EP0072247A1
Expired / Lapsed
EP
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Ghost reduction circuit for television receiver
Assignee: Hitachi Ltd
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Filing: 1982-08-10
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Granted: —
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Expires: 2002-08-10
Abstract
Abstract A wide-band ghost reduction circuit apparatus for a television receiver comprises a ghost detector (10), two transversal filters (L, M) having delay characteristics different from each other, a switch (8) for selecting one of the filters and an automatic gain control circuit (5) responsive to the output of the ghost detector for controlling the filters and the switch. Each of the transversal filters includes tap amplifiers whose gains are controlled by the automatic gain control circuit and having outputs connected, respectively, to tap inputs of delay devices formed of such as a CCD each provided with a tap and included in the associated transver- sai filter. Output end of one of the transversal filters having a smaller delay is connected to a selected one of the input tap of the other transversal filter through a switch (8) so that input video signal components join together at every input terminal or every individual tap position of the delay devices.
Inventors
- 👤 Toshinori Murata
- 👤 Tomomitsu Kuroyanagi
- 👤 Masafumi Kazumi
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-06 10:25
CPC Classifications
H; H04; H04N; H04N5/00; H04N5/14; H04N5/21; H04N5/211
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
300 words
A ghost reduction circuit apparatus for a television receiver, comprising: (a) first waveform conversion means (L) including a plurality of first delay elements connected in cascade with one another between an input terminal (6) and an output terminal (1) of the apparatus for a video signal and each delay element having a first delay characteristic and a plurality of first amplifiers (3a) connected to the input side of said first delay elements (2a), respectively; (b) second waveform conversion means (M) including a plurality of second delay elements connected in cascade with one another and each delay element having a second delay characteristic and a plurality of second amplifiers (3b) connected to the input side of said second delay elements, respectively; (c) coupling means (8) for coupling the final end of said second waveform conversion means to one of said first delay elements of said first waveform conversion means; (d) ghost detecting..means (10) for detecting ghost signal components contained in said video signal; (e) automatic gain control means (5) for controlling the gains of said first and second amplifiers on the basis of the result of the ghost detection effected by said detecting means so that a major portion of said ghost signal components is eliminated by said first waveform conversion means while the residual ghost signal components are eliminated by said second waveform conversion means; and (f) wherein said first and second amplifiers have inputs connected to said output terminal and said input terminal for the video signal, respectively, and having outputs connected to input terminals of the associated delay elements, respectively, said coupling means coupling the output of the final one of said second cascaded delay elements to the input of selected one of said first delay elements under the control of said automatic gain control means. (Fig. 6)
Claim 2
Dependent Claim
300 words
A ghost reduction circuit apparatus for a television receiver, comprising: (a) first waveform conversion means (L) including a plurality of first delay elements connected in cascade with one another between an input terminal (6) and an output terminal (1) of the apparatus for a video signal and each delay element having a first delay characteristic and a plurality of first amplifiers (3a) connected to the input side of said first delay elements (2a), respectively; (b) second waveform conversion means (M) including a plurality of second delay elements connected in cascade with one another and each delay element having a second delay characteristic and a plurality of second amplifiers (3b) connected to the input side of said second delay elements, respectively; (c) coupling means (8) for coupling the final end of said second waveform conversion means to one of said first delay elements of said first waveform conversion means; (d) ghost detecting..means (10) for detecting ghost signal components contained in said video signal; (e) automatic gain control means (5) for controlling the gains of said first and second amplifiers on the basis of the result of the ghost detection effected by said detecting means so that a major portion of said ghost signal components is eliminated by said first waveform conversion means while the residual ghost signal components are eliminated by said second waveform conversion means; and (f) wherein said first and second amplifiers have inputs connected to said output terminal and said input terminal for the video signal, respectively, and having outputs connected to input terminals of the associated delay elements, respectively, said coupling means coupling the output of the final one of said second cascaded delay elements to the input of selected one of said first delay elements under the control of said automatic gain control means. (Fig. 6)
Claim 3
Dependent Claim
65 words
A ghost reduction circuit apparatus according to claim 1, wherein said first waveform conversion means (L) has an input end connected to said video signal output terminal (7) and an output end coupled with one input of an adder whose output is connected to said video signal output terminal (7), the other input of said adder being coupled with said video signal input terminal (6).
Claim 4
Dependent Claim
58 words
A ghost reduction circuit apparatus according to claim 2, wherein said coupling means (8) is constituted by a switch through which the output end of said second waveform conversion means (M) is coupled to the output side of one of said first amplifiers (3a) which is controlled by said automatic gain control means to exhibit the greatest gain.
Claim 5
Dependent Claim
64 words
A ghost reduction circuit apparatus according to claim 2, wherein said coupling means (8) is constituted by a switch through which the output end of said second waveform conversion means (M) is coupled to the output side of one of said first amplifiers (3a) which is in the vicinity of the amplifier controlled by said automatic gain control means to exhibit the greater gain.
Claim 6
Dependent Claim
63 words
A ghost reduction circuit apparatus according to claim 1, 2, 3 or 4, wherein said coupling means (8) is constituted by a switch which is closed upon elapsing of a predetermined time after initialization for a ghost eliminating operation by said first waveform conversion means, said ghost detecting means and said automatic gain control means and thereafter remains fixed in the closed state.
Claim 7
Dependent Claim
38 words
A ghost reduction circuit apparatus according to claim 1, 2, 3 or 4, wherein said coupling means (8) is constituted by a switch, the gains of said first amplifiers (3a) being fixed after said switch has been closed.
Claim 8
Dependent Claim
46 words
7 . A ghost reduction circuit apparatus according to claim 1, 2, 3 or 4, wherein said coupling means (8) is constituted by a switch, the gains of said second amplifiers (3b) being controlled by said automatic gain control means after said switch has been closed.
Claim 9
Dependent Claim
43 words
A ghost reduction circuit apparatus according to claim 1, 2, 3 or 4 wherein said coupling means is constituted by a switch, the gains of said second amplifiers (3b) being fixed upon elapsing of a predetermined time after said switch has been closed.
Claim 10
Dependent Claim
37 words
A ghost reduction circuit apparatus according to claim 1, 2, 3 or 4, wherein the delay time of each of said first delay elements is longer than the delay time of each of said second delay elements.
Claim 11
Dependent Claim
35 words
A ghost reduction circuit apparatus according to claim 1, 2, 3 or 4, wherein said ghost detection means detects ghost signal components contained in the video signal delivered from said video signal output terminal (7).
Claim 12
Dependent Claim
45 words
A ghost reduction circuit apparatus according to claim 1, 2, 3 or 4, wherein the first delay elements and adders between the delay elements and the first amplifiers are formed of a charge-coupled device and the second delay elements are formed of another charge-coupled device.
Claim 13
Dependent Claim
233 words
A wide band ghost reduction circuit for a television receiver, comprising: (a) an input terminal and an output terminal for an input video signal; (b) ghost detecting means connected to said output terminal for detecting ghost signal components contained in said video signal; (c) first and second transversal filters having delay characteristics differing from each other, said first and second transversal filters being coupled to said input terminal and said output terminal in a feedback connection and a feedforward connection, respectively, each of said transversal filters including a number of cascaded delay elements and tap amplifiers having outputs connected to tap inputs of the delay elements each having a tap and constituting said transversal filters, respectively; (d) coupling means responsive to a tap selection signal for coupling the output end of said second transversal filter to a selected one of the tap inputs of said first transversal filters; and (e) automatic gain control means (5) responsive to the detection output of said ghost detecting means for controlling said tap amplifiers of said first and second transversal filters and supplying the tap selection signal to said coupling means, in such a manner that a major part of the detected ghost components is reduced by said first transversal filter, while said second transversal filter reduces the residual ghost signal components, wherein video signal components are joined together at every input end of said delay elements.
Claim 14
Dependent Claim
233 words
A wide band ghost reduction circuit for a television receiver, comprising: (a) an input terminal and an output terminal for an input video signal; (b) ghost detecting means connected to said output terminal for detecting ghost signal components contained in said video signal; (c) first and second transversal filters having delay characteristics differing from each other, said first and second transversal filters being coupled to said input terminal and said output terminal in a feedback connection and a feedforward connection, respectively, each of said transversal filters including a number of cascaded delay elements and tap amplifiers having outputs connected to tap inputs of the delay elements each having a tap and constituting said transversal filters, respectively; (d) coupling means responsive to a tap selection signal for coupling the output end of said second transversal filter to a selected one of the tap inputs of said first transversal filters; and (e) automatic gain control means (5) responsive to the detection output of said ghost detecting means for controlling said tap amplifiers of said first and second transversal filters and supplying the tap selection signal to said coupling means, in such a manner that a major part of the detected ghost components is reduced by said first transversal filter, while said second transversal filter reduces the residual ghost signal components, wherein video signal components are joined together at every input end of said delay elements.
Claim 15
Dependent Claim
91 words
A wide-band ghost reduction circuit according to calim 12, wherein the cascaded delay elements of each transversal filter are formed of a charge-coupled device (CCD), the delay time of each delay element of said first transversal filter is longer than that of each delay element of said second transversal filter, and the outputs of said second transversal filter and said tap amplifiers of the first transversal filter being added on the input side of the CCD in the charge conditions and supplied to said tap inputs of the first transversal filter.
Claim 16
Dependent Claim
91 words
A wide-band ghost reduction circuit according to calim 12, wherein the cascaded delay elements of each transversal filter are formed of a charge-coupled device (CCD), the delay time of each delay element of said first transversal filter is longer than that of each delay element of said second transversal filter, and the outputs of said second transversal filter and said tap amplifiers of the first transversal filter being added on the input side of the CCD in the charge conditions and supplied to said tap inputs of the first transversal filter.
References Cited (Backward Citations)
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