Abstract: A SECAM decoder and an FM modulator therefor are disclosed, in which a demodulated color signal is provided to indicate deviations in the frequency of modulated color information from a nominal subcarrier frequency. The demodulator comprises numerator and denominator filters operating on the modulated color information, and a divider providing a ratio result by dividing the numerator filter output by the denominator filter output. The demodulator may include two sets of numerator and denominator filters offset in phase from one another, where one of the two sets is selectively employed in order to mitigate divide-by-zero problems. Also disclosed are methods for demodulating digitized FM color signals in a SECAM decoder.

Abstract: A dual-loop PLL circuit is provided with a clamping circuit 12, an A/D conversion circuit 14, a reference color burst outputting circuit 18, a PLL circuit 24, and phase detecting circuit 34. The phase of a reference color burst KK outputted from the circuit 18 is changed at a slice level SL, and the level SL is changed by a reference phase value in the phase detecting circuit 34. The sampling clocks outputted from the PLL circuit 24 to the A/D conversion circuit 14 are converted to a signal of a frequency of 4 Fsc, and the phase of the signal can be changed continuously by using the reference phase value. In addition, since the phase of the sampling clocks can be adjusted to a desired value and the output signal of the A/D conversion circuit 14 can be converted onto a prescribed color difference signal by a signal conversion circuit and outputted, the color difference signals can be demodulated easily with high accuracy.

Abstract: A system with chrominance delay lines has a first sampled channel including at least one smoothing filter, and has a second unsampled channel. A continuous bypass filter is placed in the second channel to balance the pulse response from these two channels.

Abstract: An absolute-value difference arithmetic section obtains an absolute-value difference from a first component and a second component. A component discriminating section or a signal discriminating section (circuit) discriminates an inputted chroma signal by phase discrimination and distance discrimination using the absolute-value difference. A correction executing section corrects the phase of the inputted chroma signal using the absolute-value difference. The absolute-value difference arithmetic section is formed by an adder and/or a subtracter on a small circuit scale.

Abstract: An image processing apparatus and method which can reduce the size of circuits for &agr;-blending and dithering and realize high speed processing which perform in parallel processing for finding an amount of update of present image data to be drawn with respect to image data already stored in a display buffer by using a blending coefficient in a subtractor and a multiplier and processing for adding noise data to the image data already stored in the display buffer in a first adder and adding the data obtained by the two processing at a second adder so as to find data comprised of noise data added to data obtained by linear interpolation of two colors, then extracting color valid values at a clamp circuit, thinning out the extracted data in a rounding-off circuit, and writing it back to the display buffer.

Abstract: A color comb filter (46), video decoder (40) and method for separating chroma (U,V) and luma (Y) signals from a composite video signal (41). The comb filter (46) includes circuitry (48) for generating color filter selections for filtering a chroma video signal (41) and control logic (62) for determining the filter selections based on color boundary properties of the chroma video signal (U,V). The video decoder (40) includes a comb filter (46), a demodulator (42), low pass filter (44), a remodulator (48) and a subtractor (50). The filtered, remodulated chroma signal (Uout,Vout) is subtracted from the composite video signal (41) to produce a luma signal absent hanging dots and false colors.

Abstract: The demodulating device for a chrominance signal includes an oscillator with a controlled frequency, and an adjuster for adjusting the oscillator frequency as a function of a charge voltage of a memory capacitor. The adjuster preferably includes a fine adjustment channel to output a first adjustment value that depends on the charge voltage of the memory capacitor, and a coarse adjustment channel to output a second adjustment value. The second adjustment value is modified when the charge voltage of the memory capacitor is not within a given range. The device is used, for example, in integrated SECAM decoders.

Abstract: A signal processing system and process for digitally filtering a single tone digital signal is disclosed. The system includes a single tone signal generator, which may or may not perform frequency modulation. The single tone signal generator receives an input signal and generates a frequency indicator which is used internally by the single tone signal generator and is also communicated to a direct realization filter. The direct realization filter uses the frequency indicator to generate a phase offset indicator, which is communicated back to the single tone signal generator. The single tone signal generator uses the frequency indicator and the phase offset indicator to generate a phase-adjusted single tone signal. The direct realization filter generates a filter gain and multiplies the single tone signal with the filter gain to produce a filtered single tone signal.

Abstract: A television receiver includes a tuner for receiving either analog or digital signals. Separate analog and digital demodulators are selectively coupled to the tuner through an RF switch that is controlled by the signal from a sync detector in the output of the analog demodulator. The selected one of the demodulators develops an AGC signal that is coupled to the tuner through a current mirror. Operating potential for the demodulators is coupled through the RF switch so that the oscillator in the non-selected demodulator is disabled and precluded from interfering with the oscillator in the enabled demodulator.

Abstract: A television receiver includes a tuner for receiving either analog or digital signals. Separate analog and digital demodulators are selectively coupled to the tuner through an RF switch that is controlled by a sync detector in the output of the analog demodulator. The selected one of the demodulators develops an AGC signal that is coupled to the tuner through the RF switch. In one embodiment, a two pole RF switch is used with one pole switching the IF signal and the other pole switching the AGC signal In another embodiment, a single pole RF switch is used with the tuner signal and the AGC signal being multiplexed through the switch. This is accomplished by the provision of a high frequency path and a low frequency path between each of the RF switch and the tuner, the RF switch and the analog demodulator, and the RF switch and the digital demodulator.

Abstract: The circuit configuration provides for the combined color decoding and decimation of a video signal, particularly for picture-in-picture insertion in television sets. The color subcarrier is determined from a video signal for the purpose of recovering the chrominance signal components. The video signal is multiplicatively combined with orthogonal color subcarrier components and then filtered through low-pass filters. For the luminance signal components, the video signal is filtered by a further low-pass filter. In order to obtain decimated luminance and chrominance signal components, subsampling is carried out after the low-pass filters. Given suitable dimensioning of the low-pass filters matched to the decimation factor, a single low-pass filter in each of the chrominance signal paths is sufficient and, in the luminance signal path, an otherwise necessary notch filter is obviated.

Abstract: An apparatus for processing television signal including an A/D converter which converts a television signal (a luminance signal) into a digital television signal. A sampling circuit samples television signal data outputted from the A/D converter in response to a sampling clock outputted from a VCO included in a PLL, and outputs sampled data. An output of the A/D converter is also applied to a band elimination filter which outputs luminance signal data that a chrominance signal component is completely eliminated. The sampled data and the luminance signal data are compared with each other by a comparator, and an output of the comparator is applied to a low-pass filter included in the PLL during a burst period. An output of the low-pass filter becomes a control voltage signal for the VCO, whereby an oscillation frequency (phase) of the VCO is controlled.

Abstract: A color system determination circuit for use with an input video signal having a frequency component is disclosed. The circuit includes a color trap filter for attenuating the frequency component in the input video signal with the color trap filter providing a color burst output signal, a comparator for comparing the color burst output signal of the color trap filter and the frequency component of the input video signal, a maximum value detector which receives the color burst output signal of the color trap filter and a color burst sampling signal and detects a maximum value of the color burst output signal of the color trap filter during a period of the color burst sampling signal, and another maximum value detector which receives the video signal and the color burst sampling signal and detects a maximum value of the video signal during the period of the color burst sampling signal.

Abstract: The SECAM chrominance signal demodulator includes an oscillator with a controlled frequency, a phase comparator with a first input connected to an oscillator output, a second input to receive a chrominance signal, and an output connected to an input loop of the oscillator. The demodulator further includes a fixed current source, also connected to the loop input, a current mirror to copy a current equal to the sum of the fixed current and a comparator output current in the output branches comprising first and second calibration resistors respectively, in series with a common resistor. Output voltages corresponding to the red and blue components of the chrominance signal are measured at the terminals of the calibration resistors respectively. The demodulator is used in television sets, for example.

Abstract: A color video signal demodulating apparatus is provided. The apparatus includes a color subcarrier signal generator for generating a color subcarrier signal synchronously with a color burst, an abnormal burst detector for detecting an abnormal color burst included in a color video signal, such as a signal for the DVD, and a color subcarrier signal generation controller for controlling the color subcarrier signal generator such that no color subcarrier signal corresponding to the abnormal color burst is generated in response.

Abstract: An apparatus to modulate the digital color signal using a simple circuit that utilizes neither multiplier nor ROMs to multiplying a sine wave and cosine wave. The digital color signal modulating apparatus includes a first selector, a second selector 3, and a third selector. The first selector and the second selector provide the U signal component and the V signal component of the digital color signal to the third selector at a half cycle, rate respectively. The third selector alternately selects one of those signals, which is combined with the sub-carrier wave. For both modulations with the sine wave and with the cosine wave, the input signal is inverted and the fourth selector selects the outputs of the through path and the inversion path in turn, thus producing the modulated outputs.

Abstract: A method and system for separating chrominance and luminance information from a composite spectral signal is disclosed. The method and system comprises demodulating the composite signal prior to separation of the chrominance or luminance information to provide a first U subcomponent and a first V subcomponent and then processing and filtering the first U subcomponent and the first V subcomponent to provide a second U subcomponent and a second V subcomponent, respectively. The method and system also includes combining the second U subcomponent and the second V subcomponent to provide the remodulated chrominance information. In so doing chrominance information is provided in which artifacts are substantially attenuated.

Abstract: A clock generation circuit for a digital video processing apparatus which has a simple structure and can be stably worked in both luminance and color signal systems. A color burst phase error signal indicative of phase difference of a color burst signal is produced on the basis of two color difference signals, a sampling clock signal is generated in accordance with the color burst phase error signal, the sampling clock is divided in order to produce a chrominance subcarrier signal, and the phase of the chrominance subcarrier signal is adjusted in accordance with the color burst phase error signal.

Abstract: A device and method for generating a composite color signal are disclosed. The device includes a first memory unit for storing digital cosine data, a second memory unit for storing digital sine data, a first arithmetic unit for multiplying digital color difference data Cr input thereto with the digital cosine data, a second arithmetic unit for multiplying digital color difference data Cb input thereto with the digital sine data, and an adder for adding outputs of the first and arithmetic units to generate a digital composite color signal. The method includes the steps of storing digital cosine data and sine data in at least one of first and second memories, modulating digital color data using the stored digital sine and cosine data, and generating a composite color signal using the modulated digital color data.

Abstract: In accordance with an illustrative embodiment of the invention, a composite video signal is decoded as follows. A filtered and optionally re-sampled luminance component is obtained by vertical low-pass filtering the composite video signal using a vertical low-pass filter. The vertical low-pass filter may also be a re-sampler so that the output is optionally a filtered and re-sampled luminance signal. (Note that the use of a single vertical low-pass filter and re-sampler is more efficient than the prior art which uses a luma comb filter followed by a vertical filter/re-sampler to obtain the filtered and optionally re-sampled luminance component). Filtered and re-sampled chrominance components are obtained by first vertically high-pass filtering and re-sampling the composite video signal using a vertical high pass filter/re-sampler. This results in filtered and re-sampled but still quadrature modulated chroma signals.

Abstract: A device for encoding sequences of frames constituted by video-type images of a first frequency (for example, 30 Hz) and film-type images whose original frequency is lower than this first frequency (for example, 24 Hz) and which are converted by means of the "3:2 pulldown" technique.The encoding device comprises;a circuit for detecting the sequences of film-type images from the stream of input data, anda device for preprocessing these sequences for realizing an inverse conversion of the frequency by eliminating, before encoding, the redundant information introduced by the use of the "3:2 pulldown" method.

Abstract: The invention relates to a detector for detecting reception of a color television signal coded according to the SECAM standard of the type including a filter pretuned by a general control of the filters of an integrated circuit for identifying the standard according to which the television signal is coded and a phase comparator receiving the input and output signals of the filter, and including circuitry for tuning the frequency of the filter on the actual mean frequency of two consecutive lines of the signal.

Abstract: A video signal decoder using a sample clock tied to a frequency that is an integer multiple of four times the color subcarrier (4*Fsc). By using a 4*Fsc rate on a given input wave, the decoder determines the phase shift between the sample clock and the original wave being sampled. Then, the decoder calculates the color based upon that shift. Circuitry for implementing the decoder contains two major circuit paths. The decoding process consists of two main phases and each path performs a different function during each phase. During the first phase, the first path calculates constants based upon a user's hue and saturation adjustments used for chroma demodulation. Also during the first phase, the second path examines the color burst signal and from that signal finds the black level of the incoming video signal. During the second phase, the first path decodes the color in the TV signal using the constants calculated during the first phase.

Abstract: A circuit arrangement for the digital identification of television transmission standards, particularly PAL, SECAM and NTSC. Provision is made for transmission standard demodulation stages connected in parallel to which a signal composed of a chromaticity signal and a synchronizing character is directed and which are each cyclically activated by control signals for a certain period of time. A trigger is also provided, together with an up-down counter, a circuit arrangement for the evaluation of the value delivered by the up-down counter, and a control logic.

Abstract: In a digital chrominance signal demodulating device receiving a carrier chrominance signal obtained by digitizing an analog composite video signal, a frequency component near the horizontal frequency of the color subcarrier is extracted, and color-difference signals are output. An identifying circuit forms a selection signal for identifying one of the color-difference signals contained in the carrier chrominance signal, within a color burst signal period, on the basis of a system clock and a horizontal sync signal. A selecting circuit selects the color-difference signals on the basis of the selection signal. The color-difference signals obtained by sampling in accordance with the system clock are kept in phase with the color burst signal. Accordingly, the digital chrominance signal can be demodulated by the use of less expensive digital circuits.

Abstract: A PAL system demodulator capable of delivering high quality color signals even in the cases of poor vertical correlation comprising 1H delay line 1 delaying the chroma signal by one horizontal period, 1H delay-line 2 delaying a reference signal by one horizontal period wherein the output of the 1H delay line 1 is defined by reference signal, color demodulating circuit 3 canceling hue error by conducting an operation between the scanning lines covering from the input and the output of the 1H delay line 1, color-demodulating circuit 4 canceling the hue error by conducting an operation between the scanning lines covering from the input and the output of the 1H delay line 2, vertical correlation detecting circuit 5 detecting the vertical correlation between the chroma signal of the reference signal and the chroma signal of the adjoining line or the chroma signal of the adjoining line separated by one-line, and selector 6 selecting the output of the color demodulating circuit 3 or the output of color demodulating

Abstract: A dual chrominance signal processor is disclosed which may be used in a combination television and video cassette recorder system, for example. Such a chrominance signal processor includes first and second modulated chrominance signal sources, and first and second demodulating carrier signal sources, corresponding to the first and second modulated chrominance signal sources, respectively. A demodulator is responsive to a chrominance signal and a demodulating carrier signal, for demodulating the chrominance signal. A signal selector is coupled between the signal sources and the demodulator, and selectively couples one of the first and second chrominance signal sources, and the corresponding one of the first and second demodulating carrier signal sources, to the demodulator in response to a selection signal.

Abstract: A video-scrambling system induces a random wobble i.e., time shifting, in the location of active portion of the video frame, without affecting the horizontal sync signal and colorburst in each video line, thus providing both security and concealment. The security is enhanced by filling in the gap between the nominal beginning of active video and the actual beginning of active video with a synthesized video signal which replicates the adjacent active video using a digitally generated filling pattern. Also, a random noise overlay further conceals the location of the gap. Additional concealment is provided by wiggling in time the location of the horizontal sync signal using one or two frequencies and also by randomly altering the location of the vertical sync signal. The NTSC digital encoding in accordance with the invention is simplified by using only two channels, chrominance and luminance, and by a heterodyne circuit for chrominance stability.

Abstract: An adaptive type color demodulation apparatus for the PAL system includes a first color demodulating circuit (PAL-D) for demodulating a PAL system chrominance signal between scanning lines and a second color demodulating circuit (PAL-S) for demodulating the PAL system chrominance signal on a scanning line. Also included is a vertical correlation detecting circuit for detecting a vertical correlation between chrominance signals which are separated by two horizontal periods and a selector for selecting either an output of the first color demodulating circuit or an output of the second color demodulating circuit in response to the detected result of the correlation detecting circuit. Accordingly, hue distortion of the chrominance signal which occurs during signal transmission is cancelled even if the phase distortion is large and a precise color signal is demodulated even if there is no correlation between adjacent scanning lines.

Abstract: A frequency-multiplexed video signal is generated in which a color-under signal and a second under signal are linearly combined with at least partially overlapping frequency spectra to form a composite under signal for an FM luma signal. The frequency-multiplexed video signal is suited for recording on magnetic tape using helical scanning methods and for being played back from the magnetic tape using helical scanning methods. The second under signal is generated in such way that line-comb filtering can be used during playback to separate color-under signal and second under signal each from the composite signal despite their frequency spectra being at least partially overlapping in the composite signal.

Abstract: A color signal demodulation circuit demodulates a color signal in correspondence with different chrominance subcarrier frequencies. The input color signal is delayed by .pi./2 using a so-called Hilbert transformer and the carrier signal for use in the demodulation is generated from a carrier generator. The input color signal and the carrier signal are selectively multiplied and added so as to demodulate a color difference signal of the desired baseband, to thereby correspond to the chrominance subcarriers having different frequencies while simplifying the hardware. A method for demodulating the chrominance signal, which method is particularly adapted to the demodulation circuit is also detailed.

Abstract: A synchronous demodulator is controlled by a phase locked loop for tuning to a pilot in a television signal. A start-up interval is commenced upon initiation of tuning (either after power-up or a channel change) during which a substitute signal at the pilot frequency is supplied to the phase locked loop to rapidly bring the VCO close to its lock-up frequency. Thereafter the IF signal is supplied. The start-up interval is defined by an AFC Defeat signal from a microprocessor and controls an IF switch. The substitute signal is from a crystal oscillator.

Abstract: A video signal processing device comprises: a unit for extracting a first color burst signal from a first video signal; a unit for generating a first subcarrier in synchronism with the first color burst signal extracted from the first video signal; a unit for extracting a second chrominance signal and a second color burst signal from a second video signal; a unit for demodulating the second chrominance signal and the second color burst signal on the basis of the first subcarrier to obtain a demodulated second color signal and a demodulated second color burst signal; and an operating unit for performing operation process of the demodulated second color signal on the basis of the demodulated second color burst signal in a manner such that the demodulated second color signal is converted into a corrected color signal which is substantially the same as an imaginal second color signal which is obtained on the assumption that the second chrominance signal is demodulated on the basis of a second subcarrier synchroni

Abstract: An I-axis phase pulse is allowed to be detected at the sampling point of a chrominance signal with a digitally-implemented circuit. A chrominance signal (sampling frequency f.sub.1) is subsampled by a frequency f.sub.2 (f.sub.1 /N) and subsampling pulses generated in N subsampling pulse generators 10 for N phases, the adjacent ones of the pulses being shifted by one clock (1/f.sub.1) with respect to one another. The subsampled chrominance signal is input to an I-axis determining circuit 17. The I-axis determining circuit operates to detect a maximum value M.sub.1 of a color burst signal (sampling frequency f.sub.1) and the data M.sub.2 after one clock and compare both of the values with each other. Based on the compared result, a selecting signal S.sub.4 is detected for selecting an I-axis phase pulse at the sampling point of the chrominance signal. A selecting circuit 18 selects, as an I-axis phase pulse S.sub.

Abstract: An automatic on-screen color signal converting circuit is disclosed, which includes a color signal level detecting part (30), an inverting part (40), and combining/switching part (70), wherein the color signal level detecting part (30) detects the level of the video color signal from the input color difference signal and luminance signal and the inverting part (40) inverts the output signal of the color signal level detecting part (30) to combine them with an on-screen signal blanking signal outputted from an OSD generating part (60). Therefore, the cathode ray tube driving circuit (20) is provided with an OSD color signal which is complementary to that of the video signal and the on-screen signal can be always clearly distinguished from the video signal during their simultaneous display and also automatically converted according to changing of the video signals.