Electrical audio signal processing systems and devices – Binaural and stereophonic – Hearing aid
Patent
1987-10-05
1989-07-25
Salce, Patrick R.
Electrical audio signal processing systems and devices
Binaural and stereophonic
Hearing aid
381 51, 3645135, G10L 500
Patent
active
048521795
ABSTRACT:
A method of operating a vocoder so that a variable frame rate results while maintaining a constant bit rate is disclosed. A base frame rate remains constant. However, spectral change is measured to determine an appropriate subframe rate within the base frame. Only one of a plurality of separate vector quantization processes is selected in response to spectral change for performance of a vector quantization operation on LPC spectrum coefficients. Each of the plurality of vector quantization operations utilizes its own codebook that contains a different quantity of reference patterns from that contained in the other codebooks. Each vector quantization operation produces a reference pattern descriptor code that contains a different number of bits from that produced by the other vector quantization processes. Vector quantization operations producing smaller, less spectrally accurate outputs are selected when more subframes are included with a base frame, and vector quantization operations producing larger, more spectrally accurate outputs are selected when fewer subframes are included within a base frame.
REFERENCES:
patent: 4701955 (1987-10-01), Taguchi
"The Application of a Functional Perceptual Model of Speech to Variable-Rate LPC System", Viswanathan et al., IEEE, A.S.S.P. Conference, 1977, pp. 219-222.
"Vector Quantization in Speech Coding", Makhoul et al., Proceedings of the IEEE, vol. 73, No. 11, Nov. 1985, pp. 1551-1588.
"Vector Quantization: A Pattern-Matching Technique for Speech Coding", Gevsho et al., Proceedings of the IEEE, Dec. 1983, pp. 87-105.
Bogacz Frank J.
Motorola Inc.
Salce Patrick R.
Todd Voeltz Emanuel
LandOfFree
Variable frame rate, fixed bit rate vocoding method does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Variable frame rate, fixed bit rate vocoding method, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Variable frame rate, fixed bit rate vocoding method will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2364775