Coded data generation or conversion – Analog to or from digital conversion – Differential encoder and/or decoder
Patent
1988-04-08
1990-07-10
Shoop, Jr., William M.
Coded data generation or conversion
Analog to or from digital conversion
Differential encoder and/or decoder
341144, 341155, 341139, 375 30, 375 33, H03M 302
Patent
active
049409778
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-linearly processed to provide the control signal.
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Dolby Laboratories Licensing Corporation
Gallagher Thomas A.
Shoop Jr. William M.
Williams H. L.
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