JPH07143076A - Coding device, decoding device and coding/decoding device - Google Patents

Abstract

PURPOSE:To perform coding and decording of a modem signal with higher quality without impairing the quality of a sound signal and to enable the transmission of the modem signal with a higher bit rate. CONSTITUTION:In a coding part, a code book 4 for sound signal is preliminarily prepared by a sound signal in the code book that a coder 3 uses for a coding. A code book 5 for modem signal is preliminarily prepared by a modem signal. A modem signal detector 2 detects the modem signal from an input sound signal. A selector 6 switches the code book inputted in the coding device 3 by the output of a modem signal detector 2. A multiplex device 13 multiplexes the mode of coding data. In a decoding part, a code book 9 for sound signal which is used for a decoding by a decoder 8 and is the same as the code book 4 for coding and a code book 10 for modem signal are provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a speech signal coding apparatus, decoding apparatus and coding / decoding apparatus using the CELP system, and more particularly to optimum coding, decoding and coding / decoding of a speech signal and a modem signal. Regarding conversion.

[0002]

2. Description of the Related Art A conventional speech coding / decoding apparatus has (1)
Use the same encoding and decoding method as the audio signal,
(2) It has a plurality of encoders and decoders with different internal parameters, and is used in combination with the encoder and decoder with the best quality compared to the input signal.

[0003]

In this conventional coding / decoding device, it is difficult to reduce the bit rate in order to secure the signal quality together with the voice signal and the modem signal. Moreover, since a plurality of decoders and decoders are configured, the processing becomes complicated.

[0004]

An encoding apparatus according to the present invention comprises an encoder for encoding an input voice signal and a codebook used by the encoder for encoding, which is prepared in advance from the voice signal. A voice signal codebook, a modem signal codebook created in advance by a modem signal, a modem signal detector for detecting a modem signal from an input voice signal, and an output of the modem signal detector to the encoder. It is characterized by having a selector for switching the input codebook and a multiplexer for multiplexing modes of encoded data.

A decoding device according to the present invention comprises a decoder for decoding received coded data into a voice signal, a codebook for voice signals used by the decoder for decoding,
A codebook for modem signals, and a frame mode detector that detects a frame mode from received encoded data,
A selector for switching the codebook input to the decoder according to the output of the frame mode detector.

A coding / decoding apparatus according to the present invention is a coding device for coding an input speech signal, and a speech signal prepared in advance by a speech signal by a codebook used by the coding device for coding. A codebook, a codebook for modem signals created in advance by modem signals, a modem signal detector for detecting a modem signal from an input voice signal, and an input to the encoder by an output of the modem signal detector An encoder having a selector for switching codebooks, a multiplexer for multiplexing modes of encoded data, a decoder for decoding received encoded data into a voice signal, and the decoder for decoding An audio signal codebook that is the same as the encoding codebook used for encoding;
A codebook for modem signals, and a frame mode detector that detects a frame mode from received encoded data,
And a selector having a selector for switching the codebook input to the decoder according to the output of the frame mode detector.

[0007]

Embodiments of the present invention will now be described with reference to the drawings.

Referring to FIG. 1, in one embodiment of the present invention, a voice signal input to an input terminal 1 is input to an encoder 3 and a modem signal detector 2. The modem signal detector 2 detects whether the input signal is a modem signal or a non-modem signal, and the detected output is input to the selector 6 and the encoder 3 for switching the coding codebook.

When the input signal is a voice signal, the modem signal detector 2 outputs a non-modem signal detection state and the selector 6
Selects the audio signal codebook 4 side as the codebook to be input to the encoder 3. As a result, the encoder 3 performs the optimum encoding for the audio signal by the audio signal codebook 4.

When the input signal is a modem signal, the modem signal detector 2 outputs a modem signal detection state, and the selector 6 is a codebook for the modem signal as a codebook to be input to the encoder 3. Select the 5 side. As a result, the encoder 3 performs the optimum encoding for the modem signal by the modem signal codebook 5 and outputs the digital data to the line as digital data. A bit for identifying whether the data is encoded data of a voice signal or encoded data of a modem signal is added to the encoded data output at this time by the multiplexer 13.

An example of this encoded data format is shown in FIG. One frame of this coded data format is 20 milliseconds, and a frame synchronization bit S (alternating pattern "0" and "1" in frame units) and a frame mode bit M ("0": A voice signal encoded data frame, "1": modem signal encoded data frame) is arranged. After this, the encoded data is arranged.

On the other hand, the encoded data is input to the decoder 8 and the frame mode detector 7. The frame mode detector 7 detects whether the coded data is coded data of a voice signal or coded data of a modem signal, and the detection result is sent to the selector 11 and the decoder 8 which switch the decoding codebook. Is entered.

When the input coded data is the coded data of the voice signal, the frame mode detector 7 outputs the voice signal detection state, and the selector 11 is used as a codebook to be input to the decoder 8 for the voice signal. Select the codebook 9 side. As a result, the decoder 8 uses the codebook 9 for audio signals to perform optimal decoding for decoding audio signals.

When the input coded data is the coded data of the modem signal, the frame mode detector 7 outputs the modem signal state, and the selector 11 is used as a codebook to be input to the decoder 8 for the modem signal. Codebook 10
Select the side. As a result, the decoder 8 performs the optimum decoding for decoding the modem signal by the codebook 10 for the modem signal and outputs it from the output terminal 12.

[0015]

As described above, in the coding apparatus according to the present invention, the input signal is discriminated, the voice signal codebook is used in the case of the voice signal, and the modem signal is used in the case of the modem signal. By using the codebook, encoding is performed using the optimum codebook. Further, in the decoding device according to the present invention, the received signal to which the identification information is added is discriminated, and when the input coded data is the voice signal coded data, the codebook for the voice signal is used and the modem signal is used. In the case of encoded data, the codebook for modem signals is used to perform decoding using the optimum codebook. As a result, it is possible to encode and decode the modem signal with higher quality without deteriorating the quality of the voice signal, and it is possible to transmit the modem signal with a higher bit rate.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention.

FIG. 2 is a diagram showing an encoded data format in the embodiment shown in FIG.

[Explanation of symbols]

 1 Input Terminal 2 Modem Signal Detector 3 Encoder 4 Voice Signal Codebook 5 Modem Signal Codebook 6 Selector 7 Frame Mode Detector 8 Voice Signal Codebook 9 Voice Signal Codebook 10 Modem Signal Codebook 11 Selector 12 Output terminal 13 Multiplexer

Claims (3)

[Claims] 1. A coder for coding an input voice signal, a codebook for a voice signal created in advance by a voice signal by a codebook used by the coder, and a modem signal in advance. A generated codebook for modem signals, a modem signal detector for detecting a modem signal from an input voice signal, a selector for switching the codebook input to the encoder by the output of the modem signal detector, And a multiplexer that multiplexes modes of encoded data. 2. A decoder for decoding the received encoded data into a voice signal, a voice signal codebook used by the decoder for decoding, a modem signal codebook, and a received encoding. A decoding device comprising: a frame mode detector that detects a frame mode from data; and a selector that switches the codebook that is input to the decoder by the output of the frame mode detector. 3. An encoder for encoding an input audio signal, an audio signal codebook created in advance from an audio signal by a codebook used by the encoder for encoding, and a modem signal in advance. A generated codebook for modem signals, a modem signal detector that detects a modem signal from an input voice signal, a selector that switches the codebook that is input to the encoder by the output of the modem signal detector, and a code An encoder having a multiplexer for multiplexing modes of encoded data, a decoder for decoding the received encoded data into a voice signal, and a decoder used by the decoder for decoding A voice signal codebook that is the same as the codebook, a modem signal codebook, and a frame mode detector that detects the frame mode from the received encoded data. , Coding and decoding device characterized by comprising a decoding device and a selector for switching the codebook to be input to the decoder by an output of the frame mode detector.