JPH0150149B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides high-density bipolar
This invention relates to a control signal transmission method in a PCM relay transmission method using bipolar (HDB) 3 codes.

Conventionally, control signal transmission in this type of PCM relay transmission system has been carried out by superimposing low-frequency signals of different frequencies on a center-of-gravity line consisting of two pairs of transmitting and receiving lines.

However, since this method uses a low frequency signal, it takes a very long time to transmit and receive the control signal, making it impossible to transmit the control signal at high speed. Furthermore, since this low frequency signal is attenuated along the relay transmission line, it cannot be used for long distance transmission lines. Furthermore, the oscillation and detection of this low frequency signal has the disadvantage of requiring relatively high precision equipment such as low frequency oscillators and band wave generators.

The object of the present invention is to relate to a control signal transmission system that eliminates the above-mentioned drawbacks.

The control signal transmission system of the present invention is characterized in that a control signal is transmitted by configuring a special pattern in a pulse signal propagating on a PCM relay transmission path.

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

FIG. 1 shows an example of an HDB-3 code. HDB
In the -3 code, if there are four consecutive 0s, the fourth 0 is converted to a mark (1). If we call this a violation pulse (V) as a pulse that disturbs the bipolar law, the polarity of this V pulse must be the same as the previous mark, and if the previous mark is not the same polarity, then is the first
The 0th 0 is converted into a mark with the same polarity as the V pulse. This is called the B pulse. In addition, the V pulse train is an AMI (alternative pulse train) in which 1 is repeated alternately.
Mark Inversion) rules must be followed.

In contrast, in the present invention, as shown in FIG.
Extend the series of 0's to 4, make this a frame pattern, and use the following X's,
A plurality of types of control signal patterns are transmitted by changing the combination of Y and Z bits. Furthermore, by increasing the length of one frame, a desired type of control signal pattern can be constructed. In addition,
"1" is added to the first bit and last bit of the frame pattern to prevent more than four 0s.

In addition, in the HDB-3 system, as a signal error detection method for HDB-3 signals, the polarity of the V pulse is
Since a detection method is adopted in which signal errors are detected by checking whether the rules are followed, such a detection method does not detect the above-mentioned pattern as a signal error.

In the present invention, consecutive zeros are extended to four consecutive zeros compared to three in the HDB-3 code, but in order to increase the average mark rate per frame, for example, in the signal pattern shown in Figure 2, one of the XY and Z bits is By marking at least two bits of the clock signal, the repeater on the PCM relay transmission path can easily extract the clock component for reproduction.

Next, as an application example of this method, FIG. 3 shows the configuration of a PCM30CH automatic line switching device having a transmission rate of 2.048 Mbit/s. FIG. 4 shows the control signal pattern used in the apparatus of FIG.

This device attempts to continue service by immediately switching over to a backup relay transmission line when some kind of failure occurs in the PCM relay transmission line in use. In FIG. 3, when a fault occurs in the repeater 1, the fault is detected in the signal error detector 2 of the B station. At this time, at the B station, the changeover switch 3 is switched to the standby relay transmission line side, and at the same time, the control signal generator 4 sends the changeover signal shown in FIG.
The TRF is transmitted to station A via relay transmitter 5.
This switching signal TRF is detected by the control signal receiver 6 of the A station, activates the backup relay transmission line 7 of the A station, and switches the faulty relay transmission line to the backup relay transmission line. After the fault has been recovered, the recovery signal shown in Figure 4 will be sent from one of the stations.
By sending RST, the backup relay transmission line can be restored to the original main relay transmission line again.

Note that the detection circuit 6 for detecting such a control signal
For example, a shift register that can store one frame, a memory that stores frame patterns,
It can be constructed from a comparator that compares the frame pattern from this memory with the corresponding length 6-bit output of the frame pattern from the shift register. In this case, if the 6-bit output of the shift register and the frame pattern match, it can be determined that the signal input to the shift register is a control signal, and the control bits X, Y, and Z in Figure 2 can be decoded. It is possible to determine what type of control signal it is.

Next, as another example, 2.048Mbit/
The configuration of the automatic loopback device at each repeater in the sPCM relay transmission line will be explained with reference to FIG.

The control signal generator 8 of station A generates a control signal pattern assigned to each repeater. These control signals are detected in the control signal detector 9 of each repeater 8, and if the detected signal pattern is assigned to that repeater board, that repeater board detects the return switch 10. close and turn back the relay transmission line. In order to cancel this loopback, the control signal pattern containing the cancellation command must be sent to A.
It is sent from the signal generator 8 of the station.

In the above two embodiments, the control signal generators 4 and 8 generate control pattern signals multiple times in order to prevent malfunctions caused by the pseudo-generation of the various control signal patterns described above due to signal errors in the relay transmission path. The control signal is transmitted continuously, and the control signal detector performs a control operation only when the signal is detected several times in succession.

As described above, according to the present invention, control signal transmission can be realized at high speed and can be applied to long-distance relay transmission lines.

[Brief explanation of drawings]

Figure 1 is a diagram explaining the HDB-3 code, Figure 2 is a diagram explaining the HDB-3 code,
3 and 4 are block diagrams showing one embodiment of the present invention and a specific pattern of the control signals, and FIG. FIG. 2 is a block diagram showing an embodiment. In Figures 3 and 5, TE...
PCM30CH terminal equipment, SW...PCM30CH automatic line switching equipment, LT...PCM30CH terminal relay equipment,
LR...PCM30CH line relay device, 4...Control signal generator, 2, 6...Signal error detector/control signal detector.

Claims (1)

[Claims] 1 Binary 1 corresponds to 1 or -1 and binary 0 corresponds to 0
We used a high-quality bipolar (HDB) 3 code that has a rule that converts the fourth zero to 1 when there are four consecutive zeros between the codes.
In the control signal transmission method in the PCM relay transmission method, the control signal is composed of a pattern that does not disturb the rules of the HDB-3 code and does not occur at all in the HDB-3 code, and a plurality of control bits that follow this pattern. The control signal to be sent to the HDB-
A control signal transmission method that is characterized in that it is transmitted together with a PCM signal using 3 codes.