(12) United States Patent ao) Patent No.: Us 7,409,338 Bi
Men (45) Date of Patent: Aug. 5,2008
(54) SOFTBIT SPEECH DECODER AND RELATED METHOD FOR PERFORMING SPEECH LOSS CONCEALMENT
(75) Inventor: Hsi-Wen Nien, Hsin-Chu County (TW)
(73) Assignee: Mediatek Incorporation, Hsin-Chu Hsien (TW)
( * ) Notice: Subject to any disclaimer, the term of this patent is extended or adjusted under 35 U.S.C. 154(b) by 773 days.
(21) Appl.No.: 10/904,429
(22) Filed: Nov. 10, 2004
(51) Int. CI.
(52) U.S. CI 704/200; 704/229; 704/500;
(58) Field of Classification Search 704/200,
704/229, 226, 500; 714/758 See application file for complete search history.
(56) References Cited
U.S. PATENT DOCUMENTS
5,502,713 A 3/1996 Lagerqvist
5,572,622 A * 11/1996 Wigrenetal 704/228
6,377,553 Bl* 4/2002 Varyetal 370/252
6,377,755 Bl 4/2002 Vary
6,714,908 Bl * 3/2004 Naka 704/228
6,912,498 B2* 6/2005 Stevens et al 704/235
6,952,668 Bl * 10/2005 Kapilow 704/206
A softbit speech decoder includes a speech loss concealment circuit receiving bit information, bit error probability data, and a speech information flag from an equivalent channel based on a received signal provided to the equivalent channel. The speech loss concealment circuit also contains a speech data judging circuit forjudging whether the speech information flag indicates that the received signal contains speech data, a parameter generating circuit for generating output information, including a speech-parameter error probability vector when the speech information flag indicates that the received signal does not contain speech data. When the received signal does not contain speech data, the speechparameter error probability vector generated by the parameter generating circuit allows the softbit speech decoder to continue operating.
16 Claims, 5 Drawing Sheets