US 5,706,392 A · Perceptual speech coder and method

Abstract

Simultaneous and temporal masking of digital speech data is applied to an MBE-based speech coding technique to achieve additional, substantial compression of coded speech over existing coding techniques, while enabling synthesis of coded speech with minimal perceptual degradation relative to the human auditory system. A real-time perceptual coder and decoder is disclosed in which speech may be sampled at 10 kHz, coded at an average rate of less than 2 bits/sample, and reproduced in a manner that is perceptually transparent to a human listener. The coder compresses speech segments that are inaudible due to simultaneous or temporal masking, while audible speech segments are not compressed.

Claims5

Dependent claims

A method for coding an analog speech signal, said method comprising the steps of:

filtering, sampling, and digitizing said analog speech signal to produce a digital speech signal, said digital speech signal comprising a plurality of frames;
performing frequency analysis on said digital speech signal to produce spectral output data for each of said frames, said spectral output data comprising segments, at least two of said segments being approximately 25 Hz or closer in frequency;
performing auditory analysis on said spectral output data to identify segments of said frames that are inaudible to the human auditory system due to simultaneous or temporal masking effects;
and
coding said spectral output data into an output data stream in which said inaudible segments are compressed and audible segments are not compressed.

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Dependencies are inferred from the claim text.

Perceptual speech coder and method

Life of this patent

Perceptual speech coder and method

Life of this patent

Abstract

Claims5