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1. (WO2001006492) METHOD AND APPARATUS FOR SUBSAMPLING PHASE SPECTRUM INFORMATION

Pub. No.:    WO/2001/006492    International Application No.:    PCT/US2000/019601
Publication Date: Fri Jan 26 00:59:59 CET 2001 International Filing Date: Wed Jul 19 01:59:59 CEST 2000
IPC: G10L 19/02
Applicants: QUALCOMM INCORPORATED
Inventors: MANJUNATH, Sharath
Title: METHOD AND APPARATUS FOR SUBSAMPLING PHASE SPECTRUM INFORMATION
Abstract:
A method and apparatus for subsampling phase spectrum information includes a speech coder for analyzing and reconstructing a prototype of a frame by using intelligent subsampling of phase spectrum information of the prototype. To analyze the prototype, the speech coder produces phase parameters of a reference prototype, generates phase parameters of a current prototype, and correlates the phase parameters of the current prototype with the phase parameters of the reference prototype in multiple frequency bands. To reconstruct the prototype using linear phase shift values, the speech coder produces phase parameters of the reference prototype, generates a set of linear phase shift values associated with the prototype, and composes a phase vector from the phase parameters and the linear phase shift values across multiple frequency bands. To reconstruct the prototype using circular rotation values, the speech coder produces a set of circular rotation values associated with the prototype, generates a set of bandpass waveforms in multiple frequency bands, the bandpass waveforms being associated with the phase parameters of the reference prototype, and modifies the bandpass waveforms based upon the circular rotation values.