JPS6235728A - Staff control system - Google Patents

Abstract

PURPOSE:To perform AIS signal frequency control only at a reception side by providing a state change detecting circuit to a reception-side destaff control circuit and controlling a pseudo write clock generating circuit which converts a signal to a low order group into an AIS signal forcibly when a circuit state is unchanged for a certain time. CONSTITUTION:When staff specifying pulses enter an all-staff state or nonstaff state in case of a break of a transmission-side low-order group input signal, the output of the staff specifying detecting circuit in a destaff control circuit 14 is '1' or '0' at any time. The change state is detected by the state change detecting circuit 15 and when the same state is held continuously for a specific time without change of '0 1' nor '1 0', that means the break of the transmission-side low-order group input signal and the circuit 15 generates a pseudo write clock controlled with a mean staff rate from a pseudo write clock generating circuit 16, thereby writing an all-'1' signal in a receiving memory.

Description

[Detailed Description of the Invention] [Summary] In the stuffing multiplex conversion device, when the output of the stuffing designation detection circuit in the destuffing control circuit on the receiving side remains unchanged for a certain period of time, the signal to the lower order group is forcibly converted to AIS. By converting it into a signal, it eliminates the need for star-nov control on the transmitting side.

[Industrial application field]

The present invention relates to an improvement of a stuffing control method when transmitting an IS signal to a stuffing synchronous multiplex converter.

In digital transmission systems, when a failure occurs, in order to clarify the location of the failure, ・）IS (＾
farm Indication 5i ((nal)
Sends the signal from the fault detection point to the transmission path. At the time of the Δrs signal, the transmission signal is converted to an all "1" signal, and devices from the next point onwards can know the occurrence of a fault and the fault point from this ^Is signal.

Under no fault conditions, the stuffing multiplexer converts the signal within the frequency range defined by each digital interface (
The staff ratio is within a certain range.

However, when a failure occurs, the input signal itself becomes a failure.
When the output signal is changed to all "L"s, there is no frequency guarantee for the output signal frequency, that is, the IS signal. Therefore, it is desirable to control the stuffing rate so that the AIS signal falls within the specified frequency range by controlling the stuffing rate so that the AIS signal falls within the specified frequency deviation.

[Conventional technology]

Cases in which AIS signals are sent in digital transmission systems include: i) when the low-order group input signal is disconnected, the AIS signal is sent only to the corresponding channel of the opposite station, ii) when the high-order group signal is disconnected or out of synchronization, etc. When there is a failure, A is sent to all channels on the receiving side.
There are cases where IS signals are received.

FIG. 2 shows a block configuration of an example of a digital transmission system.

In FIG. 2, for example, if the signal is disconnected at the part (■) before the communication path conversion circuit 1-1 on the transmitting side, it corresponds to i), and in this case, 1, for example, the corresponding communication path conversion circuit 4 on the receiving side. An ATS signal is sent only to -1.

When the low-order group human power signal is disconnected, the staff becomes either all-staffed or all-non-staffed, and in order to keep the signal frequency within the specified range of the opposite station's signal, it is necessary to control the stuffing rate on the transmitting side. .

FIG. 3 shows a block circuit of the stuff control device on the transmitting side.

The low-order group signal disconnection is detected by the input signal disconnection detection circuit 7, and the detection circuit 7 gives a command to the stuff control circuit (9) via the pseudo stuff command generation circuit (8) to average the stuffing rate on the transmitting side. Set the staff rate and perform staff multiplexing.

In addition, in FIG. 2, for example, if a failure occurs at the location (3) between the multiplexer MLIX2 and the demultiplexer DMUX3, then ii) will apply. In this case, the AIS signal frequency control circuit is shown in FIG.

A fault in the higher-order group signal is detected by the fault detection circuit 10,
The signal is applied to the pseudo write clock generation circuit 11. The generating circuit generates a pseudo write clock controlled by the average stuff rate, and writes all "1" signals to the receiving memory via the write clock control circuit 13.

[Problem that the invention seeks to solve]

In the conventional stuff control method described above, a pseudo stuff sending circuit is provided on the transmitting side in response to a low-order group signal failure, and a pseudo-write clock generation circuit is provided on the receiving side in response to a high-order group failure. Requires AIS signal frequency control circuit.

An object of the present invention is to simplify the AIS signal frequency control circuit and to enable ^Is signal frequency control only on the receiving side.

[Means for solving problems]

The above problem can be solved by installing a state change output circuit (15) in the destuffing control circuit (14) on the receiving side, and forcing the signal to the lower order group to output the AIS signal when the circuit state does not change for a certain period of time. This problem is solved by the stuff control method of the present invention, which controls a pseudo write clock generation circuit (16) that converts into

[Effect]

According to the present invention, the state change detection circuit (5) provided in the destuffing control circuit on the receiving side is connected to the low-order group on the transmitting side (M
In this case, since the stuff designation pulse is in an all-suxoff or non-stuff state, it is detected that the circuit state always remains at 1'' or "0" by detecting the stuff designation pulse, and the pseudo write clock generation circuit is controlled. This is to forcibly convert the signal to the lower order group into an AIS signal.

〔Example〕

The details of the stuff control method of the present invention will be explained according to the embodiment shown in the block diagram of FIG.

In the figure, 14 is a destuff control circuit, 15 is a state change detection circuit, 16 is a pseudo write clock generation circuit, and 1
7 represents a failure detection circuit, and 18 represents a write clock control circuit.

When a high-order group signal failure occurs, the operation of the failure detection circuit 17 is as follows:
It is similar to the circuit shown in the figure.

According to the present invention, when the transmission (j, l + low-low order large input signal is cut off), the stuffing designation pulse becomes all-stuffed or non-stuffed, and the stuffing designation pulse detection circuit in the destuffing control circuit is activated. Focusing on the fact that the output is always 1'' or 0, the state of change is detected by the state change detection circuit 15. There is no change of 0-1 or 1-0 for a specific time. If the same state is maintained continuously, it means that the low-order group input signal on the transmitting side is disconnected. In this case, the circuit 15 generates a pseudo write clock controlled by the average stuff rate from the pseudo write clock generation circuit 16. This causes all "1" signals to be written in the reception memory.

〔Effect of the invention〕

According to the present invention, even if a low-order group input signal disconnection occurs on the transmitting side, a method is provided that enables reliable stuff synchronization by simply providing a simple circuit on the receiving side to detect a change in the state of the stuffing designated pulse. can be provided, and its effects are extremely large.

[Brief explanation of drawings]

FIG. 1 is a block circuit diagram showing an embodiment of the stuffing control method of the present invention; FIG. 2 is a block diagram of a digital transmission system; FIG. 3 is a block circuit diagram of a conventional stuffing control device on the transmitting side; FIG. 4 is a block circuit diagram of a conventional destuffing control device on the receiving side. In the figure, 1-1 to 1-n and 4-1 to 4-n are channel units, 2.5 is a multiplexer, 3.6 is a demultiplexer, 7 is an input signal disconnection detection circuit, and 8 is a pseudo stuff instruction. 9 is a stuff control device, 10.17 is a failure detection circuit, 11.16 is a pseudo write clock generation circuit, 12.1
4 is a destuff control circuit, 13.18 is a write clock control circuit, and 15 is a state change detection circuit. 1st rjj Digital transmission system block diagram 2
Figure 3 Figure 4

Claims (1)

[Claims] A state change detection circuit (15
), and a pseudo write clock generation circuit (16) for forcibly converting the signal to the lower order group into an AIS signal by the output of the detection circuit (15) when the circuit state does not change for a certain period of time. A staff control method characterized by control.