JP5588544B1 - Signal transmission system, signal transmission apparatus, and signal transmission method - Google Patents

Abstract

A frequency separation characteristic is reduced when a transmitted signal is separated by narrowing a frequency interval.
A first conversion unit configured to perform frequency conversion of a plurality of wireless signals in different frequency bands included in a received signal in a frequency band order in a predetermined frequency band with a predetermined frequency interval; The predetermined frequency within the frequency band is such that in-phase signals and opposite-phase signals are alternately arranged in order of frequencies with respect to the radio signals converted by the first converter in the frequency band order of the radio signals. A second conversion unit that converts the frequency at intervals, and a transmission unit that converts each of the signals obtained by the first and second conversion units into a digital signal and transmits a multiplexed signal obtained by multiplexing the digital signal A receiving unit that receives the multiplexed signal from the transmitting unit, separates the digital signal into two digital signals, and converts the digital signal into an analog signal; a signal adding unit that adds the two analog signals; And a signal subtraction unit for subtracting the analog signal.
[Selection] Figure 1

Description

  The present invention relates to a signal transmission system, a signal transmission device, and a signal transmission method.

  Non-Patent Document 1 discloses a wireless communication apparatus that converts a plurality of signals transmitted by frequency division multiplexing into wireless signals having different frequencies and wirelessly transmits the signals. In this wireless communication apparatus, a plurality of signals transmitted by frequency division multiplexing are separated by a band pass filter circuit.

Yoshiteru Morihiro, Shuzo Kato, Masafumi Onuki, "Satellite Relay Network System-DIANET-", Journal of IEICE, Vol.74, No.5, pp.439-456, May 1991

  As in the wireless communication device described above, when transmitting a plurality of signals efficiently by frequency division multiplexing with a narrow frequency interval of signals, the band-pass filter circuit that separates each signal has a steep frequency separation characteristic. Is required. However, in order to satisfy the steep frequency separation characteristic, there are problems that the circuit scale of the band-pass filter circuit is increased and the cost is increased.

  In view of the above circumstances, the present invention provides a signal transmission system, a signal transmission device, and a signal transmission method capable of relaxing frequency separation characteristics required for a band-pass filter that separates transmitted signals by narrowing a frequency interval. It is intended to provide.

One aspect of the present invention is defined a low noise amplifier for amplifying and outputting a received signal including a plurality of radio signals of different frequency bands, the radio signal respectively output from the previous SL low noise amplifying unit in advance a first frequency conversion section for frequency conversion while maintaining order of frequency of the radio signal at a predetermined frequency interval in the frequency band, before Symbol the radio signal the respective first output from the low noise amplifying unit a signal phase of the signal and the opposite phase to the corresponding signals obtained by frequency conversion by the frequency conversion section of the alternately arranged in order of frequency, obtained by frequency conversion by the first frequency conversion section a second frequency conversion section for frequency conversion to a corresponding signal the same frequency, each said first signal obtained by the frequency conversion unit and said second frequency converter into a digital signal, the digital A transmitter for transmitting a multiplexed signal obtained by multiplexing the signal, a receiver for receiving the multiplexed signal from the transmitter, separating the signal into two digital signals, and converting the digital signal into an analog signal, and the two analog signals A signal transmission system comprising: a signal adding unit that adds the signal and a signal subtracting unit that subtracts the two analog signals.

Another embodiment of the present invention is to establish a low noise amplifier for amplifying and outputting a received signal including a plurality of radio signals of different frequency bands, the radio signal respectively output from the previous SL low noise amplifying unit in advance a first frequency conversion section for frequency conversion while maintaining order of frequency of the radio signal to be frequency band at a predetermined frequency interval, said radio signals respectively output from the previous SL low noise amplifying unit wherein so that a signal phase of the signal and the opposite phase to the corresponding signals obtained by frequency conversion by the first frequency conversion unit arranged alternately in order of frequency, resulting in frequency conversion by the first frequency conversion section A second frequency conversion unit that converts the frequency to the same frequency as the corresponding signal, and the signals obtained by the first frequency conversion unit and the second frequency conversion unit are converted into digital signals, De A transmission unit for transmitting a multiplexed signal obtained by multiplexing the barrel signal, a signal transmission device, characterized in that it comprises a.

Another embodiment of the present invention is to establish a low noise amplifier for amplifying and outputting a received signal including a plurality of radio signals of different frequency bands, the radio signal respectively output from the previous SL low noise amplifying unit in advance a first frequency conversion section for frequency conversion while maintaining order of frequency of the radio signal to be frequency band at a predetermined frequency interval, said radio signals respectively output from the previous SL low noise amplifying unit wherein so that a signal phase of the signal and the opposite phase to the corresponding signals obtained by frequency conversion by the first frequency conversion unit arranged alternately in order of frequency, resulting in frequency conversion by the first frequency conversion section A second frequency conversion unit that converts the frequency to the same frequency as the corresponding signal, and the signals obtained by the first frequency conversion unit and the second frequency conversion unit are converted into digital signals, De A receiving unit that receives the multiplexed signal, separates the digital signal into two digital signals, and converts the digital signal into an analog signal; A signal transmission device comprising: a signal adding unit that adds two analog signals; and a signal subtracting unit that subtracts two analog signals.

Another embodiment of the present invention is to establish a low noise amplification step for amplifying and outputting the received signal comprising a plurality of radio signals of different frequency bands, the radio signal respectively outputted before Symbol low noise amplification step in advance a first frequency conversion step of frequency conversion while maintaining order of frequency of the radio signal to be frequency band at a predetermined frequency interval, before Symbol the said radio signals respectively outputted at the low noise amplification step so that a signal phase of the signal and the opposite phase to the corresponding signals obtained by frequency conversion by the first frequency conversion step alternating order of frequency, resulting in frequency conversion by the first frequency conversion section response and second frequency conversion step of frequency converting the signal of the same frequency, the first frequency conversion step and said second frequency conversion step was Each of the obtained signals is converted into a digital signal, a transmission step for transmitting a multiplexed signal obtained by multiplexing the digital signal, and a multiplexed signal transmitted in the transmission step is received and separated into two digital signals. And a signal transmission method comprising: a reception step for converting the digital signal into an analog signal; a signal addition step for adding the two analog signals; and a signal subtraction step for subtracting the two analog signals. It is.

  According to the present invention, the adjacent radio signal in the signal output from the second frequency conversion unit is out of phase with the signal output from the first frequency conversion unit. The other radio signal adjacent to each radio signal is canceled in the signal to be performed. Further, in the signal output from the signal subtracting unit, other radio signals adjacent to each radio signal canceled in the signal output from the signal adding unit are canceled. As a result, the interval between the radio signals in the signals output from the signal addition unit and the signal subtraction unit is widened, so that the frequency separation characteristics required for the band-pass filter that separates the radio signals can be relaxed.

It is a block diagram which shows the structural example of the signal transmission system in this embodiment which concerns on this invention. It is a figure which shows an example of the operation | movement outline | summary of the signal transmission system in the embodiment.

  Hereinafter, a signal transmission system, a signal transmission device, and a signal transmission method according to embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram illustrating a configuration example of a signal transmission system according to the present embodiment. The signal transmission system receives the transmission signal transmitted from the transmission apparatus 1 and the transmission apparatus 1 on the transmission side that transmits a plurality of radio signals received in order to acquire surrounding radio wave conditions, and transmits the transmission signal. And a transmission device 2 on the receiving side for separating each radio signal included in the signal.

  When sensing the surrounding radio wave conditions, the transmission apparatus 1 down-converts radio signals in a plurality of frequency bands to adjacent predetermined frequency bands (for example, a baseband band or an IF (Intermediate Frequency) band) and simultaneously converts them. To transmit. In this case, it is equivalent to transmitting radio signals in a plurality of frequency bands by frequency division multiplexing in a predetermined frequency band.

  The transmission apparatus 1 on the transmission side includes an antenna 11, a broadband low noise amplifier 12, a plurality of local oscillation signal generators 13-1 to 13-k, a signal distributor 14, a mixer 15, a mixer 16, an analog / digital converter 17, An analog / digital converter 18 and a parallel / serial converter 19 are provided.

  The broadband low noise amplifier 12 amplifies a reception signal received by the antenna 11 and including a plurality of radio signals, and outputs the amplified signal to the mixer 15 and the mixer 16. The wireless signal is two or more signals to be transmitted between the transmission device 1 and the transmission device 2 in the signal transmission system, and is a signal in a different frequency band.

  The local oscillation signal generators 13-1 to 13-k are provided corresponding to radio signals, and local oscillation for converting the corresponding radio signals to a predetermined frequency band, for example, a baseband band or an IF band. A signal is generated, and the generated local oscillation signal is output to the signal distributor 14. The frequency of the local oscillation signal is such that when the radio signal is frequency-converted to a predetermined frequency band, the order of the signals corresponding to each radio signal matches the order of the radio frequency frequency bands, and the interval between the signals is The predetermined frequency interval is determined in advance based on the frequency band of the radio signal and a predetermined frequency band.

  The signal distributor 14 outputs the local oscillation signals output from the local oscillation signal generators 13-1 to 13 -k to the mixer 15 and the mixer 16. The local oscillation signal output from the signal distributor 14 to the mixer 15 is the local oscillation signal itself output from each of the local oscillation signal generators 13-1 to 13-k. On the other hand, the local oscillation signal output from the signal distributor 14 to the mixer 16 is in phase with the local oscillation signal output from the signal distributor 14 to the mixer 15 in the frequency band order of the radio signal corresponding to each local oscillation signal. The phase of the local oscillation signal is shifted by π so that the local oscillation signal and the local oscillation signal of opposite phase appear alternately.

  The mixer 15 (first frequency conversion unit) multiplies the signal output from the wideband low noise amplifier 12 and each local oscillation signal output from the signal distributor 14 and analogizes the signal obtained by the multiplication. / Output to digital converter 17. By the multiplication in the mixer 15, each radio signal included in the signal is down-converted to a predetermined frequency band. The order in the frequency direction of the signal corresponding to each radio signal frequency-converted to a predetermined frequency band matches the magnitude relationship of the frequency of each radio signal.

  The mixer 16 (second frequency conversion unit) has a phase opposite between the signal output from the broadband low noise amplifier 12 and the local oscillation signal output from the signal distributor 14 and having a frequency close to each other. Multiply by the local oscillation signal. The mixer 16 outputs a signal obtained by the multiplication to the analog / digital converter 18. By the multiplication in the mixer 16, each radio signal included in the signal is down-converted to a predetermined frequency band. A signal corresponding to each radio signal frequency-converted to a predetermined frequency band output from the mixer 16 is a signal having a phase opposite to that of another adjacent signal (a signal having a phase shifted by π). Further, the signal corresponding to each radio signal output from the mixer 16 is such that in-phase signals and opposite-phase signals are alternately arranged in order of frequency with respect to the signals corresponding to the respective radio signals output from the mixer 16. Become.

  The analog / digital converter 17 converts the signal output from the mixer 15 from an analog signal to a digital signal at a predetermined sampling rate, and outputs the analog signal to the parallel / serial converter 19. The analog / digital converter 18 converts the signal output from the mixer 16 from an analog signal to a digital signal at the same sampling rate as the analog / digital converter 18 and outputs the converted signal to the parallel / serial converter 19.

  The parallel / serial converter 19 (transmission unit) converts the digital signal sequence output from the analog / digital converter 17 and the digital signal sequence output from the analog / digital converter 18 into one digital signal sequence. The digital signal sequence obtained by the conversion is transmitted as a transmission signal to the transmission device 2 on the reception side.

  The transmission device 2 on the reception side includes a serial / parallel converter 21, a digital / analog converter 22, a digital / analog converter 23, a signal adder 24, a signal subtractor 25, a switch 26, and a band pass filter 27-1. ~ 27-k.

  The serial / parallel converter 21 (receiver) receives the multiplexed signal transmitted from the parallel / serial converter 19 of the transmission apparatus 1 on the transmission side. The serial / parallel converter 21 converts the multiplexed signal into two digital signal sequences by conversion corresponding to the conversion performed by the parallel / serial converter 19. The serial / parallel converter 21 inputs one of the two digital signal sequences to the digital / analog converter 22 and inputs the other digital signal sequence to the digital / analog converter 23.

  The digital / analog converter 22 converts the digital signal sequence input from the serial / parallel converter 21 into an analog signal at a sampling rate corresponding to the sampling rate in the analog / digital converter 18. The digital / analog converter 22 outputs the analog signal obtained by the conversion to the signal adder 24 and the signal subtractor 25.

  Similarly to the digital / analog converter 22, the digital / analog converter 23 converts the digital signal sequence input from the serial / parallel converter 21 into an analog signal at a sampling rate corresponding to the sampling rate in the analog / digital converter 18. Convert to The digital / analog converter 23 outputs the analog signal obtained by the conversion to the signal adder 24 and the signal subtractor 25.

  The signal adder 24 adds the analog signal output from the digital / analog converter 22 and the analog signal output from the digital / analog converter 23, and outputs the addition result signal to the switch 26. The radio signal down-converted by the local oscillation signal whose phase is different (π shifted) by the mixer 15 and the mixer 16 of the transmission apparatus 1 on the transmission side by the addition by the signal adder 24 is added with a signal having an opposite phase. Cancel each other and cancel each other. In other words, every k radio signals down-converted to a predetermined frequency band and frequency-division multiplexed at a certain frequency interval in the transmission apparatus 1 on the transmission side appear on the frequency axis of the addition result signal. It will be.

  The signal subtracter 25 subtracts the analog signal output from the digital / analog converter 23 from the analog signal output from the digital / analog converter 22 and outputs a signal resulting from the subtraction to the switch 26. By subtraction by the signal subtracter 25, the radio signal down-converted by the local oscillation signal of the same phase in the mixer 15 and the mixer 16 of the transmission apparatus 1 on the transmission side is canceled and canceled because the signal of the same phase is subtracted. Is done. In other words, every k radio signals down-converted to a predetermined frequency band and frequency-division multiplexed at a certain frequency interval in the transmission apparatus 1 on the transmission side appear on the frequency axis of the subtraction result signal. It will be.

  The switch 26 outputs either the addition result signal output from the signal adder 24 or the subtraction result signal output from the signal subtractor 25 to the bandpass filters 27-1 to 27-k. The switch 26 switches signals output to the band pass filters 27-1 to 27-k at a predetermined timing.

  The bandpass filters 27-1 to 27-k are filters that are provided corresponding to radio signals and have a frequency band when the corresponding radio signal is down-converted to a predetermined frequency band. The band pass filters 27-1 to 27-k separate the signal component of the radio signal corresponding to the signal from the signal output from the switch 26 and output the separated signal component.

  In the signal transmission system of the present embodiment, a frequency converter (mixer 16) that converts frequency-multiplexed radio signals to opposite phases every other frequency in order, and a frequency converter (mixer 15) that also converts frequencies to all in-phase. ), A signal adder 24 for adding and outputting the outputs of the two frequency converters, and a signal subtractor 25 for subtracting and outputting the outputs of the two frequency converters. By providing this configuration, the nearest frequency component is suppressed in the output of the signal adder 24 and the output of the signal subtractor 25, and the signals obtained by down-converting the radio signal appear alternately in the frequency order. Thus, the requirements for the bandpass filters 27-1 to 27-k can be relaxed compared to direct filtering of frequency-multiplexed radio signals.

  FIG. 2 is a diagram illustrating an example of an operation outline of the signal transmission system according to the present embodiment. FIG. 2A is a diagram showing an outline of a signal input to the wideband low noise amplifier 12. In the figure, the horizontal axis represents frequency and the vertical axis represents power. FIG. 2 (a) shows five radio signals in different frequency bands. The signal indicated by the broken line indicates that when five radio signals are down-converted, the signals corresponding to the radio signals are frequency-converted with a certain frequency interval. A signal indicated by a broken line is a signal input to the mixer 15 and the mixer 16.

  FIG. 2B is a diagram illustrating an outline of a signal corresponding to each radio signal down-converted by the mixer 15. FIG. 2C shows a signal corresponding to each radio signal down-converted by the mixer 16. In each figure, the horizontal axis represents frequency and the vertical axis represents phase. Each signal is hatched in the same manner as the corresponding radio signal in FIG. As shown in FIG. 2B and FIG. 2C, the signals corresponding to the down-converted radio signals are in-phase and opposite-phase signals between the signals output from the mixer 15 and the mixer 16. Are down-converted so that and appear alternately.

  FIG. 2 (d) is a diagram showing an outline of the addition result signal output from the signal adder 24. FIG. 2 (e) is a diagram showing an outline of a subtraction result signal output from the signal subtracter 25. In each figure, the horizontal axis represents frequency and the vertical axis represents phase. Each signal is hatched in the same manner as the corresponding radio signal in FIG. 2A, as in FIGS. 2B and 2C. As shown in FIGS. 2D and 2E, in the addition result signal and the subtraction result signal, every other signal corresponding to each radio signal is canceled, and the frequency interval between the signals is wide. It has become.

  In the signal transmission system of this embodiment, a plurality of radio signals transmitted by frequency division multiplexing are branched into two in-phase. With respect to the signals of these two paths, the local oscillation signal having the same phase and the local oscillation signal having the opposite phase are alternately supplied in the order of frequency to perform frequency conversion. By alternately performing in-phase synthesis and reverse-phase synthesis for the converted signals in order of frequency, the nearest signal can be suppressed, and the frequency separation characteristics required for the bandpass filters 27-1 to 27-k can be obtained. It can be mitigated.

  In other words, when the signal obtained by down-converting the radio signal to be transmitted is frequency division multiplexed and transmitted, and when the signal component of each radio signal is separated from the transmitted signal, the frequency division multiplexing is performed. The frequency interval between signals can be made wider than the frequency interval between signals. As a result, the frequency separation characteristics required for the band-pass filters 27-1 to 27-k for separating the signal component of the radio signal from the signal transmitted by frequency division multiplexing can be relaxed.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and includes designs and the like that do not depart from the gist of the present invention. For example, FIG. 1 shows a configuration example in which the transmission apparatus 1 and the transmission apparatus 2 are communicably connected by a wire, for example, a coaxial line, an optical fiber, or the like. You may make it transmit / receive.

  In addition, a low-pass filter that passes a signal in a predetermined frequency band (for example, a baseband band or an IF band) is provided between the mixer 15 and the analog / digital converter 17, and the signal output from the mixer 15 is provided. Analog / digital conversion may be performed after removing the included harmonics. Similarly, a low-pass filter that passes a signal of a predetermined frequency band may be provided between the mixer 16 and the analog / digital converter 18. Further, instead of the parallel / serial conversion in the transmission apparatus 1 on the transmission side and the parallel / serial conversion in the transmission apparatus 2 on the reception side, another multiplexing method may be used.

  In the above-described embodiment, the configuration in which the wireless signal received by the transmission apparatus 1 is frequency-multiplexed and transmitted is described. However, the present invention is not limited to this, and a signal obtained by some technique, for example, an optically transmitted signal, Signals received via a plurality of radio receiving stations may be frequency multiplexed and transmitted.

  The present invention can also be applied to applications where it is essential to separate a frequency division multiplexed signal using a filter.

DESCRIPTION OF SYMBOLS 1, 2 ... Transmission apparatus 11 ... Antenna 12 ... Broadband low noise amplifier 13-1, 13-2, 13-k ... Local oscillation signal generator 14 ... Signal distributor 15, 16 ... Mixer 17, 18 ... Analog / digital conversion 19: Parallel / serial converter 21 ... Serial / parallel converter 22, 23 ... Digital / analog converter 24 ... Signal adder 25 ... Signal subtractor 26 ... Switch 27-1, 27-2, 27-k ... Band Pass filter

Claims (4)

A low-noise amplifier that amplifies and outputs a received signal including a plurality of radio signals in different frequency bands;
A first frequency conversion section for frequency conversion while maintaining order of frequency of the radio signal at a predetermined frequency interval before Symbol the radio signal predetermined frequency band, respectively output from the low noise amplifying unit ,
Alternately before SL to the signal and the frequency order of the radio signal phase of the signal to the corresponding signals obtained respectively by the frequency conversion by the first frequency converter and the anti-phase output from the low noise amplifying unit A second frequency converter that converts the frequency to the same frequency as the corresponding signal obtained by the frequency conversion by the first frequency converter,
A transmission unit that converts each of the signals obtained by the first frequency conversion unit and the second frequency conversion unit into a digital signal and transmits a multiplexed signal obtained by multiplexing the digital signal;
A receiver that receives the multiplexed signal from the transmitter, separates the digital signal into two digital signals, and converts the digital signal into an analog signal;
A signal adder for adding the two analog signals;
A signal subtracting unit for subtracting two analog signals;
A signal transmission system comprising: A low-noise amplifier that amplifies and outputs a received signal including a plurality of radio signals in different frequency bands;
A first frequency conversion section for frequency conversion while maintaining order of frequency of the radio signal at a predetermined frequency interval before Symbol the radio signal predetermined frequency band, respectively output from the low noise amplifying unit ,
Alternately before SL to the signal and the frequency order of the radio signal phase of the signal to the corresponding signals obtained respectively by the frequency conversion by the first frequency converter and the anti-phase output from the low noise amplifying unit A second frequency converter that converts the frequency to the same frequency as the corresponding signal obtained by the frequency conversion by the first frequency converter,
A transmission unit that converts each of the signals obtained by the first frequency conversion unit and the second frequency conversion unit into a digital signal and transmits a multiplexed signal obtained by multiplexing the digital signal;
A signal transmission device comprising: Low and noise amplifying unit, before Symbol the radio signal a predetermined frequency in a predetermined frequency band, respectively output from the low noise amplifier for amplifying and outputting the received signal comprising a plurality of radio signals of different frequency bands first frequency conversion unit, a frequency by the radio signal to each of the first frequency converter which is outputted from the pre-Symbol low noise amplifier for frequency conversion while maintaining order of frequency of the radio signal at intervals The same frequency as the corresponding signal obtained by the frequency conversion by the first frequency conversion unit so that the in-phase signal and the reverse-phase signal are alternately arranged in order of frequency with respect to the corresponding signal obtained by the conversion. and a second frequency converter for frequency conversion, respectively obtained signal by the first frequency converter and the second frequency converter into a digital signal, the multi-multiplexed the digital signal From device provided with a transmission section for transmitting a signal, a receiving unit that converts the digital signal is separated into two digital signals to receive the multiplexed signal into an analog signal,
A signal adder for adding the two analog signals;
A signal subtracting unit for subtracting two analog signals;
A signal transmission device comprising: A low-noise amplification step for amplifying and outputting a received signal including a plurality of radio signals in different frequency bands;
A first frequency conversion step of frequency conversion while maintaining order of frequency of the radio signal at a predetermined frequency interval before SL low-noise amplification the radio signal predetermined frequency band respectively outputted in step ,
Alternately before Symbol to the radio signal corresponding order of frequency and a signal in-phase signal and the opposite phase to the signal obtained by frequency conversion by the respective said first frequency conversion step is output at the low noise amplification step A second frequency conversion step for converting the frequency to the same frequency as the corresponding signal obtained by the frequency conversion by the first frequency conversion unit ;
Transmitting each of the signals obtained in the first frequency conversion step and the second frequency conversion step into a digital signal and transmitting a multiplexed signal obtained by multiplexing the digital signal;
A reception step of receiving the multiplexed signal transmitted in the transmission step, separating the multiplexed signal into two digital signals, and converting the digital signal into an analog signal;
A signal addition step of adding the two analog signals;
A signal subtraction step of subtracting the two analog signals;
A signal transmission method comprising:

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