Variable rate vocoder
Number of patents in Portfolio can not be more than 2000
United States of America Patent
Stats
-
Jul 7, 1998
Issued Date -
N/A
app pub date -
Jan 23, 1997
filing date -
Jun 11, 1991
priority date (Note) -
In Force
status (Latency Note)
Importance
Abstract
An apparatus and method for performing speech signal compression, by variable rate coding of frames of digitized speech samples. The level of speech activity for each frame of digitized speech samples is determined and an output data packet rate is selected from a set of rates based upon the determined level of frame speech activity. A lowest rate of the set of rates corresponds to a detected minimum level of speech activity, such as background noise or pauses in speech, while a highest rate corresponds to a detected maximum level of speech activity, such as active vocalization. Each frame is then coded according to a predetermined coding format for the selected rate wherein each rate has a corresponding number of bits representative of the coded frame. A data packet is provided for each coded frame with each output data packet of a bit rate corresponding to the selected rate. At the decoder, if a frame is lost due to a channel error, the error is masked by maintaining a fraction of the previous frame's energy and smoothly transitioning to background noise.
First Claim
Family
International Classification(s)
Cited Art Landscape
Patent Citation Ranking
Advertisement
Advertisement
Advertisement
Recipient Email Address
Recipient Email Address
Comment
Recipient Email Address
Add to Portfolio(s)
To add this patent to one, or more, of your portfolios, simply click the add button.
This Patent is in these Portfolios:
Add to additional portfolios:
Last Refreshed On:
Changes done successfully