JPH0681124B2 - Test signal switching method - Google Patents

Description

The present invention relates to a test signal switching system, and in particular, a test signal for line quality inspection in a digital wireless transmission line is provided in each line system of the digital wireless transmission line (hereinafter, The present invention relates to a test signal switching system for introducing a line system into a system).

[Conventional technology]

Generally, a digital wireless transmission line is formed by an active system and a standby system, and when inspecting the line quality of each system, the system is switched to the standby system and a predetermined test signal is sent to the system. It is a normal procedure to introduce it in. Usually, a transmission terminal station device in a digital radio transmission line and a digital multiplex conversion device in a line transmission terminal station are connected by a coaxial line, and the line length thereof changes according to the distance between the two devices. . Due to the intervention of the line length, waveform deterioration occurs in the digital multiplexed signal received on the transmitting end station side, and therefore each of the systems is provided with a line compensating circuit. However, when the frequency region of the digital multiplexed signal becomes higher, the AGC is increased over the entire line length region (for example, 0 to 500 m) as the line length increases.
It is difficult to perform line compensation due to the dynamic range of. For this reason, each system is provided with a predetermined line length correction circuit before the line compensation circuit, and when the line length is in a relatively short range (for example, 0 to 250 m), the line length is In the correction circuit, the pseudo line circuit is inserted into the system, and when the line length is in the long comparison point range (for example, 250 to 500 m), the pseudo line circuit is controlled so as to be excluded from the system. To be done.

Therefore, in the transmitting terminal equipment of the digital radio transmission line, when the test signal is introduced into the system in order to inspect the line quality as described above, the pseudo line corresponding to the line length division is used. It is necessary to insert the circuit into the system. For this reason, in the conventional test signal switching system, an operation of sending a switching control signal to the test signal introducing circuit provided in each system to introduce the test signal and inserting the pseudo line circuit into the system. It is common to do in a duplicated form.

[Problems to be solved by the invention]

In the above-mentioned conventional test signal switching system, in order to make the line compensation characteristic of the line compensation circuit effective in parallel with the introduction of the test signal to the system whose line quality is to be inspected, the pseudo line circuit is provided. It is required to be inserted before the line compensation circuit. Therefore, as an operation procedure for inspecting the line quality of each system, every time the control operation for introducing the test signal is performed, the operation for inserting the pseudo line circuit into the system must be performed each time. However, there is a drawback in that the working efficiency is extremely lowered in the operation of the transmitting terminal equipment in the digital radio transmission line. In particular, when the transmission terminal station device and the monitor control unit are arranged apart from each other, the work efficiency is further reduced.

[Means for solving problems]

According to the test signal switching method of the present invention, in a digital radio transmission line constituted by an active system and a standby system provided between opposite terminal stations, a predetermined system is specified for the active system at the time of line quality inspection of the active system. In the test signal switching system for introducing the test signal of No. 1, the signal input lines of the digital multiplex signal for communication in the working system and the test signal for the line quality inspection for the working system are connected, and the working system is connected. In operation, the digital multiplexed signal input from the signal input line is received and output, and at the time of line quality inspection of the active system, the test signal input from the signal input line is switched to a predetermined value. A response corresponding to the input of the switching control signal, which is selected and output according to the control signal A test signal introducing means for outputting the item,
A test for generating and outputting the switching control signal to the test signal introducing means and for generating and outputting a predetermined pseudo line insertion control signal by inputting the response signal at the time of line quality inspection of the active system. A signal switching control unit and a pseudo line circuit that is inserted and connected to a signal path by the pseudo line insertion control signal are provided inside, and at the time of line quality inspection of the active system, a test signal output from the test signal introducing unit is included. The line length correction means for setting and outputting the level to a proper level for correcting the line length by the pseudo line circuit is provided at least in the terminal station of each active system, and at the time of line quality inspection of the active system, The level-corrected test signal output from the line length correction means is automatically selected as the line quality inspection test signal by the switching control signal. It is characterized by the introduction of the corresponding active system.

〔Example〕

 Hereinafter, the present invention will be described with reference to the drawings.

FIG. 1 shows a partial block diagram of a transmitting terminal station device corresponding to an embodiment of the present invention, and a part of an active system of an i system (i + 1) system. As shown in FIG. 1, in this embodiment, the test signal introducing circuits 1 (i) and 1 (i + 1) are used.
And line length correction circuits 2 (i) and 2 (i + 1), line compensation circuits 3 (i) and 3 (i + 1), a test signal generation circuit 4, and a test signal switching control circuit 5. .

In FIG. 1, when the i-system and (i + 1) -system active systems are in operation, the digital multiplexed signals 101 (i) and 1 (1) and 1 sent from the digital multiplex converter are shown.
01 (i + 1) is the test signal introduction circuits 1 (i) and 1 (i + 1), and the line length correction circuits 2 (i) and 2 (i), respectively.
(I + 1), line compensation circuits 3 (i) and 3 (i + 1)
Etc. via the corresponding BU converter (B-U is Bipola
r-Unipolar). In this case, if the 101 (i) signal comes through a long line, the line length correction circuit 2
In (i), the pseudo line circuit corresponding to the line length is not inserted.

Now, when inspecting the circuit quality of the i-system active system, the digital multiplexed signal 101 of the i-system active system is used.
(I) is not switched to the standby system and sent to the test signal introducing circuit 1 (i). A switching control signal 103 (i) is output from the test signal switching control circuit 5 and input to the test signal introduction circuit 1 (i). A test signal 102 for line quality inspection is sent from the test signal generation circuit 4 to the test signal introduction circuit 1 (i), and the switching control signal 1
Circuit switching is performed via 03 (i), and the test signal 102 is introduced to the i-system active system via the test signal introducing circuit 1 (i). The test signal introduction circuit 1 (i) outputs a predetermined answerback signal 104 (i) in response to the input of the switching control signal 103 and returns it to the test signal switching control circuit 5. In the test signal switching control circuit 5,
In response to the input of the answer back signal 104 (i), the pseudo line insertion control signal 105 (i) is automatically output and sent to the line length correction circuit 2 (i). Line length correction circuit 2 (i)
In (1), the pseudo line insertion control signal 105 (i) is controlled to insert the pseudo line circuit which has not been inserted while the line is operating. Therefore, the test signal introduced into the i-system active system in the test signal introduction circuit 1 (i) is set to an appropriate level by passing through the pseudo line circuit in the line length correction circuit 2 (i), It is input to the compensation circuit 3 (i). It goes without saying that the waveform compensation circuit 3 (i) corrects the waveform deterioration caused by the line propagation and sends it to the BU converter.
Thus, the code error rate of the i-system active system in the digital radio transmission line is measured via the test signal, and the quality of the line quality is judged.

As described above, in response to the line quality inspection, the pseudo line circuit is automatically inserted in the line length correction circuit 2 (i) when the test signal is switched to the system, and the line quality is inspected. . This also applies to the (i + 1) system active system and other systems.

〔The invention's effect〕

As described above, according to the present invention, when inspecting the line quality,
By automatically controlling the insertion of the pseudo wire circuit in response to the introduction of the test signal to the system under inspection, it is possible to improve the operational efficiency of the operation of the transmitting terminal equipment in the digital wireless transmission line. The effect is that you can do it.

[Brief description of drawings]

FIG. 1 is a partial block diagram of a transmitting terminal station device corresponding to an embodiment of the present invention. In the figure, 1 (i), 1 (i + 1) ... Test signal introduction circuit, 2 (i), 2 (i + 1) ... Line length correction circuit, 3
(I), 3 (i + 1) ... Line compensation circuit, 4 ... Test signal generation circuit, 5 ... Test signal switching control circuit.

Claims (1)

[Claims] 1. A digital radio transmission line comprising a working line system and a protection line system provided between opposite terminal stations, wherein the working line system is predetermined at the time of line quality inspection of the working line system. In the test signal switching system for introducing the test signal, the signal input lines of the digital signal for communication in the working line system and the test signal for testing the line quality for the working line system are connected, When the working line system is in operation, it receives and outputs the digital multiplexed signal inputted from the signal input line, and at the time of the line quality inspection of the working line system, the test signal inputted from the signal input line. Is output according to a predetermined switching control signal and the switching control signal is input. A test signal introducing means for outputting a response signal corresponding to the input power, and at the time of line quality inspection of the working line system, generate and output the switching control signal to the test signal introducing means and input the response signal. And a test signal switching control means for generating and outputting a predetermined pseudo line insertion control signal, and a pseudo line circuit that is inserted and connected to a signal path by the pseudo line insertion control signal. At the time of line quality inspection, the level of the test signal output from the test signal introducing unit is set to an appropriate level for correcting the line length by the pseudo line circuit, and the line length correcting unit is output. A level-corrected test signal which is provided at least in the terminal of the system and is output from the line length correction means during the line quality inspection of the working line system. , Said automatically selected by the switching control signal as a test signal for circuit inspection, and introducing into the corresponding working line system test signal switching system.