a clock signal input terminal 31c, a combined signal input terminal 31d, a combined signal output terminal 31e, and a band signal input terminal 31a. Is converted to a predetermined intermediate frequency band (heterodyne conversion) by a mixing process with the local signal L input to the local signal input terminal 31b, and the output signal y of the frequency conversion circuit 32 is converted to the clock signal input terminal 31c. A / D converter 33 that samples and converts to a digital signal sequence in synchronization with clock signal C input to A, and a digital signal sequence Y output from A / D converter 33 in accordance with band demultiplexing. Correction processing circuit 34 for correcting the error generated by the signal, the signal Yh corrected by the correction processing circuit 34 and the combined signal input terminal 3 And multiplexes the signals input to the d, are integrated respectively and a combining circuit 35 to be output from the multiplexed signal output terminal 31e (suffixes omitted).

For example, as shown in FIG. 3, each frequency conversion circuit 32 _{1 to} 32 _M extracts a mixer 32a that mixes each band signal and the local signal L, and extracts a heterodyne component (intermediate frequency band) as a difference from the mixed component. It is composed of a band pass filter (BPF) 32b. Here, the bands of the band-pass filters 32b of the frequency conversion circuits 32 _{1 to} 32 _M can be obtained by setting the frequency of the local signal L to f _L as shown in (b1) to (bM) of FIG.
| F _L −fc ₁ | ± f _W / 2
| F _L −fc ₂ | ± f _W / 2
………
| F _L −fc _M | ± f _W / 2
The center frequency is converted to a different intermediate frequency band while maintaining the mutual frequency interval when being demultiplexed, sampled at a timing synchronized with the clock signal C, and converted to a digital signal sequence The

  The correction processing circuit 34 demultiplexes a wideband input signal into signals of a plurality of bands, and performs frequency conversion processing and A / D conversion processing on each of the signals, thereby causing phase and amplitude errors of signals generated between the bands. The correction processing is performed by, for example, an FIR type digital filter that performs a product-sum operation on a predetermined number of input data.

  The correction coefficient (product coefficient) necessary for performing correction by this digital filter is determined based on the data obtained by inputting a non-modulated reference signal in advance and sweeping the frequency thereof. It is assumed that the phase characteristic is determined to be a predetermined reference characteristic, and is stored and set in advance for each module.

  In this way, the signal sequence Yh that has been subjected to correction processing by band demultiplexing is input to the multiplexing circuit 35. In the multiplexing circuit 35, the combined signal input from the combined signal input terminal 31d and the corrected signal are combined, but the correction processing signal Yh basically has a timing shift between the modules. However, there is always a delay in the multiplexing process (for example, one clock), so that the sum of the correction processing signals input to each multiplexing circuit at the same timing is correctly output from the last stage. It is necessary to anticipate the delay amount from the first stage to the last stage.

That is, as shown in FIG. 4, if four in case of connecting the modules, the correction processing signal Yh, respectively A1, B1, C1 input to the same processing timing T1 to the multiplexing circuit ₃₅ 1 to 35 ₄ of each module , when D1, multiplexing circuit 35 ₁ of the first stage, and outputs the next processing timing T2 to A1 + 0 (no input) as the wave signal, to match it, the next stage of the multiplexing circuit 35 _2, correction processing After delaying the signal B1 by one processing timing internally, the combined signal A1 and the correction processing signal B1 are combined at the next processing timing T3 to output a signal A1 + B1.

Similarly, the third stage of the multiplexing circuit 35 _3, the correction signal C1 from the delayed second processing timing component internally, a and multiplexing signals A1 + B1 and correction signal C1 multiplexes the next processing timing T4 outputs a signal A1 + B1 + C1 Te, multiplexing circuit 35 ₄ of the final stage, if the correction process signal D1 from the delayed 3 processing timing component internally, a and multiplexing signals A1 + B1 + C1 to the next processing timing T5 and correction signals D1 And output signal A1 + B1 + C1 + D1.

  In other words, each multiplexing circuit has a function of delaying the input correction processing signal by the processing time corresponding to the connection order of the modules and then combining with the combined signal. It is assumed that the number of delay processing stages of the multiplexing circuit can be arbitrarily set from the outside (a control unit 50 described later).

  The plurality of modules 31 are held by the module holding means 40 in a detachable state in the apparatus.

  Here, the form of the module holding means 40 is arbitrary as long as it corresponds to the structure of the module. For example, when a module is formed on a printed circuit board and an edge connector is provided on the printed circuit board, a connector for receiving the edge connector of the module is arranged on one side of the motherboard as the module holding means 40, and a plurality of modules are arranged. A structure in which they are held side by side on the motherboard can be considered. In this case, the module holding means 40 serves not only as a mechanical holding function but also as an electrical connection function. Further, only a mechanical holding function may be used.

  The band signal connection means 41 connects the band signal input terminal 31a of each module 31 held in the module holding means 40 and each band signal output terminal 24 of the signal demultiplexing unit 21 with a connector, and sends each band signal. The module 31 is given.

  The band signal connection means 41 is provided according to the form of the band signal output terminal 24 of the signal branching unit 24 and the band signal input terminal 31 a of the module 31.

  For example, as a simple structure, if the band signal output terminal 24 is a high-frequency coaxial connector, the band signal input terminal 31a is also connected as a similar coaxial connector with a coaxial cable having coaxial connectors provided at both ends.

  The band signal connecting means 41 can also be used as the module holding means 40 having a structure in which the connector is fixed to the one surface side of the mother board. In that case, a circuit of the signal demultiplexing unit 21 is formed on the mother board, and each band signal output terminal 24 and a specific pin of a plurality of connectors on the mother board are connected in a pattern, respectively, and a module attached to each connector A contact corresponding to a specific pin of the edge connector is defined as a band signal input terminal 31a. In this case, however, it is necessary to pattern-form a transmission line (such as a microstrip line) that transmits a high-frequency signal without loss. If the module holding means 40 is also used in this way, connection is also made by mounting the module.

  The conversion signal connection means 42 includes a local signal input terminal 31b and a clock signal input terminal 31c of each module 31 held by the module holding means 40, and a local signal output terminal 26a and a clock signal output terminal 26b of the signal generator 26. As in the case of the band signal connection means 41, any of a coaxial cable connection and a method of connecting to a connector on a motherboard can be adopted. In this case, the signal generator 26 may be a module that can be attached to and detached from the apparatus similarly to each module 31, or may be provided in a state of being fixed on the motherboard.

Further, the multiplexed signal connecting means 43 is configured to connect the multiplexed signal output terminal 31e _i and the multiplexed signal input terminal 31d _{i + 1} between the different modules 31 _i and 31 _{i + 1} for the plurality of modules 31 held by the module holding means 40. The connectors are connected in order, and the combined signal output terminal 31e _{M of the} final stage module outputs the signal X combined for all the bands.

  As the combined signal connecting means 43, when handling a digital multi-bit parallel data signal, it is advantageous to attach an edge connector to the module holding means 40 having a structure in which the connector is fixed to one side of the mother board. Yes, a combined signal input terminal 31d and a combined signal output terminal 31e are provided at the edge connector of each module, and the combined signal output terminal 31e and the combined signal input between adjacent modules are provided simultaneously with module holding by mounting the module. Connection with the terminal 31d is performed simultaneously.

  The control unit 50 starts sampling of each module 31 in synchronization with the control of the signal generation unit 26 and each module 31, for example, the local signal frequency setting process and the clock signal C. Further, the module held by the module holding means 40 is detected, and the parameter setting process including the delay amount setting described above is performed. The connection for the control is arbitrary, but the method performed through the edge connector attached to the connector of the mother board is advantageous, and the analysis processing for the combined signal and the signal generator 26 for each module. In this example, the combined signal connecting means 43 is also connected to each module 31 and the signal generator 26 (the input / output terminals of the controller 50 are omitted). ing). Note that the controller 50 may be connected to each module 31 and the signal generator 26 by dedicated connection means.

  In the frequency conversion device 20 configured as described above, an input signal to be converted is demultiplexed into a plurality of adjacent band signals, and is converted into an intermediate frequency band by each module 31 that is detachably held. 2 are corrected and sequentially combined, and converted into a digital signal sequence of a lower intermediate frequency band in which the information of the original input signal is stored, as shown in FIG.

  For this reason, the module 31 for the bandwidth required by the user is installed in the apparatus, and the signal demultiplexing unit 21 and each module are connected by a connector, so that the apparatus can be constructed without wasting costs. Can do. For example, when the signal to be converted falls within three bands as in the example of FIG. 2, only three modules need be mounted.

  In addition, since the hardware configuration of each module 31 may be the same, the design cost can be reduced, and the modules for performing the frequency conversion processing are independent for each band. Only the band module needs to be replaced with a normal one, and the repair cost can be reduced when the band is large.

  Although the mechanical structure of the apparatus is arbitrary, for example, as shown in FIG. 5, the signal demultiplexing unit 21, the signal generation unit 26, and each module 31 are detachably mounted from the front side where the frame 100 is opened. An example of a structure in which a connector is connected to a mother board (not shown) on the back side of the frame 100 is shown.

  In this case, the control unit 50 may be provided on the mother board, or the control unit 50 may be configured with a personal computer so as to be able to communicate with the frame 100. In FIG. 5, reference numeral 40 a denotes a screw for fixing the signal demultiplexing unit 21, the signal generation unit 26, and each module 31 that are modularized, reference numeral 40 b denotes a screw hole, and reference numeral 40 c denotes each module inside. It is a notch for a guide when inserting in.

In the above-described embodiment, the common local signal L is given to the frequency conversion circuit 32 of each module 31 and converted into intermediate frequency bands each having a different center frequency. By doing so, the signal X retaining the frequency relationship of the original signal is output. However, as shown in FIG. 6, a local signal generator 27 is provided for each module 31, and the center frequency of the input band signal is set. by providing a local signal _L 1 ~L _M having a frequency corresponding respectively to the frequency converting circuit 32, the respective band signal (a) in FIG. 7, as shown in FIG. (b1) ~ (bM), center frequency ( fi) and the bandwidth fw can be converted to the same intermediate frequency band.

However, if the signals are multiplexed as they are, the signals in the entire band are overlapped within the width f _W , so that a frequency shift circuit 38 is provided as shown in FIG. On the other hand, as shown in (c1) to (cM) of FIG. 7, a frequency difference equal to the frequency interval (f _BW / M = Δf) of the original band signal is given, and the frequency shifted signal Yhs. Are respectively input to the multiplexer 35. The frequency shift circuit 38 includes an offset local signal generator 38a that outputs offset local signals Ls1 to LsM having frequencies fs1 to fsM having a difference in frequency wave interval Δf, and a frequency conversion circuit 38b (these are numerical calculation processes for digital values). Can be realized).

Since as described above the frequency of the local signal L ₁ ~L _M different, when the sampling timing of the A / D converters 33 are common, with respect to the converted signal to an intermediate frequency band between the bands each A phase error corresponding to the phase difference of the local signal occurs. This phase error can be compensated by adjusting the initial phase of the offset local signals Ls1 to LsM of the frequency shift circuit 38 by the synchronization circuit 39.

  By combining the frequency-shifted and phase-compensated signal Yhs in the same manner as described above, a digital signal sequence obtained by converting the original signal into a lower frequency band is obtained as shown in FIG. be able to.

  In the above embodiment, each module 31 is provided with the local signal generator 27. However, the signal generator 26 may be provided with a local signal generator for each module.

  DESCRIPTION OF SYMBOLS 20 ... Frequency converter, 21 ... Signal demultiplexing part, 22 ... Input terminal, 23 ... Band-pass filter, 24 ... Band signal output terminal, 25 ... Frequency conversion / synthesis processing part, 26 ... Signal Generation unit 27... Local signal generator 28... Clock signal generator 31... Frequency conversion / combining processing module 31 a... Band signal input terminal 31 b. Signal input terminal, 31d: combined signal input terminal, 31e: combined signal output terminal, 32: frequency conversion circuit, 33: A / D converter, 34: correction processing circuit, 35: combining Circuits 38... Frequency shift circuit 39... Synchronous circuit 40. Module holding means 41... Band signal connecting means 42... Conversion signal connecting means 43 43 Combined signal connecting means 50. ... Control unit

Claims (3)

A signal demultiplexing unit (21) for demultiplexing an input signal in a high frequency band into a plurality of adjacent band signals having a narrower width than the band of the input signal, and outputting each band signal from a plurality of output terminals (24), respectively. When,
Each band signal is subjected to frequency conversion processing to an intermediate frequency band, each signal converted to the intermediate frequency band is subjected to A / D conversion, and error correction processing caused by band demultiplexing is performed. A frequency converting / combining processing unit (25) for combining the input signals, and converting the input signal into a signal of a lower frequency band,
The frequency conversion / combining processing unit
A band signal input terminal (31a) for inputting the band signal, a frequency conversion circuit (32) for frequency-converting the band signal input to the band signal input terminal to a predetermined intermediate frequency band, and an output signal of the frequency conversion circuit A / D converter (33) that samples the signal and converts it into a digital signal sequence, and a correction that performs a correction process for errors caused by band demultiplexing on the digital signal sequence output from the A / D converter A processing circuit (34), a combined signal input terminal (31d) for inputting a combined signal, and a signal for combining the signal corrected by the correction processing circuit and the signal input to the combined signal input terminal A plurality of frequency conversion / combination processing modules (31) integrated with a wave circuit (35) and a combined signal output terminal (31e) for outputting a combined signal combined by the combining circuit )When,
Module holding means (40) for holding the plurality of frequency conversion / multiplexing processing modules in the apparatus in a detachable state;
A connector is connected between each band signal input terminal of each of the plurality of frequency conversion / multiplexing processing modules held by the module holding means and each output terminal of the signal branching unit, and each band signal is sent to each Band signal connection means (41) to be given to the frequency conversion / multiplexing module;
For the plurality of frequency conversion / multiplexing processing modules held in the module holding means, the connectors between the combined signal output terminal and the combined signal input terminal are sequentially connected between different modules, and the final stage A frequency conversion comprising: a combined signal connection means (43) for outputting a combined signal for all bands from a combined signal output terminal of the combining circuit of the frequency conversion / combining processing module. apparatus.   The frequency of the local signal used by the frequency conversion circuit of each of the frequency conversion / multiplexing processing modules is equal, and the center of each intermediate frequency band is equal to the difference between the center frequencies of a plurality of adjacent bands of the signal demultiplexing unit. The frequency converter according to claim 1, wherein the frequency converter is provided. The frequency of the local signal used by the frequency conversion circuit of each frequency conversion / multiplexing processing module has a difference equal to the difference between the center frequencies of a plurality of adjacent bands of the signal demultiplexing unit, While converting the signal to a common intermediate frequency band,
A frequency shift circuit that gives a difference equal to a difference between center frequencies of a plurality of adjacent bands of the signal demultiplexing unit to signals input to the multiplexing circuit of each of the frequency conversion / multiplexing processing modules ( 38)
A synchronization circuit (39) for compensating for a phase error between bands caused by a difference in frequency of a local signal used by the frequency conversion circuit of each frequency conversion / combination processing module by phase correction of the local signal of the frequency shift circuit; The frequency converter according to claim 1, wherein the frequency converter is provided.

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