Voice coder/decoder and methods of coding/decoding

Electrical audio signal processing systems and devices – One-way audio signal program distribution – Public address system

Patent

Rate now

  [ 0.00 ] – not rated yet Voters 0   Comments 0

Details

381 34, 381 36, 381 51, G10L 500, G10L 302, G10L 502

Patent

active

051897016

ABSTRACT:
The pitch frequency of voice signals in successive time frames at a voice coder may be determined as by (1) Cepstrum analysis (time between successive peak amplitudes in each time frame), (2) harmonic gap analysis (amplitude differences between peaks and troughs of the peak amplitude signals in the frequency spectrum) (3) harmonic matching, (4) filtering of the frequency signals in successive pairs of time frames and the performance of (1)-(3) on the filtered signals to provide pitch interpolation on the first frame in the pair and (5) pitch matching. The amplitude and phase of the pitch frequency and harmonic signals are determined by refined techniques to provide amplitude and phase signals with enhanced resolution. Such amplitudes are simplified digitally by (a) taking the logarithm of the frequency signals, (b) selecting the signal with the peak amplitude, (c) offsetting the amplitudes of the logarithmic signals relative to such peak amplitude, (d) companding the offset signals, (e) reducing the number of harmonics to a particular limit by eliminating selective harmonics, (f) taking a discrete cosine transform of the remaining signals and (g) digitizing the transformed signals. If the pitch frequency has a continuity within particular limits in successive time frames, the phase difference of the signals between successive time frames is provided. At a displaced voice decoder, the signal amplitudes are determined by performing, in order, the inverse of steps (g) through (a). These signals and the signals representing pitch frequency and phase are processed to recover the voice signals.

REFERENCES:
patent: 3566035 (1971-02-01), Noll et al.
patent: 4076960 (1978-02-01), Buss et al.
patent: 4667340 (1987-05-01), Arjmand et al.
patent: 4771465 (1988-09-01), Bronson et al.
patent: 4827516 (1989-05-01), Tsukahara et al.
patent: 4827517 (1989-05-01), Atal et al.
patent: 4885790 (1989-12-01), McAulay et al.
patent: 4945565 (1990-07-01), Ozawa et al.
patent: 5018200 (1991-05-01), Ozawa
patent: 5054072 (1991-10-01), McAulay et al.

LandOfFree

Say what you really think

Search LandOfFree.com for the USA inventors and patents. Rate them and share your experience with other people.

Rating

Voice coder/decoder and methods of coding/decoding does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Voice coder/decoder and methods of coding/decoding, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Voice coder/decoder and methods of coding/decoding will most certainly appreciate the feedback.

Rate now

     

Profile ID: LFUS-PAI-O-2211715

  Search
All data on this website is collected from public sources. Our data reflects the most accurate information available at the time of publication.