JP2570569B2 - Line switching device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a line switching device used in a digital microwave radio communication system.

[0002]

2. Description of the Related Art As is well known, a digital microwave radio communication system has a protection line for relieving deterioration of line quality or line disconnection due to a failure of an operation line, and a line for switching between working and protection synchronization. A switching device is provided. 2. Description of the Related Art As this type of line switching device, for example, the one shown in FIG. 2 is conventionally known.

[0003] In this line switching device, the transmitting end is configured as shown in FIG.
As shown in FIG. 2A, a line control circuit 21, a working transmission circuit 22, a spare transmission control circuit 23, and a spare transmission circuit 24 are basically provided, and the receiving end is provided as shown in FIG. ,
Working receiving circuit 25, working fixed delay time difference adjusting circuit 26, received signal switching circuit 27, working signal monitoring terminal 28, standby receiving circuit 29, standby fixed delay time difference adjusting circuit 30, standby line control circuit 31, receiving end standby control circuit 32 And a spare signal monitor terminal 33 basically.

At the transmitting end, an input signal S201 is applied to an active transmission circuit 22 and one input of a standby transmission control circuit 23. The control signal S202 is supplied from the line control circuit 21 to the other input of the preliminary transmission control circuit 23.

First, during normal operation, the line control circuit 2
1 does not generate the control signal S202, and therefore, the receiving-end preliminary control circuit 32 does not generate the receiving-end control signal S211. The reception signal switching circuit 27 outputs the output of one of the inputs, the working fixed delay time difference adjusting circuit 26. It is controlled to select.

That is, at the transmitting end, the working transmitting circuit 22 sends out the input signal S201 to the line as the working line signal S205. At the receiving end, the working reception circuit 25 performs reception processing on the working line signal S205 fetched from the working line, and restores the working reception signal S207 composed of a data portion. This signal passes through the working fixed delay time difference adjustment circuit 26 as it is, and is sent out of the figure as a reception signal S212 from the reception signal switching circuit 27.

[0007] When, for example, deterioration of the line quality is detected from the state of the received signal S212, an output command of a control signal is externally given to the line control circuit 21 and the receiving-end standby control circuit 32, and the standby system operates. Start.

That is, in parallel with the above operation at the time of operation, at the sending end, the preliminary transmission control circuit 23 takes in the input signal S201 into the standby system in response to the input of the control signal S202,
The spare transmission circuit 24 sends it to the line as a spare line signal S206.

At the receiving end, the spare receiving circuit 29 performs reception processing on the signal S206 fetched from the spare line, and restores the spare received signal S208 comprising a data portion. This is passed through the spare fixed delay time difference adjusting circuit 30 as it is and becomes one input of the spare line control circuit 31. Protection line control circuit 3
The other input of 1 is the receiving end control signal S211 from the receiving end standby control circuit 32. Since this is generated, the standby line control circuit 31 takes in the output of the standby fixed delay time difference adjusting circuit 30 and fetches the received signal. It is given to the other input of the switching circuit 27.

The received signal switching circuit 27 selects the output of the working fixed delay time difference adjusting circuit 26 as described above, but the working signal monitoring terminal 28 and the spare signal monitoring terminal 3
3, the working signal S209 and the standby signal S210
Are displayed on the screen and monitored, and the delay time set in the working fixed delay time difference adjustment circuit 26 and the spare fixed delay time difference adjustment circuit 30 is manually adjusted so that the phase difference between the two becomes zero, and the delay correction is performed. When the phases of the working signal S209 and the spare signal S210 match, a switching command is issued to the received signal switching circuit 27, and the spare signal S210 is taken out as the received signal S212.

[0011]

However, in the conventional line switching device, in order to synchronize the active system and the standby system, the delay time of both systems is adjusted while manually monitoring the monitor. However, there is a problem that it takes a considerable amount of time until the two systems can be synchronized, and line switching cannot be performed quickly.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide a line switching apparatus capable of automatically synchronizing a working system and a standby system, and thereby performing a line switching quickly. To provide.

[0013]

In order to achieve the above object, a line switching apparatus according to the present invention has the following configuration. That is, the line switching device of the present invention is a line switching device that performs synchronous switching between a working line and a protection line; a sending end unit outputs a control signal for permitting signal transmission to the protection line; A working multiplexing circuit for multiplexing an input signal, the control signal and an externally applied frame signal;
A working transmission circuit for sending an output of the working multiplexing circuit to the line as a working line signal; a spare transmission control circuit for outputting the input signal and the frame signal in response to the input of the control signal; A pre-multiplexing circuit for multiplexing an input signal and a frame signal output from the transmission control circuit; and a pre-transmission circuit for transmitting an output of the pre-multiplexing circuit to the line as a pre- line signal. A working receiving circuit for receiving and processing the working line signal fetched from the line to separate and output a working line received signal and a working frame signal; and receiving the output of the working receiving circuit, A separating circuit for separating a working line reception signal into a working reception signal and the control signal and outputting these three signals; A spare receiving circuit for performing a receiving process and separating and outputting a spare received signal and a spare frame signal; receiving the working received signal, the working frame signal and the spare frame signal, and setting a spare frame signal based on the working frame signal. receiving the said current frame signal the standby receiving signal and said preliminary frame signal; detecting a phase difference between at least a working received signal and working fixed delay time difference adjustment circuit for outputting giving a delay corresponding to the phase difference A spare fixed delay time difference adjusting circuit for detecting a phase difference from the working frame signal based on the spare frame signal and outputting at least a spare received signal with a delay corresponding to the phase difference; A protection line control circuit for transmitting an output of the protection time delay adjusting circuit in response to the input of a control signal; Is characterized in further comprising a; a reception signal switching circuit for sending selecting one of the outputs of the difference adjustment circuit and the standby line control circuit.

[0014]

Next, the operation of the line switching apparatus of the present invention configured as described above will be described. In the present invention, a frame signal is newly input to the transmitting end and the working system multiplexes and transmits the frame signal, the input signal and the control signal, while the standby system multiplexes the frame signal and the input signal. Send.
Then, at the receiving end, the delay time difference adjusting circuits of the respective systems automatically correct the delay so that the phase difference between the working frame signal and the spare frame signal becomes zero, and the two systems are connected to the receiving signal switching circuit. Are input synchronously.

Therefore, the time from the start of the operation of the standby system to the switching is greatly reduced, and the switching can be performed quickly.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a line switching device according to one embodiment of the present invention. As shown in FIG. 1 (a), this line switching device includes a line control circuit 1, a working multiplexing circuit 2, a working transmitting circuit 3, a spare transmitting control circuit 4, a spare multiplexing circuit 5, Basically, a transmitting circuit 6 is provided, and a receiving end is provided as shown in FIG.
As shown in (b), the working reception circuit 7, the separation circuit 8, the working fixed delay time difference adjustment circuit 9, the reception signal switching circuit 10, the protection reception circuit 11, the protection fixed delay time difference adjustment circuit 12, the protection line control circuit 13, And a frame signal S2 is always supplied from the outside at the sending end.

At the transmitting end, the input signal S1, the frame signal S2, and the control signal S3 are input in parallel to the working multiplexing circuit 2 and the spare transmission control circuit 4, but the control signal S3 is
As described above, the line control circuit 1 is generated based on an external command to indicate the start of the operation of the standby system.
That is, the control signal S3 is, for example, "1" when the operation of the standby system is started, and is "0" otherwise.

Therefore, during normal operation, the spare transmission control circuit 4 does not operate because the control signal S3 is "0" as in the conventional case, and only the working multiplexing circuit 2 multiplexes three signals. do. That is, the frame signal S2 and the control signal S
3 are arranged, for example, near the head of the data portion in one frame of the input signal S1. The multiplexed signal (working transmission signal S4) is sent out to the line by the working transmission circuit 3 as a working line signal S6.

At the receiving end, the active receiving circuit 7 receives the active line signal S6 fetched from the active line, separates the frame signal, and multiplexes the "data portion" and the "control signal S3" with the active line signal. Line receiving signal S8 and working frame signal S
9 is output. These are input to the separation circuit 8.

The separation circuit 8 separates the working line reception signal S8 into a working reception signal S10 and a control signal S3 each consisting of a data portion, based on the working frame signal S9, and the working frame signal S9 and the working reception signal S10 It outputs to the fixed delay time difference adjusting circuit 9 and the control signal S3 to the protection line control circuit 13. The working frame signal S9 is also output to the spare fixed delay time difference adjusting circuit 12.

The working fixed delay time difference adjusting circuit 9 receives the spare frame signal S12 from the spare receiving circuit 11 and detects the phase difference from the spare frame signal S12 based on the working frame signal S9. Signal S
Since 12 is "0", delay correction for the input signal is not performed.

Therefore, the working reception signal S10 and the working frame signal S9 pass through the working fixed delay time difference adjustment circuit 9 as they are and become one input of the reception signal switching circuit 10, and the reception signal S15 and the reception signal S15 are received from the reception signal switching circuit 10. It is sent out of the figure as a reference signal S18. The output of the reception reference signal S18 is not essential and is provided for convenience in a processing system (not shown).

When, for example, deterioration of the line quality is detected from the state of the received signal S15, a control signal output command is externally given to the line control circuit 1 as in the prior art, and the standby system starts operating.

That is, in parallel with the above operation at the time of operation, at the sending end, the preliminary transmission control circuit 4 sets the control signal S3 to "1".
In response to the input signal S1 and the frame signal S
2 is input to the standby system, and is supplied to the standby multiplexing circuit 5 to generate the standby transmission signal S5.

At the receiving end, the spare receiving circuit 11 performs a receiving process on the signal S7 fetched from the spare line, and separates and forms the spare received signal S11 and the spare frame signal S12 each consisting of a data portion. Delay time difference adjustment circuit 1
2 and the spare frame signal S12 to the working fixed delay time difference adjusting circuit 9.

Therefore, the working fixed delay time difference adjusting circuit 9 detects the phase difference from the spare frame signal S12 based on the working frame signal S9, and the spare fixed delay time difference adjusting circuit 12 uses the spare frame signal S12 as a reference. Then, a phase difference from the current frame signal S9 is detected, and delay correction is applied to each input signal so that the detected phase difference becomes zero.

In the working fixed delay time difference adjusting circuit 9, the working signal S 14 and working reference signal S
17 to one input of the reception signal switching circuit 10. In addition, the spare fixed delay time difference adjusting circuit 12 supplies the spare signal S13 and the spare reference signal S16 whose delay has been corrected as described above to the spare line control circuit 13.

In the protection line control circuit 13, since the control signal S3 from the separation circuit 8 is "1", the input protection signal S13 and protection reference signal S16 are directly applied to the other input of the reception signal switching circuit 10.

The reception signal switching circuit 10 selects the output of the working fixed delay time difference adjusting circuit 9, but it is assumed that the automatic adjustment of the delay correction is performed and the working system and the standby system are synchronized. At the time point, a spare signal S13 and a spare reference signal S16 are selected in response to a switching command given from the outside, and are sent to the outside as a received signal S15 and a received reference signal S18.

[0030]

As described above, in the line switching apparatus of the present invention, a frame signal is newly input to the transmitting end, and in the working system, the frame signal, the input signal and the control signal are multiplexed and transmitted. On the other hand, in the standby system, the frame signal and the input signal are multiplexed and transmitted. Then, at the receiving end, the delay time difference adjusting circuits of the respective systems automatically correct the delay so that the phase difference between the working frame signal and the spare frame signal becomes zero, and the two systems are connected to the receiving signal switching circuit. Are synchronously input, so that the time from the start of the operation of the standby system to the switching is greatly reduced, and the switching can be performed quickly.

[Brief description of the drawings]

FIG. 1 is a configuration block diagram of a line switching device according to an embodiment of the present invention.

FIG. 2 is a configuration block diagram of a line switching device according to one embodiment of the related art.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 line control circuit 2 working multiplex circuit 3 working transmission circuit 4 protection transmission control circuit 5 protection multiplexing circuit 6 protection transmission circuit 7 working reception circuit 8 separation circuit 9 working fixed delay time difference adjustment circuit 10 reception signal switching circuit 11 protection reception circuit 12 Preliminary fixed delay time difference adjustment circuit 13 Preliminary line control circuit

Claims (1)

(57) [Claims] 1. A line switching apparatus for performing synchronous switching between a working line and a protection line; a line control circuit for outputting a control signal for permitting signal transmission to the protection line;
A working multiplexing circuit for multiplexing an input signal, the control signal and an externally supplied frame signal; a working transmitting circuit for sending an output of the working multiplexing circuit to a line as a working line signal; an input of the control signal A pre-transmission control circuit for outputting the input signal and the frame signal in response to the input signal; and a pre-multiplexing circuit for multiplexing the input signal and the frame signal output from the pre-transmission control circuit;
Wherein the output of the pre-multiplexing circuit and the spare transmission circuit for sending to the line as a backup line signal; includes a receiving end portion, said the working line signal to the receiving process working line received signal and the current frame signal taken from line A receiving circuit for receiving the output of the working receiving circuit, separating the working line received signal into a working received signal and the control signal based on the working frame signal, and outputting these three signals A spare receiving circuit that performs reception processing on the spare line signal taken in from the line and separates and outputs a spare received signal and a spare frame signal; and the working received signal, the working frame signal, and the spare frame signal. In response to this, a phase difference from the spare frame signal is detected based on the working frame signal, and at least the working received signal is delayed by a delay corresponding to the phase difference. A working fixed delay time difference adjustment circuit for outputting giving extended; receiving said standby receiving signal and said preliminary frame signal and the current frame signal, detecting a phase difference between current frame signal on the basis of the preliminary frame signal, A preliminary fixed delay time difference adjustment circuit for outputting at least the preliminary reception signal with a delay corresponding to the phase difference;
A protection line control circuit for transmitting an output of the spare fixed delay time difference adjusting circuit in response to an input of a control signal as a separation output of the separation circuit; and one of the working fixed delay time difference adjusting circuit and the protection line control circuit. And a receiving signal switching circuit for selecting and transmitting one of the outputs.