Speech signal quantization using human auditory models in predictive coding systems
OwnerJuin-Hwey Cheninventor
Life of this patent
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Abstract
A speech compression system called "Transform Predictive Coding", or TPC, provides for encoding 7 kHz wideband speech (160 kHz sampling) at a target bit-rate range of 16 to 32 kb/s (1 to 2 bits/sample). The system uses short-term and long-term prediction to remove the redundancy in speech. A prediction residual is transformed and coded in the frequency domain to take advantage of knowledge in human auditory perception. The TPC coder uses only open-loop quantization and therefore has a fairly low complexity. The speech quality of TPC is essentially transparent at 32 kb/s, very good at 24 kb/s, and acceptable at 16 kb/s.
Claims10
A method of coding a signal representing speech information, the method comprising:
- generating a first signal representing an estimate of the signal representing speech information;
- comparing the signal representing speech information with the first signal to form a second signal representing a difference between said compared signals;
- determining a quantizer resolution in accordance with a perceptual noise masking signal which is determined by a model of human audio perception;
- quantizing the second signal in accordance with the determined quantizer resolution;
- and
- generating a coded signal based on said quantized signal.
A system for coding a signal representing speech information, the system comprising:
- a first signal generator adapted to generate a first signal representing an estimate of the signal representing speech information;
- a signal comparator adapted to compare the signal representing speech information with the first signal to form a second signal representing a difference between said compared signals;
- a quantization resolution determination module adapted to determine a quantizer resolution in accordance with a perceptual noise masking signal which is determined by a model of human audio perception;
- a quantizer adapted to quantize the second signal in accordance with the determined quantizer resolution;
- and
- a second signal generator adapted to generate a coded signal based on said quantized signal.
Dependencies are inferred from the claim text.