A low complexity regular pulse coding scheme with a reduced transmission delay

An attractive algorithm for the encoding of toll-quality speech below 16 kb/s is based on the so-called regular.pulse encoding (RPE) modeling scheme [1]. Basically. the RPE speech coder models the speech signal as the output of a linear predictive spectral envelope filter whose input is a short-time base-band approximation of the prediction residual. Although the complexity of the conceptual RPE algorithm is only moderate, we will demonsrate in this paper that under certain simplifying, albeit realistic, assumptions it turns out to be possible to come up with a scheme that combines the computational simplicity of a well designed base-band coder [2], with the subjective optimality of the uncompromisod RPE concept. Moreover, we shall also show that it is possible to overcome the problem of large encoding delay, wMch is of major concern in certain real-time applications.