JPH0335632A - Stuff multiplexing conversion system for repeater station - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Summary] Regarding the stuff multiplex conversion method for relay stations in a system in which a plurality of relay stations are connected between end station devices, there is a method to prevent desk dust from accumulating when a plurality of relay stations are connected. For the purpose of Next? ! From the transmitting section that multiplexes it to the I signal and sends it out (I), both methods use the elastic memory of the receiving section in each relay station by using the clock as the read clock of the elastic memory of the transmitting section. , both elastic memories are operated in conjunction with each other, and re-stuffing is not performed at the relay station located in the middle, but re-stuffing is performed only at the terminal equipment side, so that jitter accumulation due to stuff multiplexing does not occur. .

[Industrial Application Field] The present invention relates to a stuff multiplex conversion method for relay stations in a system in which a plurality of relay stations are connected between terminal devices.

[Prior Art] In a communication device, there are a synchronous multiplexing method and a stuff multiplex conversion method as methods for multiplexing low-order group signals and high-order group signals. Among these, the stuff multiple conversion method is a method in which a low-order group signal that is asynchronous with a high-order group signal is multiplexed into a high-order group signal. In this case, since the clocks are asynchronous between the low-order group and the high-order group, there will be a difference in speed, but this difference is multi-converted using stuff control.

FIG. 4 is a diagram showing an example of a conventional groove of a stuff multiplex conversion section. The low-order group data manually entered into the elastic memory 1 is written into the elastic memory 1 by the low-order group clock output from the clock generator 2. On the other hand, data read out by the output clock from the clock generator 3 enters the stuff multiplex converter 4 and is multiplexed by the stuff multiplex converter 4. The stuff multiplex conversion unit 4 outputs multiplexed higher-order group data.

On the other hand, a high-order group clock is manually input to the stuff multiplex conversion section 4, and this high-order group clock has a slightly higher frequency than the low-order group clock.

This high-order group clock is input to the clock generator 3.

In the elastic memory 1, the low-order 1: eflock and tooth extraction are the outputs of the clock generator 3 (high-order 1:f clock).
A phase comparison section 1a is provided to compare the phase difference between the two.

The phase comparator 1a compares the phase difference between the low-order group clock and the high-order group clock, and outputs a control signal when the f phase difference exceeds a predetermined amount.

This control signal is input to the clock generator 3, and the clock generator 3 performs an operation of thinning out the read clock (in other words, creates a clock) based on the value comparison result. . This tooth extraction is synchronized with the clock,
The stuff multiplex converter 4 inserts dummy data (stuff) into the multiplexed data. At this time, a signal indicating that the data is dummy data is also added.

FIG. 5 is a diagram showing an example of a conventional staff separation conversion section. The stuff multiplexing converter shown in FIG. 4 constitutes a terminal device. The high-order group data that has entered the stuff separation converter 5 is separated into data for each channel by the high-order group clock. The separated data is written to the elastic memory 6. The write clock at this time is provided from the clock generator 7.

The stuff separation converter 5 checks the position of the stuff from the information signal included in the data when separating the data, and writes the tooth extraction to the clock generator 7 when the dummy data is read and when writing the dummy data. Instructs not to output clock (light clock). Removing dummy data in this way is called destuffing. As a result, data is written to the elastic memory 6 only during destuffing.

A samurai who reads data from elastic memory 6,
A read clock is applied from the PLL circuit 8. This readout clock and the output of the clock generator 7 are compared in a phase comparator 6a included in the elastic memory 6, and the clock output from the PLL circuit 8 is synchronized with the clock. becomes.

By the way, when the distance to connect such terminal stations becomes long, a relay station is installed between the relay lines.

This relay station is not only used to amplify signals on the way, but also has a built-in mechanism for communicating with other terminal stations. Such a need arises, for example, when a relay station is installed in a desert. In other words, in order to enable communication even at relay stations in the desert,
An apparatus using a staff multiplexing and one labor-strain conversion section shown in FIG. 5 is used.

FIG. 6 is a block diagram of the configuration of such a communication system. When data enters the terminal device 11 from the input/output device (Ilo) 1.0, the terminal device 11 stuff-multiplexes the manually input data and sends it out to the other terminal device 12. Here, a plurality of relay stations 13 (NflM) are installed between the terminal devices 11 and 12. The internal configuration of these relay stations 13 is as shown in FIG. 7 (details will be described later). That is, it is composed of a stuff multiplex conversion section and a stuff separation conversion section, and the output of the stuff separation conversion section is directly input to the stuff multiplex conversion section. in this way,
Stuff separation and stuff multiplexing are performed at each relay station to shape the data waveform.

FIG. 7 is a block diagram showing the conventional configuration of a relay station, which can also be used as a terminal station. Figure 4,
Components that are the same as those in FIG. 5 are designated with the same number 7. In the figure, 20 is a frame synchronization/separation unit that synchronizes frame data sent from a terminal device or a relay station and separates the synchronized frame data. Data separated by frame synchronization/separation unit 20 (higher order group data)
The high-order group clock enters the stuff separation converter 5, is separated, and is output. The output data enters the elastic memory 6. On the other hand, the high-order group clock is inputted to the clock generator 6. The staff separation conversion unit 5 watches the staff (dummy data) of the human data, and when it is dummy data, the clock generator 7 performs tooth extraction.
A control signal is sent to the elastic memory 6 to prohibit writing of data to the elastic memory 6.

In this way, only the original data is written into the elastic memory 6. In tooth extraction, the output of the clock generator 7 and the low-order group clock are compared in a phase comparator in the elastic memory 6, so that the phases of both data match.
It is controlled by a PLL circuit 8.

The output clock of the PLL circuit 8 on the low-order group side is also used as a clock on the high-order group side. That is, the PLL circuit 8
The output of is input to the elastane memory 1 as a write clock. Data is manually input to the elastic memory 1 and written in synchronization with the high-order group clock. Here, as the manually input data, for example, the output of the elastic memory 6 is used as is.

On the other hand, the elastic memory 1 contains a read clock from the clock generator 3, and the manual operation of the clock is prohibited according to the comparison result from the phase comparator in the elastic memory 1. The stuff multiplex converter 4 multiplexes the data read from the elastic memory 1 using a high-order group clock. In this case, based on the phase comparison signal from the elastic memory 1, dummy data is used as an intermediary and read out for the portion where tooth loss has occurred. The read data enters the multiplexing section 21 and is sent to the terminal device or the next relay station.

[The invention is a cornerstone/problem to be solved] In the conventional stuff multiplexing and demultiplexing method described above, when the stuff data that has been processed on the transmitting side is destuffed (stuffed data is removed) on the receiving side, it is difficult to avoid this problem in principle. Jitter (destuffing jitter) that cannot be suppressed occurs. In Figure 6, each relay station performs stuff separation and multiplexing for each station, so
The jitter generated at the N relay stations 13 is accumulated and appears at the final terminal station 12 (see FIG. 6). It is known that this destuff jitter is accumulated by (N+1)'' times the number of relays N. Therefore, the input/output device (Ilo
) 14 is sensitive to jitter, errors will occur due to accumulated destuff jitter.

The present invention has been made in view of the above-mentioned problems, and has an object of 1-1 to provide a stuff multiplex conversion method for relay stations that prevents the accumulation of desktop noise even when a plurality of relay stations are connected. There is.

[Means for Solving the Problems] FIG. 1 is a block diagram of the principle of the present invention. Components that are the same as those in FIG. 6 are designated by the same reference numerals. In the figure, 11
．． ．． 12 is a terminal device, and these terminal devices 11. ．． A plurality of relay stations 30 are installed between 12 stations. 31 is a receiving unit that separates a received high-order group signal (high-order group data) into a low-order group signal (low-order group data); 32 is a transmitting unit that receives low-order RY data, multiplexes it into high-order BT data, and sends it out; 3
3 is an elastic memory in which separated low-order group data is written, and 34 is an elastic memory in which data read from the elastic memory 33 is written.

The clock used to write data into the elastic memory 33 is also used as a read clock to read data from the elastic memory 34. Also,
The read clock of the elastic memory 33 is also used as the write clock of the elastic memory 34.

[Function] Elastic memory 3 of receiving section 31 in each relay station 30
In step 3, by using the clock as a read clock for the elastic memory 34 of the transmitter 32, both elastic memories 33 and 34 are operated in conjunction with each other, and the relay station 30 placed in the middle is not re-stuffed. Do it like this. Then, re-stuffing is performed only on the terminal device 12 side.

This can prevent accumulation of jitter due to stuff multiplexing.

FIG. 2 is an explanatory diagram of the operation of the present invention. N IIM relay stations 30 are connected, and among each relay station 30, #1 to
In the relay station #(N-1), only the last terminal side relay station #N is re-stuffed without performing 4 stuffs.As a result, the M relay stations in the figure are reduced to 1. The present invention can be regarded as one relay station 40, and the def stuff jitter appears for one relay station. Therefore, according to the present invention, accumulation of jitter can be prevented.

[Embodiment 1] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 3 is a configuration block diagram showing one implementation rule of the present invention. Components that are the same as those in FIGS. 1 and 7 are designated by the same reference numerals. In the figure, the receiving section 31 includes the frame synchronization/separation section 20. The stuff separation conversion section 31a and the tooth extraction section are composed of a clock generator 7. The transmitter 32 includes a multiplexer 21 and a stuff multiplex converter 32a. From the stuff separation converter 31a to the stuff multiplex converter 3
2a contains a stuff control signal and a frame timing signal.

The output of the clock generator 7 on the receiving section side is stored as a read clock in the elastic memory 34 on the transmitting section side. Output of elastic memory 33 (data,
The clock) is directly connected to the elastic memory 34 of the transmitting section, and serves as a groove bottom in which the separated data is multiplexed again.

The operation of the circuit configured as described above will be explained as follows.

The high-order group data sent from the terminal equipment or relay station is
The frame synchronization/separation unit 20 is entered and frame synchronization is established. Then, the frame synchronization/separation section 20 outputs high-order group data and a clock, and the stuff separation/conversion section 3
1. Enter a. The stuff separation conversion unit 31a separates the multiplexed data into frames based on the synchronization clock,
Output.

At this time, 111 determination of destuffing is performed and the result is sent to the clock generator 7.

For tooth extraction, the clock generator 7 subtracts the clock by one and does not write data to the elastic memory 33 when the destuffing timing is correct.

The elastic memory 33 writes data sent from the staff/1) separation conversion section 31a using a clock. On the other hand, the data written in the elastic memory 3' is output once by the output clock of the PLL circuit 8.
A phase comparator (not shown) inside compares the 411 points of the write clock and read clock, and a signal corresponding to the phase difference is given to the PLL channel. And PLL
The circuit 8 generates a read clock synchronized with the write clock, and data is sequentially read from the elastic memory 33 by this read clock.

The data read from the elastic memory 33 is sequentially written to the elastic memory 34 on the sending side.
At this time, the write clock is the output of the PLL circuit 8 (
(read clock of the elastic memory 33) is used. Therefore, reading data from the elastic ink memory 33 and writing data to the elastic memory 34 are performed at the same time. On the other hand, when reading data from the elastic memory 34, a clock is used for the reception side that has performed the destuffing determination. In this way, the elastane and IC memory 3 on the receiving side and the sending side are
3.34 is linked. The data read from the elastic memory 34 is given to the stuff multiplex converter 32a.

At the same time, the staff separation conversion unit 31. From a to staff 1. The control signal and the frame timing signal are passed to the stuff multiplex converter 32a, and a frame is generated based on the frame timing signal. The stuff multiplex converter 32a uses the signal from the stuff separation converter 31a as it is as the Stanoff control signal, and in the case of stuff data, multiplexes the low-order group signal into the high-order group signal without re-stuffing.

The read data is sent to the multiplexer 21, multiplexed by the multiplexer 21, and sent to the terminal device or relay station. Additionally, the present invention eliminates jitter accumulation due to destuffing. In other words, the stuff data (dummy pigs) used at the first stage relay station is maintained as is until the final stage relay station, and is destuffed at the final stage.

[Effects of the Invention] As explained above in detail, according to Sadaaki Ki, the elastic memory of the receiving section in each relay station can be extracted by using the clock as the read clock of the elastic memory of the transmitting section. By operating the elastic memories of both nodes in conjunction, preventing re-stuffing at the intermediate station, and re-stuffing only at the terminal equipment side, jitter due to stuff multiplexing can be reduced. Accumulation can be prevented from occurring.

4. Drawing 117? -11 Explanation Fig. 1 is a basic raccoon block diagram of the method of the present invention, Fig. 2 is an explanatory diagram of the operation of the present invention, Fig. 3 is a configuration block diagram showing an embodiment of the present invention, Fig. 4 is a staff multiplexing diagram. A diagram showing an example of a conventional configuration of a conversion section, Figure 5 is a conventional example of a staff separation conversion section? , '4 configuration example, FIG. 6 is a block diagram of the configuration of a communication system, and FIG. 7 is a block diagram showing a conventional 1M relay station configuration example.

In Figure 1, 11.12 is the terminal equipment, 30 is a relay box, 31 is a receiving section; 32 is a transmitter; 33 and 34 are elastic memories.

Claims (1)

[Claims] A plurality of relay stations (30) are inserted between the terminal device (11) and the terminal device (12), and these relay stations (30)
In the case where each relay station (30) is composed of a receiving section (31) that separates a high-order group from a low-order group, and a transmitting section (32) that receives a low-order group signal and multiplexes it into a high-order group signal and sends it out, each relay station (30) By using the clock of the elastic memory (33) of the receiving section (31) in the middle as the read clock of the elastic memory (34) of the transmitting section (32), both elastic memories (33)
, (34) are operated in conjunction with each other, and the relay station (30) located in the middle is not re-stuffed, but only the end station equipment side is re-stuffed, so that jitter accumulation due to stuff multiplexing does not occur. A stuff multiplex conversion method for relay stations characterized by the following.