JPH03135124A - Compression multiplexer - Google Patents

Abstract

PURPOSE:To prevent degradation in the quality of data or information by validating a data format conversion section when a compression section and a decoding section are both invalied. CONSTITUTION:Switches 105, 106 are changed over according to a mode switching signal 109 from an exchange and the switches 105, 106 are changed over to the position of data format conversion section 101, 103 respectively in the case of a relay call and changed over to the position of a compression processing section 102, a decoding processing section 104 respectively in the case of an incoming/outgoing call. Consequently, in the case of the relay call, the function of the compression processing section 102, the decoding processing section 104 is invalidated and a function of the data format conversion sections 101, 103 is validated instead. Thus, even when there is no relation of an integral number ratio between the data speed of a compressed data and the data speed of the original data and the data or the information is sent in a way of multi- stage relay, only one data compression and decoding is enough, then the degradation in the quality of data due to multi-stage relay is prevented.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a compression/multiplexing device equipped with multiplexing/separating functions and compression/decoding functions, and particularly relates to a compression/multiplexing device that is equipped with multiplexing/separating functions and compression/decoding functions, and particularly relates to a compression/multiplexing device that combines data before compression and data after compression. The present invention relates to a compression/multiplexing device that prevents data quality from deteriorating even when data is relayed and connected in multiple stages even when the numbers are not in an integer ratio relationship.

[Prior Art] In digital networks, as a method of efficiently using transmission paths, information such as audio and images is compressed into smaller pieces of information than normal pieces of information (for example, PCM 64 kbps for audio information) and then transmitted. On the other hand, on the receiving side, by decoding the compressed audio information, almost the same information as the original audio information and image information is reproduced. Such a method is particularly useful when multiplexing a plurality of pieces of information such as audio, images, data, etc. over a single physical transmission path.

Here, an example of a transmission network including a multiplexing device according to the prior art is shown in FIG. 5, and a brief explanation thereof is as follows.

That is, as shown in the figure, each of the exchanges 1 and 11.21 installed scattered within a certain area has subscriber telephones 2.2-1 to 2.
-1.12.12-1~12-m, 22.22-1~
These exchanges 1, 11 and 21 accommodate high-speed digital transmission lines 3 and 13, transmission line interface equipment 4 and 14.14-1.24, and multiplexing equipment (compression and It is equipped with a decoding function and a multiplexing/demultiplexing function) 5, 15.15-1.25. Therefore, subscriber telephones 2.2-1 to 2-1.12.12-1 to 1 accommodated in the network
2-m and 22.22-1 to 22-n can communicate freely with each other.

However, even a network constructed in this manner is not without problems.

To explain this problem more specifically, for example, in a call between subscriber telephones 2 and 12, the voice information is only passed through the multiplexers 5 and 15, so the voice information is compressed and decoded only once. It is. However, since calls between subscriber telephones 2 and 22 must further go through the multiplexer 15-1.25, deterioration in voice quality is unavoidable. This means that although the amount of information is transmitted in a compressed state and then decoded, the quality of the decoded information is somewhat degraded compared to the original information, and it is transmitted over multiple transmission channels within the network. This is because, if the data is relayed and transmitted via a network, quality deterioration will overlap, resulting in practical problems.

In order to eliminate such problems, Japanese Patent Application Laid-Open No. 62-1866
According to Publication No. 26, the information compression/decoding function is stopped in the relay stage, and only data format conversion is performed, so that even if the information is relayed in multiple stages within the network, the compression/decoding function of audio and other information is maintained. Decryption is always limited to one time. Figure 6 shows an example of data format conversion when the compressed audio data is 16 kbps.
2kbps, 8kbps, etc.) and the original (before compression) data (
Such a method is also effective if there is an integer ratio relationship with the data rate (64 kbps).

[Problem to be Solved by the Invention] However, in the above publication, although the case where there is an integer ratio relationship between the data rate of compressed data and the data rate of original data is considered, Compression/decoding processing in the case where there is no such relationship is not separately considered, and deterioration in audio quality due to multi-stage relay transmission cannot be repaired.

It is an object of the present invention to provide a data or information processing system that does not have an integer ratio relationship between the data speed of compressed data and the data speed of the original data, and even when the data or information is relayed and transmitted in multiple stages. An object of the present invention is to provide a compression multiplexing device that can prevent quality deterioration.

[Means for Solving the Problems] The above object is that the compression multiplexing device according to the prior art includes a first processing unit common to channels that multiplexes and demultiplexes various information, and an information name in a separated state. a second processing section that performs compression/decoding processing for each of the information channels; The switching means for selectively switching the compressed part and the decoded part corresponding to the information channel to the enabled or disabled state is provided, and the switching means is further provided to switch the compressed part and the decoded part corresponding to the information channel to the disabled state. transmitting/receiving compressed data in a multi-frame format when the input data rate and the output data rate of each of the compressed part and decoded part are not in an integer ratio relationship. This is achieved by providing a data format conversion section in parallel.

[Operation] In short, when the compression part and decoding part provided for the information channel are both disabled, the data format conversion part provided in parallel to these parts is enabled. Then, using these data format conversion parts, human data is converted into a predetermined format and then output as output data.

That is, in the data format conversion section provided in parallel with the decoding section, the compressed data destined for the exchange is converted into a predetermined multi-frame format and output to the exchange. The provided data format conversion section extracts only compressed data from the multi-frame data including compressed data from the exchange and outputs it to the digital transmission path. If the insertion position of compressed data within a multi-frame is determined in advance, exactly the same data can be exchanged between compression multiplexers in the relay stage without quality deterioration. be.

[Example] The present invention will be explained below with reference to FIGS. 1 to 4.

As is well known, in a multiplexing device, uncompressed data from an exchange is generally compressed in an information channel compatible compression/decoding section, then multiplexed with other compressed data in a common channel multiplexing/decoding section, and then digitalized. While being transmitted on a transmission path, the compressed and multiplexed data from the digital transmission path is also separated in a common channel multiplexing and demultiplexing section, and then decoded in an information channel compatible compression and decoding section. FIG. 1 shows a compression/combining section as a main component of a compression/multiplexing device according to the present invention and its surroundings. As shown in the figure, a data format conversion unit 10 is used for a compression processing unit 102 as a compression part.
1, and a data format conversion section 103 is provided in parallel to a composite processing section 104 as a composite section.

Here, for example, the data rate of compressed data is 9.6 kbp.
s, 64k b from the exchange
The pS data 107 is input to the compression processing section 102 and the data format conversion section 101, and the output from each of these is also 9 or 6 kbpS data, and one of them is selectively output to the digital transmission line side by the switch 105. This is what has become. On the other hand, the 9.6 kbps data 108 from the digital transmission line side is processed by the composite processing unit 1.
04 and a data format converter 103, and the output from each of these is also outputted as 64 kbps data by a switch 106 selectively to the exchange. Switches 105, 106
Which side is switched to depends on a mode switching signal 109 from the exchange. That is, in the case of a relay call, the switches 105 and 106 are connected to the data format conversion units 101 and 103, respectively, and in the case of an outgoing/incoming call, the switches 105 and 106 are connected to the compression processing unit 102 and the composite processing unit 104, respectively. In this case, the compression processing unit 102
, the functions of the data format converters 101 and 103 are enabled instead of the functions of the composite processing section 104 being disabled.

FIG. 2 shows the processing contents in the data format converters 101 and 103. The data format converter 103 has a function of converting 9.6 kbps data to 64 kbps data, and the data format converter lot has a function of converting vice versa.The principles of these conversions are as follows. be.

That is, the frame signal of 64 kbps PCM signal is 8 kHz.
and 9.6kHz is (8kHz15) x 6=9
．． 6kHz. Therefore, the data format converter 103 outputs 9.6k.
To convert bps data to 64kbps data, 5
It is sufficient to transmit 6 bits within a frame. As shown in Figure 2, the 64 kbps data is in a so-called multi-frame format with one period of 5 frames, and the first frame contains a frame pattern indicating the beginning of the frame (in this example, the frame is composed of Among the 8 bits, the first bit is set to “0”)
is inserted, and the first bit for the next four frames is set to "1", making up 9.6 kbps data6.
Bit data (A-F) are inserted and arranged under certain rules. Also, 64kbps data can be
．． Data format conversion unit 101 to 6kbps data
As shown in Figure 2, after the frame leading pattern is detected from the 64kbps data in the multi-frame format, the 6-bit compressed data inserted at a predetermined position within the following four frames is converted. It would be good if it could be extracted.

Here, to specifically explain the network shown in FIG. 5 as an example, 9.6 kb from the high-speed digital transmission line 3
The ps data is converted into 64 kbps data by the data format converter 103 in the multiplexer 15 and then transmitted to the multiplexer 15-1 via the exchange 11. That 64kbps data is 9.6k
After being converted to bps data, high-speed digital transmission line 1
3, which is intended to be transmitted on. The situation is similar for data transmission in the opposite direction.

The above is for the case where the data rate of compressed data is 9.6 kbps, but the data rate is 4.8 kbps.
Even in the case of 2.4 kbps and 2.4 kbps, data conversion can be performed in the same way.

That is, the frame signal of 64 kbps PCM signal 8 KHz
The relationship with each is (8kHz15)X3=4.8kHz
z, (8kHz/10)X3=2.4kHz.

Therefore, within 5 frames or 10 frames, 3
If bits are transmitted, data transmission speeds of 4.8 kbps and 2.4 kbps can be achieved. By newly providing the data format converter according to the present invention in the multiplexing device according to the prior art, it is possible to convert not only 16 kbps, etc., which has an integer ratio relationship to 64 kbps, but also 9.6 kbps, etc., which have no integer ratio relationship. The data rate conversion is achieved.

When the data rate is converted in this manner, the data transmission from the high-speed digital transmission line 3 to the high-speed digital transmission line 13 as shown in FIG.
There is no alteration of equivalent data, and even for relay calls, data compression and decoding only need to be done once.

Finally, to explain the data format conversion section in detail, FIGS. 3 and 4 show the configuration of an example of the data format conversion sections 101 and 103, respectively. First, the data format converter 101 will be explained.
4kbps data 107 is 64kHz clock signal 11
1, the serial/parallel conversion circuit 201 sequentially converts the data into parallel data.

In this way, the first frame of a multi-frame is detected by the frame first pattern detection circuit 202 from the sequentially obtained parallel data. The contents of each frame are stored in data buffer 204 in sequence. on the other hand,
Under the control of the bit counter 206 based on the 9.6 kHz clock signal 112, only 6-bit data (A-F) is transferred from the data buffer 204 to the register 205 and stored, and is further converted into 9.6
This data is obtained as kbps data 110.

Regarding the data format conversion unit 103, 9
．． The 6 kbps data 108 is converted into parallel data by a serial/parallel conversion circuit 301 based on a 9.6 kHz clock signal 112, and then stored in a data buffer 303 under the control of a bit counter 302. Meanwhile, data buffer 303 is controlled by frame counter 305 based on 64kHz clock signal 111.
The 6-bit data (A-F) from the data conversion circuit 30
4, the data is converted into a multi-frame format and then obtained as 64 kbps data 113 from the parallel-to-serial conversion circuit 306.

[Effects of the Invention] As explained above, according to the compression multiplexing device according to the present invention, there is no integer ratio relationship between the data rate of compressed data and the data rate of original data;
Alternatively, even when information is relayed and transmitted in multiple stages, the data is compressed and decoded only once, so deterioration in data quality due to multi-stage relay can be prevented.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the compression/combining section and its surroundings as the main components of the compression/multiplexing device according to the present invention, and FIG. 2 is a data format conversion provided in parallel in each of the compression/decoding sections. Figures 3 and 4 are diagrams showing the configuration of an example of a data format conversion unit provided in parallel in each of the compression and decoding parts, and Figure 5 is a diagram showing the processing contents of the conventional technology. FIG. 6, which is a diagram showing an example of a transmission network including such a multiplexing device, is a diagram showing an example of data format conversion according to the prior art. 101.103...Data format conversion unit, 10
2...Compression processing section, 104...Decoding processing section

Claims (1)

[Claims] 1. A first processing unit common to channels that multiplexes and demultiplexes various types of information, and a second processing unit that performs compression and decoding processing on each piece of information in a separated state; a switching means for selectively switching the functions of the compression section and the decoding section provided for the information channel, which constitute the second processing section, into a valid or invalid state depending on a connection destination of the information channel; In the compression multiplexing device, the compression multiplexing device is configured to enable each of the compressed part and decoded part corresponding to the information channel to be enabled by a switching means when both the compressed part and the decoded part are set to be disabled; A data format converting section for transmitting and receiving compressed data in a multi-frame format is provided in parallel when the input data rate and output data rate of each of the partial and decoding sections are not in an integer ratio relationship. Compression multiplexer. 2. The compression multiplexing apparatus according to claim 1, wherein the switching between valid and invalid by the switching means is performed independently for each information channel depending on the connection destination of each information channel.