Mixed excitation linear prediction with fractional pitch

Claim 3

The method of claim 1, wherein: (a) said determining a pitch period of step (c) uses interpolation of pitch period estimates and correlation estimates based on integral multiples of said sampling period.

Claim 4

The method of claim 1, wherein: (a) said determining a pitch period of step (c) includes a first pitch period estimate using fixed length correlations followed by a second pitch period estimate using interpolation of correlations with lengths varied about said first pitch period estimate.

Claim 5

The method of claim 1, further comprising the step of: (a) determining a pitch period code as a logarithmic function of said pitch period of step (c) of claim 1.

Claim 6

A synthesizer for encoded sounds, comprising: (a) a pulse train generator with output at a first sampling rate; (b) a noise generator with output at said first sampling rate; (c) a mixer with inputs coupled to said pulse train generator and said noise generator; (d) a linear predictive filter with input coupled to an output of said mixer; and (e) wherein said pulse train generator outputs signals corresponding to a sampling rate compression of single pulses at a second sampling rate for said second sampling rate being a multiple of said first sampling rate.

Claim 7

A synthesizer for encoded sounds, comprising: (a) a pulse train generator with output at a first sampling rate; (b) a noise generator with output at said first sampling rate; (c) a mixer with inputs coupled to said pulse train generator and said noise generator; (d) a linear predictive filter with input coupled to an output of said mixer; and (e) wherein said pulse train generator outputs signals corresponding to a sampling rate compression of single pulses at a second sampling rate for said second sampling rate being a multiple of said first sampling rate.

Claim 8

The synthesizer of claim 5, wherein: (a) said pulse train generator includes a gain amplifier; and (b) said noise generator includes a gain amplifier.

Claim 9

The synthesizer of claim 5, wherein: (a) said mixer includes a first multiband filter coupled to said pulse train generator, a second multiband filter coupled to said noise generator, and an adder with inputs coupled to the outputs of said first and second multiband filters.

Claim 10

A speech system, comprising: (a) a receiver for frames of input speech with a first sampling rate; (b) an analyzer coupled to said receiver, said analyzer including: (i) a linear predictive coefficients extractor; (ii) a pitch period extractor, said pitch period extractor with resolution greater than a single period of said first sampling rate; and (iii) a correlation extractor for each of N frequency bands with N an integer greater than 1; (c) a memory coupled to said analyzer and storing outputs of said extractors; (d) a synthesizer couple to said memory, said synthesizer including: (i) a pulse train generator with output at said first sampling rate and with periodicity read from said memory; (ii) a noise generator with output at said first sampling rate; (iii) a mixer with inputs coupled to said pulse train generator and said noise generator and with the mixture of pulse train generator output and noise output read from said memory; and (iv) a linear predictive filter with input coupled to an output of said mixer and with coefficients read from said memory.

Claim 11

A speech system, comprising: (a) a receiver for frames of input speech with a first sampling rate; (b) an analyzer coupled to said receiver, said analyzer including: (i) a linear predictive coefficients extractor; (ii) a pitch period extractor, said pitch period extractor with resolution greater than a single period of said first sampling rate; and (iii) a correlation extractor for each of N frequency bands with N an integer greater than 1; (c) a memory coupled to said analyzer and storing outputs of said extractors; (d) a synthesizer couple to said memory, said synthesizer including: (i) a pulse train generator with output at said first sampling rate and with periodicity read from said memory; (ii) a noise generator with output at said first sampling rate; (iii) a mixer with inputs coupled to said pulse train generator and said noise generator and with the mixture of pulse train generator output and noise output read from said memory; and (iv) a linear predictive filter with input coupled to an output of said mixer and with coefficients read from said memory.