JPS61230451A - Data transmission system - Google Patents

Abstract

PURPOSE:To supervise an error rate at each plural transmission lines split by an intermediate repeater by allowing at least one set in intermediate repeaters to extract a frame synchronizing signal from a transmission signal to detect the error rate and sending the frame synchronizing signal of the transmission signal in place of a new frame synchronizing signal recovered from the transmission signal. CONSTITUTION:A signal inputted to an input terminal 11 from a transmission line is subject to frame synchronization by a frame synchronizing circuit 12 in an intermediate repeater 300, only the frame synchronizing signal is extracted by a frame synchronizing signal detection circuit 13 and the result is sent to an error rate detection circuit 14. The error rate detection circuit 14 identifies whether or not the frame synchronizing signal is in error to detect the error rate of the transmission line between a terminal device 100 and the repeater 300. The signal inputted to the input terminal 11 is sent further to a frame synchronizing signal insertion circuit 16, after a new frame synchronizing signal formed by a frame synchronizing signal generating circuit 15 is inserted, the result is outputted to a transmission line 200 from the output terminal 17.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is directed to dividing a transmission line between two terminal equipment into a plurality of transmission lines by an intermediate repeater, and determining the code of a signal transmitted through the transmission line. The present invention relates to a data transmission system in which the format is an mBnB code, and a frame synchronization signal is included at regular intervals in a signal transmitted over a transmission path.

[Conventional technology]

Conventionally, mBn was used as a code format for signals transmitted through a transmission line.
An intermediate relay device of a data transmission system that uses a B code (m(n)) is a running
By monitoring disparity, the error rate of the transmission line was monitored.

[Problem that the invention seeks to solve]

The mBnB code (m(n)
In the method of monitoring the error rate of a loop transmission line by monitoring the running disparity of It is not possible to monitor the error rate of each divided transmission path, but only the error rate of the entire transmission path from the terminal equipment to each intermediate relay device, so it has the disadvantage of low reliability. Ta.

[Means for solving problems]

In the data transmission system of the present invention, in the first terminal device,
A transmission signal obtained by inserting a frame synchronization signal into an mBnB code signal is sent out, a signal obtained by reproducing and relaying the transmission signal through a plurality of intermediate relay devices and transmission lines is received at a second terminal device, and from this received signal The second terminal equipment extracts the frame synchronization signal and detects its error rate, and the second terminal equipment extracts the frame synchronization signal and detects the error rate thereof.
In a data transmission system that extracts a BnB code signal and detects its 19th line, at least one of the intermediate relay devices extracts a frame synchronization signal from the transmission signal and detects the frame synchronization signal. 14, and a new frame synchronization signal reproduced from the transmission signal is sent instead of the frame synchronization signal of the transmission signal.

〔Example〕

Next, the present invention will be explained in detail with reference to the drawings.

FIG. 1 is a block diagram showing one embodiment of the present invention. First, in the terminal device 100, the frame synchronization signal generated by the frame synchronization signal generation circuit 3 is inserted into the mBn B code signal input from the input terminal 1 by the frame synchronization signal insertion circuit 2 at a predetermined position and output. Transmission line 2 from terminal 4
Output as 00.

Conversely, the signal input from the transmission line 200 to the input terminal 5 is frame synchronized by the frame synchronization circuit 6, and then only the frame synchronization signal is extracted from the input signals by the frame synchronization signal extraction circuit 7. The extracted frame rate j signal is sent to the error rate detection circuit 8. The error rate detection circuit 8 identifies whether or not the frame synchronization signal sent from the frame synchronization signal extraction circuit 7 is erroneous, and detects the error rate of the transmission path 200 between the terminal device 100 and the intermediate relay device 3000. . Furthermore, the frame synchronization signal is removed from the signal input to the input terminal 5 by an mBnB code signal extraction circuit 9, and only the mBnB code signal is sent to an error rate detection circuit 10. The error rate detection circuit 10 decodes the mHnB code signal sent from the mBnB code signal extraction circuit 9 into the original signal, and at the same time detects a disturbance in the mBnB encoding rule, and detects the disturbance between the end wJ devices. The error rate of the entire transmission path is detected.

Next, in the intermediate relay device 300, the signal input from the transmission line to the input terminal 11 is subjected to frame synchronization in the frame synchronization circuit 12, and then only the frame synchronization signal is detected from among the manually input signals in the 7-frame synchronization signal detection circuit 13. The seven extracted frame synchronization signals are sent to the error rate detection circuit 14. The erroneous vehicle detection circuit 14 identifies whether or not the frame number 4 M1 sent from the frame synchronization signal extraction circuit 13 is active, and detects whether or not the frame 4 M1 is valid.
Detect errors in the transmission path between 0 and υ. The 7'C% No. 1 input to the input terminal 11 is further sent to the frame synchronization signal intrusion circuit 16, and the new frame synchronization signal generated by the frame synchronization signal generation circuit 15 is added to the signal sent from the input terminal 11. After being inserted into the frame synchronization signal included therein, the signal is output from the output terminal 17 to the transmission line 200.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, when a plurality of intermediate relay devices are installed on a transmission path in the conventional transmission path monitoring method, each intermediate relay device This solves the drawback that it is not possible to monitor the error rate of each divided transmission path, and it is also possible to monitor the error rate of each divided transmission path from the intermediate relay device. Since the error rate of the entire transmission line sandwiched between them can also be monitored, reliability is high.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of the present invention. 1...m Bn B code signal input terminal, 2
...Frame synchronization signal insertion circuit, 3...
・Frame quarter signal generation circuit, 4...Output terminal to the transmission line, 5...Input terminal from the transmission line, 6
...Frame synchronization circuit, 7...Frame synchronization signal extraction circuit, 8...Gb rate detection (b)
road, 9...-mBnB code signal extraction circuit, 10.
...Error rate detection circuit, 11...Input terminal from transmission path, 12...Frame synchronization circuit, 1
3... Frame synchronization signal extraction circuit, 14...
...Error rate detection circuit, 15...Frame synchronization signal generation circuit, 16...Frame synchronization signal insertion circuit, 17...Output terminal to transmission path.

Claims (1)

[Claims] In the first terminal device, mBnB code signal (m<n)
A transmission signal with a frame synchronization signal inserted therein is sent out, a signal obtained by reproducing and relaying the transmission signal through a plurality of intermediate relay devices and a transmission path is received at a second terminal device, and a second terminal device receives a signal from which a frame synchronization signal is inserted. In the data transmission method, the frame synchronization signal is extracted and the error rate thereof is detected in the terminal station device, and the mBnB code signal is extracted and the error rate thereof is detected from the received signal in the second terminal station device. at least one of the intermediate relay devices extracts a frame synchronization signal from the transmission signal and detects its error rate;
A data transmission system characterized in that a new frame synchronization signal reproduced from the transmission signal is sent instead of the frame synchronization signal of the transmission signal.