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EP0422232A1 Expired / Lapsed EP ⏱️ 0.0 years remaining

Voice encoder

Assignee: Toshiba Corp
•
Filing: 1990-02-20
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Granted: —
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Expires: 2010-02-20
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Abstract

Abstract A voice signal is input to a drive signal generating unit, an estimating filter and an estimating parameter calculation circuit. The estimating parameter calculation circuit calculates a predetermined number of estimating parameters (α parameters or k parameters) by the self-correlation method or the covariance method,and supplies the calculated estimating parameters to an estimating parameter encoder circuit. The codes of the estimating parameters are supplied to a decoder circuit and a multiplexer. The decoder circuit inputs decoded values of the codes of estimating parameters to the estimating filter and the drive signal generating unit. The estimating filter calculates an estimated residue signal which is a difference between the input voice signal and the decoded estimating parameter, and sends it to the drive signal generating unit. The drive signal generating unit calculates a pulse spacing and an amplitude for each of a predetermined number of subframes based on the input voice signal, estimated residue signal, and quantized values of the estimating parameters, and encodes them, and supplies them to the multiplexer. The multiplexer combines these codes and the codes of the estimating parameters together and sends it to a transmission line as an output signal of the encoder.

Inventors

  • 👤 Masami Nakanocho Apartment 1-105 Akamine
  • 👤 Kimio Toshiba Yurigaoka Ryo No. 202 Miseki

Bibliographic Details

Application Number —
Jurisdiction EP
Data Source google_patents
Last Synchronized 2026-10-27 06:27
CPC Classifications
G; G10; G10L; G10L19/00; G10L19/04; G10L19/08; G10L19/10; G10L19/113

Claims Analysis

Total Claims: 6
Claim 1
Independent Claim 85 words
A speech coding apparatus for driving a synthesis filter by an excitation signal to acquire a synthesized signal, characterized in that a frame of said excitation signal is divided into a plurality of subframes with an equal length or different lengths, and a pulse interval of said excitation signal is determined such that a pulse sequence of one subframe has pulse intervals which are equal to one another and differ from the intervals of another subframe, in accordance with power of a prediction residual signal.
Claim 2
Dependent Claim 151 words
A speech coding apparatus comprising: means for dividing a frame of an excitation signal into a plurality of subframes with an equal length or different lengths and setting a pulse interval of said excitation signal such that a pulse sequence of one subframe has pulse intervals which are equal to one another and differ from the intervals of another subframe; storage means for storing information of an amplitude of a pulse sequence or information of an amplitude and phase of the excitation signal; means for generating the excitation signal based on information stored in said storage means; a synthesis filter excited by said excitation signal generated by said excitation signal generating means; and means for selecting information in said storage means in such a way as to minimize a power of a difference signal between a synthesized signal from said synthesis filter and an input signal, and coding said selected information.
Claim 3
Dependent Claim 165 words
A speech coding apparatus comprising: means for dividing a frame of an excitation signal into a plurality of subframes with an equal length or different lengths and setting a pulse interval of said excitation signal such that a pulse sequence of one subframe has pulse intervals which are equal to one another and differ from the intervals of another subframe; storage means for storing information of an amplitude of the pulse sequence or information of an amplitude and phase of the excitation signal; means for generating the excitation signal based on information stored in said storage means; a synthesis filter excited by said excitation signal generated by said excitation signal generating means; and means for selecting information in said storage means in such a way as to minimize a power of an audibility-weighted error signal acquired by permitting a difference signal between a synthesized signal from said synthesis filter and an input signal to pass through a perceptional weighting filter, and coding said selected information.
Claim 4
Dependent Claim 110 words
A speech coding apparatus comprising: means for generating an excitation signal comprised of a train of excitation pulses having a frame divided into plural subframes and having a variable pulse interval for each subframe; a synthesis filter excited by said excitation signal; means for determining an amplitude or an amplitude and a phase of said excitation pulse train in such a way as to minimize a power of an audibility-weighted error signal between an output signal from said synthesis filter and an input speech signal; and means for determining a density of said excitation pulse train based on a short-term prediction residual signal with respect to said input speech signal.
Claim 5
Dependent Claim 110 words
A speech coding apparatus comprising: means for generating an excitation signal comprised of a train of excitation pulses having a frame divided into plural subframes and having a variable pulse interval for each subframe; a synthesis filter excited by said excitation signal; means for determining an amplitude or an amplitude and a phase of said excitation pulse train in such a way as to minimize a power of an audibility-weighted error signal between an output signal from said synthesis filter and an input speech signal; and means for determining a density of said excitation pulse train based on a pitch prediction residual signal with respect to said input speech signal.
Claim 6
Dependent Claim 121 words
A speech coding apparatus comprising: means for generating an excitation signal comprised of a train of excitation pulses having a frame divided into plural subframes and having a variable pulse interval for each subframe; a synthesis filter excited by said excitation signal; means for determining an amplitude or an amplitude and a phase of said excitation pulse train in such a way as to minimize a power of an audibility-weighted error signal between an output signal from said synthesis filter and an input speech signal; and means for determining a density of said excitation pulse train based on a pitch prediction residual signal acquired by performing pitch prediction of a short-term prediction residual signal with respect to said input speech signal.

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