Abstract: A scene change detecting circuit (1) detects a scene change of video. An average luminance level operating circuit (2) calculates an average luminance level (APL) of a video signal (VD). A luminance overdrive amount calculating circuit (3) calculates a luminance overdrive amount (OD) based on the average luminance level (APL). A time-linked attenuating circuit (7) outputs a power consumption limit correction amount (PA) by attenuating the luminance overdrive amount (OD) with an elapse of time from a point in time of detecting the scene change. An adder (8) adds the power consumption limit correction amount (PA) and a reference power consumption limit value (Lp) to output the addition result as a power consumption limit amount (PL). An ABL circuit (4) calculates a luminance limit amount (BL) based on luminance limit characteristics, the average luminance level (APL) and the power consumption limit amount (PL).

Abstract: A scene change detecting circuit (1) detects a scene change of video. An average luminance level operating circuit (2) calculates an average luminance level (APL) of a video signal (VD). A luminance overdrive amount calculating circuit (3) calculates a luminance overdrive amount (OD) based on the average luminance level (APL). A time-linked attenuating circuit (7) outputs a power consumption limit correction amount (PA) by attenuating the luminance overdrive amount (OD) with an elapse of time from a point in time of detecting the scene change. An adder (8) adds the power consumption limit correction amount (PA) and a reference power consumption limit value (Lp) to output the addition result as a power consumption limit amount (PL). An ABL circuit (4) calculates a luminance limit amount (BL) based on luminance limit characteristics, the average luminance level (APL) and the power consumption limit amount (PL).

Abstract: The vertical/horizontal amplitude control device for controlling a vertical amplitude and a horizontal amplitude of an image display device for displaying a video signal includes a brightness level detector for detecting a brightness level of the video signal, a vertical amplitude controller for controlling the vertical amplitude based on the brightness level, and a horizontal amplitude controller for controlling the horizontal amplitude based on the brightness level. The device controls the vertical and horizontal amplitudes into constant without a delay from a change of a video signal even when the brightness level of the video signal abruptly changes.

Abstract: The automatic cut-off system includes a video data processing circuit, a cut-off control circuit, a drive circuit, and a level control section. The video data processing circuit adds a cut-off reference pulse having a predetermined level to primary-color signals of red (R), green (G) and blue (B) at different timings within a single vertical blanking interval, and outputs latch timing signals respectively indicating the timings. The cut-off control circuit shifts a level of each primary-color signal having the cut-off reference pulse added thereto based on a corresponding cut-off control signal. The drive circuit drives each cathode of a CRT (cathode-ray tube) based on a corresponding one of the shifted primary-color signals, and outputs a voltage corresponding to each cathode current as a common feedback signal. The level control section latches the feedback signal in response to each latch timing signal, and outputs the cut-off control signal of one of the primary-color signals.

Abstract: Disclosed are an apparatus and a method for YC separation and three-line correlation detection with high accuracy, which allow the YC separator to generate reliable Y signals. The correlation detecting apparatus includes a sub-correlation detector. The detector checks input signals for the presence or absence of vertical correlation, and provides the signals with a judgment “high-correlation exists” or “otherwise”. According to the judgment, the correlation detecting apparatus changes the process; i) when accepted the judgment “high-correlation exists”, the apparatus determines the judgment to be reliable and adopts it as the output, ii) when accepted “otherwise”, the apparatus increases its detecting accuracy and provides the signals with multi-leveled outputs according to the correlation levels. In this way, the main apparatus switches the detecting mode according to the result from sub-correlation detector, with the detecting accuracy greatly improved.

Abstract: A horizontal automatic frequency control (AFC) used in a display having a display device such as a cathode ray tube (CRT) is provided. The AFC circuit reduces a horizontal distortion and horizontal jitter on the CRT. The AFC circuit includes a video signal processor for demodulating and converting an input video signal into a desired signal such as a YUV signal or an RGB signal, a synchronous separator for separating a synchronizing signal from the video signal, a dual-port line memory, an Hout generator for generating a horizontal driving pulse which drives a horizontal deflection yoke, a read clock generator for generating a read clock (RCK) signal which is synchronized in phase with a flyback pulse, and a horizontal deflection driver for controlling horizontal deflection of the CRT and generating the flyback pulse. The line memory absorbs a horizontal position change of a displayed image caused by a temperature change or a load change in the horizontal deflection driver.

Abstract: The vertical/horizontal amplitude control device for controlling a vertical amplitude and a horizontal amplitude of an image display device for displaying a video signal includes a brightness level detector for detecting a brightness level of the video signal, a vertical amplitude controller for controlling the vertical amplitude based on the brightness level, and a horizontal amplitude controller for controlling the horizontal amplitude based on the brightness level. The device controls the vertical and horizontal amplitudes into constant without a delay from a change of a video signal even when the brightness level of the video signal abruptly changes.

Abstract: A contour correction circuit includes a delay circuit for delaying an input video signal, a corrected waveform generating circuit for generating a contour correction signal out of the input video signal, a variable amplifier for controlling an amplitude of the contour correction signal, a contour control circuit for outputting a gain control signal for controlling a gain in the variable amplifier,. and a first adding circuit for adding an output signal of the delay circuit to an output of the amplifier. When an amplitude-change in an edge portion of the input video signal is over a given level, the smaller amount of contour is corrected at the larger amplitude change. Therefore, even if a signal of a high contrast ratio is adjacent to a signal of a low contrast ratio, desirable contour corrections can be provided to respective signal components.

Abstract: A phase controller of a horizontal drive pulse fed into a horizontal deflection circuit supplying a horizontal deflection pulse, and a control method of the same are disclosed. A frequency discriminator identifies a format of video-input-signal by detecting a frequency of the horizontal sync signal. A reference phase generator generates a reference phase signal based on the output from the frequency discriminator. A sawtooth waveform generator generates a sawtooth waveform signal responsive to the output from the frequency discriminator. A phase difference voltage detector outputs a phase difference voltage responsive to the phase difference between the reference phase signal and the horizontal deflection pulse. A phase control signal generator generates a phase control signal using the phase difference voltage and the sawtooth waveform signal. Horizontal drive pulse generator outputs a horizontal drive pulse having a phase responsive to the phase control signal.

Abstract: A color demodulation apparatus having color demodulation capabilities as the conventional ones, with its size reduced by sharing part of processing circuit therein is provided. An adder circuit 10 and a SW circuit 11 shift the phase of a ramp wave generated by a VCO circuit 9 alternately 90 degrees and 180 degrees for each clock. A SIN data generator circuit 12 generates a phase alternate SIN wave signal from the shifted ramp wave. A multiplier circuit 3 performs R-Y and B-Y demodulation through multiplexing based on the phase alternate SIN wave signal. An accumulator circuit 6 accumulates burst signals of each of R-Y and B-Y signals of the demodulated, multiplexed signal. A second load hold circuit 8 separately outputs an R-Y burst signal to the VCO circuit 9, and a B-Y burst signal to a comparator circuit 13, constituting two feedback loops. A first load hold circuit 5 separates R-Y and B-Y signals from the multiplexed signal, and outputs these two signals.

Abstract: A color signal reproducing circuit having A/D converter 101, sync separator 102, YC separator 103, gain controller 105, multipliers 106 and 107, low-pass filters 108 and 109, burst-period cumulative adders 110 and 111, SINCOS generator 112, clock generator 113, and ramp-wave generator 114. The simple structure allows a color signal reproducing circuit to be used commonly in a different television systems without changing its clock frequency considerably in accordance with broadcasting systems and also achieves YC separation and color signal demodulation from analog composite signal with a higher degree of precision.

Abstract: The automatic cut-off system includes a video data processing circuit, a cut-off control circuit, a drive circuit, and a level control section. The video data processing circuit adds a cut-off reference pulse having a predetermined level to primary-color signals of red (R), green (G) and blue (B) at different timings within a single vertical blanking interval, and outputs latch timing signals respectively indicating the timings. The cut-off control circuit shifts a level of each primary-color signal having the cut-off reference pulse added thereto based on a corresponding cut-off control signal. The drive circuit drives each cathode of a CRT (cathode-ray tube) based on a corresponding one of the shifted primary-color signals, and outputs a voltage corresponding to each cathode current as a common feedback signal. The level control section latches the feedback signal in response to each latch timing signal, and outputs the cut-off control signal of one of the primary-color signals.

Abstract: In a horizontal deflection circuit, a waveform response of a horizontal output pulse must be adequately taken into account before and after a switching of the horizontal output pulse so that the waveform does not lack in shape and does not lose continuity at the switching. A switching apparatus for a horizontal driving apparatus includes (a) a horizontal driving pulse generator which generates a horizontal driving pulse from a horizontal synchronization signal, (b) an alternative signal generator which outputs an alternative signal different from the horizontal driving pulse, (c) a horizontal output control device which determines a timing to switch between the horizontal driving pulse and the alternative signal, and (d) a switching device which switches an output pulse with a control signal which is output from the horizontal output control device.

Abstract: A horizontal automatic frequency control (AFC) used in a display having a display device such as a cathode ray tube (CRT) is provided. The AFC circuit reduces a horizontal distortion and horizontal jitter on the CRT. The AFC circuit includes a video signal processor for demodulating and converting an input video signal into a desired signal such as a YUV signal or an RGB signal, a synchronous separator for separating a synchronizing signal from the video signal, a dual-port line memory, an Hout generator for generating a horizontal driving pulse which drives a horizontal deflection yoke, a read clock generator for generating a read clock (RCK) signal which is synchronized in phase with a flyback pulse, and a horizontal deflection driver for controlling horizontal deflection of the CRT and generating the flyback pulse. The line memory absorbs a horizontal position change of a displayed image caused by a temperature change or a load change in the horizontal deflection driver.

Abstract: Disclosed are an apparatus and a method for YC separation and three-line correlation detection with high accuracy, which allow the YC separator to generate reliable Y signals. The correlation detecting apparatus includes a sub-correlation detector. The detector checks input signals for the presence or absence of vertical correlation, and provides the signals with a judgment “high-correlation exists” or “otherwise”. According to the judgment, the correlation detecting apparatus changes the process; i) when accepted the judgment “high-correlation exists”, the apparatus determines the judgment to be reliable and adopts it as the output, ii) when accepted “otherwise”, the apparatus increases its detecting accuracy and provides the signals with multi-leveled outputs according to the correlation levels. In this way, the main apparatus switches the detecting mode according to the result from sub-correlation detector, with the detecting accuracy greatly improved.

Abstract: In a signal processing circuit for separating a color video signal into a luminance signal and a chrominance signal, whether the correlation relating to the high frequency component of luminance signal and chrominance signal of color video input signal is high or low before and after one horizontal scanning period is detected by a vertical correlation detecting circuit, and the presence or absence of correlation of the detected output signal in the horizontal scanning line is detected by a horizontal correlation detecting circuit. The output signal of the horizontal correlation detecting circuit before and after one horizontal scanning period is supplied into a logic circuit, and depending on the gate output signal obtained therein, the high frequency component of luminance signal and chrominance signal before and after one horizontal scanning period are processed in an operation processing circuit, and a chrominance signal is delivered.

Abstract: A primary color video output circuit for limiting an input video signal. The circuit includes a clipping circuit, a reference voltage generating circuit and an amplifier. The clipping circuit limits the level of the input video signal based on a reference voltage generated by the reference voltage generating circuit. The amplifier is then used to amplify the clipped video signal.

Abstract: A 2-line YC separation device reduces the number of delay circuits used for horizontal scanning time delay and minimizing arithmetic operation errors of comb-line filters.

Abstract: A noise suppression apparatus suppresses noise of a luminance signal, for example, at a fringe of area of reception in a television receiver. The noise suppression apparatus includes a tuner circuit, an intermediate frequency amplification circuit, a video detection/amplification circuit, an AGC detection/amplification circuit, an RF AGC circuit, a sound/chrominance signal separation circuit, a luminance signal processing circuit and a luminance signal noise suppression circuit.