JPH058891B2 - - Google Patents

Description

[Detailed Description of the Invention] [Summary] When time division multiplexing a time division multiplex communication channel at a relay station, a certain station loses its signal and then resynchronization when the signal is restored is improved as follows. did. In other words, a specific pattern for synchronization is transmitted from the station next to the station that recovered after the signal was cut off, and the next station synchronizes with the synchronization pattern from the recovered station while transmitting the next station after the next station. In the station, the synchronization pattern of the synchronization pattern generator of that station is preset in synchronization with the synchronization pattern sent out by the station whose signal has been cut off, thereby causing simultaneous synchronization of all stations.

[Industrial application field]

The present invention relates to a time division multiplex communication synchronization system, and more particularly to a time division multiplex communication synchronization system that uses a specific pattern for resynchronization and a preset of a synchronization pattern generator to shorten the time for resynchronization.

Some data communication systems require synchronization for data to be successfully transmitted from a transmitting end to a receiving end. The need for such synchronization is also required in time division multiplex communication systems, especially in order to be able to transmit data as quickly as possible when the previous station of an intermediate station in the system goes down and is restored. In order to restore the system, it is desirable to be able to synchronize the system in as short a time as possible.

[Conventional technology]

The synchronization technique in the time division multiplex communication system as shown in FIG. 4, especially when the input signal is cut off and then recovered, is as follows.

For example, when the terminal station 30 goes down and is restored, synchronization of the system is as follows.

When the synchronization pattern signal from the hybrid 34 is no longer given to the synchronization tester 36 at the intermediate station 32 due to the failure of the terminal station 30, a PN (pseudo noise) (synchronization pattern) signal synthesis command 35 is generated from the synchronization tester 36. , the synchronization pattern (PN) signal synchronized with the synchronization pattern signal of the terminal station 30 from the PN signal generator 38 is immediately transmitted to the multiplexer 4.
0 and is combined with the data transmitted from the intermediate station 32 and sent to the time division multiplex transmission line 44 via the switch 42. Even if the terminal station A goes down, the synchronization of each station after the intermediate station 32 is maintained. maintained.

When the terminal station 30 recovers and joins the above-mentioned degenerate system while the communication system is in a degenerate state, the intermediate station 32 first detects synchronization with the PN signal of the terminal station 30 from the synchronization tester 36. The PN pattern shift command 37 causes a pattern shift of the PN signal generator 34. By sequentially propagating such synchronization processing to the intermediate stations 46... (these intermediate stations have the same configuration as the intermediate station 32), the original communication system is restored.

[Problem that the invention seeks to solve]

As mentioned above, in a conventional time division multiplex communication system, when a certain station goes down and is restored, resynchronization of the system occurs sequentially, in other words, in series. Therefore, it takes time to complete the resynchronization of the system, which causes a decrease in the operating rate of the communication system.

The present invention was created in view of such problems, and an object of the present invention is to provide a time division multiplex communication synchronization method that provides parallel resynchronization capability and can reduce the time required for resynchronization. shall be.

[Means for solving problems]

FIG. 1 shows a block diagram of the principle of the present invention. As shown in the figure, when the signal from a certain station 3 to the subsequent station 3' constituting the time division multiplex communication system 1 is interrupted and then restored, the synchronization pattern transmitted from the certain station is While the synchronization pattern generator 4' of the local station 3' is synchronized by the synchronization means 6', a specific pattern for resynchronization is transmitted from the pattern transmission means 5' to the time division multiplex communication channel 2. Presetting means 7'' of the downstream station 3'' which receives the specific pattern for synchronization via the time division multiplex communication channel 2.
... to preset the synchronization pattern of the synchronization pattern generator 4'' of that station in synchronization with the synchronization pattern transmitted by the certain station 3, thereby realizing resynchronization of the synchronization pattern generator of each station. The present invention is constructed as follows.

[Effect]

When the signal from a certain station 3 in the time division multiplex communication system 1 to the subsequent station 3' is restored after being cut off,
A resynchronization of the synchronization pattern generator 4' of the downstream station 3' to the synchronization pattern transmitted from said certain station 3 is caused by the synchronization means 6'. At the same time, a specific pattern for resynchronization is transmitted via the time division multiplex communication channel 2 by the pattern transmitting means 5'.

This specific pattern for resynchronization is used in the preset means 7'' of each downstream station 3'' that receives it, and the synchronization pattern of the synchronization pattern generator 4'' of that downstream station 3'' is set. It is preset in synchronization with the synchronization pattern transmitted by the certain station 3.

Thus, parallel synchronization of the synchronization pattern generators of each station is achieved.

〔Example〕

FIG. 2 shows an embodiment of the invention. In this figure, 3 is a terminal station, which corresponds to, for example, a certain station 3 in FIG.
Time division multiplexing communication channel 2 transmits the signal and transmission data into corresponding time slots of the transmission frame.
It is configured to include a multiplexer 3B for transmitting to.

Reference numerals 3', . . . indicate intermediate stations, and since these have the same configuration, only the configuration of the intermediate station 3' will be described, and explanations of the other intermediate stations 3'', etc. will be omitted.
Note that a dash for distinguishing between constituent elements is attached to the reference number for reference.

10 is a hybrid transformer electrically connected to the time-division multiplex communication channel 2 formed between the terminal station 3, and the system up to the synchronization tester 12' connected to one output of this transformer is shown in FIG. This corresponds to the synchronization means 6'. The current validator 12' has an asynchronous output 12'A and a PN pattern shift command output 12'B.

4' ₁ is a PN signal generator, which corresponds to the synchronization pattern generator ₄ ' in FIG _. In addition to having B, a synchronization tester 12'
An input _41'C for receiving a PN pattern shift command to cause a shift in the PN signal pattern, and a predetermined input for synchronizing the PN signal pattern in response to a synchronization preset command from a detection unit 14', which will be described later. It has an input 4 ₁ 'D for presetting the PN signal pattern.

The detection unit 14' is connected to one output of the hybrid transformer 10' and to the asynchronous output 12'A of the synchronization tester 12'. It has an output 14'B for the PN pattern synthesis command. The system which generates the synchronous preset command of the detection section 14' and causes the PN signal generator _4'1 to produce the above-mentioned preset corresponds to the preset means 7' in FIG. This presetting means 7' is the terminal station 3.
It is necessary when the intermediate station 3' is configured to generate the above-mentioned specific pattern for resynchronization, but otherwise it is unnecessary at the intermediate station 3'.

16' is a multiplexer, which outputs the output _41'A of the PN signal generator _4'1 and the output 1 of the detector 14'.
4'B and a data input, while having an output connected to one input of switch 18'.

The other output of the hybrid transformer 10' is connected to the other input of the switch 18'.

Then, in a state where the terminal station 3 has recovered after the signal was cut off and is transmitting a signal, data input is performed in response to the fact that the PN signal generator 4' ₁ no longer generates a synchronous output. The pattern transmitting means 5' in FIG. 1 is a system that sets all "0" and transmits all "0" to the time division multiplex transmission line 2 via the multiplexer 16' and the switch 18'.

In the time division multiplex communication system having the above configuration, the operation when synchronization is maintained is exactly the same as that of the conventional system. That is, the detection unit 14' does not generate a PN pattern synthesis command, and the multiplexer 1
6' is in a state where data is exchanged through there. The switch 18' responsive to the synchronization output from the PN signal generator _4'1 is then caused to switch to and from the multiplexer 16' in its own time slot. This relationship holds true for other intermediate stations as well.

In such an operating state, if the terminal station 3 falls into a signal cut-off state, the synchronization tester 12' outputs the asynchronous output a and the test section 14' outputs the PN pattern synthesis command b. PN
The PN signal generated by the signal generator _4'1 and the input data are sent to the multiplexer 16' while maintaining the respective time slot relationships within the previous transmission frame and transmitted on the transmission frame. Therefore, each station after intermediate station 3'' maintains synchronization and continues the same operating state as before (terminal station 3
(see a in FIG. 3, which shows the data being transmitted from the intermediate station 3').

After that, the terminal station 3 recovers from a signal-off state, for example, a power-off state, to a signal-transmitting state, for example, a power-off state, and the terminal station 3 transmits data to the intermediate station 3'.
The PN signal and up to that point are being received after intermediate station 3'.
As is clear from a comparison of a, c, and d in FIG. 3, the phase with the PN signal is shifted. Therefore, the asynchronous output a and
PN pattern shift command C is output. The detection unit 14' receives an asynchronous signal, but since it receives the signal from the hybrid transformer 10',
PN signal synthesis command b is not output. In response to the lack of synchronization output from the PN signal generator _4'1 , all "O" patterns (specific patterns for resynchronization) as input data are sent to the downstream station 3" via the multiplexer 16' and the switch 18'. .... This all "O" transmission period is a period during which signal interruption can be detected at the downstream station.

In response to the PN pattern shift command c from the synchronization tester 12', the PN signal generator _4'1 is shifted until it finally becomes synchronized with the PN signal transmitted from the terminal station 3.

The downstream station 3″ that receives the specific pattern for resynchronization…
..., the synchronization preset command is output from the detection section 14'' and the PN signal generator _4''1 ...
A PN signal pattern was sent from terminal 3.
Preset in synchronization with the PN signal pattern.
In other words, the downstream stations 3'' are resynchronized almost simultaneously (in parallel).

Note that the PN pattern synthesis command b in the above embodiment may be configured to be output from the synchronization tester 12'.

〔Effect of the invention〕

As explained above, according to the present invention, a specific pattern for resynchronization and a preset function using this specific pattern for resynchronization are used to simultaneously perform the resynchronization of a time division multiplex communication system. Since it can be done all at once, the time required for resynchronization can be significantly reduced. This improves the operating rate of the communication system.

[Brief explanation of the drawing]

Fig. 1 is a principle block diagram of the present invention, Fig. 2 is a diagram showing an embodiment of the invention, Fig. 3 is a timing chart of the embodiment shown in Fig. 2, and Fig. 4 is a conventional time division multiplex communication system. It is a diagram. 1 and 2, 1 is a time division multiplex communication system, 2 is a time division multiplex communication channel, 3 is a certain station (terminal station), 3', 3''... are intermediate stations, 4', 4 _1,4 ″
... is a synchronization pattern generator, 5' ... is a pattern transmission means, 6' ... is a synchronization means, 7' ... is a preset means, 10 is a hybrid, 12 is a synchronization calibrator, 14 is a detector, 16 is a multiplexer, 1
8 is a switch.

Claims (1)

[Scope of Claims] 1. The synchronization of the time division multiplex communication channel 2 is achieved by the synchronization pattern generator 4' of the intermediate station 3', and the required time division multiplex relay is carried out at the intermediate station 3'. In a time division multiplex communication system that performs time division multiplex communication, when the signal from a certain station 3 to a subsequent station 3' constituting the time division multiplex communication system 1 is interrupted and then restored, the certain station The synchronization pattern generator 4' of the downstream station 3' is synchronized by the synchronization means 6' to the synchronization pattern transmitted from the synchronization pattern transmitted from the pattern transmission means 5', and the specific pattern for resynchronization is sent to the time division multiplex communication channel 2 from the pattern transmission means 5'. The presetting means 7'' of the downstream station 3'' which receives the specific synchronization pattern via the time division multiplex communication channel 2 transmits the synchronization pattern of the synchronization pattern generator 4'' of that station. A time division multiplex communication synchronization system characterized in that presetting is performed in synchronization with a synchronization pattern transmitted by the certain station 3.