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US5130799A
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Ghost cancelling system and control method thereof
Assignee: Toshiba Corp
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Filing: 1990-09-28
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Granted: 1992-07-14
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Expires: 2010-09-28
Abstract
Abstract A ghost cancelling system which detects a horizontal scanning line containing the reference signals and extracts 8 fields reference signals from the horizontal scanning line. A final reference signal corresponding to the 8 fields reference signals is calculated by a specified calculation algorithm, and the system corrects the tap coefficient in response to the distinguished ghost signal using the final reference signal.
Inventors
- 👤 Hiroyuki Iga
- 👤 Hiroshi Matsue
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 16:44
CPC Classifications
H; H04; H04N; H04N5/00; H04N5/14; H04N5/21; H04N5/211
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
163 words
A ghost cancelling system wherein a ghost signal is cancelled from a video signal using a reference signal of the 8-field sequence type comprising: a transversal filter having a plurality of taps with coefficients which are adjustable; a line detector for detecting a horizontal scanning line in which said reference signal is inserted from a signal at an input portion of said transversal filter; a reference signal extractor for extracting said reference signal over 8 fields, starting with said horizontal scanning line which is detected by said like line detector; a reference signal calculator for finding a final reference signal corresponding to said 8 fields reference signals which are extracted by said reference signal extractor, using a specified calculation algorithm; a ghost detection means for detecting said ghost signal using said final reference signal calculated by said reference signal calculator; and a coefficient calculation means for calculating said tap coefficients of said transversal filter using a detection output of said ghost detection means.
Claim 2
Dependent Claim
163 words
A ghost cancelling system wherein a ghost signal is cancelled from a video signal using a reference signal of the 8-field sequence type comprising: a transversal filter having a plurality of taps with coefficients which are adjustable; a line detector for detecting a horizontal scanning line in which said reference signal is inserted from a signal at an input portion of said transversal filter; a reference signal extractor for extracting said reference signal over 8 fields, starting with said horizontal scanning line which is detected by said like line detector; a reference signal calculator for finding a final reference signal corresponding to said 8 fields reference signals which are extracted by said reference signal extractor, using a specified calculation algorithm; a ghost detection means for detecting said ghost signal using said final reference signal calculated by said reference signal calculator; and a coefficient calculation means for calculating said tap coefficients of said transversal filter using a detection output of said ghost detection means.
Claim 3
Dependent Claim
21 words
A system according to claim 1, further including a clock generating circuit for generating a clock CK of a period T.
Claim 4
Dependent Claim
26 words
A system according to claim 1, wherein said line detector detects a horizontal scanning line in which said reference signal is inserted, in an odd-numbered field.
Claim 5
Dependent Claim
77 words
A system according to claim 1, wherein said reference signal calculator further including a calculating means and a signal output means, wherein the calculating means performs the calculation indicated by the following equations a=(Y.sub.1 -Y.sub.5)+(Y.sub.6 -Y.sub.2) b=(Y.sub.3 -Y.sub.7)+(Y.sub.8 -Y.sub.4) α=a+b β=a-b Δ=α-β Where Y 1 to Y 8 are respectively said first to eighth extraction reference signals, the signal output means outputs said final reference signal in accordance with the polarities of the Δ and α, β.
Claim 6
Dependent Claim
26 words
A system according to claim 1, wherein said line detector detects a horizontal scanning line in which said reference signal is inserted, in an even-numbered field.
Claim 7
Dependent Claim
77 words
A system according to claim 5, wherein said reference signal calculator further includes a calculating means and a signal output means, wherein the calculating means performs the calculation indicated by the following equations: a=(Y.sub.1 -Y.sub.5)+(Y.sub.4 -Y.sub.8) b=(Y.sub.3 -Y.sub.7)+(Y.sub.6 -Y.sub.2) α=a+b β=a-b Δ=α-β where Y 1 to Y 8 are respectively said first to eighth extraction reference signals, the signal output means outputs said final reference signals in accordance with the polarities of the Δ and α, β.
Claim 8
Dependent Claim
30 words
A system according to claim 1, further including an analog/digital conversion circuit for converting said video signal into a digital signal and supplying the converted signal to said transversal filter.
Claim 9
Dependent Claim
16 words
A system according to claim 1, wherein said coefficient calculation means corrects said tap coefficients incrementally.
Claim 10
Independent Claim
103 words
A method for controlling a ghost cancelling system having a transversal filter comprising: cancelling a ghost signal utilizing tap coefficients obtained from a video signal containing a reference signal of the 8-field sequence type, including the steps of: detecting a horizontal scanning line containing said reference signal of the 8-field sequence type; extracting said reference signal of the 8-field sequence type from said detected horizontal scanning line; calculating a final reference signal corresponding to said reference signal of the 8-field sequence type; distinguishing said ghost signal using said final reference signal; and correcting said tap coefficients in response to said distinguished ghost signal.
Claim 11
Independent Claim
103 words
A method for controlling a ghost cancelling system having a transversal filter comprising: cancelling a ghost signal utilizing tap coefficients obtained from a video signal containing a reference signal of the 8-field sequence type, including the steps of: detecting a horizontal scanning line containing said reference signal of the 8-field sequence type; extracting said reference signal of the 8-field sequence type from said detected horizontal scanning line; calculating a final reference signal corresponding to said reference signal of the 8-field sequence type; distinguishing said ghost signal using said final reference signal; and correcting said tap coefficients in response to said distinguished ghost signal.
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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) | 1995-07-14 | 1996-01-13 | 1996-07-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-07-14 | 2000-01-13 | 2000-07-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-07-14 | 2004-01-13 | 2004-07-14 | $7700.00 | Window Closed / Lapsed |