It works as follows: 8KHZ sampling is performed first then divided into frames of 20 ms each frame has 4 sub-frames, the duration of each sub-frame is 5ms, and the pure bitrate 13kbit / s
The voice compression coding technique is widely used in modern digital communications systems. In this technique, a speech coder is used to simulate human vocal organs generated by a model of the speech and noise. The form of the model parameters are transmitted by the TCH channels.
The voice coder is based on the residual excited linear prediction (REIP) coder. In addition, the long term predictor (LTP) is used to enhance the compression. LTP, the coding of the remaining data advantageous by. Vowels from the voice With 20ms as a unit of the speech coder are compressed by coding 260bits. Therefore, the code rate is 13kbps. 50 very important bits, 132 bits and 78 bits ordinary important: According to the different classes of the importance of information, the output bits can be divided into three categories.
In comparison with the conventional PCM line on which the encoded and transmitted voice directly (64 Kbps) 13kbps, the speech rate of the GSM system is considerably reduced. Can further reduce the more advanced voice coders in the future the rate to 6.5kbps (half-rate speech coding).
The voice compression coding technique is widely used in modern digital communications systems. In this technique, a speech coder is used to simulate human vocal organs generated by a model of the speech and noise. The form of the model parameters are transmitted by the TCH channels.
The voice coder is based on the residual excited linear prediction (REIP) coder. In addition, the long term predictor (LTP) is used to enhance the compression. LTP, the coding of the remaining data advantageous by. Vowels from the voice With 20ms as a unit of the speech coder are compressed by coding 260bits. Therefore, the code rate is 13kbps. 50 very important bits, 132 bits and 78 bits ordinary important: According to the different classes of the importance of information, the output bits can be divided into three categories.
In comparison with the conventional PCM line on which the encoded and transmitted voice directly (64 Kbps) 13kbps, the speech rate of the GSM system is considerably reduced. Can further reduce the more advanced voice coders in the future the rate to 6.5kbps (half-rate speech coding).
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