资 源 简 介
The HC-55564 is a half duplex modulator/demodulator CMOSintergrated circuit used to convert voice signals into serial NRZdigital data and to reconvert that data into voice. The conversionis by delta-modulaTIon, using the ConTInuously VariableSlope (CVSD) method of modulaTIon/demodulaTIon.While the signals are compatible with other CVSD circuits, the internaldesign is unique. The analog loop filters have been replaced byvery low power digital filters which require no external timing components.This approach allows inclusion of many desirable featureswhich would be difficult to implement using other approaches.The fundamental advantages of delta-modulation, along with itssimplicity and serial data format, provide an efficient (low datarate/low memory requirements) method for voice digitization.The HC-55564 is usable from 9kbits/s to above 64kbps. See theHarris Military databook for a MIL-STD-883C compliant CVSD.Application Note 607.
