JPH0630458B2 - Circuit switching circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention comprises a protection line in addition to a working line (1 + N).
The present invention relates to a line switching circuit in a wireless digital transmission system.

[Conventional technology]

The line provided between the demodulator on the receiving end side of the conventional wireless digital transmission system and the wired transmission device is called a 1: N system configuration, and is composed of a plurality of N working lines for one protection line. Each working line is provided with an interface converter that converts the transmission signal from the demodulator into an interface signal, and a signal switching selector that switches between the demodulation circuit and the interface converter to switch to the protection line due to a failure of the working line. .

[Problems to be solved by the invention]

However, the signal switching selection circuit provided on the working line can transfer signals from the protection line to the working line, but cannot transfer signals from the working line to the protection line, so maintenance and inspection of the working line cannot be performed. There are drawbacks.

[Means for solving problems]

According to the present invention, each of the first to Nth working lines is provided in each of the first to Nth stage signal branch switching selectors connected in parallel and provided in one spare line, And a signal branch selector connected to the signal branch switching selector of the stage,
The signal branch selector sends a first protection line input signal sent through the protection line as first and second branch signals, the first branch signal, and the first stage. A second switching line input signal sent from the signal branching / switching selector of, and a signal switching device for sending one of the two signals to the backup line,
The first to (N-1) th stage signal branch switching selectors respectively branch a first input signal from the working line into third and fourth branch signals; A second signal branching device for branching the second input signal from the previous stage into fifth and sixth branching signals, and sending the sixth branching signal to a signal branching switch selector of the next stage; Of the first branch signal and the fifth branch signal, which selectively sends one of the fifth branch signal and the fifth branch signal, to the fourth branch signal and the third input signal from the next stage. A second signal switcher for selectively sending one of them to the preceding stage, and the signal branching switch selector of the Nth stage receives the first and third input signals from the working line. A signal branching device that branches into four branch signals and outputs the fourth branch signal to the preceding stage as the third input signal; Line switching circuit, characterized in that it comprises a signal switch for sending either one of said sixth branch signal and the third branch signal from stage selectively the working line is obtained.

〔Example〕

FIG. 1 is a block diagram showing a receiving end side line switching circuit configuration of a 1: N system configuration according to an embodiment of the present invention. In the figure, the wireless receiver and demodulator are omitted. FIG. 2 shows the internal structure of the signal branch selector 10 and the signal branch switch selector 2 in the receiving side line switching circuit structure of FIG. 1 and the signal flow.

Normally, the signal 1 (first input signal) transmitted through the working first line is branched by the signal branching device (first signal branching device) 2a in the signal branching switching selector 2 of the working first line, The one-branch output signal called the third branch signal is selected by the signal switcher (first signal switcher) 2b and is used as the signal 3 for the first active signal.
It is sent to the interface converter 4 of the line and output as the interface signal 5. On the other hand, the branch output called the other fourth branch signal branched by the signal branching device 2a is sent to the signal switching device (second signal switching device) 2d, but the signal switching device 2d selects the adjacent signal branching switching selection. The signal from the container 2 is selected as the third input signal and the fourth branch signal is not output. Similarly, in the working N-th line, the transmitted signal (first input signal) 6 is branch-selected by the signal branching switch selector 2 of the working N-th line, and is output as the output signal 7 to the interface of the working N-th line. Sent to the converter 4 and output as the interface signal 8.

On the other hand, the signal transmitted through the protection line (first protection line input signal) 9 (for example, pilot signal) is branched by the signal branching device 10a in the signal branching selector 10 and output called a second branching signal. The signal 11 is branched as a second input signal by the signal branching device (second signal branching device) 2c in the signal branching switching selector 2 of the working first line, and one branching output of the signal branching device 2c is the fifth branching signal. Although it is sent to the signal switch 2b as a branch signal, it is not selectively output. Signal splitter 2 of the first working line
The other branch output signal branched by c (sixth branch signal)
A protection line signal 9 is guided to the working N line by using the signal branching switch 2c in each signal branch switching selector 2 of the working second line, the working third line, ..., The working N line. .
The other branch output signal of the signal branching unit 2c of each working line is sent to the signal switching unit 2b but not selectively output. On the other hand,
The output signal called the other first branch signal branched by the signal branching device 10a is selected by the signal switching device 10b, is sent to the interface converter 4 of the protection line as the signal 14, and is output as the output signal 15. To be done.

Next, when the switching operation of the working first line is performed, the transmission signal 1 of the working first line is transmitted from the sending end side to the protection line.
The same signal 9 as is input to the signal branch selector 10. The input signal 9 becomes the output signal 14 of the signal branch selector 10 as in the case of the normal transmission state before the switching operation,
A signal branching unit 2c in the signal branching switching selector 2 of each working line
Is transmitted as input / output, and the transmission signal 9 of the protection line is guided to the working Nth line. The protection line transmission signal 9 that is the same as the working first line that has been guided to the working N line is protected from the working first line transmission signal 1 by the signal switch 2b in the signal branch switching selector 2 of the working first line. The line transmission signal 9 is switched and selected, and is input as the signal 3 to the interface converter 4 of the first working line. That is, the switching of the working first line is completed.

The switching operation of the working N-th line is the same, and the working N-th line is selected by the signal switch 2b in the signal branch switching selector 2 of the working N-line.
Switching from the line transmission signal 6 to the backup line transmission signal 9 is selected and output as the signal 7, and the switching is completed.

On the other hand, when the test circuit of the working line is configured during this switching operation, for example, in the case of the working first line, the signal 1 is not an interface signal even if it is the output terminal of the testing circuit of the working first line by the signal 1. A fourth branch signal obtained by branching the signal 1 by the signal branch switch 2a in the signal branch switch selector 2 of the working first line is selectively output by the signal switch 2d to output the signal 1
7 is led to the signal branching selector 10 of the protection line. The signal branch selector 10 receives the signal 17 as the second protection line input signal, and the signal switching unit 10b changes the protection line transmission signal 9 to the second protection line input signal, that is, the working first line transmission signal 1. Switching selection output is performed, the working first line transmission signal 1 is sent as the output signal 14 to the interface converter 4 of the protection line, and is output as the interface signal 15. In this way, by guiding the working first line transmission signal 1 as the interface signal 15 to the protection line, it is possible to construct a test circuit that is converted into an interface level suitable for maintenance and inspection.

Regarding the configuration of the signal branching / switching selector 2 of the working Nth line, the signal branching unit 2c and the signal switching unit 2d in FIG. 2 (b) are unnecessary, and the signal 16 is the signal switching unit 2b as it is.
Sent to. On the other hand, for the input signal 6 of the working N-th line, the signal branched by the signal branching unit 2a (the fourth branching signal) is output as it is as the signal 18, and the protection line is passed through the signal branching switching selector 2 of each working line. Signal branch selector 10
Output as the interface signal 15 by the interface converter 4 and a test circuit for maintenance and inspection of the working Nth line can be constructed.

〔The invention's effect〕

As described above, according to the present invention, since the signal branch switching selector is provided on the working line and the signal branch selector is provided on the protection line, the working line and the protection line can be transmitted / received, and the signal branch selection is made on the protection line. Since the interface converter that converts the output signal from the equipment to the interface level suitable for the test inspection is installed, the maintenance and inspection of the working line can be dealt with by using the standby line.

[Brief description of drawings]

FIG. 1 is a block diagram of a line switching circuit of a 1: N system showing a configuration of an embodiment of the present invention, and FIG. 2 (a) is a configuration showing an internal configuration and a signal flow of a signal branch selector in FIG. Figure,
FIG. 2 (b) is a configuration diagram showing the internal configuration and signal flow of the signal branch switching selector in FIG. 2 ... Signal branch selector, 4 ... Interface converter,
10 ... Signal branch switching selector, 2a, 2c, 10a ...
Signal switch 2b, 2d, 10b ... Signal switch.

Claims (1)

[Claims] 1. A signal branching / switching selector of the first to Nth stages, which are provided in each of the first to Nth working lines and are connected in parallel, and one standby line, and the first stage. And a signal branch selector connected to the signal branch switch selector, the signal branch selector using the first protection line input signal sent through the protection line as first and second branch signals. The signal branching device to be sent out, the first branching signal and the second protection line input signal sent from the first stage signal branching switching selector are received, and one of the two signals is received. A signal switch for sending to the protection line, and the signal branching / switching selectors of the first to (N−1) th stages respectively output the first input signal from the working line to the third and fourth signals.
Signal branch selector for branching the first input signal from the previous stage to the fifth and sixth branch signals for branching the second input signal from the previous stage to the sixth branch signal A second signal splitter for sending to the third branch signal, the third branch signal and the fifth signal
Of the first branch signal and the third input signal from the next branch signal, and the first signal switch that selectively sends one of the branch signals to the working line. And a second signal switcher for sending to the preceding stage, and the signal branching switch selector of the Nth stage is the first signal from the working line.
Input signal is divided into third and fourth branch signals to obtain the fourth
Signal branching device that outputs the branch signal to the preceding stage as the third input signal, and selectively outputs one of the sixth branch signal and the third branch signal from the preceding stage to the working line. A line switching circuit having a signal switching device for switching.