JPS63304735A - Branching and inserting repeater - Google Patents

Abstract

PURPOSE:To attain the reception and branch of an input signal by switching a transmission counter so as to act it like a reception counter through the detection of a fault if the reception counter is faulty. CONSTITUTION:If the reception counter 4 is faulty, a fault detection circuit 1 discriminates a fault from a counter signal outputted from the reception counter 4 and outputs a switching signal to switch a signal path to changeover circuits 3, 6. The changeover circuit 3 is thrown to output the signal inputted to a terminal 11 from a terminal 13, a synchronizing signal from a synchronizing signal circuit 2 is outputted from the terminal 13 of the changeover circuit 3 and inputted to a transmission counter 5. Since the transmission counter 5 is able to act like a reception counter, the counter 5 outputs a counter signal to a terminal 16 of the changeover circuit 6 on behalf of the faulty reception counter 4. Thus, the counter signal from the transmission counter 5 is outputted from a terminal 17 of the changeover circuit 6 and inputted to a branch circuit 7. Thus, the reception and branch of a high-order group input signal are attained.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a relay device for a digital transmission system,
In particular, the present invention relates to a drop/add repeater that receives and drops high-order group signals.

[Conventional technology]

The add/drop repeater is a medium-sized device that branches multiplex-converted and transmitted high-order group signals into low-order group signals and outputs them, and also converts input low-order group signals into high-order group signals and transmits them.

In this type of add/drop repeater, a synchronous circuit controls a reception counter based on the transmitted high-order group signal, and this reception counter controls a branch circuit, so that this branch circuit receives the high-order group signal. Branches and outputs a low-order group signal. Further, the transmission counter controls the insertion circuit, so that the insertion circuit converts the input low-order group signal into a high-order group signal and transmits the signal.

In such a drop/add repeater, the receiving counter exclusively controls the branch circuit, and the transmitting counter exclusively controls the inserting circuit.

[Problem that the invention seeks to solve]

In the conventional add/drop repeater described above, the reception counter is dedicated to the branch circuit, and the transmission counter is dedicated to the insertion circuit, so if the reception counter fails, it will be impossible to receive and branch the input signal. There is a drawback.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate such drawbacks and provide a drop/add repeater that can receive and branch input signals even in the case of a failure of the reception counter.

[Means for solving problems]

In the present invention, a synchronous circuit outputs a synchronous signal based on a high-order group signal that has been multiplexed and transmitted, further generates a counter signal from this synchronous signal, and a branch circuit receives the high-order group signal using this counter signal and branches it. A drop/add repeater that outputs the next group signal includes a reception counter that outputs a counter signal in response to an input synchronization signal, and a reception counter that can operate as the reception counter and outputs a counter signal in response to the input synchronization signal. a transmission counter; a failure detection circuit that detects a failure in the reception counter circuit based on a counter signal from the reception counter circuit;
- By the switching signal output from the failure detection circuit, when the reception counter circuit is normal, the synchronization signal from the synchronization circuit is output to the reception counter, and when a failure occurs,
A first switching circuit that outputs this synchronization signal to the transmission counter and a switching signal output from the failure detection circuit switch the counter signal from the reception counter to the branch when the reception counter circuit is normal. output to the circuit,
The present invention is characterized in that it includes a second switching circuit that outputs a counter signal from the transmission counter to the branch circuit when a failure occurs.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

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

This drop/add repeater includes a synchronization circuit 2 that outputs a synchronization signal based on a transmitted high-order group signal that is a human signal;
A reception counter 4 outputs a counter signal in response to a synchronization signal output from a terminal 12 of a switching circuit 3, which will be described later. A transmission counter 5 outputs a counter signal based on a synchronization signal, a failure detection circuit l determines a failure from the counter signal of the reception counter 4, and outputs a switching signal, A synchronizing signal is output to the receiving counter 4 from the terminal 12, and this synchronizing signal is sent to the terminal 13 when a failure occurs.
The switching circuit 3 outputs the output to the transmission counter 5, and the switching signal from the failure detection circuit 1 outputs the counter signal from the reception counter 4 during normal operation, and outputs the counter signal from the transmission counter 5 when a failure occurs. a switching circuit 6;
The high-order group signal is input by the counter signal from the switching circuit 6, and the branch circuit 7 branches and outputs the low-order group signals aI+..., a, (m is a positive integer), and the counter signal from the transmission counter 5 is input. The lower-order group signal b1. ...,bn
(n is a positive integer) into a higher-order group signal and transmits the signal.

The high-order group signal that is the input signal is input to the synchronous circuit 2, and the synchronous signal output from the synchronous circuit 2 is sent to the terminal 1 of the switching circuit 3.
1 is input. The synchronizing signal output from the terminal 12 of the switching circuit 3 is input to the receiving counter 4, and the synchronizing signal output from the terminal 13 of the switching circuit 3 is input to the transmitting counter 5. The counter signal output from the reception counter 4 is input to the terminal 15 of the switching circuit 6 and the failure detection circuit l. The switching signal output from the failure detection circuit 1 is input to the terminal 14 of the switching circuit 3 and the terminal 18 of the switching circuit 6.

A counter signal outputted from the transmission counter 5 is input to the terminal 16 of the switching circuit 6 and the insertion circuit 8.

The counter signal output from the terminal 17 of the switching circuit 6 is input to the branch circuit 7.

Next, the operation of this embodiment will be explained.

The synchronization circuit 2 synchronizes with the high-order group signal as the input signal and outputs a synchronization signal to the switching circuit 3.

On the other hand, the failure detection circuit 1 detects a failure of the reception counter 4 based on the counter signal output from the reception counter 4. When the receiving counter 4 is normal, the switching circuit 3 is activated by the switching signal output from the failure detection circuit l.
The signal input to the terminal 11 is switched to be output from the terminal 12. Therefore, the synchronization signal from the synchronization circuit 2 is output from the terminal 12 of the switching circuit 3 and input to the reception counter 4. The reception counter 4 is controlled by a synchronization signal from the switching circuit 3 and outputs a counter signal. This counter signal is input to the terminal 15 of the switching circuit 6, but the switching circuit 6 is switched to output the signal input to the terminal 15 from the terminal 17 by the switching signal from the failure detection circuit l. . Therefore, the switching circuit 6
The counter signal from the receiving counter 4 is outputted to the branch circuit 7 from the terminal 17 of the receiving counter 4 . The branch circuit 7 branches and outputs the low-order group output signals al+ . . . , al from the high-order group input signal according to the counter signal from the receiving counter 4 .

Next, when the reception counter 4 fails, the failure detection circuit l determines the failure from the counter signal output from the reception counter 4, and outputs a switching signal to switch the signal path to the switching circuit 3.6. do. In response to this switching signal, the switching circuit 3 is switched so that the signal inputted to the terminal 11 is outputted from the terminal 13. Therefore, the synchronization signal from the synchronization circuit 2 is output from the terminal 13 of the switching circuit 3 and input to the transmission counter 5. Since the transmission counter 5 can operate as a reception counter, it outputs a counter signal to the terminal 16 of the switching circuit 6 in place of the failed reception counter 4. The switching circuit 6 is switched to output the signal input to the terminal 16 from the terminal 17 in response to a switching signal from the failure detection circuit 1 . Therefore, the counter signal from the transmission counter 5 is transmitted to the terminal 1 of the switching circuit 6.
7 and input to the branch circuit 7.

In this manner, it is possible to receive and branch high-order group input signals in accordance with the counter signal from the transmission counter that replaces the failed reception counter 4.

! The insertion circuit 8 is controlled by a transmission counter, and converts the low-order group signals b1° .

〔Effect of the invention〕

As explained above, the present invention enables even if a receiving counter fails in a drop/add repeater of a digital transmission system, by detecting the failure and switching the transmitting counter to operate as a receiving counter.
This has the effect of being able to receive and branch input signals.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention. ■・・・Failure detection circuit 2...Synchronous circuit 3.6...Switching circuit 4...Reception counter 5...Transmission counter 7...Branch circuit 8...Insertion circuit

Claims (1)

[Claims] (1) The synchronization circuit outputs a synchronization signal based on the high-order group signal that has been multiplexed and transmitted, further generates a counter signal from this synchronization signal, and the branch circuit receives the high-order group signal using this counter signal and branches it to the lower order A drop/add repeater that outputs a group signal includes a reception counter that outputs a counter signal in response to an input synchronization signal, and a transmission counter that can operate as the reception counter and outputs a counter signal in response to an input synchronization signal. a reliability counter; a failure detection circuit that detects a failure in the reception counter circuit based on a counter signal from the reception counter circuit; and a switching signal output from the failure detection circuit to detect when the reception counter circuit is normal; A synchronization signal from the synchronization circuit is output to the reception counter, and when a failure occurs,
A first switching circuit outputs this synchronization signal to the transmission counter, and a switching signal output from the failure detection circuit causes the counter signal from the reception counter to be switched to the branch when the reception counter circuit is normal. A branch/add/drop relay device comprising: a second switching circuit that outputs a counter signal from the transmission counter to the branch circuit when a failure occurs.