Baud-rate-independent ASVD transmission built around G.729 speech- coding standard

摘要

A method and device for analog simultaneous voice and data transmission over an analog channel encodes at a voice signal sampling rate a sampled voice signal including spectral and pitch information. During encoding, the spectral and pitch information is extracted from the sampled voice signal to produce a residual signal, and the residual signal is converted into a sequence of residual vectors at a Baud rate. Then, a bitstream including non voice data and the extracted spectral and pitch information is produced. A modem unit, operating at Baud rate and producing an output carrier wave supplied to the analog channel, produces a sequence of symbol vectors in response to the sequence of residual vectors and the bitstream, and modulates the output carrier wave in response to the sequence of symbol vectors. A fractional sampling-rate conversion is conducted on the residual signal by shifting the voice signal sampling rate by a factor M/N, where M and N are the smallest integers that verify, or closely verify, the equality M/N=2R/F, where R is the Baud rate and F is the voice signal sampling rate. This fractional sampling-rate conversion further involves anti-aliasing filtering of the residual signal. In this manner, encoding operates at a voice signal sampling rate independent of the modem's Baud rate.