Electrical audio signal processing systems and devices – One-way audio signal program distribution – Public address system
Patent
1989-12-22
1992-03-17
Kemeny, Emanuel S.
Electrical audio signal processing systems and devices
One-way audio signal program distribution
Public address system
381 46, 381 47, 371 31, 371 377, G10L 500
Patent
active
050975072
ABSTRACT:
Protection of a digital multi-pulse speech coder from fading pattern bit errors common in a digital mobile radio channel is accomplished with error detection techniques which are simple to implement and require no error correcting codes. A synthetic regeneration algorithm is employed which uses only the perceptually significant bits in the transmitted frame. Separate parity checksums for line spectrum pair frequency data, pitch lag data and pulse amplitude data are added to each frame of speech coder bits in the transmitter. The bits are then transmitted through a mobile environment susceptible to fading that induces bursty error patterns in the stream. At the receiving station, the parity checksum bits and speech coder bits are used to determine if an error has occurred in a particular section of the bit stream. Detected errors are flagged and supplied to the speech decoder. The speech decoder uses the error flags to modify its output signal so as to minimize perceptual artifacts in the output speech. Separate checksums are developed for subsets of line spectrum pair (LSP) coefficients and related speech data, whereby a single subset may be error-detected and replaced, rather than an entire frame.
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Koch Steven R.
Toy Raymond L.
Zinser Richard L.
Davis Jr. James C.
General Electric Company
Kemeny Emanuel S.
Snyder Marvin
Zale Lawrence P.
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