Telephonic communications – Subscriber line or transmission line interface – Network interface device
Patent
1997-08-01
2000-07-11
Isen, Forester W.
Telephonic communications
Subscriber line or transmission line interface
Network interface device
308322, H04M 900, G06F 1710
Patent
active
060884452
ABSTRACT:
An adaptive filter is provided which has fixed point or floating point data stored in a data RAM (74) and block scale floating point coefficients stored in a coefficient RAM (84). The data and coefficients are utilized in a filter algorithm which utilizes a multiplier and an accumulator to provide a convolution result. Coefficients are updated by adding the multiplied result of the data RAM value and the error value to the old value of the coefficient. This is done for all the coefficient values in the coefficient RAM. The error value indicates the difference between the filter output and the sampled near-end signal that is the echo. These new coefficients are examined and if any have a value above or all have a value below a predetermined threshold, then the mantissas of all the coefficients are shifted and the exponent adjusted in the next filter cycle.
REFERENCES:
patent: 4592006 (1986-05-01), Hagiwara et al.
patent: 5303174 (1994-04-01), Okamoto
patent: 5323458 (1994-06-01), Park et al.
patent: 5526426 (1996-06-01), McLaughlin
patent: 5638311 (1997-06-01), Fujii et al.
patent: 5751902 (1998-05-01), Hofman
patent: 5790440 (1998-08-01), Fujii et al.
Camagna John
Chadha Mandeep
Hemkumar Nariankadu Datatreya
McCaslin Shawn Robert
Crystal Semiconductor Corp.
Howison Gregory M.
Isen Forester W.
Saint-Surin Jacques
LandOfFree
Adaptive filter system having mixed fixed point or floating poin does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Adaptive filter system having mixed fixed point or floating poin, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Adaptive filter system having mixed fixed point or floating poin will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-549933