JPS63240145A - Digital signal transmission system - Google Patents

Abstract

PURPOSE:To attain changeover of active and standby modules with low power and low cost by providing a switch signal generating circuit and an output signal inhibition circuit and a fault detection circuit to each active/standby module respectively. CONSTITUTION:The active and the standby sides are provided with fault detection circuits 15, 16, control signal generating circuits 17, 18 outputting an active/ standby switching control signal and output digital signal inhibition circuits 19, 20 of the same structure. The changeover of active/standby module is applied by using setting signals 1, 6 and fault signals 8, 9 are inputted to the circuits 17, 18. When the active side is normal, only an active output signal 13 is outputted from the circuit 19, the circuit is switched in case of the faulty active side and the normal standby side and only the output signal 14 is outputted from the circuit 20. When both the active/standby sides are faulty, no changeover is applied and the output of the circuit 19 is clamped. Thus, the changeover of active/standby sides is attained with low power and low cost.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a digital signal transmission system, and particularly to a digital signal transmission system that has a function of switching between active and standby in the event of a failure.

(Prior Art) Conventionally, this type of digital signal transmission equipment has a structure in which switching between active and backup functions is performed manually, or a common alarm control module is used. It was configured to be controlled through.

(Problems to be Solved by the Invention) The above-mentioned conventional digital transmission devices are manually switched, and therefore have the disadvantage that manual operations are troublesome, time consuming, maintenance costs, etc. increase. Furthermore, it cannot be controlled without using a common alarm control module, which increases the size of the entire device and increases power consumption.

The present invention enables each module on the active side and standby side to generate a control signal to control the output signal,
The object of the present invention is to provide a digital signal transmission device that can perform switching between active and standby signals with low power consumption and low cost.

(Means for Solving the Problems) The digital signal transmission system according to the present invention includes the same fault detection circuit for each module on the active side and the standby side, respectively.
It has a working/standby control signal generation circuit and an output digital signal inhibition circuit, and the working/standby setting is performed by an initial control signal, and both the working side fault detection signal and the standby side fault detection signal are used as the working/standby control signal. input to the generating circuit,
Switching to the standby side is performed only when there is a failure on the working side and when both standby sides are faulty, and the working side is selected and fixed without sending failure signals on the working side or the standby side.

(Example) Next, the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of a digital signal transmission device having a working and standby switching function applied to carry out the present invention. The transmission device according to the present invention has the same circuit configuration on both the working and standby sides. In the illustrated embodiment, the upper half (indicated by symbol A) of the diagram is the active circuit, and the lower half (indicated by symbol B) is the protection circuit. That is, the fault detection circuits 15 and 16 that are the same on the working side and the standby side, the control signal generation circuits (working and standby control signal generation combinational logic circuits) 17 and 18 that output the working and standby switching control signals, and the output digital signal inhibit circuits 19 and 20, and these circuits constitute active and standby modules, respectively. Setting signals 1 and 6 at the time of initial setting are input to the active side failure detection circuit 15 and the standby side failure detection circuit,
Each has a working and a reserve. The received digital signal 2 and the received clock signal 3 on the working side are input to a working side failure detection circuit 15, and the circuit 15 detects a failure on the working side. Similarly, the received digital signal 5 on the standby side
The received clock signal 4 is then input to the standby fault detection circuit 16 to detect a fault. Fault detection circuit 1 on active side
The fault signal 8 on the working side detected in step 5 is input to both the working and standby control signal generation circuits 17, 18, and the fault signal 9 on the standby side detected by the fault detection circuit 16 on the standby side is similarly input to the control signal generating circuits 17, 18 for both the working and standby sides. The control signal 11.1 is inputted to both preliminary control signal generation circuits 17.18, and the control signal 11.1
2 is output, and the fault detection circuit 15.2 on the active and standby sides is output.
The digital signals 7.10 retimed at 16 are controlled by respective output digital signal inhibit circuits 19.20. Here, when the working side is normal, only the working output signal 13 is output from the output digital signal prohibition circuit 19, and when there is a failure on the working side and both backup sides are in failure, switching to the backup side is performed and the signal is switched to the backup side. Only the output signal 14 is output from the side output digital signal prohibition circuit 20, and the current
If both the standby and standby modules are at fault, no switching is performed, and each module generates a control signal based on its own judgment, and the output is identified by the output digital signal prohibition circuit 19 on the working side.

(Effects of the Invention) As explained above, according to the present invention, by providing the same fault detection circuit, switching signal generation circuit, and output signal inhibition circuit in each of the active and standby modules, each module,
1- The control signal can be generated by itself and the output signal can be controlled.
This also brings about the effect of being able to switch between active and standby with low power consumption and low cost.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a digital signal transmission device having an output signal switching function according to an embodiment of the present invention. 1.6... Current and backup setting signals, 2.5... Received digital signal, 3.4... Received clock signal, 7.10... Retimed digital signal, 8
．． 9... Current and backup failure signals, 11, 12... Control signals, 13.14... Output signals, 15, 16... Failure detection circuits 17, 18... Control signal generation circuits, 19. 20...Output digital signal inhibition circuit.

Claims (1)

[Claims] Each module on the working side and standby side has the same fault detection circuit, working/standby control signal generation circuit, and output digital signal inhibition circuit, and the working/standby setting is performed by the initial control signal, and the working side failure detection circuit is the same. Both the detection signal and the standby side failure detection signal are input to the working/standby control signal generation circuit, and the switching to the standby side is performed only when there is a failure on the working side and when the standby side is normal, and the switching is performed when both the working side and the standby side are in failure. A digital signal transmission method that selects and fixes the current side without transmitting data.