JPS58147245A - Switching device for intermediate frequency band circuit - Google Patents

Abstract

PURPOSE:To obtain input and output isolation by turning off the power source for a branch amplifier on a stand-by circuit side in normal operation at the transmission part of a switching device for intermediate frequency band circuits. CONSTITUTION:A control signal transmitted from a reception side through a circuit controller is applied to the base of a transistor (TR)1 to drive TRs 2 and 3. In normal operation, the TR2 is cut off and no voltage is applied to the amplifier 12 of a stand-by circuit; and the TR3 is on and the amplifier 11 of an in-use circuit is in operation. In switching operation, they operate reversely and a normal voltage is applied to the amplifier 12, but only a voltage set through a variable resistor RV1 is applied to the amplifier 11.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an intermediate frequency (hereinafter referred to as IF) switching device used in microwave communications for multiplex telephone signal transmission.

Conventionally, IP''@ which is conveniently used in the microwave communication method
The line switching device monitors the line pilot signal and the noise level on the receiving side, and when it detects 41k, which is an abnormality in either of them, it operates the switch on the transmitting side through the switching resistance control device k. The same signal is transmitted through the protection line, a so-called sending-end parallel operation is performed, and the receiving end checks the pilot signal and noise level of the protection line, and only if it is compact is the switch at the receiving end operated, and the switch is activated. The switching from the line to the protection line is completed.

FIG. 1 shows a configuration diagram of a typical IP line switching device.

The sending section side is composed of a branch amplifier 1 and a switch section 2, and the output of the branch amplifier 1 to the protection line is connected to its terminator by the switch 2 during normal operation. In addition, on the receiver side, there is a pilot signal and noise detector 3 for the working line.
Pilot detector for protection line4. Receiving side switch f! l
l55, FM oscillator 6t-contains.

This transmitter 1i41J requires isolation of 80 dB or more for each mining circuit to ensure transmission quality, and therefore the switch section 2 has a complex configuration and is tightly shielded. Membership fees were charged for the chassis, etc., which was an obstacle to lowering the price and downsizing. On the other hand, due to the review of the power situation and power resources, there are many cases where solar cells, etc. are used, and there is a strong need to reduce the power consumption of devices.
It's starting to become more common.

SUMMARY OF THE INVENTION An object of the present invention is to provide an IP band line switching device having an inexpensive and small circuit configuration, which reduces power consumption in the transmitting side part and simplifies the configuration of the transmitting side switch.

The configuration of the present invention is that, in an intermediate frequency band line switching device including a branch amplifier and a transmitting section working/standby changeover switch, during normal operation, the power of the standby line side amplifier of the branching amplifier is cut off and the power is switched only to the working line side amplifier. power supply control means that applies power to the standby line amplifier in response to a control signal that detects the abnormality when the line is abnormal, and lowers the power supply voltage of the working four-wire side amplifier even more than in normal conditions; Having t-characteristics.

When an abnormality is detected in the pilot signal or noise on either of the working lines on the receiving end side, the transmitting side switch is activated and the same signal as the working line with the abnormality is transmitted to the protection line. be done. Therefore, the output of the amplifier for the protection line is terminated during normal operation, and there is no need for multi-signal amplification. For this reason, if the operation of the amplifier on the protection line is stopped during normal operation, the difference between input and output, including the gain of the amplifier, will be 30 to 40%.
Since it is possible to obtain an isolation gain of about dB, the isolation value required for the switch part is 40 to 50.
It gets better in dB. Therefore, the configuration of the switch part can be greatly simplified, and the power consumption of the amplifier is not required. In addition, if an abnormality occurs in the working line and it is switched to the protection line, the signal will be transferred to the protection line. Since the signal is transmitted by lightly relying on the signal, the pilot signal and noise are only monitored at the receiving end in the working line. In this case, even if there is deterioration in transmission quality such as distortion, the power consumption of the working line amplifier can be reduced to the extent that it does not interfere with the detection of pilot signals and noise on the receiving end side. The relationship between the gain of this amplifier and the power supply voltage varies depending on the circuit used and the operating conditions, but in the case of amplifiers used in such devices, the gain does not decrease much even if the power supply voltage is reduced by about half. There is no problem in detecting the pilot signal and noise. The present invention will be explained in detail below with reference to the drawings.

FIG. 2 is a block diagram of one embodiment of the present invention.

In the figure, the transistors TfL1 to TfL3 are the drive path of the branch amplifier 1, and the control signal transmitted through the line control device is applied to the base of the transistor TfL1, and the control signal is applied to the base of the transistor TfL1. , TR3. During normal operation, the transistor TR2 is cut off, and no voltage is applied to the amplifier 12 of the protection line, and the transistor T
Ra is turned on and the amplifier 11U of the current line is operating. Also, at the time of switching, the amplifier 12
Although a regular voltage is applied to the amplifier, only the voltage set by the variable resistor RV1 of the 11 amplifiers is applied. Therefore, during normal operation, it is possible to reduce switching time-based power consumption, and at the same time, sufficient isolation can be obtained during normal operation.

As explained above, in the transmission section of the IF band switching device, during normal operation, isolation between the input and output is achieved by cutting off the power to the amplifier on the protection line side among the branch amplifiers. It has become possible to simplify the structure of the exhaust part, make it smaller and lower cost, and also reduce power consumption.

Furthermore, by lowering the power supply voltage of the amplifier on the working line side during line switching, power consumption can be reduced without interfering with the line switching operation.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a general IF band line switching device, and FIG. 2 is a block diagram of an embodiment of the present invention. In the figure, 1...branch amplifier, 2...sending end switch,
3... Working pilot and noise detector, 4-
A standby pilot and noise detector, 5...receiving end switch, 6...FM oscillator, 11...working amplifier, 12...standby side amplifier. Agent Patent Attorney Susumu Uchihara

Claims (1)

[Claims] In an intermediate frequency band line switching device including a branching amplifier and a transmitter working/standby switch, the branching layer S
Turn off the power to the amplifier on the protection line side of the
Applying power only to the side amplifier, times*J! The control signal that detects this abnormality always causes the reserve interval ll1li14!
An intermediate frequency A/I circuit switching device characterized by comprising a power supply control means for applying power to the IJ11 amplifier to lower the power supply voltage of the working circuit amplifier even in a normal state.