JP2003018016A - Simultaneous transmission system for control information in adpcm audio transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transmission system that can simultaneously transmit ADPCM(adaptive differential pulse-coded modulation) audio data together with control information, without the need for redundant data transmission through addition of a header. SOLUTION: An audio data stream is configured by periodically inserting 3-bit coded ADPCM audio data, with 1-bit being added to tem as control information to a 4-bit coded ADPCM audio data stream, a receiver side detects the audio data stream as a control information bit stream, so as to transmit the control information at the same time, when the ADPCM audio data are transmitted.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to ADPCM audio transmission capable of simultaneously transmitting control information. [0002] In 2ch ADPCM voice transmission over a widely used 64 Kbps digital leased line,
Since each channel is assigned as an information channel of a 4 bit × 8 Kbps stream, control information could not be transmitted. For this reason, it is not possible to transmit a state change or dial information occurring during communication between communication terminals using the digital leased line, which hinders the service function. An AD that does not perform redundant data transmission by adding a header and has little signal degradation
PCM audio data can be transmitted simultaneously with control information. [0004] A three-bit coded A
One bit (FIG. 3) is sequentially added to the DPCM audio data (FIG. 2) from the control information bit string, and transmitted as 4-bit audio stream data. Next, 4-bit encoded ADPCM audio data is continuously generated three times and transmitted as audio stream data. In this way, one bit of control information is periodically inserted to form an audio data stream (FIG. 4). [0005] The control information is transmitted to the ADP by examining one bit of the control information bit periodically inserted on the receiving side.
The transmission can be performed together with the CM audio data, and the amount of redundant data is small, so that highly efficient audio transmission can be performed.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 Stream of 4 bits / word. Arrows indicate the transmission direction. FIG. 2 shows a data stream in 24-bit ADPCM encoding (3-bit encoding mode). FIG. 3 shows insertion of control information bits into a data stream in a 3-bit encoding mode. FIG. 4 shows a stream of 4 bits / word including control information bits (lower) and a control information bit string (upper). [Explanation of Codes] Empty bits in a data packet in the 3-bit encoding mode. Control information bits inserted into the empty bits. Control information bit string.

   ────────────────────────────────────────────────── ─── Continuation of front page    (72) Inventor Koichi Sodeyama             1-22-23 New Works, Takatsu-ku, Kawasaki City, Kanagawa Prefecture               Elex Industrial Co., Ltd. (72) Inventor Shigeyoshi Naito             1-22-23 New Works, Takatsu-ku, Kawasaki City, Kanagawa Prefecture               Elex Industrial Co., Ltd. (72) Inventor Naoto Yamada             1-22-23 New Works, Takatsu-ku, Kawasaki City, Kanagawa Prefecture               Elex Industrial Co., Ltd. F term (reference) 5J064 AA02 AA05 BA05 BB01 BB10                       BC26 BD02                 5K028 AA11 EE08 FF04 KK16 MM01                       MM12                 5K034 AA02 CC05 HH01 HH02 HH07

Claims (1)

Claims: 1. A stream of 4 bits / word (FIG. 1)
Above, ITU-TG. When transmitting the ADPCM audio data specified in H.726, it is possible to dynamically switch between the 4-bit encoding mode and the 3-bit encoding mode, so that a gap is generated in the ADPCM audio data stream (FIG. 2).
, And embeds a bit string of control information X in a specific format (FIG. 3), and performs verification on the receiving side to convert the control information bit string X0, X1,... Xk (FIG. 4) into a 4-bit coded ADPCM. ADPC with almost no deterioration in comparison
A control method that enables transmission in the same stream together with M audio data.