Reducing sparseness in coded speech signals

Data processing: speech signal processing – linguistics – language – Speech signal processing – For storage or transmission

Reexamination Certificate

Rate now

  [ 0.00 ] – not rated yet Voters 0   Comments 0

Details

C704S267000, C704S268000

Reexamination Certificate

active

06301556

ABSTRACT:

FIELD OF THE INVENTION
The invention relates generally to speech coding and, more particularly, to the problem of sparseness in coded speech signals.
BACKGROUND OF THE INVENTION
Speech coding is an important part of modern digital communications systems, for example, wireless radio communications systems such as digital cellular telecommunications systems. To achieve the high capacity required by such systems both today and in the future, it is imperative to provide efficient compression of speech signals while also providing high quality speech signals. In this connection, when the bit rate of a speech coder is decreased, for example to provide additional communication channel capacity for other communications signals, it is desirable to obtain a graceful degradation of speech quality without introducing annoying artifacts.
Conventional examples of lower rate speech coders for cellular telecommunications are illustrated in IS-641 (D-AMPS EFR) and by the G.729 ITU standard. The coders specified in the foregoing standards are similar in structure, both including an algebraic codebook that typically provides a relatively sparse output. Sparseness refers in general to the situation wherein only a few of the samples of a given codebook entry have a non-zero sample value. This sparseness condition is particularly prevalent when the bit rate of the algebraic codebook is reduced in an attempt to provide speech compression. With very few non-zero samples in the codebook to begin with, and with the lower bit rate requiring that even fewer codebook samples be used, the resulting sparseness is an easily perceived degradation in the coded speech signals of the aforementioned conventional speech coders.
It is therefore desirable to avoid the aforementioned degradation in coded speech signals when the bit rate of a speech coder is reduced to provide speech compression.
In an attempt to avoid the aforementioned degradation in coded speech signals, the present invention provides an anti-sparseness operator for reducing the sparseness in a coded speech signal, or any digital signal, wherein sparseness is disadvantageous.


REFERENCES:
patent: 5195137 (1993-03-01), Swaminathan
patent: 6029125 (2000-02-01), Hagen et al.
patent: 6058359 (2000-05-01), Hagen et al.

LandOfFree

Say what you really think

Search LandOfFree.com for the USA inventors and patents. Rate them and share your experience with other people.

Rating

Reducing sparseness in coded speech signals does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Reducing sparseness in coded speech signals, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Reducing sparseness in coded speech signals will most certainly appreciate the feedback.

Rate now

     

Profile ID: LFUS-PAI-O-2606528

  Search
All data on this website is collected from public sources. Our data reflects the most accurate information available at the time of publication.