JPH0722873A - Repeater amplifier for communication system - Google Patents

Abstract

(57) [Abstract] [Purpose] Sufficient isolation between a communication circuit in one direction and a communication circuit in the other direction is ensured to improve stability and increase the amplification degree of an amplifier. [Structure] A pair of circulators 2x and 2y are connected to the communication cables Cx and Cy, and each circulator 2x and 2y is connected.
In between, amplifiers 4p and 4q for amplifying the communication signals Dp and Dq
Unidirectional communication circuit 3p and other directional communication circuit 3q
Are connected in parallel. In addition, a switch function unit 5p for opening and closing the communication circuits 3p and 3q,
There is provided a control unit 6 that connects 5q and that alternately controls opening and closing of the switch function units 5p and 5q by switching control signals Sp and Sq having a predetermined frequency.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a relay amplification device for a communication system for connecting a communication cable and amplifying a communication signal.

[0002]

2. Description of the Related Art Generally, in a wireless communication facility (communication system) in an underground mall or a high-rise building, a linear service area is secured by a leaky coaxial line, and a planar service area is secured by a ceiling antenna.

By the way, when the floor area is expanded, the number of floors is increased, and the necessity for connection to another communication system arises, the communication cable (coaxial line) becomes long and the loss of the communication cable itself and Branching equipment (distributor)
Can not be ignored. FIG. 5 shows attenuation characteristics of transmission power with respect to transmission distance in a communication system. As is apparent from the figure, for example, when the one-way communication signal Dp is transmitted from the transmission start point J, the communication cable becomes longer as the distance from the transmission start point J increases, so that the transmission power is gradually attenuated and the distributor. At the position T where there is, the transmission power greatly decreases. Therefore, normally, when the communication cable becomes long, a relay amplification device for amplifying the communication signal is connected in the middle of the communication cable.

In the conventional relay amplifier, a pair of circulators (directional couplers) are connected to a communication cable, and a unidirectional communication circuit provided with an amplifier for amplifying a communication signal between the circulators and a unidirectional communication circuit (reverse direction). ) Communication circuits were connected in parallel.

In FIG. 5, point H indicates the installation point of the relay amplifier, the communication signal Dp in one direction is amplified as Dps shown by the solid line, and the communication signal Dq in the other direction is also shown as Dqs shown by the solid line. It shows the state of being amplified. The dotted line shows the attenuation characteristic when the relay amplifier is not provided.

[0006]

However, in the above-described conventional relay amplifying apparatus, since the communication signals in one direction and the other direction are distributed to the respective communication circuits by using the circulator, the communication characteristic of one of the communication circuits depends on the coupling characteristic of the circulator. There is a problem that a signal leaks to the other communication circuit and the leaked communication signal is amplified to cause a feedback phenomenon. For this reason, it becomes difficult to secure sufficient isolation, which causes instability of the device, and it is difficult to increase the amplification degree of the amplifier.

The present invention solves the problems existing in such conventional techniques, and secures sufficient isolation between a communication circuit in one direction and a communication circuit in the other direction to improve stability. At the same time, it is an object of the present invention to provide a relay amplification device of a communication system capable of increasing the amplification degree of the amplifier.

[0008]

The present invention is a communication cable C.
Connect a pair of circulators 2x and 2y to x and Cy,
Communication signals Dp and Dq are provided between the circulators 2x and 2y.
When constructing the relay amplification device 1 of the communication system in which the one-way communication circuit 3p including the amplifiers 4p and 4q for amplifying and the other-direction communication circuit 3q are connected in parallel, A control unit 6 is provided to connect switch function units 5p and 5q for opening and closing the communication circuits 3p and 3q, and to alternately open and close each switch function unit 5p and 5q by switching control signals Sp and Sq having a predetermined frequency. It is characterized by

In this case, the switching control signals Sp, S
The frequency of q is higher than the audible frequency, and the communication signal Sp,
It is selected lower than the carrier frequency of Sq. Further, filters for removing unnecessary spectral components, for example, bandpass filters 7p and 7q are connected to the respective communication circuits 3p and 3q.

[0010]

According to the relay amplifying device 1 of the communication system of the present invention, the unidirectional communication signal Dp transmitted by the one communication cable Cx by the basic circuit is supplied to the unidirectional communication circuit 3p by the circulator 2x. To be done. The communication signal Dp is given to the amplifier 4p via the switch function unit 5p in the communication circuit 3p, amplified to a predetermined size, and further given to the bandpass filter 7p to remove unnecessary spectral components. , Is transmitted to the other communication cable Cy via the circulator 2y. The communication signal Dq in the other direction transmitted by the other communication cable Cy is supplied to the communication circuit 3q in the other direction by the circulator 2y. The communication signal Dq is transmitted to the amplifier 4q via the switch function unit 5q in the communication circuit 3q.
, Is amplified to a predetermined size, is further applied to the bandpass filter 7q to remove unnecessary spectral components, and is then transmitted to one communication cable Cx via the circulator 2x.

By the way, the respective switch function parts 5p and 5q.
Are alternately controlled to be opened and closed by switching control signals Sp and Sq having a predetermined frequency given from the control unit 6. As a result, the communication signals 3p and 3q are mutually transmitted on the communication cables Cx and Cy in a time division manner, and the communication signal Dp (or the communication signal Dq) is transmitted by the one communication circuit 3p (or the communication circuit 3q). While being amplified, the other communication circuit 3q (or the communication circuit 3p) is cut off, so that sufficient isolation between the communication circuits 3p and 3q is secured. The switching control signal Sp,
The frequency of Sq is higher than the audible frequency, and the communication signal S
Since it is selected to be lower than the carrier frequencies of p and Sq, the audio signal in each communication signal Sp and Sq is reproduced faithfully to the original sound.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, preferred embodiments according to the present invention will be described in detail with reference to the drawings.

First, in order to clarify the present invention, the configuration of a communication system using the relay amplifying apparatus 1 will be described with reference to FIG.

In FIG. 2, M indicates a communication system installed in the building B, and the central monitoring room Bc is provided with a centralized monitoring device 11. On the other hand, the antennas 12 and 13 are installed on each floor of the building B, and each antenna 1
Central monitoring devices 11 and 12 are connected via communication cables C ...
Connect to. In this case, the distributor 1 arranged at a predetermined position
4, the communication cables C ... Are branched. Further, the relay amplifying device 1 is connected in the middle of the communication cable C which becomes longer. Reference numerals 15 and 16 represent transceivers for communication.

Next, the configuration of the relay amplifying apparatus 1 according to this embodiment will be described with reference to FIG.

In FIG. 1, Cx and Cy are the communication cables C.
Is a communication cable that is separated into front and rear, and one circulator (directional coupler) 2x is connected to an end of one communication cable Cx and the other communication cable Cy is connected.
The other circulator 2y is connected to the end of the. A communication circuit 3p in one direction and a communication circuit 3q in the other direction are connected in parallel between the circulators 2x and 2y. In this case, regarding the coupling direction of the circulators 2x and 2y, the communication signal Dp transmitted from one communication cable Cx is transmitted to the other communication cable Cy through the path of the circulator 2x, the one-way communication circuit 3p, and the circulator 2y. At the same time, the communication signal Dq transmitted from the other communication cable Cy is selected so as to be transmitted to the one communication cable Cx via the circulator 2y, the communication circuit 3q in the other direction, and the circulator 2x.

The unidirectional communication circuit 3p is formed by connecting the switch function section 5p, the amplifier 4p and the bandpass filter 7p in series in the transmission direction, and the unidirectional communication circuit 3q is connected in series. The switch function unit 5q, the amplifier 4q, and the bandpass filter 7 with respect to the transmission direction
It is configured by connecting in series in the order of q. Furthermore, the switch function units 5p and 5q are connected to the switching control signals Sp and S.
A control unit 6 that alternately controls opening and closing by q is provided. In this case, the frequencies of the switching control signals Sp and Sq are higher than the audible frequency (approximately several tens kHz), and the communication signals Sp and Sq are
Carrier frequency of Sq (approximately 150 MHz to 400 MH
z) etc.).

Next, the operation of the relay amplifying apparatus 1 according to this embodiment will be described with reference to FIGS.

First, the communication signal Dp transmitted from one communication cable Cx is supplied to the switch function unit 5p of the one-way communication circuit 3p via the circulator 2x. In this case, the communication signal Dp is a signal obtained by modulating a voice signal with a carrier frequency (AM system, FM system, etc.), and FIG.
(A) is a communication signal D transmitted by the communication cable Cx
p is shown.

On the other hand, the switch function unit 5p is provided with the switching control signal Sp shown in FIG.
The opening and closing is controlled by. In this case, the switching control signal Sp and the switching control signal Sq shown in FIG. 3 (C) are simultaneously output from the control section 6 at the timing shown in FIG. 3, whereby the switch function sections 5p and 5q are alternately opened and closed. Controlled. As shown in FIG. 3, a predetermined interval time Ti is set between the time when one switch function unit is turned off and the time when the other switch function unit is turned on. And the adverse effect on isolation are prevented.

As a result, the communication signal Dp passes through the switch function unit 5p only while the switch function unit 5p is on, and the output side of the switch function unit 5p has the intermittent communication shown in FIG. 3 (D). Obtain the signal Dpc. Then, the communication signal Dpc is given to the amplifier 4p and amplified to a predetermined size. In this case, the power loss due to the intermittent communication signal is sufficiently compensated by the amplifier 4p. The output signal Dpo of the amplifier 4p is shown in FIG.

The output signal Dpo is applied to the bandpass filter 7p to remove unnecessary spectral components, and then the other communication cable C is passed through the circulator 2y.
transmitted to y. FIG. 4 shows the magnitude of the spectrum with respect to the frequency of the output signal Dpo. In FIG. 4, the dotted line shows the pulse spectrum of the output signal Dpo, the solid line shows the modulation spectrum, and the chain line shows the bandpass filter 7.
The filter characteristic of p is shown.

The other direction communication signal Dq transmitted from the other communication cable Cy is processed in the same manner as the communication signal Dp. That is, the communication signal Dq is supplied to the communication circuit 3q in the other direction via the circulator 2y. Then, the switch function unit 5q, the amplifier 4q, and the bandpass filter 7
q, one communication cable C via the circulator 2x
transmitted to x. In FIG. 3, (E) shows an intermittent communication signal Dqc output from the switch function unit 5q.

The embodiment has been described in detail above.
The present invention is not limited to such an embodiment.
For example, the communication system can be applied to a digital wireless communication system as well. In addition, the detailed configuration, method, and the like can be arbitrarily changed without departing from the scope of the present invention.

[0025]

As described above, according to the present invention, a pair of circulators are connected to a communication cable, and between each circulator,
In a relay amplification device of a communication system in which a communication circuit in one direction including an amplifier for amplifying a communication signal and a communication circuit in the other direction are connected in parallel, each communication circuit is connected with a switch function unit for opening and closing the communication circuit. In addition, since a control unit that alternately controls opening and closing of each switch function unit by a switching control signal having a predetermined frequency is provided, sufficient isolation between the communication circuit in one direction and the communication circuit in the other direction can be secured. Thus, the remarkable effect that the stability can be improved and the amplification degree of the amplifier can be increased is achieved.

[Brief description of drawings]

FIG. 1 is a block circuit diagram of a relay amplifier device according to the present invention,

FIG. 2 is a schematic configuration diagram of a communication system including the relay amplifying device,

FIG. 3 is a time chart of signals in each part in FIG.

FIG. 4 is a characteristic diagram of frequency vs. spectrum size of an output signal of an amplifier in the relay amplifying device;

FIG. 5 is a characteristic diagram of transmission distance versus transmission power in a communication system,

[Explanation of symbols]

 1 Relay Amplifier 2x Circulator 2y Circulator 3p Unidirectional communication circuit 3q Other direction communication circuit 4p Amplifier 4q Amplifier 5p Switch function part 5q Switch function part 6 Control part 7p Bandpass filter 7q Bandpass filter Cx Communication cable Cy Communication cable Dp One-way communication signal Dq Other-direction communication signal Sp Switching control signal Sq Switching control signal

Claims (3)

[Claims] 1. A relay of a communication system in which a pair of circulators are connected to a communication cable, and a communication circuit in one direction and a communication circuit in the other direction, which include an amplifier for amplifying a communication signal, are connected in parallel between the circulators. In the amplifier device, a switch function unit that opens and closes each communication circuit is connected to each communication circuit, and a control unit that alternately controls opening and closing of each switch function unit by a switching control signal having a predetermined frequency is provided. A repeater amplification device for a featured communication system. 2. The relay amplifying device for a communication system according to claim 1, wherein the frequency of the switching control signal is selected to be higher than the audible frequency and lower than the carrier frequency of the communication signal. 3. A relay amplification apparatus for a communication system according to claim 1, wherein a filter for removing unnecessary spectral components is connected to each communication circuit.