JPS58184835A - Monitoring system of communication system - Google Patents

Abstract

PURPOSE:To attain a long-distance relay transmission, by discriminating and reproducing a monitoring signal and preventing the deterioration in the S/N ratio of the said signal. CONSTITUTION:A transmission signal and an FM-modulated digital monitoring signal from a transmission terminal station (not shown) are transmitted via a communication cable 1 and an intermediate line 2 and relayed and transmitted to a reception terminal station (not shown) via many relay stations 5-2-5-n. Each relay station, e.g., 5-2 consists of a relay device 7-2 for a transmission signal and a monitoring circuit 8-2 having an MODEM. When a failure takes place in a transmission line 1 including a relay device 7-2, the relay device 7-2 transmits a failure detection signal to a coupling circuit 12 in the monitoring circuit 8-2. The monitoring circuit 8-2 demodulates the monitor signal transmitted via the line 2 at a demodulator 9, and after the timing is picked up at a circuit 10, a digital monitoring signal is discriminated and reproduced at a discrimination circuit 11. The coupling circuit 12 inserts a failure detection signal in a monitoring signal frame and transmits it to the relay station at the next stage via a modulator 13. This monitoring signal is received at a monitor at the reception terminal.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Technical Field of the Invention The present invention relates to a monitoring method for a communication system using intervening communication cables, and in particular to a method for monitoring a modulated digital monitoring signal using a monitoring circuit using a modem. Concerning a monitoring method for reproducing and relaying.

(b) Prior Art and Problems In a communication system monitoring system in which a transmission signal is transmitted via a communication cable and a digital monitoring signal for monitoring the transmission signal is transmitted via an intervening line of the communication cable, the digital monitoring signal is FM modulated. , sent to the intervening line as an FM digital monitoring 4y signal, and monitored using a modem IF! In a monitoring system for a communication system in which relay transmission is performed over a single path, as the distance of the intervening line increases, the S/N of the digital monitoring signal deteriorates due to the line loss of the intervening line. Therefore, what is the applicable distance of the communication system? ! :ll will be limited.

FIG. 1 shows a conventional communication system monitoring system.

In the 1 river diagram, the transmission signal is transmitted through the communication cable 1, and the digital monitoring signal that monitors the transmission signal is intervening liIil2.
to transmit.

Transmission 2 transmitted from the transmission device 4-1 of the terminal station 3-1! s 悄ji is Naka Naka Kumijo (hereinafter referred to as Naka) 5-1.

5-2...5-n each repeater 7-1.7-2...
...7-n, and is transmitted to the transmission device 4-2 of the terminal station 3-2.

On the other hand, the digital monitoring signal F'M modulated by the monitoring device 6-1 of the terminal station 3-1 is internally transmitted to each of the repeaters 7-1 to 7-n of the terminal stations 5-1 to 5-n. Monitoring circuit (hereinafter also referred to as SV) 8'-1 to 8-n for one modem installed in
The signal is then relayed to the monitoring device 16-2 of the terminal station 3-2.

Now, when the repeater 7-2 of 5-2 becomes a fault or detects a fault, the fault signal is sent to the S circuit 8'-2.
is man-powered. In S■ circuit 8'-2, F from 6-1
M digital supervisory signals are equalized and amplified. The FM-modulated fault signal is added to the FM digital monitoring signal and transmitted to the monitoring device 6-2 via the intervening string 2.

The above FM modulated digital monitor signal is attenuated by the line loss of the intervening line 2.

The attenuation is compensated for by equalizing amplifiers (not shown) in each of the 87 circuits 8'-1 to 8'-n. However, with this method, as the transmission path becomes longer, the S/
N deteriorates and the transmission signal cannot be monitored.

For this reason, a monitoring system that allows long-distance transmission of transmission signals is desired.

(c) Purpose of the Invention In order to solve the above-mentioned drawbacks, the present invention provides a novel communication system that identifies and regenerates monitoring signals to prevent S/N deterioration of the monitoring signals, thereby enabling long-distance transmission of transmission signals. The purpose is to provide a system monitoring method.

(d) Structure of the Invention For this purpose, the present invention relays and transmits a modulated digital monitoring signal for monitoring the transmission signal to an intervening line of a follow-up cable that transmits the transmission signal using a monitoring circuit using a modem. Fault monitoring method for communication system 1'1 In the formula 1'1, there is provided a means for converting the digital monitoring signal modulated in the monitoring shaft connection into a digital monitoring signal, and a means for extracting a cyclic pulse from the nuclear digital monitoring signal. and means for identifying and reproducing the digital surveillance signal No. 16 using mosquito clock pulses, and means for inserting a failure detection signal of the previous 6 self-transmissions that caused the failure into the identified and reproduced digital surveillance signal. This is achieved by modulating the digital monitoring signal 16 into which the fault detection signal is inserted.

(EL Investigation Example) The present invention will be explained below based on the embodiment shown in FIG.
-1 to 7-n are being transmitted.

Assume that a fault occurs in the transmission line including the repeater 7-2 in the above state, and the fault detection signal is sent out by the 87 circuit 8-2. The fault detection signal is injected into the Sv cycle using a modem and sent to the monitoring device 1li6-2 via the intervention-1!2.
shall be transmitted to.

In the second circuit, the FM-modulated digital monitoring signal from the monitoring device 6-1 (see Figure 1) is transmitted from 51 to n track 2.
' is input to the SV circuit 8-2 through
The differential signal monitoring signal is demodulated into a clock pulse (hereinafter referred to as "meshi clock") in a timing circuit 10, and the demodulated digital monitoring signal is sent to an identification circuit 11 using a cough clock. identification playback 12,
The reproduced signal is input to the coupling circuit 12. The circuit 12
The fault detection signal from the repeater 7-2 is inserted into the frame of the identified and reproduced digital monitoring signal.
3, and the FM modulated digital signal is demodulated, reproduced, and FM modulated regeneration relay is repeated in successive 87 circuits 8-3 (not shown), . . . 8-n, and then monitored. The fault and address are detected by the monitoring device j-2 (see Figure 1). Since the 87 circuits in each repeater perform separate reproduction, the S/N of the monitoring signal often deteriorates. Therefore, it has the advantage that the transmission path can be extended over a longer distance.

[Brief explanation of the drawing]

FIG. 1 shows a conventional communication system monitoring system. Second
The figure shows an embodiment of the invention. In the figure, l is )Iglf11! cable, 2it intervening line,
3-1゜3-2 is a terminal station, 4-1.4-2 is a transmission device, 5
-1 to 5-n each intermediate relay station, 6-1 to 6-n each monitoring circuit, 7-1 to 7-n each intermediate tiller, 8-1 to 8-n each monitoring 1-14> , 9 is a ~adjuster, 10 is a timing circuit, 11 is an identification circuit, 12 is a coupling circuit, and 13 is an FM converter.

Claims (1)

[Claims] Nucleus 12,
In the fault monitoring system of Tsui, J/Suam, which relays and transmits the modulated digital monitoring signal that monitors the 1d signal using a modem,
In addition, there is a means for inheriting the digital monitoring signal from the modified PA to the digital monitoring fδ, a means for extracting clock pulses from the digital monitoring signal, and using 6-3]+7 clock pulses, the digital monitoring signal is transferred to the digital monitoring signal fδ. It has a means for generating a supervisory signal (+1), and a means for inserting a fault signal of the transmission signal which has become a fault into the internally generated digital supervisory signal, and the fault detection signal is inserted. A communication system monitoring method characterized by modulating a digital monitoring signal.