An adaptive‐transform baseband coder

In a baseband coder, the baseband may be coded in a number of different ways. In this paper, we describe coding of the baseband LPC residual using adaptive transform coding (ATC). At the receiver, high‐frequency regeneration is accomplished by our recently developed method of spectral duplication. Care is taken to ensure that the harmonic structure is not interrupted as a result of the spectral duplication process. The results will be compared to time‐domain coding of the baseband residual.