Linear predictive speech encoding systems with efficient combination pitch coefficients computation

• US 5,794,182 A
• Filed: 09/30/1996
• Issued: 08/11/1998
• Est. Priority Date: 09/30/1996
• Status: Expired due to Term

• Current Assignee: Apple Inc.
• Original Assignee: Apple Computer Incorporated (Apple Inc.)
• Inventors: Wu, Hsi-Jung, Chu, Ke-Chiang, Ponceleon, Dulce, Manduchi, Roberto
• Primary Examiner(s): Hudspeth, David R.
• Assistant Examiner(s): ABEBE, DANIEL DEMELASH
• Application Number:
  US08/724,174
• Time in Patent Office: 680 Days
• Field of Search: 704/219, 704/223, 704/262, 704/220, 704/230, 704/207
• US Class Current: 704/219
• CPC Class Codes: G10L 19/09 Long term prediction, i.e. removing periodical redundancies, e.g. by using adaptive codebook or pitch predictor
• CPC Class Codes: G10L 19/125 Pitch excitation, e.g. pitch synchronous innovation CELP [PSI-CELP]
• CPC Class Codes: G10L 25/90 Pitch determination of speech signals

Abstract

Method and system aspects for linear predictive speech encoding are disclosed. These aspects comprise the definition of an error function, the computation of an optimal vector of continuous pitch coefficients together with an optimal pitch, and the weighted vector quantization of the continuous pitch coefficients. The techniques allows the faster computation of the optimal combination pitch--continuous coefficient values without substantial loss of optimal results.

Claims

1. A method for linear predictive speech encoding comprising the steps of:

a) defining an error function that includes a constant value, the constant value comprising a chosen offset within a predetermined pitch interval;

b) determining an optimal continuous vector;

c) determining an error from the optimal continuous vector;

d) determining if the error is less than a minimum error;

e) providing optimal combination pitch-continuous coefficient values based upon in the minimum error; and

f) providing a weighted vector quantization of an optimal continuous vector of continuous coefficient values.

2. A method for linear predictive speech encoding comprising the steps of:

a) defining an error function that includes a constant value;

wherein the constant value comprises a chosen offset within a predetermined pitch interval;

b) determining an optimal continuous vector;

c) determining an error from the optimal continuous vector;

d) determining if the error is less than a minimum error;

e) providing optimal combination pitch-continuous coefficient values based upon in the minimum error;

f) providing a weighted vector quantization of an optimal continuous vector of continuous coefficient values; and

g) performing steps b)-d) over a predetermined pitch interval.

3. A system for providing combination pitch-coefficients with improved efficiency in linear predictive speech encoding, the system comprising:

speech signal generation means for generating speech signals; and

speech processing means for processing the generated speech signals with linear predictive speech encoding, the processing further comprising;

a) defining an error function that includes a constant value, the constant value comprising a chosen offset within a predetermined pitch interval;

b) determining an optimal continuous vector;

c) determining an error from the optimal continuous vector;

d) determining if the error is less than a minimum errors;

e) providing optimal combination pitch-continuous coefficient values resulting in the minimum error; and

f) calculating a weighted vector quantization of an optimal continuous vector of continuous coefficient values.

4. The system of claim 3 further comprising performing steps b)-d) over a predetermined pitch interval.

5. A method for providing combination pitch coefficients with improved efficiency in a linear predictive speech encoding system, the method comprising:

limiting calculation at a chosen offset from a given pitch in an error function calculation;

determining one or more continuous coefficient vectors from any vector in real space; and

determining an optimal combination pitch-continuous coefficient vector that minimizes the error function calculation.

6. The method of claim 5 further comprising performing weighted vector quantization of the optimal continuous vector of continuous coefficient values.

7. A system for providing combination pitch coefficients with improved efficiency in linear predictive speech encoding, the system comprising:

a speech generator of speech signals; and

a central processing unit, the central processing unit coupled to the speech generator and capable of coordinating a limitation of calculation at a chosen offset from a given pitch in an error function calculation, a determination of one or more continuous coefficient vectors from any vector in real space, and a determination of an optimal combination pitch-continuous coefficient vector that minimizes the error function calculation.

8. The system of claim 7 wherein the central processing unit further coordinates performing weighted vector quantization of the optimal continuous vector of continuous coefficient values.

9. A computer readable medium containing program instructions for linear predictive speech encoding, the program instructions comprising:

a) defining an error function that includes a constant value, the constant value comprising a chosen offset within a predetermined pitch interval;

b) determining an optimal continuous vector;

c) determining an error from the optimal continuous vector;

d) determining if the error is less than a minimum error;

e) providing optimal combination pitch-continuous coefficient values based upon the minimum error; and

f) providing a weighted vector quantization of an optimal continuous vector of continuous coefficient values.

10. A computer readable medium containing program instructions for linear predictive speech encoding, the program instructions comprising:

a) defining an error function that includes a constant value;

b) determining an optimal continuous vector;

c) determining an error from the optimal continuous vector;

d) determining if the error is less than a minimum error;

e) providing optimal combination pitch-continuous coefficient values based upon the minimum error;

f) providing a weighted vector quantization of an optimal continuous vector of continuous coefficient values; and

g) performing steps b)-d) over a predetermined pitch interval.

11. A computer readable medium containing program instructions for linear predictive speech encoding, the program instructions comprising:

limiting calculation at a chosen offset from a given pitch in an error function calculation;

determining one or more continuous coefficient vectors from any vector in real space; and

determining an optimal combination pitch-continuous coefficient vector that minimizes the error function calculation.

12. The program instructions of claim 11 further comprising performing weighted vector quantization of the optimal continuous vector of continuous coefficient values.