Dynamic ratio quantiser

An instantaneously adaptive nonlinear ratio quantiser, called a dynamic ratio quantiser (d.r.q.) is described. It enables a wide range of input signals to be quantised with a nearly constant signal/noise ratio (s.n.r.). The d.r.q. consists of an instantaneously adaptive nonlinear element EL, whose output samples are a function of the ratio of the input and the feedback samples. Theoretically, EL will transform input samples of any amplitude to samples within the range of a fixed uniform quantiser. The feedback samples are produced from the quantised output samples with the aid of an inverse EL and a transversal filter. The theory of the d.r.q. is presented, and its s.n.r. performance for different adaptation algorithms is given.