1992-02-12
1995-09-05
Knepper, David D.
395 2, G10L 700
Patent
active
054486807
ABSTRACT:
A voice communication processing system and method for processing a speech waveform as a digital bit stream having a reduced number of bits representing speech parameters. The bit representation of amplitude parameters is reduced by storing only probable amplitude parameter transitions corresponding to amplitude parameter indices in an amplitude table and by joint encoding the amplitude parameter indices over multiple frames. The bit representation of the pitch period is reduced by storing a range of pitch periods in a pitch table and by joint encoding pitch period indices corresponding to an average pitch period over two frames. The bit representation of the vocal tract filter coefficients is reduced by storing only probable filter coefficient transitions corresponding to filter coefficient indices in a filter coefficient table and by joint encoding the filter coefficient indices over two frames. Voicing decisions are inferred by an associated vocal tract filter coefficient index obtained by searching the filter coefficient table where the table is divided according to the voicing decisions, and thus separate voicing decisions do not have to be transmitted. By providing a reduced bit representation of the various speech parameters as explained above, the present invention processes the speech waveform at a more efficient data rate. In addition, the present invention converts prediction coefficients (PCs) into line spectra pairs (LSPs) to be used as filter parameters when performing a linear predictive coder (LPC) analysis. Thus, by using LSPs, the present invention is able to more efficiently encode and decode speech.
REFERENCES:
patent: 4815134 (1989-03-01), Picone
patent: 5012518 (1991-04-01), Liu
Stark, "Introduction to Numerical Methods", Macmillan Publishing Co., Inc., ew York, .COPYRGT.1970 by Peter A. Stark, pp. x and 103-110.
Kang et al., "Low-bit rate speech encoders based on line-spectrum frequencies (LSFs)", Naval Research Laboratory Report 8857, Jan. 1985.
Analog to Digital Conversion of Voice By 2,400 Bit/Second Linear Predictive Coding, Nov. 28, 1984, National Communications System Office of Technology & Standards.
Kang et al., "High-Quality 800-b/s Voice Processing Algorithm," NRL Report 9301, Feb. 25, 1991.
Kang, et al., "Error-Resistant Narrowband Voice Encoder," NRL Report 9018, Dec. 26, 1986.
Fransen Lawrence J.
Kang George S.
Knepper David D.
McDonnell Thomas E.
Miles Edward F.
The United States of America as represented by the Secretary of
LandOfFree
Voice communication processing system does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Voice communication processing system, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Voice communication processing system will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-479811