US 5,960,388 AGranted

Voiced/unvoiced decision based on frequency band ratio

AssigneeSony Corporation

InventorsMasayuki Nishiguchi, Jun Matsumoto, Shinobu Ono

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Abstract

Input audio signal is divided on a block-by-block basis. Frequency domain conversion is done on each of the blocks. Voiced bands of the frequency domain data for one of the blocks are searched for a voiced band B.sub.VH with the highest center frequency if it is decided that there are one or more shift points of voiced (V)/unvoiced (UV) decision data of all the bands. The number N.sub.V of voiced bands having center frequency less than that of the band B.sub.VH is found, so as to decide whether a proportion of the voiced bands is equal to or higher than a predetermined threshold N.sub.th, thereby deciding one V/UV boundary point. Thus, it is possible to replace the V/UV decision data for each band by information on one demarcation in all bands, thereby reducing data volume and bit rate.

Claims4

Dependent claims

A method for processing an audio signal, comprising the steps of:

generating frequency domain data by dividing an input audio signal on a block-by-block basis thereby determining blocks of data, and performing time domain to frequency domain conversion on each of the blocks thereby generating the frequency domain data;
dividing the frequency domain data for at least one of the blocks into plural bands;
deciding, for each of the bands for one of the blocks, whether said each of the bands is voiced or unvoiced;
if at least one of the bands for said one of the blocks is voiced, identifying as a highest frequency voiced band a voiced band whose center frequency is F, where F is the highest center frequency among said at least one of the bands for said one of the blocks which are voiced;
and
generating boundary point data indicative of a boundary point between a voiced sound region and an unvoiced sound region of said one of the blocks in accordance with the number B.sub.VH of bands of the frequency domain data for said one of the blocks which have center frequency less than the center frequency F.

3 more elements

Dependencies are inferred from the claim text.

Facts

Application: 08/871,335Filed 9 Jun 1997 · division
Priority: JP P4-9142218 Mar 1992
Granted: 28 Sep 1999
Term ends: Not estimatedThe source records don’t support an estimate.

Classification12 codes

G10L 25/90
Speech or voice analysis techniques not restricted to a single one of groups G10L15/00 - G10L21/00: pitch determination of speech signals
G10L 19/0212
Using spectral analysis, e.g. transform vocoders or subband vocoders: using orthogonal transformation
G10L 19/038
Quantisation or dequantisation of spectral components: vector quantisation, e.g. TwinVQ audio
G10L 19/12
Determination or coding of the excitation function; Determination or coding of the long-term prediction parameters: the excitation function being…