Adaptive echo canceller with sparse dynamically positioned taps

Telephonic communications – Subscriber line or transmission line interface – Network interface device

Patent

Rate now

  [ 0.00 ] – not rated yet Voters 0   Comments 0

Details

370 321, H04B 323

Patent

active

048052159

ABSTRACT:
This invention relates to an echo canceller, for a transmission line, including a shift register having an input for receiving an input signal from a signal source and having a plurality of output taps for providing a plurality of equally spaced delayed signals. A tap coefficient storage memory stores a plurality of tap coefficients. A multiplier multiplies certain of the delayed signals by certain tap coefficients to produce multiplier outputs. A tap allocation circuit determines, on a tap by tap basis, how many and which of the taps are to be turned ON so that its corresponding tap coefficients are multiplied by the multiplier. A subtracter cancels echoes by subtracting the multiplier outputs from signals received on the transmission line. Taps which are turned OFF may be assigned a status of STANDBY and these taps may be activated to compensate for changes in the characteristics of the transmission line.

REFERENCES:
patent: 3535473 (1970-10-01), Flanagan et al.
patent: 3721777 (1973-03-01), Thomas
patent: 3723911 (1973-03-01), Forney, Jr.
patent: 3787645 (1974-01-01), Ochiai et al.
patent: 4024357 (1977-05-01), Sourgens et al.
patent: 4087654 (1978-05-01), Mueller
patent: 4464545 (1984-08-01), Werner
patent: 4578544 (1986-03-01), Colin de Verdiere et al.
patent: 4582963 (1986-04-01), Danstrom
patent: 4593161 (1986-06-01), Desblache et al.
patent: 4602133 (1986-07-01), O'Neill
patent: 4732410 (1986-05-01), Mackechnie
U.S. translation of Japanese Patent Publication 57-42242, United States Patent and Trademark Office.
IBM Technical Disclosure Bulletin, vol. 21, No. 5, Oct. 1978, (New York, U.S.) "Centering Transversal Equalizer Tap Coefficients".
IEEE Global Telecommunications Conference, Houston, Texas, Dec. 1-4, 1986, "A DSP-Based Echo-Canceller with Two Adaptive Filters", pp. 1674-1678.
Signal Analysis, Athanasios Papoulis, 1977.
Shin-ichi Kawamura and Mitsutoshi Hatori, "A Tap Selection Algorithm for Adaptive Filters", Proceedings of ICASSP, pp. 2979-2982, 1986.
Makoto Itami, Takashi Mochizuki and Mitsutoshi Hatori, "Hardware Implementation of FM Multipath Distortion Canceller", Proc. of ICASSP, pp. 1301-1304, 1986.
Bede Lie, "Effect of Finite Word Length on the Accuracy of Digital Filters-A Review", IEEE Trans. Circuit Theory, pp. 361-369, Nov. 1971.
Oscar Agazzi, David G. Messerschmitt and David A. Hodges, "Nonlinear Echo Cancellation of Data Signals", IEEE Transactions on Communications, pp. 2421-2433, Nov. 1982.
Stephen B. Weinsten, "Echo Cancellation in the Telephone Network", IEEE Communications Society Magazine, pp. 9-15, Jan. 1977.
M. M. Sondhi, "An Adaptive Echo Canceller", The Bell System Technical Journal, pp. 497-511, Mar. 1967.

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

Adaptive echo canceller with sparse dynamically positioned taps 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 echo canceller with sparse dynamically positioned taps, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Adaptive echo canceller with sparse dynamically positioned taps will most certainly appreciate the feedback.

Rate now

     

Profile ID: LFUS-PAI-O-1372088

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