JPH01194522A - Hot stand-by transmission circuit - Google Patents

Abstract

PURPOSE:To prevent a silent failure condition by discovering the abnormality of the switching operation of a switcher. CONSTITUTION:According to the switching condition of switchers 3a and 3b, a signal is detected by either of detectors 10a or 10b and the switching information of the switchers 3a and 3b can be supervised by a switching control board 11. Accordingly, when both switchers 3a and 3b are troubled in a conducting condition, since there is no reflected wave by the switchers 3a and 3b, the signal is not sent to the detectors 10a and 10b. Reversely, when both switchers 3a and 3b are troubled in an interrupting condition, both present and auxiliary signals are detected by the detectors 10a and 10b, in these conditions, it can be known that either the switcher 3a or 3b is troubled and a line is interrupted or an abnormal signal is transmitted. Thus, by discovering the abnormality of the switching operation of the switchers 3a and 3b, the silent failure condition can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field 1] The present invention relates to a transmitting circuit used in a hot standby system.

[Prior Art] Conventionally, in a hot standby transmission circuit, the same signal output from a plurality of transmitters is switched between a working signal and a backup signal in a switch placed between the transmitter and the duplexer. When using the working signal, a switch prevents the backup signal from being sent to the duplexer.

FIG. 2 shows a block diagram of a conventional hot standby transmission circuit. The signals transmitted from the transmitters R1a and 1b pass through isolators 2a and 2b and are transferred to the switch 3a.
, 3b. The switching devices 3a and 3b are the switching control panel 11
However, if the switch 3a is conductive and the switch 3b is cut off, the signal sent from the transmitter ala will pass through the switch 3a, the circulator 5.6 and the duplexer 7, and then It is transmitted by the antenna 13.

Since the signal from the transmitter 1b is blocked by the switch 3b,
It is not transmitted because it is absorbed by isolator 2b.

[Problems to be solved] In the hot standby transmission circuit described above, the switching device 3a,
3b performs a switching operation based on a switching signal from a switching control panel 11 that receives a switching signal from a communication monitoring device 12 or a transmitting/receiving device, but if the switching device itself fails, the switching device will fail while it is in a conductive state. Then, the working and standby signals are combined without being phase-combined and sent to the demultiplexer 7, and if the switch fails in the cut-off state, the working and standby signals are also cut off.

Furthermore, the switching device performs switching operation by opening and shorting high-frequency diodes or mechanically, and damage to the diode, failure of the alarm signal circuit due to mechanical malfunction, and combination of transmitted signals due to failure of the switching device. Even if deterioration or disconnection occurs, it is not known that the abnormality in the transmitted signal is due to a failure in the switching device, resulting in a silent failure condition (a state in which an abnormality occurs in the line without a device alarm being issued). There is a drawback.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to solve the above-mentioned conventional problems and provide a hot standby transmission system that can prevent silent failure by providing a configuration that can detect abnormalities in the switching operation of a switching device. The purpose is to provide circuits.

[Means for Solving Problems] The hot standby transmission circuit of the present invention includes a switch for switching transmission signals between the active device and the standby device, and a directional coupler for combining a part of the signal reflected by the switch. A detector configured to detect the signal coupled by the directional coupler; and a monitoring device configured to monitor the operation of the switch based on the detected signal.

Through such monitoring, it is possible to detect a silent failure condition due to a failure of a switching device.

[Example] Next, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of one embodiment of the present invention.

Signals sent from transmitters 1a, 1b pass through isolators 2a, 2b and directional couplers 9a, 9b, and reach switches 3a, 3b. The switching devices 3a, 31) are the switching control panel 1
For example, if the transmitter 1a is in use and the transmitter 1b is a backup, the switch 3a is turned on and the switch 3b is cut off.The signal from the transmitter 1a passes through the switch 3a. The signal passes through a circulator 5.6 and a duplexer 7, and is transmitted from an antenna 13.

Further, the signal from the transmitter 1b is reflected because the switch 3b is cut off, and this reflected signal is transmitted to the directional coupler 9.
b, and the remaining signal is sent to isolator 2.
It is absorbed by b. The signal combined by the directional coupler 9b is sent to the detector 10b. The signal detected by the detector 10b is sent to the switching control panel 11, and further sent to the communication control device 12 as switching information. Therefore, depending on the switching state of the switches 3a, 3b, a signal is detected by either the detectors 10a, 10b, and the switching control panel 11 can monitor the switching information of the switches 3a, 3b.

As a result, if the switching devices 3a and 3b are both in a conductive state and fail, no signal will be sent to the detectors 10a and 10b because there will be no reflected waves from the switching devices 3a and 3b.
On the other hand, if the switchers 3a and 3b are both cut off and fail, the detectors 10a and 10b will detect both the working and standby signals, so in these states, the switchers 3a and 3
It can be seen that one of the terminals b is out of order, the line is disconnected, and an abnormal signal is being transmitted.

Note that the present invention is not limited to the above embodiments,
Various modifications are possible within the scope of the invention.

[Effects of the Invention] As explained above, the present invention closes the circuit by the switching device, extracts and detects the reflected signal with the directional coupler, monitors the switching operation of the switching device, and detects the signal reflected by the switching device. By detecting an abnormality in the switching operation of the switch, it is possible to prevent a silent failure state.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a hot standby transmitting circuit according to an embodiment of the present invention, and FIG. 2 is a block diagram of a conventional hot standby transmitting circuit. 1a, 1b... Transmitter 2a, 2b... Isolator 3a, 3b... Switcher 4a, 4b... Isolator 5.6... Circulator 7... Brancher 8... Termination device 9a, 9b...Directional coupler 1-Oa, 10b...-Detector 11...Switching control panel 12...Communication monitoring device 13...Antenna agent Patent attorney Kihira Watanabe÷,

Claims (1)

[Scope of Claims] In a hot standby transmission circuit that switches between a working signal and a backup signal used in a hot standby system by opening and closing a switch provided in the transmission circuit, for switching the transmission signal of the working device and the backup device. a directional coupler that couples a part of the signal reflected by the switch; a detector that detects the signal coupled by the directional coupler; and an operation of the switch based on the detected signal. A hot standby transmission circuit comprising: monitoring means for monitoring.