Signal codec device and method in communication system
View Patent ↗The present invention relates to a codec device and method for encoding/decoding voice and audio signals in a communication system, wherein: a fixed codebook excited signal is generated by using a pulse index for a voice signal; a first adaptive codebook excited signal is generated by using a pitch index for the voice signal; a fixed codebook signal is generated by multiplying the fixed codebook excited signal by a fixed codebook gain; a first adaptive codebook signal is generated by multiplying the first adaptive codebook excited signal by a first adaptive codebook gain; and a synthesized filter excited signal is generated by adding the fixed codebook signal and the first adaptive codebook signal.
1. A method of a codec apparatus for coding/decoding a signal in a communication system, the method comprising:
generating, with a generator, a fixed codebook excited signal by using a pulse index for a speech signal;
generating a first adaptive codebook excited signal by using a pitch index for the speech signal;
generating a fixed codebook signal by multiplying the fixed codebook excited signal by a fixed codebook gain;
generating a first adaptive codebook signal by multiplying the first adaptive codebook excited signal by a first adaptive codebook gain;
generating a synthesis filter excited signal by summing up the fixed codebook signal and the first adaptive codebook signal:
generating a second adaptive codebook excited signal by filtering the first adaptive codebook excited signal through a Low-Pass Filter (LPF); and
generating a second adaptive codebook signal by multiplying the second adaptive codebook excited signal by a second adaptive codebook gain corresponding to a filtering of the LPF,
wherein the second adaptive codebook gain is calculated using the second adaptive codebook excited signal.
2. The method of claim 1 , further comprising selecting one of the first adaptive codebook signal and the second adaptive codebook signal as a final adaptive codebook signal based on a speech factor of the speech signal.
3. The method of claim 2 , wherein the generating of a synthesis filter excited signal comprises generating the synthesis filter excited signal by summing up the fixed codebook signal and the final adaptive codebook signal.
4. The method of claim 2 , wherein the speech factor is a value indicating a probability that the speech signal will be a speech signal having a speech sound.
5. The method of claim 4 , wherein the selecting of one of the first adaptive codebook signal and the second adaptive codebook signal as a final adaptive codebook signal comprises selecting the first adaptive codebook signal as the final adaptive codebook signal if the speech signal is a speech signal having a speech sound.
6. The method of claim 4 , wherein the selecting of one of the first adaptive codebook signal and the second adaptive codebook signal as a final adaptive codebook signal comprises selecting the second adaptive codebook signal as the final adaptive codebook signal if the speech signal is a speech signal having a speechless sound.