LPAS speech coder using vector quantized, multi-codebook, multi-tap pitch predictor and optimized ternary source excitation codebook derivation

In a system having a working memory and a digital processor, an apparatus for encoding speech signals comprising:

• a pitch predictor to remove certain redundancies in a subject speech signal, the pitch predictor having vector quantized parameters and being a multi-tap pitch predictor utilizing a codebook subdivided into at least a first vector codebook and a second vector codebook;
• and
• a source excitation codebook coupled to receive speech signals from the pitch predictor, the source excitation codebook indicating pulses in the subject speech signal by deriving corresponding vector values.

In a system having working memory and a digital processor, a multi-tap pitch predictor for performing vector quantization, comprising:

• at least one pitch predictor codebook having predictor coefficients;
• and
• an adaptive codebook adjusted with a contribution from the adaptive codebook in combination with the predictor coefficients, the predictor coefficients being selected by searching the at least one pitch predictor codebook.

In a system having working memory and a digital processor, an apparatus for performing multi-tap pitch predictor vector quantization, the apparatus comprising:

• at least one pitch predictor codebook having predictor coefficients;
• and
• means for adjusting the adaptive codebook with a contribution from the adaptive codebook in combination with the predictor coefficients, the predictor coefficients being selected by searching the at least one pitch predictor codebook.

In a system having working memory and a digital processor, a method for producing a fixed codebook for a speech signal encoder, comprising:

• filtering a target speech signal;
• and
• forming entries in the fixed codebook of derived vector values indicating pulses in the filtered target speech signal.

In a system having working memory and a digital processor, a fixed codebook for a speech signal encoder, comprising:

• a filter filtering a target speech signal;
• and
• entries in the fixed codebook of derived vector values indicating pulses in the filtered target speech signal.

In a system having working memory and a digital processor, an apparatus for producing a fixed codebook for a speech signal encoder, comprising:

• means for filtering a target speech signal;
• and
• means for forming entries in the fixed codebook of derived vector values indicating pulses in the filtered target speech signal.