JPS6118891B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for branching and combining signals in a relay station that performs direct relay in a frequency division multiplexing FM system.

Conventionally, branching and coupling of lines at frequency division multiplexing FM relay stations has been performed at baseband or intermediate frequency depending on whether the relaying method is baseband relay or IF relay.

FIG. 1 shows an example of a configuration in which lines are branched and coupled at a baseband relay station.

The main line signal of frequency f ₁ input from antenna A ₁ passes through antenna sharing device DUP ₁ and band pass filter BPF ₁ , and is received by mixer MIX ₁ and received by the local oscillator.
It is mixed with the output of RLO ₁ to generate an intermediate frequency signal, which is passed through an intermediate frequency amplifier IFA ₁ and demodulated by a demodulator DEM ₁ to generate a baseband signal. The baseband signal is branched to each line and converted to an intermediate frequency signal by modulators MOD ₁ and MOD ₂ , respectively, and then mixed with the output of transmitting local oscillators TLO ₁ and TLO ₂ by frequency converters UC ₁ and UC ₂ , respectively. and generate signals with frequencies f ₂ ′ and f ₃ ′, respectively, which are sent to the other station from antennas A ₂ and A ₃ , respectively, via band pass filters BPF ₂ and BPF ₃ and antenna duplexers DUP ₂ and DUP ₃ , respectively. . Frequencies f ₂ ' and f ₃ ' form a branch line, and the signal channels of each are positioned on the baseband so as to constitute the signal channel of the main line.

On the other hand, the branch circuit signals of frequencies f ₂ and f ₃ that are input to antennas A ₂ and A ₃ , respectively, are sent to mixers via antenna sharing devices DUP ₂ and DUP ₃ , and bandpass filters BPF ₄ and BPF ₅ , respectively.
Receive local oscillator RLO ₂ , MIX ₂ and MIX ₃ , respectively.
It is mixed with the output of RLO ₃ to produce an intermediate frequency signal, which is demodulated by demodulators DEM ₂ and DEM ₃ through intermediate frequency amplifiers IFA ₂ and IFA ₃ , respectively, to produce a baseband signal. The respective baseband signals are added together and converted back into an intermediate frequency signal by the modulator MOD ₃ , and mixed with the output of the transmitting local oscillator TLO ₃ by the frequency converter UC ₃ to generate a signal of frequency f ₁ , which is then sent to the antenna sharing device. DUP ₁ , antenna
It is sent to the other station via _A1 . Frequency f ₁ forms the main line and is positioned on the baseband such that its signal channel is equal to the combined signal channel of the branch lines signals f ₂ and f ₃ .

In this way, lines are branched and combined,
This has the disadvantage that the configuration of the equipment becomes extremely complicated. The same applies to the case where lines are branched and coupled in intermediate frequency signals.

In response to this, a direct relay method has come into use in which the signal is relayed as is or after shifting the frequency without first converting the signal into a baseband signal or intermediate frequency signal. This is based on advances in low noise microwave semiconductor devices and the like. FIG. 2 shows an example of the structure of the direct relay system.

The input signal with frequency f ₁ is an antenna sharing device.
DUP ₁₁ , bandpass filter BPF ₁₁ , amplifier
Shift oscillator SFO ₁₁ with mixer MIX ₁₁ via AMP ₁₁
is mixed with the output of the frequency (f ₁ ~ f ₂ ′) of the frequency
Amplifier AMP ₁₂ that produces a signal of f ₂ ′, bandpass filter BPF ₁₂ , antenna sharing device DUP ₁₂ , antenna
It is sent to the other station via _A12 . The signal of frequency f ₂ from the other station is sent to antenna A ₁₂ and antenna sharing device.
DUP ₁₂ , bandpass filter BPF ₁₃ , amplifier
Shift oscillator SFO ₁₂ with mixer MIX ₁₂ via AMP ₁₃
is mixed with the output of the frequency (f ₂ ~ f ₁ ′) of the frequency
A signal of f ₁ ' is generated and sent to the other station via amplifier AMP ₁₄ , bandpass filter BPF ₁₄ , antenna sharing device DUP ₁₁ , and antenna A ₁₁ . In this case the frequency
The signal of f ₁ and the signal of frequency f ₂ ′ and the signal of frequency f ₂ and the signal of frequency f ₁ ′ each carry the same baseband signal.

This type of direct relay system does not require a local oscillator or modem for transmitting and receiving, and has the feature of significantly simplifying the equipment configuration. However, on the other hand, it is difficult to branch and couple the lines, so branching and coupling is required. It could not be used for lines that

An object of the present invention is to provide a system that allows signals to be easily branched and combined at a relay station that performs direct relay in the frequency division multiplexing FM system.
A detailed explanation will be given below based on examples.

FIG. 3 is a block diagram showing the configuration of an embodiment of the line coupling system of the present invention. In Figure 3
A ₂₁ , A ₂₂ , A ₂₃ are transmitting and receiving antennas, DUP ₂₁ ,
DUP ₂₂ , DUP ₂₃ are antenna sharing devices, BPF ₂₁ ,
BPF ₂₂ , BPF ₂₃ , BPF ₂₄ , BPF ₂₅ , BPF ₂₆ are band pass filters, AMP ₂₁ , AMP ₂₂ , AMP ₂₃ ,
AMP ₂₄ , AMP ₂₅ , AMP ₂₆ are amplifiers, MIX ₂₁ ,
MIX ₂₂ , MIX ₂₃ , MIX ₂₄ are mixers, SFO ₂₁ , SFO ₂₂
is the shift oscillator and LOC ₁ is the local oscillator.

The main line signal has a carrier frequency _f1 , and baseband signals of an arbitrary number of channels are frequency-division multiplexed and transmitted using a frequency modulation method. The input signal f ₁ is input to the antenna A ₂₁ and passes through the antenna sharing device DUP ₂₁ to the bandpass filter BPF _21.
After removing unnecessary signals from the image signal, the amplifier
After receiving the required amplification in AMP ₂₁ , it is divided into two halves, and one is mixed with the output of the frequency (f ₁ to _{f 2} ′) of the shift oscillator SFO ₂₁ in mixer MIX ₂₁ to generate a signal with frequency f ₂ ′, which is then sent to the amplifier. After receiving the required amplification in the AMP ₂₂ , unnecessary wave components are removed in the bandpass filter BPF ₂₂ , and the signal is sent to the antenna via the antenna sharing device DUP ₂₂ .
A ₂₂ sends it to the other station. The other is a mixer as well.
Frequency by oscillation frequency (f ₁ ~ f ₃ ′) in MIX ₂₂
f ₃ ′, amplifier AMP ₂₃ , bandpass filter BPF ₂₃ , antenna sharing device DUP ₂₃ , antenna
It is sent to the other station via _A23 . Therefore, since both the branched signal of frequency f ₂ ′ and the signal of frequency f ₃ ′ carry baseband signals with the same number of channels as the signal of frequency f ₁ of the main line, each partner station receives its own signal. The channel signal to be used can be selected, and the purpose of line branching can be achieved.

In addition, signals from the branch lines carried at frequencies f ₂ and f _3, respectively, are transmitted through antennas A 22 and A ₂₂ , respectively.
A ₂₃ , input to the antenna sharing device DUP ₂₂ ,
Each band pass filter via DUP ₂₃
The signals are input to BPF ₂₄ and BPF ₂₅ , and after being removed from unnecessary signals such as image signals, they are sent to amplifiers AMP ₂₄ and AMP _25, respectively.
receives the required amplification. The output signal of amplifier AMP ₂₅ is applied to mixer MIX ₂₄ at the frequency of local oscillator LOC ₁ {f ₃
~ (f ₁ ′ ~ f ₂ )} is mixed with the output of the frequency (f ₁ ′ ~
f ₂ ) signal. The signal of frequency (f ₁ ′ to _{f 2} ) of mixer MIX ₂₄ is mixed with the signal of frequency f ₂ from amplifier AMP ₂₄ in mixer MIX ₂₃ to generate a signal of frequency f ₁ ′. The signal of frequency f ₁ ' of mixer MIX ₂₃ is amplified to the required level by amplifier AMP ₂₆ , unnecessary wave components are removed by bandpass filter BPF ₂₆ , and then sent from antenna A ₂₁ to the main line partner via antenna sharing device DUP ₂₁ . transmitted to the station. The signal of frequency (f ₁ ' to _{f 2} ) from mixer MIX ₂₄ carries the signal of the channel from one of the branch lines carried at frequency f ₃ . The output signal of amplifier AMP ₂₄ , on the other hand, carries the channel signal from the other branch line carried at frequency _f2 . Therefore, the signal of frequency f ₁ ′ obtained by mixing the signal of frequency (f ₁ ′ to _{f 2} ) and the signal of frequency f ₂ in mixer MIX ₂₃ has baseband signals from both branch lines. The purpose of the bond is achieved. In this case, it goes without saying that the respective channel signals from both branch lines should be positioned on the baseband so that they together constitute the main line signal.

FIG. 4 is a block diagram showing the configuration of another embodiment of the line coupling system of the present invention. In the same figure
MIX ₂₅ and MIX ₂₆ are mixers, and LOC ₂ is a local oscillator. The meanings of other symbols are the same as in FIG. 3. In this embodiment, the case where signals are branched is the same as in the embodiment shown in FIG. Signals of frequencies f ₂ and f ₃ from the branch circuits inputted to antennas A ₂₂ and A ₂₃ , respectively, are inputted to bandpass filters BPF ₂₄ and BPF ₂₅ , respectively, via antenna sharing devices DUP ₂₂ and DUP ₂₃ , respectively.
After removing the image signal and other unnecessary signals, the signals are amplified as required by amplifiers AMP ₂₄ and AMP _25, respectively, and then mixed by mixer MIX ₂₅ to generate a signal of frequency (f ₂ -f ₃ ). The signal at the frequency (f ₂ - f ₃ ) of the mixer MIX ₂₅ is further mixed with the output of the frequency {f ₁ ' - (f ₂ - f ₃ )} generated _by the local oscillator LOC ₂ in the mixer MIX 26 to produce the signal at the frequency f ₁ ′ signal is generated. mixer MIX ₂₆
The signal at frequency f ₁ ' is amplified as required by amplifier AMP ₂₆ , unnecessary wave components are removed by bandpass filter BPF ₂₆ , and then transmitted to the other station on the main line via antenna sharing device DUP ₂₁ and antenna A ₂₁ . be done. The output signal of the amplifier AMP ₂₄ carries the signal of one channel of the branch line carried at frequency f ₂ , and the amplifier
The output signal of AMP ₂₅ carries the signal of the other channel of the branch line carried at frequency _f3 . Therefore, the signal of frequency (f ₂ to _{f 3} ) obtained by mixing the signal of frequency f ₂ and the signal of frequency f ₃ in mixer MIX ₂₅ has baseband signals from both branch lines, so the line coupling is The purpose is achieved. In this case as well, it goes without saying that the respective channel signals from both branch lines should be positioned on the baseband so that they together constitute the main line signal.

From the above explanation, it will be understood that the line coupling system of the present invention allows signals to be branched and coupled at a relay station that performs direct relay in the frequency division multiplexing FM system.

It goes without saying that the oscillation frequency of the shift oscillator and local oscillator in the embodiments of FIGS. 3 and 4 is not limited to the difference frequency between the input signal and the desired output signal frequency, but may be the sum frequency.

Further, in each of the above-mentioned embodiments, the description has been made assuming that branching and coupling to two branch lines are performed, but it can be easily extended to branching and coupling to three or more branch lines. When increasing the number of branches, simply provide the required number of pairs of shift oscillators and mixers with different oscillation frequencies, input the signals from the main line in parallel, and perform frequency conversion on each. This makes it easy to convert the signals to the branch lines. can be created. In addition, when increasing the number of connections, for example, in the case of the embodiment shown in Fig. 3, a mixer is added instead of the local oscillator LOC ₁ in the same figure, and the frequency of the signal of the third branch line is set to f ₄ . A local oscillator capable of oscillating a frequency such as f ₄ ~ {f ₃ ~ (f ₁ ′ ~ f ₂ )} is provided, and the signal on the third branch line is frequency-converted to produce a frequency f ₃ ~ (f ₁ ′ ~ f _{2 )} . )
This signal is generated as a local oscillation signal and further mixed with the signal of frequency f ₃ by the mixer MIX ₂₄ . The same applies when the number of branches becomes 4 or more. In the case of the embodiment shown in FIG. 4, the mixer MIX ₂₅ mixes the signals of the two branch lines (f ₂ , f ₃ ), and then another signal (f ₄ ) is mixed, and then the mixer MIX ₂₆ mixes the signals of the two branch lines (f 2 , f ₃ ). ~
The number of connections can be increased by mixing with local oscillator signals having frequencies such as {f ₄ -(f ₂ -f ₃ )}. The same applies when the number of branches is four or more. All of these are extremely easy extensions for those skilled in the art, and there may be many other frequency conversion methods.

In the above explanation, the block diagrams in FIGS. 1 to 4 merely illustrate the main functions.
For example, various amplifiers have AGC function,
It goes without saying that the mixer should be provided with a filter function for removing image signals.

As explained above, according to the line coupling method of the present invention, it is possible to easily branch and couple signals with a simple configuration in a relay station that performs direct relay of frequency division multiplexing FM method, and it is extremely effective. It is both practical and economical.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an example of the configuration of a baseband relay station for branching and adding lines.
FIG. 2 is a block diagram showing an example of the structure of the direct relay system, FIG. 3 is a block diagram showing the structure of an embodiment of the line coupling method of the present invention, and FIG. 4 is a block diagram showing another example of the line coupling method of the present invention. FIG. 2 is a block diagram showing the configuration of an embodiment. A ₁ , A ₂ , A ₃ , A ₁₁ , A ₁₂ , A ₂₁ , A ₂₂ , A ₂₃ ...
Antenna, DUP ₁ , DUP ₂ , DUP ₃ , DUP ₁₁ ,
DUP ₁₂ , DUP ₂₁ , DUP ₂₂ , DUP ₂₃ ... Antenna sharing device, BPF ₁ , BPF ₂ , BPF ₃ , BPF ₄ , BPF ₅ ,
BPF ₆ , BPF ₁₁ , BPF ₁₂ , BPF ₁₃ , BPF ₁₄ ,
BPF ₂₁ , BPF ₂₂ , BPF ₂₃ , BPF ₂₄ , BPF ₂₅ , BPF ₂₆
...Band pass filter, MIX ₁ , MIX ₂ ,
MIX ₃ , MIX ₁₁ , MIX ₁₂ , MIX ₂₁ , MIX ₂₂ , MIX ₂₃ ,
MIX ₂₄ , MIX ₂₅ , MIX ₂₆ ...Mixer, IFA ₁ ,
IFA ₂ , IFA ₃ ...Intermediate frequency amplifier, RLO ₁ ,
RLO ₂ , RLO ₃ ...Reception local oscillator, DEM ₁ ,
DEM ₂ , DEM ₃ ...Demodulator, MOD ₁ , MOD ₂ ,
MOD ₃ ...Modulator, UC ₁ , UC ₂ , UC ₃ ...Frequency converter, TLO ₁ , TLO ₂ , TLO ₃ ...Transmission local oscillator, AMP ₁₁ , AMP ₁₂ , AMP ₁₃ , AMP ₁₄ ,
AMP ₂₁ , AMP ₂₂ , AMP ₂₃ , AMP ₂₄ , AMP ₂₅ ,
AMP ₂₆ ...Amplifier, SFO ₁₁ , SFO ₁₂ , SFO ₂₁ ,
SFO ₂₂ ...Shift oscillator, LOC ₁ , LOC ₂ ...Local oscillator.

Claims (1)

[Claims] 1. In a relay station for direct relay of frequency division multiplexing FM system, the frequency of the sum or difference between the transmission frequency in the first direction and the reception frequency from the second direction and the reception frequency from the third direction. a first mixer means for generating a signal having a difference or sum frequency by mixing a local oscillation signal having the same frequency as the sum or difference frequency and a signal received from a third direction; a second means for mixing the output signal of the means and the signal received from the second direction to generate a signal at a difference or sum frequency;
mixer means, and by making the output signal of the second mixer means a signal to be transmitted in the first direction, the signal from the second direction and the signal from the third direction are combined and sent to the first direction. A line coupling method characterized by transmitting signals. 2. In a frequency division multiplexing FM direct relay relay station, a first mixer means that mixes the signal received from the second direction and the signal received from the third direction to generate a signal with a sum or difference frequency; , a local oscillation signal of the same frequency as the sum or difference signal of the reception frequency from the second direction and the reception frequency from the third direction, the sum or difference frequency of the transmission frequency in the first direction, and the first a second mixer means for generating a difference or sum frequency signal by mixing the output signal of the mixer means;
mixer means, by making the output signal of the second mixer means a signal to be transmitted in the first direction, the signal from the second direction and the signal from the third direction are combined, and the signal from the third direction is combined. A line coupling method characterized by transmitting data in both directions.