Adaptive Delta Modulation

Abstract

In this paper, design principles of a delta modulator are discussed to arrive at the design parameters. For a sampling rate of 25 K/bits and reference frequency of speech at 1·12 KHz, the maximum signal to quantization noise ratio is found to be around 24 db. The concept of reference frequency of speech spectrum is explained while deriving the design parameters. The parameter S/K, which is the ratio of signal amplitude to quantizing step, is then, used for discussing the principles of companding, keeping the signal to quantizing noise power ratio constant. Syllabic compandor and instantaneous compander are then discussed. Performance characteristics of a companded system is also given.