A modified adaptive transform coding scheme with post-processing-enhancement

The purpose of this paper is to describe a scheme for low-bit-rate transmission of speech. The scheme consists of a cascade of a codec with a post-processor. The codec is based on a modified version of the LPC Vocoder Driven Adaptive Transform Coding algorithm. The Post-Processor performs a short-time Fourier analysis/synthesis at the receiver output and, by exploring the known structure of the quantization noise introduced by the codec, it is capable of speech enhancement. The performance of this scheme will be demonstrated at 9.6 kb/s and at 7.2 kb/s.