Electrical audio signal processing systems and devices – One-way audio signal program distribution – Public address system
Patent
1989-11-14
1992-01-21
Shaw, Dale M.
Electrical audio signal processing systems and devices
One-way audio signal program distribution
Public address system
375 27, G10L 300
Patent
active
050833103
ABSTRACT:
A compression and expansion apparatus and method for compressing and expanding digital audio signals using adaptive differential pulse-coding-modulation for high fidelity music is described. The apparatus comprises a predictor, a first and second adder, a first and second adjuster, a quantizer, an inverse quantizer and a step-size adaptor. An input digital signal and predicted signal are added by the first adder, producing the difference between the two signals. The output of the first adder is coupled to the first adjuster which acts as a multiplier to alter the gain and normalize the signal. The signal is then quantized by the quantizer. The output of the quantizer is sent to both the inverse quantizer and the adaptor. The adaptor acts like an automatic-gain-control to control the gain provided by the first adjuster. After inverse quantization by the inverse quantizer, the signal is sent to the second adjuster to remove the effects of the first adjuster process, i.e. denormalize and remove gain. Then the signal is sent to the second adder to add back in the predicted signal removed by the first adder. Next the signal is outputted and sent to the predictor. The predictor uses the output signal to prepare another predicted signal for a subsequently inputted digital signal. Wherein, an inputted digital audio signal and a corresponding outputted digital audio signal are substantially similar.
REFERENCES:
patent: 1930962 (1978-06-01), Ishiguro et al.
patent: 4319082 (1982-03-01), Gilloire et al.
patent: 4354273 (1982-10-01), Areseki et al.
patent: 4375013 (1983-02-01), Cointot et al.
patent: 4592070 (1986-05-01), Chow et al.
patent: 4751736 (1988-06-01), Gupta et al.
J. R. Boddie, J. D. Johnston, C. A. McGonegal, J. W. Upton, D. A. Berkley, R. E. Crochiere, and J. L. Flanagan. "Adaptive Differential Pulse-Code-Modulation Coding", The Bell System Technical Journal, vol. 60, No. 7, Sep. 1981, pp. 1546-1561.
B. Widrow, S. D. Stearns. Adaptive Signal Processing, Englewood Cliffs, N. J.: Prentice-Hall Inc., 1985, Particularly pp. 115-220 and 303-312.
N. S. Jayant, P. Noll. Digital Coding of Waveforms, Bell Telephone Laboratories, Inc. 1984, particularly pp. 99-116 and 141-145.
S. Haykin. Adaptive Filter Theory, Englewood Cliffs, N. J.: Prentice-Hall, Inc., 1986, particularly pp. 216-220.
Apple Computer Inc.
Doerrler Michelle
Shaw Dale M.
LandOfFree
Compression and expansion technique for digital audio data does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Compression and expansion technique for digital audio data, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Compression and expansion technique for digital audio data will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-120689