JPH0426238A - Signal loopback system for pcm repeater - Google Patents

Abstract

PURPOSE:To search the fault of a relevant repeater even when the repeater at the stage behind a standardizing point generates the fault in the case of standardizing the fault point according to a test signal by setting and resetting the loopback signal of each repeater. CONSTITUTION:A tester 1 generates the first and second test signals according to positive and negative pulse trio signals a1 and a2 for setting and resetting the loopback to PCM repeating lines and transmits these test signals to the PCM repeating lines with a frequency corresponding to a filter 4 for monitoring repeaters 2 and 3. For these repeaters 2 and 3, when the number of pulses in the positive pulse trio signal detecting the first test signal by a first detection circuit 13 is a value set in advance, a first counter 15 sets the loopback of the ascending and descending PCM repeating lines. When the number of pulses in the negative pulse trio signal detecting the second test signal by a second detection circuit 16 is a value set in advance, a second counter 17 resets the return. Thus, even when the repeater in the stage behind the standardizing point generates the fault in the case of standardizing the fault according to the test signal, the relevant repeater can be searched.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a signal loopback method for a PCM repeater, and particularly to a PCM repeater that locates a fault point using signals looped back at each repeater.
The present invention relates to a signal return method for a relay device.

[Conventional technology]

As shown in FIG. 3, the signal looping system of a conventional PCM repeater includes a tester 1a that generates a test signal called a pulse trio signal, a transmission regeneration relay line 201, a reception regeneration relay circuit 202, and a pulse trio signal. A terminal repeater 2a having a detection circuit 203 and a signal switching relay 204, a downstream regenerative relay circuit 301, and an upstream regenerative relay circuit 30.
Each repeater is connected to a monitoring filter 4a having a different frequency, and this monitoring filter 4a is connected to an intervening match 5a.

The tester 1a inputs a generated pulse trio test signal to the end station repeater 2a corresponding to the frequency assigned to each repeater. At this time, in the terminal repeater 2a on the far end side,
This test signal is detected by a pulse trio signal detection circuit 203, and switched by a signal switching relay 204 to execute signal return. For example, from the tester 1a, the frequency f2
When a test signal corresponding to frequency f2 is sent out, this test signal is looped back at the end station repeater 2 at the far end, and the test signal output from the intermediate repeater 3a corresponding to frequency f2 is passed through the monitoring filter 4.
Extract it as a sine wave corresponding to the f2 signal in a and use the intervening match 5
Output to. The tester 1a inputs this sine wave via the intervening signal 5, receives this input signal, and measures the input level, thereby making it possible to locate the fault point of the repeater.

[Problem to be solved by the invention]

With this conventional PCM repeater signal return method, signal return is possible only at the end station repeater, so when performing fault location using pulse trio test signals, if a fault occurs in a repeater downstream from the control point, the corresponding There was a problem in that it was not possible to search for repeaters and it was not possible to locate them.

[Means to solve the problem]

The signal loopback system of the PCM relay device of the present invention includes means for generating first and second test signals based on positive and negative pulse trio signals for loopback setting and loopback setting recovery in the PCM relay line; means for transmitting a second test signal to the PCM relay line at a frequency corresponding to a monitoring filter of the repeater; means for detecting the second test signal and setting the loopback when the number of pulses of the negative pulse trio signal is a preset value; and a means for restoring it.

〔Example〕

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

FIG. 1 is a block diagram of an embodiment of the present invention, FIG. 2 is a detailed block diagram of a repeater of this embodiment, and FIG. 4 is a diagram showing a pulse trio signal of this embodiment.

In this practical example, tester 1 connects the fourth
The first and second pulse trio signals al and a2 of positive and negative pulses for setting the loopback and restoring the loopback setting shown in the figure.
A test signal is generated, and the first and second test signals are sent to the PCM relay line at frequencies corresponding to the monitoring filters 4 of the repeaters 2 and 3.

The repeater 2.3 detects the first test signal when the number of pulses of the positive pulse trio signal detected by the first detection circuit 13 is a value preset by the setting switch 14. When the number of pulses of the negative pulse trio signal detected by the second detection circuit 16 is a value preset by the setting switch 14, the second test signal is set to return the PCM relay line. restores the callback settings.

Next, the operation will be explained.

In FIG. 1, the tester 1 has a frequency f of the monitoring filter.
In addition to the pulse trio test signals corresponding to o to f n (fo < f n), pulse trio test signals corresponding to frequencies lower than fo are generated, and the frequencies of these test signals are set to foo to fn. .

At this time, in the repeater shown in FIG. 2, a number corresponding to each different frequency fko (one of the frequencies foo to fno) is set in advance using the counter value setting switch 6.

Next, when the first test signal a1 of the positive polarity pulse trio is output from the tester l, signal detection is performed in the first detection circuit 13, and the number of received first signal patterns is counted by the first counter. 15, and when the number of patterns matches the number set with the counter setting switch 14,
The state of the first counter 15 is held, the switching circuit 11 is switched, and the signal regenerated by the downstream regenerative relay circuit 12 is looped back. When the signal is output, the signal is detected by the second detection circuit 16, and the number of received second signal patterns is counted by the second counter 17, and the number of patterns is equal to the number set by the counter setting switch 14. If they match, the second counter 17 resets the first counter 15, restores the switching circuit 11, and cancels signal return.

In addition, if you want to perform loopback from the lower station, the first detection circuit 13° for the first test signal, the first counter 15', and the second Detection circuit 16', second counter 17' and signal switching circuit 1
1' allows execution and cancellation of signal loopback.

〔Effect of the invention〕

As explained above, the present invention makes it possible to set and restore signal loopback at each repeater, so that when locating a fault point using a test signal, even if a repeater downstream from the fault point is faulty, This has the effect of being able to search for repeater failures.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of an embodiment of the present invention, Fig. 2 is a detailed block diagram of a repeater of this embodiment, and Fig. 3 is a conventional PCM.
Block diagram illustrating an example of a signal return method of a relay device, No. 4
Figures (A) to (C) are waveform diagrams showing pulse trio signals of this embodiment. DESCRIPTION OF SYMBOLS 1... Tester, 2... Terminal repeater, 3... Intermediate repeater, 4... Monitoring filter, 11... Signal switching circuit, 12... Regenerative repeater circuit, 13. 16... First and second detection circuit, 14... Setting switch, 15.17
...first and second counters.

Claims (1)

[Claims] means for generating first and second test signals based on positive and negative pulse trio signals for return setting and return setting recovery in a PCM trunk line; and means for generating the first and second test signals for monitoring a repeater. The above P at the frequency corresponding to the filter
means for transmitting the signal to the CM trunk line; and means for detecting the first test signal and setting the uplink and downlink PCM trunk lines to return when the number of pulses of the positive pulse trio signal is a preset value; , means for detecting the second test signal and restoring the return setting when the number of pulses of the negative pulse trio signal is a preset value.