EP0420688A2
Expired / Lapsed
EP
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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: —
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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 C/O Intellectual Property Div. Iga
- 👤 Hiroshi C/O Intellectual Property Div. Matsue
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-07 13:55
CPC Classifications
H; H04; H04N; H04N5/00; H04N5/14; H04N5/21; H04N5/211
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
165 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 which coefficients are adjustable; a line detector for detecting a horizontal scanning line in which the reference signal is inserted from the signal of the input portion or the output portion of the transversal filter; a reference signal extractor for extracting the reference signal over 8 fields, starting with the horizontal scanning line which is detected by the line detector; a ghost detection means for detecting the ghost signal using the final reference signal; and a coefficient calculation means for calcuIating the coefficients of the transversal filter using the detection output of the ghost detecticn means, CHARACTERIZED IN THAT the system further comprises a reference signal calculator for finding the final reference signal corresponding to the 8 fields reference signals which are extracted by the reference signal extractor, using a specified calculation algorithm.
Claim 2
Dependent Claim
165 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 which coefficients are adjustable; a line detector for detecting a horizontal scanning line in which the reference signal is inserted from the signal of the input portion or the output portion of the transversal filter; a reference signal extractor for extracting the reference signal over 8 fields, starting with the horizontal scanning line which is detected by the line detector; a ghost detection means for detecting the ghost signal using the final reference signal; and a coefficient calculation means for calcuIating the coefficients of the transversal filter using the detection output of the ghost detecticn means, CHARACTERIZED IN THAT the system further comprises a reference signal calculator for finding the final reference signal corresponding to the 8 fields reference signals which are extracted by the reference signal extractor, using a specified calculation algorithm.
Claim 3
Dependent Claim
26 words
A system according to claim 1, wherein the line detector detects a horizontal scanning line in which a reference signal is inserted, in an odd-numbered field.
Claim 4
Dependent Claim
99 words
A system according to claim 2, wherein the 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 = (Y₁ - Y₅) + (Y₆ - Y₂) b = (Y₃ - Y₇) + (Y₈ - Y₄) α = a + b β = a - b Δ = α - β where Y₁ to Y₈ are respectively the first to eighth extraction reference signals, the signal output means outputs the fjnal referance signal in accordance with the polarities of the Δ and α, β.
Claim 5
Dependent Claim
26 words
A system according to claim 1, wherein the line detector detects a horizontal scanning line in which a reference signal is inserted, in an even-numbered field.
Claim 6
Dependent Claim
100 words
A system according to claim 4, wherein the reference signal calculator further including a calculating means and a signal out ut means, wherein the calculating means performs the calculation indicated by the following equations a = (Y₁ - Y₅) + (Y₄ - Y₈) b = (Y₃ - Y₇) + (Y₆ - Y₂) α = a + b β = a - b Δ = α - β where Y₁ to Y₈ are rcspectively the first to eighth extraction reference signals, the signal output means outputs the final reference signal in accordance with the polarities of the Δ and α, β.
Claim 7
Dependent Claim
30 words
A system according to claim 1, further including an analogue/digital conversion circuit for converting the video signal into a digital signal and supplying the converted signal to the transversal filter.
Claim 8
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 9
Dependent Claim
17 words
A system acccrding to claim 1, wherein the tap coefficient calculation means corrects the tap coefficients incrementally.
Claim 10
Independent Claim
96 words
A method for controlling a ghost cancelling system utilizing a transversal filter having a plurality of taps which coefficients are adjustable, by cancelling a ghost signal from a video signal using a reference signal of the 8-field sequence type, distinguishing the ghost signal using the final reference signal and correcting the tap coefficient in response to the distinguished ghost signal, CHARACTERIZED BY detecting a horizontal scanning line containing the referonce signals; extracting the 8 fields reference signals from detected tho horizontal scanning line; and calculating a final reference signal corresponding to the 8 fields reference signals.
Claim 11
Independent Claim
96 words
A method for controlling a ghost cancelling system utilizing a transversal filter having a plurality of taps which coefficients are adjustable, by cancelling a ghost signal from a video signal using a reference signal of the 8-field sequence type, distinguishing the ghost signal using the final reference signal and correcting the tap coefficient in response to the distinguished ghost signal, CHARACTERIZED BY detecting a horizontal scanning line containing the referonce signals; extracting the 8 fields reference signals from detected tho horizontal scanning line; and calculating a final reference signal corresponding to the 8 fields reference signals.
References Cited (Backward Citations)
No citation records indexed.
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