Signal quantizer with reduced output fluctuation

A method of quantizing a signal x comprising the steps of:

• determining quantization error for a current input;
• determining mismatch between amount of fluctuation of input vs. output;
• and
• generating a quantized output signal based on said quantization error and said mount of fluctuation of input vs. output.

In a speech encoding system comprising

• sampling of speech signal and A/D converting to digital signal;
• a coefficient analyzer responsive to said digital signal, said coefficient analyzer comprising:
• means for determining quantization error for a current input;
• means for determining mismatch between amount of fluctuation of input vs. output, and
• a quantizer which generates an output signal based on said quantization error for the current input and said mismatch between said amount of fluctuation of input vs. output.

An encoder system comprising:

• a simple encoder with reduced bit rate;
• a full encoder operating at normal bit rate with a quantizer with reduced output fluctuations;
• a speech/noise detector responsive to input speech for detecting the presence of speech and if noise coupling the noise to said simple encoder and if speech coupling to said full encoder;
• and
• said quantizer with reduced output fluctuations in said full encoder comprising:
• means for determining quantization error for a current input;
• means for determining mismatch between amount of fluctuation of input vs. output, and
• a quantizer which generates an output signal based on said quantization error for the current input and said mismatch between said amount of fluctuation of input vs. output.