JPH0730645A - Communication system using adpcm - Google Patents

Abstract

PURPOSE:To transmit high-speed or high-function information by utilizing an existent communication line by compressing voice data with an ADPCM inside the limited band of the S interface of an ISDN. CONSTITUTION:As the signal of 32kbps, a signal composed of ADPCM compressed voice data is transmitted by using the four bits of B10'-B13' at a B1 channel as a first channel. On the other hand, as the signal of 96kbps, image data composed of non-compressed signals are transmitted by using the 12 bits of B20-B27 at a B2 channel and B28, B29, B2A and B2B at the B1 channel as second channels. Thus, since the voice data are compressed by using the ADPCM, the number of bits required for transmitting signals at the S interface of the ISDN can be reduced. Further, since the number of non-used bits caused by the compression of voice data are used for transmitting the image data, the communication speed of image data can be accelerated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication system using ADPCM, and more particularly to the use of ADPCM which is capable of transmitting higher speed or higher function information by utilizing an existing communication line. It relates to a communication method.

A method of transmitting voice and images by an ISDN S interface is already known. As a communication method in this case, ADPCM is added to a voice signal.
It is desired to enable more varied communication by applying the method and compressing.

[0003]

2. Description of the Related Art When communication is carried out using an ISDN S interface, each of the data channels is 64k.
Two channels, B1 channel and B2 channel, which are composed of bps, are prepared.

As a conventional channel assignment for voice and image data, a method of assigning 64 kbps to an audio signal and 64 kbps to image data is generally used.

FIG. 8 shows a bit structure in the conventional communication system, and shows a B1 channel and a B2 channel in the IS interface of the ISDN. 8 bits of B10 to B17 in the B1 channel are used as a 64 kbps signal for voice or data transmission, and 8 bits of B20 to B27 in the B2 channel are used as a 64 kbps signal for voice or data transmission. There is.

[0006]

For example, in the case of a videophone, a communication speed of 64 kbps is sufficient for voice, but there is a problem that only static images can be sent for image data at a communication speed of 64 kbps. It was

The present invention is intended to solve the problems of the prior art as described above, and in the limited band of the ISDN S interface, the voice data is ADPC'd.
The object of the present invention is to improve the communication speed of image data, improve the quality of audio signals, or convert audio into stereo by compressing with M to enable more varied communication. I am trying.

[0008]

[Means for Solving the Problems] (1) FIG. 1 shows a principle configuration of the present invention. In the communication method using the ISDN S interface, the voice data is ADPC
A signal compressed by the M method is transmitted on a first channel 1 provided on either the B1 or B2 channel, and a second channel 2 is formed by combining the surplus bits in this one channel and the other channel. In, other information consisting of uncompressed signals is transmitted.

(2) In the communication system using the ISDN S interface, the voice data in the 7 kHz band is ADPC
Two series of signals compressed into the 3.4 kHz band by the M method are transmitted by the B1 channel and the B2 channel, respectively.

(3) In the communication system using the S interface of ISDN, four series of signals obtained by compressing voice data by the ADPCM system are converted into B1 channel and B signal.
First to fourth channels 3 to 6 obtained by dividing two channels
To transmit by.

(4) In the communication method using the ISDN S interface, audio data is compressed by the ADPCM method, and two series of signals respectively assigned to the right channel and the left channel of the stereo method are converted into B1 or B2 channels. One of the channels is divided into first and second channels 7 and 8 for transmission, and the other channel transmits image data.

[0012]

Since the voice signal has a high degree of redundancy, it is possible to compress the band, and there are few problems in use.
Therefore, by compressing the audio data using ADPCM, the number of bits required for signal transmission in the ISDN S interface can be reduced.

By using the number of unused bits due to the compression of the audio data for the transmission of the image data, the communication speed of the image data can be improved.

In this case, a high-quality voice signal is output from the ADPC.
Band compression by M can provide higher quality voice communication.

Further, by using the two channels of the IS interface of the ISDN for transmitting the voice signals compressed by ADPCM, it is possible to carry out the simultaneous communication of the voice signals of four channels, for example.

Further, one channel in the S interface of ISDN is used for transmitting image data, and the other channel is compressed by ADPCM.
By using the channel for transmitting audio data, a stereo audio system videophone can be realized.

[0017]

FIG. 2 shows an embodiment (1) of the present invention, showing a case where compressed audio and image data are transmitted in an S interface of ISDN. In addition,
In the following, the bit of the compressed signal will be indicated by adding "'" to distinguish it.

That is, 4 bits of B10 'to B13' in the B1 channel (B1-ch) are used as the first channel, and ADP is used as a signal of 32 kbps.
A signal composed of CM-compressed audio data is transmitted. As the second channel, B2 channel (B2-ch)
B20 to B27 in B1 and B2 in B1 channel
Using 12 bits of 8 to B2B, image data composed of non-compressed signals is transmitted as a 96 kbps signal.

FIG. 3 shows an embodiment (2) of the present invention, and shows a case where two channels of compressed high quality voice are transmitted in the ISDN S interface. That is, as the B1 channel, B10 ′ to B1
7'of 8 bits are used, and B2 is used as B2 channel.
Uses 8 bits from 0 'to B27', 64 kb each
As a ps signal, a high-quality 7 kHz voice signal is 3.4 k
Audio data that is ADPCM compressed to Hz is transmitted.

FIG. 4 shows an embodiment (3) of the present invention, showing a case of transmitting 4-channel compressed voice data in the ISDN S interface. That is, 4 bits of B10 ′ to B13 ′ in the B1 channel are used as the first channel, and the second bit is used.
B20 'to B in the B1 channel
23 '4 bits are used and B2 is used as the third channel
4 bits of B30 'to B33' in the channel are used, and B4 in the B2 channel is used as the fourth channel.
32k each using 4 bits of 0'-B43 '
As the bps signal, ADPCM-compressed 4-channel audio data is transmitted.

FIG. 5 shows an embodiment (4) of the present invention, showing a case where compressed stereo audio data and image data are transmitted in the IS interface of the ISDN. That is, as the first channel, B
4 bits of B10 'to B13' in one channel are used, and B in the B1 channel is used as the second channel.
Uses 4 bits from 30 'to B33', 32k each
As the bps signal, ADPCM-compressed audio data of two channels is transmitted, for example, the first channel is used as a stereo right (RIGHT) channel, and the second channel is used as a stereo left (LEFT) channel. Further, 8 bits of B20 to B27 are used as the B2 channel, and image data composed of an uncompressed signal is transmitted as a signal of 64 kbps.

FIG. 6 shows a block configuration in a terminal in one embodiment of the present invention, which is the same as the above-mentioned embodiment.
It corresponds to the case of (1). In the figure, 11 is a driver / receiver (DR / DV), 12 is a frame assembly /
Decomposition unit, 13 is an audio ADPCM modulation / demodulation unit, 14 is an image data conversion unit, 15 is a D-ch control unit, 16 is a microphone unit for audio transmission, 17 is a speaker unit for audio reception, and 18 is a camera for image capturing. And 19 are cathode ray tubes (C
RT) section.

In FIG. 6, the driver / receiver 11
Is ISDN between the line circuit (LC) (not shown).
The S interface frame is transmitted and received. In the transmission state, the frame assembling / disassembling unit 12 assembles the signals of the B1 channel and B2 channel of the ISDN S interface and the D channel for control into a frame,
In the receive state, it decomposes the frame into each of these channels.

The audio ADPCM modulation / demodulation unit 13 performs mutual conversion between the audio signal input from the microphone unit 16 and the audio signal output to the speaker unit 17 and the B1 channel signal of 32 kbps. The image data conversion unit 14 performs mutual conversion between an image signal input from the camera unit 18 and an image signal output to the CRT unit 19 and a B2 channel signal of 96 kbps. The D-ch control unit 15 transmits / receives a 16-channel D channel signal to / from the frame assembling / disassembling unit 12 to perform various controls.

FIG. 7 shows an example of the structure of the frame assembling / disassembling section, in which the same elements as those in FIG. 6 are indicated by the same numbers. In the frame assembly / disassembly section 12,
Reference numeral 21 is a layer 1 frame assembling / disassembling unit, 22 is a layer 1 B-ch data control unit, 23 is a layer 1 start / stop unit, 24 is a layer 1 transmission / reception control unit, 25 is a layer 2 D-ch data transmission / reception control unit, and 26 is It is a CPU interface unit. Further, 31 indicates a CPU bus, and 3
2 is a CPU, 33 is a RAM, and 34 is a ROM.

In FIG. 7, the layer 1 frame assembly
The disassembling unit 21 transmits / receives data to / from the driver / receiver 11,
Assemble and disassemble the layer 1 frame in the ISDN S interface. The layer 1 B-ch data control unit 22 inputs / outputs the B1 channel and the B2 channel between the layer 1 frame assembling / disassembling unit 21 and the audio ADPCM modulator / demodulator 13 and the image data converter 14 shown in FIG. 6, for example. Control.

The CPU 32 uses the program stored in the ROM 34 connected via the bus 31 and the data stored in the RAM 33 via the CPU interface 26 through the layer 1 start / stop unit 23 and the layer 1 transmission / reception control unit 24. Control layer 1, which activates layer 1
The stop unit 23 and the layer 1 transmission / reception control unit 24 control the assembly and disassembly of the layer 1 frame in the layer 1 frame assembly / disassembly unit 21. Layer 2D-c
h The data transmission / reception control unit 25, between the CPU 32 side,
It controls transmission / reception of control data transmitted / received by the D channel in the layer 1 frame.

[0028]

As described above, according to the present invention, I
In an existing communication line using the S interface of SDN, by compressing voice by ADPCM, it becomes possible to transmit information at a higher speed than in the case of the conventional method, and further, the function or quality is improved. Will be able to improve communication.

[Brief description of drawings]

FIG. 1 is a diagram showing a principle configuration of the present invention.

FIG. 2 is a diagram showing an embodiment (1) of the present invention.

FIG. 3 is a diagram showing an embodiment (2) of the present invention.

FIG. 4 is a diagram showing an embodiment (3) of the present invention.

FIG. 5 is a diagram showing an embodiment (4) of the present invention.

FIG. 6 is a diagram showing a block configuration in a terminal in an embodiment of the present invention.

FIG. 7 is a diagram showing a configuration example of a frame assembling / disassembling unit.

FIG. 8 is a diagram showing a bit configuration in a conventional communication system.

[Explanation of symbols]

 1 1st channel 2 2nd channel 3 1st channel 4 2nd channel 5 3rd channel 6 4th channel 7 1st channel 8 2nd channel

Claims (4)

[Claims] 1. A communication system using an ISDN S interface, wherein a signal obtained by compressing voice data by an ADPCM system is used,
An uncompressed signal transmitted on a first channel (1) provided on either one of the B1 or B2 channels, and on a second channel (2) in which a surplus bit in the one channel is combined with the other channel. A communication system using ADPCM, which is characterized by transmitting other information including 2. A communication system using an ISDN S interface, wherein audio data in a 7 kHz band is processed by an ADPCM system.
The two series of signals compressed in the 4 kHz band are
A communication system using ADPCM, which is characterized in that transmission is performed by one channel and B2 channel. 3. A communication system using an IS interface of ISDN, wherein four series of signals obtained by compressing voice data by the ADPCM system are divided into B1 channel and B2 channel to first to fourth channels (3 to 4). 6) A communication method using ADPCM, which is characterized in that 4. In a communication method using an S interface of ISDN, audio data is compressed by an ADPCM method, and two series of signals respectively assigned to a right channel and a left channel of a stereo method are converted into B1 or B2 channel signals. ADP characterized in that either one of the channels is transmitted by the first and second channels (7, 8) formed by dividing the channel, and the image data is transmitted by the other channel.
Communication method using CM.