JPS63302630A - Transmission communication system - Google Patents

Abstract

PURPOSE:To discriminate the disconnection of the transmission lines of respective repeaters and faults in the repeaters by detecting an AM pilot signal which sets a central supervisory station to an initial stage in detection means in the repeaters consisting only of receiving elements and transmitting a detected result to a preceding stage. CONSTITUTION:The AM pilot signal from a pilot signal generator 10 in the central supervisory station 31 of the initial stage is inputted to a coupler 35 in the repeater 33 of the subsequent stage through transmission line 32, is detected in a BPF36 and a detection part 37 consisting only of the receiving element which operates even when a power is turned off, and the presence and absence of an envelope signal, which is the detected result, is transmitted to the supervisory station 31 of the initial stage through couplers 38 and 35. On the other hand, an input pilot signal passing through the coupler 35 is supplied to a similar repeater 34 of the subsequent stage through a coupler 40 and the detected result is similarly supplied to the supervisory station 31 of the initial stage through the repeater 33 of the preceding stage. Consequently, the disconnection of the transmission line is decided by the presence and absence of the envelope signal of every repeater and the power-off of the repeater itself by the no response of a data processing part 44 in the repeater at the time of detecting the envelope signal, and the central supervisory station can discriminate the faults.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a transmission communication system, and more particularly to a transmission communication system suitable for use in CAT■.

BACKGROUND OF THE INVENTION Conventionally, in this type of transmission communication system, each of a plurality of repeaters has a pilot signal generator for generating a pilot signal. The pilot signal passes through the transmission line,
The signal was sent to a central monitoring station, and the presence or absence of the pilot signal was used to monitor repeater failures and transmission line disconnections.

A conventional example thereof will be explained using drawings. FIG. 2 is a system diagram of a conventional transmission communication system. In the figure, a central monitoring station 31 monitors cascaded repeaters 33 and 34 via a transmission line 32.

The repeater 33 always sends out the bit signal from the pilot signal generator 10 to the previous stage (central monitoring station 31) via the coupler 16, 46, 35. Further, the repeater 33 receives a pilot signal which is similarly sent out by the repeater 34 which is a subsequent stage, via the directional coupler 40°19, determines the presence or absence of this pilot signal in the determining section 20, and performs this determination. The results are sent to the data processing section 44. The central monitoring station 31 sends a sending command to the repeater 33 requesting the sending of the determination result. In response to the sending command, the data processing unit 44 converts the determination result into a predetermined type of information, and sends it to the central monitoring station 31.
Send to. Based on the information, the central monitoring station 31 determines that the repeater 33 has not detected the pilot signal sent out by the subsequent repeater 34, so that the transmission path between the repeater 33 and the repeater 34 is Was it severed?
Alternatively, it is determined whether the repeater 34 has failed.

However, in such a monitoring system, each repeater monitors the operating status of the next repeater based on the presence or absence of a pilot signal that is constantly sent from the next repeater, so The problem was that it was not possible to correctly distinguish between cases where the transmission line between the transmitter and the transmitter was disconnected and the pilot signal could not be detected, and cases where the pilot signal could not be detected due to a failure in the immediately following repeater itself. . Therefore,
This was not a good idea for maintenance of the transmission communication system.

OBJECTS OF THE INVENTION An object of the present invention is to provide a transmission communication system in which a central monitoring station can determine whether a transmission path between repeaters is disconnected or a failure occurs in the repeater itself.

1151 The transmission communication system of the present invention is a transmission communication system in which a plurality of repeaters and a central monitoring station that monitors the repeaters are connected in cascade through a transmission path, with the central monitoring station being the first stage. , the central monitoring station has a signal generating means for generating a predetermined AM pilot signal, and each of the repeaters includes a detecting means for AM-detecting the AM pilot signal, and a detecting means for AM-detecting the AM pilot signal, and a detecting means for detecting the AM pilot signal from a subsequent stage. It is characterized by comprising a detection means for detecting the presence or absence of a detection output by the means, and a sending means for sending the detection output and the detection output of the detection means to a preceding stage.

1 presentation 1 Hereinafter, the present invention will be explained in detail using the drawings.

FIG. 1 is a system diagram showing an embodiment of a transmission communication system according to the present invention, and parts equivalent to those in FIG. 2 are designated by the same reference numerals. In the figure, a central monitoring station 31 includes a pilot signal generator 10 that generates a predetermined AM-modulated pilot signal.
, and monitors repeaters 33 and 34 that are cascade-connected by the transmission line 32. Here, it is assumed that the repeater 34 has the same internal configuration as the repeater 33.

The repeater 33 performs envelope detection on the AM-modulated pilot signal, which is constantly sent from the central monitoring unit 831 to the subsequent stage, via the coupler 35 and the band-pass filter 36, by the detection unit 37, which is composed only of passive elements. do. Here, the bandpass filter 36 is for extracting only the pilot signal component from the communication data. Furthermore, the reason why the detection section 37 is composed only of passive elements is to enable detection to be performed even if a failure occurs in the repeater itself and its N source is cut off.

The repeater 33 transmits the envelope detected envelope signal to the combiner 3
8 and coupler 35 to the previous stage. Also,
The AM modulated pilot signal is also sent to the subsequent repeater 34 via the amplifier 39 and coupler 40 in the repeater 33, so the AM modulated pilot signal is also sent from the repeater 34. The envelope signal, which is the detection output of , is sent to the previous stage. The envelope signal sent from the repeater 34 is input to a signal detection section 43 that determines the presence or absence of an envelope signal via a coupler 40, an amplifier 41, and a distributor 42 in the repeater 33. The determination result is sent to the data processing unit 4.
4, and a predetermined type of information (for example, "1" for presence,
It is sent out in response to a command from the central monitoring station 31 with the blank changed to "O"). A wave remover 4 is installed in the relay 333 to prevent the envelope signal detected within the own repeater from mixing with the envelope signal sent from the subsequent repeater 34 at the coupling 338.
5 is provided.

Next, a description will be given of how the central monitoring system 831 determines a failure when a failure occurs in the transmission communication system of this embodiment. First, when the repeater 33 detects that the envelope signal from the repeater 34 is "absent", the central monitoring 831 indicates that the transmission line 32 connecting the repeater 33 and the repeater 34 is disconnected. You can judge by. On the other hand, when the data processing unit 44 in the repeater 34 does not respond to the command from the central monitoring 831 even though the repeater 33 detects the envelope signal from the repeater 34 as "right" In this case, the central monitoring station 31 can determine that the relay 34 is powered off.

By performing the above-mentioned operations at each of the repeaters (not shown) downstream of the repeater 34, the central monitoring station 31 can prevent the transmission path between each repeater from being disconnected and the occurrence of a failure in the repeater itself. It is possible to determine the

In addition to being applied to the 0ATV communication network, the above embodiment can be widely used in transmission communication systems configured by cascading multiple repeaters.

DETAILED DESCRIPTION OF THE INVENTION As described in detail, the present invention performs envelope detection on an amplitude-modulated pilot signal sent from a central monitoring station using a detection section consisting only of passive elements in each repeater, and sends the signal to the previous stage. This has the effect that it is possible to discriminate between a disconnection of the transmission line between each repeater and the occurrence of a failure in the repeater itself.

[Brief explanation of drawings]

FIG. 1 is a system diagram of a transmission communication system according to an embodiment of the present invention, and FIG. 2 is a system diagram of a conventional transmission communication system. Explanation of symbols of main parts 31...Central monitoring station 32...Transmission line 33.34...Relayer

Claims (1)

[Claims] A transmission communication system in which a plurality of repeaters and a central monitoring station that monitors the repeaters are connected in cascade through a transmission path with the central monitoring station as the first stage, and the central monitoring station receives a predetermined AM pilot signal. has a signal generating means for generating,
Each of the repeaters comprises only passive elements, and includes a detection means for performing AM detection on the AM pilot signal, a detection means for detecting the presence or absence of a detection output by the detection means from a subsequent stage, and a detection means for detecting the detection output from the detection means from the subsequent stage. 1. A transmission communication system comprising: a detection output and a transmission means for transmitting a detection output to a preceding stage.