A Discretely Adaptive Delta Modulation Codec

Abstract
A discretely variable slope delta modulation (DVSD) codec is described, which is suitable for integrated circuit realization. The step size is varied by a pulse number modulation method that does not require a precision digital-to-analog conversion circuit. An adaptation algorithm is discussed, taking into consideration the effect of transmission errors. The quantizer and integrator portion has been fabricated on a monolithic chip using MOS technology. Results obtained from an experimental 32 kbit/s codec demonstrate its excellent performance.

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