A new structural preprocessor for low-bit rate speech coding

In this paper, we apply a new structural approach to generalized analysis-by-synthesis (GAbS) for system identification as a preprocessor of a low-bit-rate speech coder. In our approach, the coder-decoder (CODEC) system is separately estimated and then applied to modify the current input signal. This is different from that originally proposed where the CODEC system is sequentially estimated and then applied to the next input signal. The proposed estimation scheme is compared to the conventional method in terms of the signal modification approach under the various noise data and in several SNR conditions, and shows better performance.