US5539773A
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US
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Method and apparatus for ghost cancelling and/or equalizing
Assignee: Vantiva SA
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Filing: 1993-02-09
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Granted: 1996-07-23
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Expires: 2013-02-09
Abstract
Abstract A method for signal equalization/ghost cancellation with an equalizing filter includes synthesizing a first equalizing filter function (LMS 1) with N (an integer) taps and associated coefficients. The respective coefficients are adjusted to minimize the error between a received reference signal output by the synthesized equalizing filter function and a non-distorted reference signal. The adjusted coefficients are evaluated to determine P (an integer) groups of M (an integer) taps and associated coefficients which contribute to said synthesized equalizing filter function according to a predetermined criterion and wherein P times M is less than N. A second equalizing filter function is synthesized corresponding to the first equalizing filter function with coefficients other than the P groups of M coefficients set to zero, and the P groups to M coefficients are adjusted to minimize the error. The adjusted P groups of M coefficients are applied to a programmable filter to configure the programmable filter to execute an equalizing filter function on received signal.
Inventors
- 👤 Michael Knee
- 👤 Andreas Zipp
- 👤 Andrew Hackett
- 👤 Nelly Bruneau
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 09:15
CPC Classifications
H; H03; H03H; H03H21/00; H03H21/0012; H04; H04N; H04N5/00; H04N5/14; H04N5/21; H04N5/211
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
184 words
A method for signal equalization/ghost cancellation with an equalizing filter wherein filter coefficients are adapted to minimize the error (E, E) between a received reference signal output by the equalizing filter and a non-distorted reference signal, said method comprising: synthesizing a first equalizing filter function (LMS1) with N (an integer) taps and associated coefficients, wherein respective coefficients are adjusted to minimize the error between received reference signal output by the synthesized equalizing filter function and said non-distorted reference signal; evaluating adjusted said coefficients to determine P (an integer) groups of M (an integer) taps and associated coefficients which contribute to said synthesized equalizing filter function according to a predetermined criterion and wherein P times M is less than N; synthesizing a second equalizing filter function corresponding to said first equalizing filter function with coefficients other than said P groups of M coefficients set to zero, and adjusting said P groups to M coefficients to minimize said error; applying adjusted said P groups of M coefficients to a programmable filter to configure said programmable filter to execute said second equalizing filter function on received signal.
Claim 2
Independent Claim
184 words
A method for signal equalization/ghost cancellation with an equalizing filter wherein filter coefficients are adapted to minimize the error (E, E) between a received reference signal output by the equalizing filter and a non-distorted reference signal, said method comprising: synthesizing a first equalizing filter function (LMS1) with N (an integer) taps and associated coefficients, wherein respective coefficients are adjusted to minimize the error between received reference signal output by the synthesized equalizing filter function and said non-distorted reference signal; evaluating adjusted said coefficients to determine P (an integer) groups of M (an integer) taps and associated coefficients which contribute to said synthesized equalizing filter function according to a predetermined criterion and wherein P times M is less than N; synthesizing a second equalizing filter function corresponding to said first equalizing filter function with coefficients other than said P groups of M coefficients set to zero, and adjusting said P groups to M coefficients to minimize said error; applying adjusted said P groups of M coefficients to a programmable filter to configure said programmable filter to execute said second equalizing filter function on received signal.
Claim 3
Dependent Claim
45 words
The method set forth in claim 1 wherein respective coefficients are adjusted according to a least mean square (LMS) algorithm using an adaptation constant μ, which adaptation constant μ is adapted according to statistics of said error and which is updated during successive LMS calculations.
Claim 4
Dependent Claim
34 words
The method set forth in claim 1 wherein the step of evaluating comprises forming values corresponding to squares of respective coefficients and forming respective sums of predetermined numbers of said values corresponding to squares.
Claim 5
Dependent Claim
35 words
The method set forth in claim 2 wherein the step of evaluating comprises forming values corresponding to squares of respective e coefficients and forming respective sums of predetermined numbers of said values corresponding to squares.
Claim 6
Dependent Claim
24 words
The method set forth in claim 3 wherein one of said values corresponding to the squares in each sum is assigned a greater weight.
Claim 7
Dependent Claim
24 words
The method set forth in claim 4 wherein one of said values corresponding to the squares in each sum is assigned a greater weight.
Claim 8
Dependent Claim
25 words
The method set forth in claim 6 further including selecting the P largest sums and forming said respective groups from coefficients contributing to respective sums.
Claim 9
Dependent Claim
25 words
The method set forth in claim 3 further including selecting the P largest sums and forming said respective groups from coefficients contributing to respective sums.
Claim 10
Dependent Claim
205 words
A signal equalization/ghost cancellation filter apparatus wherein filter coefficients are adapted to minimize the error (E, E) between a received reference signal output by the equalizing filter and a non-distorted reference signal, said apparatus comprising: a source of signal to be processed by said equalization/ghost cancellation filter apparatus, said signal including a received reference signal; a source of a non-distorted reference signal; circuitry for synthesizing a first equalizing filter function (LMS1) with N (an integer) taps and associated coefficients, including means for adjusting said coefficients to minimize any error between received reference signal output by the synthesized equalizing filter function and said non-distorted reference signal; means for evaluating adjusted said coefficients to determine P (an integer) groups of M (an integer) taps and associated coefficients which contribute to said first equalizing filter function according to a predetermined criterion and wherein P times M is less than N; means for synthesizing a second equalizing filter function corresponding to said first equalizing filter function with coefficients other than said P groups of M coefficients set to zero and for adjusting said P groups to M coefficients to minimize said error; a programmable filter; and means for programming said programmable filter to execute said second equalizing filter function.
Claim 11
Dependent Claim
205 words
A signal equalization/ghost cancellation filter apparatus wherein filter coefficients are adapted to minimize the error (E, E) between a received reference signal output by the equalizing filter and a non-distorted reference signal, said apparatus comprising: a source of signal to be processed by said equalization/ghost cancellation filter apparatus, said signal including a received reference signal; a source of a non-distorted reference signal; circuitry for synthesizing a first equalizing filter function (LMS1) with N (an integer) taps and associated coefficients, including means for adjusting said coefficients to minimize any error between received reference signal output by the synthesized equalizing filter function and said non-distorted reference signal; means for evaluating adjusted said coefficients to determine P (an integer) groups of M (an integer) taps and associated coefficients which contribute to said first equalizing filter function according to a predetermined criterion and wherein P times M is less than N; means for synthesizing a second equalizing filter function corresponding to said first equalizing filter function with coefficients other than said P groups of M coefficients set to zero and for adjusting said P groups to M coefficients to minimize said error; a programmable filter; and means for programming said programmable filter to execute said second equalizing filter function.
Claim 12
Dependent Claim
83 words
The apparatus set forth in claim 9 wherein said circuitry for synthesizing a first equalizing filter function (LMS1) comprises: a delay means, coupled to said source of signal to be processed, and arranged to store said received reference signal; a central processor which accesses said received reference signal from said delay means and non-distorted reference signal from said source of non-distorted reference signal, and responsive to said received and non-distorted reference signals, calculates respective said coefficients according to a least mean squares algorithm.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-07-23 | 2000-01-22 | 2000-07-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-07-23 | 2004-01-22 | 2004-07-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-07-23 | 2008-01-22 | 2008-07-23 | $7700.00 | Window Closed / Lapsed |