Claims
- 1. In a differential pulse code modulation encoder including means for converting an analog input signal into a digital output signal, a decoder for reconverting said output signal to a good prediction of said input signal, said decoder comprising
- (1) first means including an N stage delay line having output taps 1 through N for receiving said output signal,
- (2) N attenuators having attenuation coefficients a.sub.1 -a.sub.n connected to respective ones of said output taps,
- (3) second means for algebraically summing the outputs of said attenuators to form said good prediction, and
- (4) third means for feeding back said good prediction to said first means, wherein said attenuation coefficients satisfy the relationship ##EQU25##
- 2. The invention defined in claim 1 wherein said analog signal has a bandwidth f.sub.o and said converting means includes a quantizer adapted to sample said analog signal at a rate at least five times greater than f.sub.o.
- 3. A predictive encoder for converting an analog input signal to a digital output signal representative thereof, said encoder including
- (1) a forward loop comprising a quantizer for digitizing an error signal applied thereto, and
- (2) a feedback loop comprising
- (a) a delay line having an input and n serially connected stages each having an output tap, `(b) means for applying said digital output signal to said delay line input,
- (c) n attenuators having attenuation coefficients a.sub.1 through a.sub.n connected to respective ones of said output taps,
- (d) means for algebraically summing the outputs of said attenuators to form a feedback signal,
- (e) means for adding said feedback signal to said digital output signal applied to said delay lines, and
- (f) means for subtracting said feedback signal from said analog input signal to form said error signal
- wherein said attenuation coefficients are selected in accordance with the relationship ##EQU26##
- 4. The invention defined in claim 3 wherein said applying means includes a digital to analog converter.
- 5. The invention defined in claim 3 wherein said analog signal has a bandwidth f.sub.o and said quantizer is arranged to sample said error signal at a rate of at least 5 f.sub.o.
Parent Case Info
This is a division, of application Ser. No. 608,524, filed Aug. 28, 1975 now U.S. Pat. No. 4,017,849.
US Referenced Citations (2)
Number |
Name |
Date |
Kind |
3822404 |
Croisier |
Jul 1974 |
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3912917 |
Nussbaumer |
Oct 1975 |
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Divisions (1)
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Number |
Date |
Country |
Parent |
608524 |
Aug 1975 |
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