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Publication of MY107870ApublicationCriticalpatent/MY107870A/en
Compression, Expansion, Code Conversion, And Decoders
(AREA)
Abstract
AN ADAPTIVE SINGLE-BIT ENCODER AND DECODER HAS ITS ADAPTIVE FUNCTION DETERMINED BY DYNAMICALLY DIVIDING THE MESSAGE FREQUENCY BAND INTO DELTA-SIGMA AND DELTA MODULATION REGIMES OF OPERATION. IN A PRACTICAL EMBODIMENT THIS IS ACCOMPLISHED BY VARYING THE CORNER FREQUENCY OF A VARIABLE-FREQUENCY LOW-PASS FILTER IN A LEAKY INTEGRATOR SO THAT BELOW THE CORNER FREQUENCY THE OPERATION IS THAT OF DELTA-SIGMA MODULATION AND ABOVE THE CORNER FREQUENCY THE OPERATION IS THAT OF DELTA MODULATION. AN ADAPTATION CONTROL CIRCUIT REMOVES THE CLOCK SIGNAL COMPONENT FROM THE ENCODED BIT STREAM TO PROVIDE AN ANALOG SIGNAL REPRESENTATIVE OF BIT STREAM INFORMATION OR LOADING FOR USE IN GENERATING THE CONTROL SIGNAL. THE ANALOG SIGNAL IS PEAK RECTIFIED, SMOOTHED, AND (OPTIONALLY) NON- LINEALY PROCESSED TO PROVIDE THE CONTROL SIGNAL.(FIG. 1)
MYPI91000387A1989-09-251988-09-08Adaptive-filter single-bit digital encoder and decoder and adaptation control circuit responsive to bit-stream loading.
MY107870A
(en)