EP0173439B1
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Luminance/chrominance separator
Assignee: Sony Corp
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Filing: 1985-07-11
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Granted: 1989-09-27
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Expires: 2005-07-11
Abstract
Abstract When separating a composite video signal into a luminance signal component and the chrominance signal component by the use of filtering a high frequency cross-talk component of the luminance signal is present in the chrominance signal and this may be cancelled using a horizontal correlator that imparts time delays and detects maximum and minimum levels relative to a reference level. In such luminance cross-talk cancellation by means of the horizontal correlator the usable chrominance signal length is shortened by almost one wave length out of four, thereby reducing the usable chrominance signal each time such luminance/chrominance signal separation occurs in a dubbing operation, for example. By utilizing two chroma separators in series each including a nonadditive mixer circuit, the resultant output from the second chroma separator circuit has substantially the same length as the portion of the composite video signal fed as the input. As a further safety factor in preventing the chrominance signal from being produced with excessive noise, a time delayed version of the composite video signal is level checked with the output of the second chroma separator unit and the signal having the lesser level is produced as the output.
Inventors
- 👤 Masafumi Ishige
- 👤 Yoshitaka Kanemoto
- 👤 Tamio Yokoyama
- 👤 Ichitaro Sato
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 22:43
CPC Classifications
H; H04; H04N; H04N9/00; H04N9/77; H04N9/78
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
215 words
Apparatus for removing high-frequency luminance cross-talk components from a chrominance signal modulated on a chrominance subcarrier signal and formed as part of a composite video signal of specified length, includes a horizontal correlator (9, 46A) receiving said composite video signal and has a first delay circuit (31, 32) for imparting a first time delay based on a period of said chrominance subcarrier signal to the composite video signal and the delayed composite video signal and a first signal synthesizer (45) receiving the composite video signal and the delayed composite video signal for producing therefrom a horizontally correlated synthesized output signal formed of the chrominance signal having reduced cross-talk components and being of a length less than the specified length; characterized in that a chroma separator (46B) receives said synthesized output signal from said horizontal correlator (46A) and includes a second delay circuit (51, 52) for imparting to said synthesized output signal a time delay corresponding to said first time delay and producing a time delayed output signal therefrom and further includes a second signal synthesizer (53) receiving said time delayed output signal and said synthesized output signal from said horizontal correlator (46A) for producing a second horizontally correlated synthesized output signal having a length substantially equal to said specified length of said composite video signal.
Claim 2
Dependent Claim
215 words
Apparatus for removing high-frequency luminance cross-talk components from a chrominance signal modulated on a chrominance subcarrier signal and formed as part of a composite video signal of specified length, includes a horizontal correlator (9, 46A) receiving said composite video signal and has a first delay circuit (31, 32) for imparting a first time delay based on a period of said chrominance subcarrier signal to the composite video signal and the delayed composite video signal and a first signal synthesizer (45) receiving the composite video signal and the delayed composite video signal for producing therefrom a horizontally correlated synthesized output signal formed of the chrominance signal having reduced cross-talk components and being of a length less than the specified length; characterized in that a chroma separator (46B) receives said synthesized output signal from said horizontal correlator (46A) and includes a second delay circuit (51, 52) for imparting to said synthesized output signal a time delay corresponding to said first time delay and producing a time delayed output signal therefrom and further includes a second signal synthesizer (53) receiving said time delayed output signal and said synthesized output signal from said horizontal correlator (46A) for producing a second horizontally correlated synthesized output signal having a length substantially equal to said specified length of said composite video signal.
Claim 3
Dependent Claim
32 words
Apparatus according to claim 1, in which said second delay circuit includes a delay line (51) having a time delay equal to the period of 1/2 wavelength of said chrominance subcarrier signal.
Claim 4
Dependent Claim
43 words
Apparatus according to claim 2, in which said chroma separator (46B) includes a signal inverter (54) for inverting said time delayed output signal, said time delayed output signal and said inverted time delayed output signal being fed to said second signal synthesizer (53).
Claim 5
Dependent Claim
59 words
Apparatus according to claim 4, in which said second delay circuit further includes a second delay line (52) having a time delay equal to the period of 1/2 wavelength of said chrominance subcarrier signal and receiving said time delayed output signal from said first delay line (51) and producing an output therefrom fed to said second signal synthesizer (53).
Claim 6
Dependent Claim
55 words
Apparatus according to claim 1, in which the chroma separator (46) includes a selector circuit (46C) receiving said time delayed composite video signal (S 3 ) and said output signal (S 7 ) from said second signal synthesizer (53) for reproducing as an output signal (S 3 ) a signal having the lowest relative level.
Claim 7
Dependent Claim
217 words
Apparatus according to claim 5, in which said selector circuit (46C) includes first maximum detecting circuit (35) receiving time delayed composite video signal and a reference level signal for reproducing the signal having the greater level as an output signal; second maximum detecting circuit (36) receiving said output signal from said second signal synthesizer (53) and said reference level signal for reproducing the signal having the greater level as an output signal; first minimum detector circuit (42) receiving said output signals from first and second maximum detecting circuits for reproducing the signal having the lesser level as an output signal; second minimum detecting circuit (38) receiving said time delayed composite video signal and said reference level signal for reproducing the signal having the lesser level as an output signal; third minimum detecting circuit (39) receiving said output signal from said second signal synthesizer (53) and said reference level signal for reproducing the signal with the lesser level as an output signal; third maximum detecting circuit (43) receiving said output signals from said second and third minimum level detecting circuits for reproducing the signal having the greater level as an outputsignal; and a mixer (44) receiving said output signals from first minimum detecting circuit and said third maximum detecting circuit for producing a nonadditive mixed output signal therefrom.
Claim 8
Dependent Claim
121 words
Apparatus according to claim 1, in which said second signal synthesizer (53) includes a maximum detecting circuit (35, 36, 37, 55) receiving said time delayed output signal, said output signal from said first synthesizer (45), and a reference level signal for producing an output signal corresponding to the highest level positive signal fed thereto; a minimum detecting circuit (38, 39, 40, 56) receiving said time delayed output signal, said output signal from said first synthesizer (45), and said reference level signal for producing an output signal corresponding to the lowest level negative signal fed thereto; and a mixer (44) receiving said output signals from said maximum detecting circuit and said minimum detecting circuit for producing a nonadded mixed output signal therefrom.
Claim 9
Dependent Claim
96 words
Apparatus according to claim 7, in which said maximum detecting circuit includes a plurality of maximum level detecting circuits (35, 36, 37) each receiving at one input said reference level signal and at another input one of said time delayed output signal or said output signal from said first synthesizer and each producing an output signal corresponding to the signal having the greater level and a further maximum level detecting circuit (55) receiving said outputs from said plurality of maximum level detecting circuits for producing an output signal corresponding to the signal having the highest level.
Claim 10
Dependent Claim
95 words
Apparatus according to claim 7, in which said minimum detecting circuit includes a plurality of minimum level detecting circuits (38, 39, 40) each receiving at one input said reference level signal and at another input one of said time delayed output signal or said output signal from said first synthesizer and each producing an output corresponding to the signal having the lowest level and a further minimum level detecting circuit (56) receiving said outputs from said plurality of minimum level detecting circuits for producing an output corresponding to the input signal having the lowest level.
References Cited (Backward Citations)
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