Method for protecting multi-pulse coders from fading and random pattern bit errors
First Claim
Patent Images
1. A method for protecting multi-pulse linear predictive speech coders from fading and random pattern bit errors comprising the steps of:
- selecting perceptually significant bits of multi-pulse coded speech parameters to be protected, the parameters being a set of line spectrum pair frequency coefficient bits, pitch lag bits, voiced/unvoiced bits, pitch tap gain bits, pulse amplitude bits, and pulse position bits;
generating checksums of said selected bits;
combining said checksums and said selected bits;
coding the selected bits and said checksums according to a convolutional code to protect transmitted data from random errors;
combining the convolutionally coded selected bits, checksums, and nonselected bits of the multi-pulse encoded speech; and
transmitting the combined convolutionally coded selected bits, checksums, and nonselected bits.
3 Assignments
0 Petitions
Accused Products
Abstract
A low-overhead method of protecting multi-pulse speech coders from the effects of severe random or fading pattern bit errors combines a standard error correcting code (convolutional rate 1/2 coding and Viterbi trellis decoding) for protection in random errors with cyclic redundancy code (CRC) error detection for fading errors. Compensation for detected fading errors takes place within the speech coder. Protection is applied only to the perceptually significant bits in the transmitted frame.
-
Citations
11 Claims
-
1. A method for protecting multi-pulse linear predictive speech coders from fading and random pattern bit errors comprising the steps of:
-
selecting perceptually significant bits of multi-pulse coded speech parameters to be protected, the parameters being a set of line spectrum pair frequency coefficient bits, pitch lag bits, voiced/unvoiced bits, pitch tap gain bits, pulse amplitude bits, and pulse position bits; generating checksums of said selected bits; combining said checksums and said selected bits; coding the selected bits and said checksums according to a convolutional code to protect transmitted data from random errors; combining the convolutionally coded selected bits, checksums, and nonselected bits of the multi-pulse encoded speech; and transmitting the combined convolutionally coded selected bits, checksums, and nonselected bits. - View Dependent Claims (2, 3, 4, 5, 6)
-
-
7. A multi-pulse speech coder/decoder system which minimizes the effects of fading and random pattern bit errors, said system comprising transmitter means including:
-
frame sorter means for selecting perceptually significant bits of multi-pulse encoded speech to be protected; a convolutional encoder coupled to said frame sorter means for coding the selected bits to protect transmitted data from random errors; and a multiplexer coupled to said frame sorter and said convolutional encoder for combining the convolutionally coded selected bits and nonselected bits of the multi-pulse encoded speech for transmission to receiver means. - View Dependent Claims (8, 9, 10, 11)
-
Specification