Digital Coding of Speech Waveforms Using the Proposed ADM

This paper presents an Adaptive Delta Modulation (ADM) with one-bit quantization in which the speech is first pre-processed. We define such a system as the `proposed ADM¿. For example large variations in the input signal require larger step sizes. If step size is not increased, it leads to slope overload error. The large variations in the input signal are removed/smoothened by a suitable pre-processing method, one of which is using an integrator which can smoothen the rapid changes. The SONG and modified ABATE algorithm is used for the adaptation of step size. With signal-to-quantization error ratio (SNR) as a performance measure, the proposed ADM with preprocessed signals shows a better improvement in its performance as compared to the conventional ADM. The proposed ADM also leads to a high dynamic range performance and shows a reduction in the noise power as compared to the conventional ADM.