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公开(公告)号：CA959571A
公开(公告)日：1974-12-17
申请号：CA118915
申请日：1971-07-22
Applicant: RCA CORP
Inventor： HARWOOD LEOPOLD A
IPC: H04N9/64
Abstract: Tint correction is provided in a color television system by altering the phase of the color subcarrier reference signal before application of this signal to color demodulators. Phase alteration is accomplished by monitoring the chrominance signals prior to demodulation to determine whether they possess phase components about the flesh axis. If such components exist, the chrominance signal is vectorially added to the reference oscillator signal to provide a new phased oscillator signal which, when applied to the demodulators, causes them to provide color signals representative of flesh tone.
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公开(公告)号：CA1228669A
公开(公告)日：1987-10-27
申请号：CA490855
申请日：1985-09-16
Applicant: RCA CORP
Inventor： HARWOOD LEOPOLD A , WARGO ROBERT A
Abstract: An adaptive filtering system is disclosed. The system may be used in a digital television receiver to extract low frequency vertical detail information from a comb filtered chrominance signal. This system provides wide bandwidth vertical detail information when the amplitude of the chrominance component of the composite video signal is low and narrower bandwidth vertical detail signals as the amplitude of the chrominance component increases. Adaptive filtering is accomplished by passing the comb filtered chrominance signal through a first low-pass filter, developing two reduced amplitude replicas of the filtered signal which are mutually supplementary. The ratio of the amplitudes of these two replicas is variable with a control signal. One replica is passed through a second low-pass filter and combined with the other replica to produce a vertical detail signal. The embodiment of the system that is disclosed includes means for developing a control signal that is proportional to the instantaneous amplitude of the chrominance component of the composite video signal.
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Patent Agency Ranking
公开(公告)号：CA1217857A
公开(公告)日：1987-02-10
申请号：CA440759
申请日：1983-11-08
Applicant: RCA CORP
Inventor： HARWOOD LEOPOLD A
Abstract: Quadrature-related outputs of synchronized color reference oscillator at +(R-Y) and +(B-Y) phases are applied to a matrix to develop a third oscillatory signal of a third intermediate phase. Additional operations on the oscillator outputs develop oscillatory signals of different phases symmetrically disposed about the third phase. A differential amplifier, of substantially fixed gain, with differential inputs respectively responsive to the developed oscillatory signals, further develops a fourth oscillatory signal, with a phase in quadrature relation with said third phase, across an output load. The reference signal input for a demodulator is derived from signals appearing across said output load. A controlled amplifier, fed with the third oscillatory signal, is disposed to supply said third oscillatory signal as an additional oscillatory signal to said output load, when desired for hue adjustment purposes, with the magnitude of the supplied additional signal dependent upon the magnitude of difference, if any, between an adjustable control voltage and a reference voltage, and the polarity of the supplied additional signal dependent upon the sense of said difference.
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公开(公告)号：CA1192969A
公开(公告)日：1985-09-03
申请号：CA422929
申请日：1983-03-04
Applicant: RCA CORP
Inventor： HARWOOD LEOPOLD A , SHANLEY ROBERT L II
Abstract: A pair of differential amplifier stages are connected in cascade to form a multistage amplifier for signal amplification purposes. The base-emitter paths of current source transistors which establish the operating currents for the respective stages are connected in series across a common source of forward bias voltage. The collector-emitter path of an additional transistor is shunted across the base-emitter path of one of the current source transistors. As biasing of the additional transistor is varied, the distribution of gain between the respective cascaded stages is altered substantially without disturbance of the overall gain of the multistage amplifier.
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公开(公告)号：CA1175560A
公开(公告)日：1984-10-02
申请号：CA398510
申请日：1982-03-16
Applicant: RCA CORP
Inventor： HARWOOD LEOPOLD A , WITTMANN ERWIN J
Abstract: RCA 74,884 A frequency selective signal translating circuit is disclosed for use in a color television receiver including an automatic flesh tone color correction network which provides a reference signal for color demodulators of the receiver. The circuit comprises an input bandpass filter for attenuating unwanted frequency components from the reference signal output of the correction network. The filter is followed by a phase shifter for shifting the phase of the filtered reference signal as required for proper demodulator operation. The filter comprises a fixed alignment, single-tuned, series resonant circuit coupled in series between the correction network output and the demodulator reference signal inputs.
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公开(公告)号：CA1159948A
公开(公告)日：1984-01-03
申请号：CA368421
申请日：1981-01-13
Applicant: RCA CORP
Inventor： SHANLEY ROBERT L II , HARWOOD LEOPOLD A , WITTMANN ERWIN J
Abstract: RCA 73,113 A circuit for generating a composite keying signal comprises a burst gate circuit and a voltage translating network in a color television receiver also including keyed signal processing circuits and means for deriving horizontal and vertical blanking signals and a horizontal sync signal from a composite color television signal containing a color burst component. The burst gate circuit responds to the horizontal sync signal to develop a burst gate pulse encompassing the burst interval. A voltage level developed by the translating network in response to the horizontal and vertical blanking signals is combined with the burst gate pulse to produce a composite keying signal. The composite keying signal comprises a first pulse component of a desired level as determined by the translating network and occurring during the blanking intervals, and a second pulse component as provided from the burst gate circuit, superimposed on the first pulse and encompassing the burst interval. Means are also included for inhibiting the output of the keying signal generator during picture intervals of the television signal, to prevent false keying of the keyed circuits in response to keying signals generated by the keying signal generator in the presence of spurious input signals occurring during picture intervals.
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公开(公告)号：CA1156375A
公开(公告)日：1983-11-01
申请号：CA366743
申请日：1980-12-12
Applicant: RCA CORP
Inventor： HARWOOD LEOPOLD A , WITTMANN ERWIN J , SHANLEY ROBERT L II
Abstract: RCA 73,402 An automatic kinescope beam current limiter for a television receiver comprises a source of signal representative of kinescope beam current conduction, a first transistor responsive to the representative signal over first, second and third ranges of excessive beam currents above a threshold level, and a second transistor. A first control signal derived from the first transistor modifies the video signal peak-to-peak amplitude (contrast level) when beam currents above the threshold level occur. The output of the first transistor is selectively coupled to an input of the second transistor when beam currents beyond the first range occur. A second control signal derived from the second transistor modifies the video signal D.C. component (brightness level) to limit beam currents beyond the first range, whereby both the peak amplitude and D.C. components are modified over the second range. The first control signal is clamped to a fixed level in response to beam currents beyond the second range, whereby the video signal D.C. component is modified alone to limit beam currents over the third range.
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