Abstract: HDMI is a digital audio and video communications protocol commonly used in consumer electronics. HDMI is particularly synonymous with high fidelity audio and video. Even though HDMI is a digital communications protocol, the audio quality can be impaired by analog signal impairments and distortions even if there are no digital decoding errors. In particular, the very process by which the audio is converted from Digital (HDMI) to human audible “Analog Audio” can be prone to errors. This occurs when the Digital to Analog Converter (DAC) clock, which is derived from the HDMI TMDS clock or HDMI source, is “distorted” due to its jitter, resulting in erroneous sampling or outputting of vital audio samples, thereby reducing the audio quality of the experience. The present invention reduces the jitter on the TMDS clock, and hence the audio DAC clock, resulting in lower audio distortion.

Abstract: A receiver circuit includes an analog front-end and a digital processing unit. The analog front-end includes an input for receiving a radio frequency (RF) signal, a first control input for receiving a gain adjustment signal, a second control input for receiving a timing signal, and a signal output for providing a digital intermediate frequency (IF) signal. The analog front-end updates gains of a plurality of gain stages according to the gain adjustment signal and in synchronism with the timing signal. The digital processing unit is configured to produce at least one output signal derived from the digital IF signal. The digital processing unit includes a timing recovery circuit configured to generate the timing signal based on the digital IF signal to control timing of the updating gains of each of the plurality of adjustable gain stages.

Abstract: According to one embodiment, an electronic device includes a reproduction controller and a transmitter. The reproduction controller is configured to reproduce a first type of information of a first content. The first content includes a plurality of types of information. The transmitter is configured to transmit an instruction to reproduce a second type of information of the first content to other electronic device.

Abstract: In certain flat screen TV sets, such as LCD monitors, geometric errors can be induced in a video signal by positive going pulses. That is, a shift in a display is provided when one or more positive going pulse is added to the video signal following one or more sync pulse. To illustrate, AGC pulses, generally used for content control and or copy protection in the last lines of an active video field, cause a shift (horizontal displacement) in the picture for these last lines in the active field. Alternatively, turning off or attenuating such positive going pulses in the last lines of the active field, eliminates or reduces the picture shift.

Abstract: An AGC control section (110) has a first operation mode for controlling the gain of a variable gain amplifier (103) to maintain the amplitude of the sync signal measured by a sync signal amplitude measuring circuit (108) at a constant value, and a second operation mode for preventing the gain from being increased even when the amplitude of the sync signal measured by the video signal processing circuit (109) is smaller than the predetermined first reference value and reducing the gain of the variable gain amplifier (103) only when the amplitude of the video signal exceeds a predetermined second reference value. During operation in the first operation mode, when the amplitude of the sync signal is smaller than the predetermined first reference value and the amplitude of the video signal is greater than the predetermined second reference value, the mode is switched to the second operation mode.

Abstract: Disclosed is an AGC detector device and an AGC detecting method for television receivers displaying video pictures consisting of a plurality of horizontal lines to be built up successively, wherein a CVBS signal is inputted which includes horizontal sync pulses having a front porch region and a back porch region and occurring once a horizontal line during a horizontal sync period when generating a current video picture, and further includes vertical sync pulses occurring during a vertical sync period before the generation of a new video picture and including serration pulses which occur during a serration pulse region being part of the vertical sync period. Further, gating pulses are generated having a period which is equal to the line period of the horizontal sync pulses. Said gating pulses are adjusted such that they occur at the back porch region of the horizontal sync pulses.

Abstract: Disclosed are methods and systems for automatic gain control (AGC) in circuits. The disclosed methods and systems provide accurate and rapidly converging automatic gain control suited for video applications. According to disclosed preferred embodiments of the invention, a signal amplitude controlling method is responsive to gain underflow or overflow. A new fine gain control value is extrapolated and a new coarse gain control value is determined. The new fine gain and new coarse gain control values are applied to the signal to produce an output signal within a pre-selected output amplitude range.

Abstract: Systems and methods for adjusting image contrast are provided. An exemplary method for adjusting image contrast includes determining a format of a television signal and outputting in conjunction with the television signal a reference level. If the television signal has a first format, then the reference level is caused to be substantially equal to a luminance level representing a black color in the first format. However, if the television signal has a second format, then the reference level is caused to be substantially equal to a luminance level representing a black color in the second format.

Abstract: A modulation factor is kept immune from the influence of temperature variation. A modulator is provided with an operational amplifier to one of whose input ends are inputted video signals and to the other is applied a reference voltage and a video mixer into which are entered carrier wave signals and video signals amplified by the operational amplifier, wherein the reference voltage is raised or lowered as the gain of the video mixer increases or decreases, respectively, with a variation in temperature.

Abstract: In a video signal character converting device, a sampling window signal generator generates a signal for sampling an input video signal “a”. A video scene amplitude discrimination circuit samples the video signal in response to the sampling signal, detects a change in image level either field by field or frame by frame based on an integrated value for every duration of vertical scanning, and outputs a resetting pulse when the change in picture level exceeds a predetermined level. A video scene periodicity discrimination circuit measures a time interval between two successive resetting pulses, and outputs a control signal if the time interval is shorter than a predetermined period. A video scene conversion circuit converts a video scene in response to the control signal.

Abstract: A video clamping apparatus is described which uses transistors manufactured in a CMOS process to clamp an input video signal to a reference level during a SYNC period. A closed-loop system is provided which includes a buffer amplifier, a sample-and-hold device, a summer, a low-pass filter and a clamping circuit. The summer compares the output of the sample-and-hold device to a reference voltage which causes an output of an analog-to-digital converter to be the digital word zero.In order to maintain a high enough bandwidth of the closed loop system, a first current source is operatively coupled to the transistors of the clamping circuit during the SYNC period. When the SYNC period has ended, the first current source is decoupled from the transistors of the clamping circuit. The transconductance of the loop is, therefore, high when needed during the SYNC period.

Abstract: A technique for delivering analog video over fiber-to-the-home (FTTH) networks addresses a fundamental problem of the standard signal format, i.e., power budget constraint, by increasing the usable optical signal efficiency. In particular, a technique is provided for transmitting an efficient modified analog video which is compatible with existing receivers. More specifically, the synchronization portion of a standard NTSC video signal is reduced in amplitude during transmission, producing an appreciable increase in the allowable optical modulation index (OMI).

Abstract: An analog to digital converter circuit having sync control is constructed to monitor the sync condition of the digital output. When sync is lost, for example due to a low input signal level or due to an out of phase situation, the gain of the output increased to relatively high level so as to enhance the possibility of detecting the sync condition. As soon as sync is reestablished the gain is immediately turned down to a level lower than the blanking level and then gradually increased to the blanking level. The gain levels at startup and during the sync reestablishment intervals are fixed but under selective control.

Abstract: A circuit for identifying the standard of a color television signal includes a gain-controlled amplifier for standardizing an amplitude of oscillations of a composite video baseband signal during a reference burst centered on a reference level. The burst is designed for use by band-pass filters for identifying the standard and is preceded by a line synchronization pulse. The circuit also includes a device upstream of the amplifier for eliminating line synchronization pulses.

Abstract: A technique and apparatus for developing AGC voltage in a receiver capable of receiving VSB signals that do not have the average magnitudes of the data symbol levels and the sync symbol levels related so as to produce the same average level. One technique eliminates the sync symbols from determination of the AGC voltage. A preferred technique corrects for the different symbol levels of the sync by multiplexing in an offset at the proper time or multiplying the sync symbols by a compensating factor.

Abstract: A configurable video output channel architecture includes a plurality of parallel video pipelines arranged to drive a video display; a device for selecting an output of one of the video pipelines and generating a readback signal representative thereof; and a device for adjusting a display specification of at least one of the video pipelines using the readback signal. The display specification adjusted may include the maximum video level, the blanking level, and the sync level of the video waveform. The adjusting device may also adjust the characteristic impedance of each pipeline. The selecting device includes a multiplexer and an analog to digital converter, and the adjusting device includes a controller which monitors the readback signal and generates a control signal to adjust the display specification if the readback signal is outside of a desired range.

Abstract: A device for adjusting a video signal so that its black level is in coincidence with a predetermined reference level includes a capacitor having a first terminal that receives the video signal and a second terminal that provides the adjusted video signal, and means for discharging the capacitor at a constant current when the adjusted video signal exceeds the reference level, and for charging the capacitor at a constant current when the adjusted video signal is below the reference level, the ratio between the charging and discharging currents ranging from 4.3 to 12.6. The device further includes means for significantly reducing the current ratio at least during a portion of a frame synchronization pulse train.

Abstract: A clamp signal generation-control circuit includes a clamp signal controller for discriminating the existence of a sync on green signal and a separate sync signal supplied from a video card to a monitor to output a control signal according to the discrimination, and a clamp signal generator for automatically changing a generated point of the clamp signal, and a method for controlling the circuit is also provided. The generated point of the clamp signal supplied to the monitor is controlled to automatically shift the clamping position of a video signal, thereby preventing malfunction caused by a nonprofessional user's manipulation, abnormal picture display or the generation of a segment phenomenon. The circuit is adoptable to monitors supplied with various kinds of sync signals.

Abstract: A digital television signal includes data sent as multilevel symbols in successive data segments each including a synchronizing sync character. The detected synchronizing sync character produces a characteristic having two opposite polarity levels separated by a zero reference level, with the levels occurring at successive sampling points of the television signal, and a detection signal that has a peak occurring in time coincidence with the zero reference level. The detection signal controls sampling of the received television signal. The gain of the received signal is controlled by an AGC circuit that also responds to the detection signal.

Abstract: AGC pulses and other undesirable signals are removed from a video signal by generating a replica of the AGC pulses or other signals and then mixing the replica with the original video to effect their removal.

Abstract: An RGB preamplifier for a video display includes respective multipliers independently operable for adjusting the contrast of input primary and secondary video signals. The contrast adjusted video signals are added to form a combined display signal, the combined signal being applied to the first inputs of primary and secondary comparators each of which is also supplied with a respective reference DC level. The primary and secondary video signals are alternately nulled at horizontal line rate by nulling the corresponding multipliers. The primary comparator samples the combined signal when the secondary signal is nulled for clamping the DC level of the primary signal in relation to the primary reference DC level and the secondary comparator samples the combined signal when the primary signal is nulled for clamping the DC level of the secondary signal in relation to the secondary reference DC level.

Abstract: An automatic gain control circuit includes a first amplifier for receiving a video signal to produce a first signal with a gain varied in response to a control signal, a low-pass filter for removing a color component from the first signals to produce a second signal, a sync separator for separating synchronizing pulses from the second signal to produce a third signal, a delay circuit for delaying the third signal for a given time to produce a fourth signal, a clamper for clamping the second signal upon a constant reference voltage generated from a constant voltage generator 26, a sample and hold circuit 26 for receiving the fourth signal and a fifth signal to produce a sixth signal maintaining for a given time a level of a back porch of the fifth signal, a transconductance amplifier for comparing the sixth signal with a constant reference voltage to produce a difference signal as a seventh signal, a capacitor for integrating the seventh signals to produce a direct current error voltage as an eighth signal, an

Abstract: The present invention provides a contrast control circuit capable of controlling the contrast even if the back porch is comparatively short. The contrast control circuit comprises monostable multivibrators (24, 26) which provides a background pulse and a reference pulse alternately, respectively, a switch (SW1) which clamps a video signal while the background pulse is HIGH so that the potential of the pedestal level is zero on an (N+1)th horizontal scanning line, and a switch (SW2) samples the leading edge of a reference pulse inserted in the video signal while the reference pulse is HIGH on an nth horizontal scanning line.