Other

Vidicraft, Inc.

James A Karlock

Roger A Marin

Improved circuitry for adjusting the video gain, black level, chroma gain and burst phase of a video signal includes composite to Y/C splitter, luminance processing section, sync separator and chroma processor. Unity and split mode selection is provided. A meter circuit provides display of black and white levels as well as clip indication.

Video processing circuit

A shift in the bias point of a sync separator is used to detect the presence of a video signal. The sync separator, which is initially in a low power mode, is then switched to a normal power mode in the presence of a video signal. Power for additional circuitry is likewise switched in response to the video signal's presence.

Power saving video circuit and sync separator

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.

Method and apparatus for removing AGC pulses and other undesirable

A standard video signal is processed by including an interval of an insertion signal whose potential varies continuously between the video sync tip level and a level substantially above blanking level during at least part of the active interval of at least one blank line in the vertical blanking interval.

Method and apparatus for modifying a video signal

Simplified apparatus for controlling the phase and amplitude of the chroma subcarrier of a television signal is disclosed. The phase control includes compensation so that the color burst amplitude is stable as the phase is varied.

Chroma adjustment circuit

A phase shift circuit having an input terminal for receiving an input signal having a sinusoidal waveform and an output terminal for providing an output signal that has a sinusoidal waveform and is adjustable in phase relative to the input signal, comprises a bipolar transistor having a base connected to the input terminal, an emitter at which it provides a signal at the same frequency as the input signal and in phase therewith, and a collector at which it provides a signal at the same frequency as the input signal and out of phase therewith, the circuit also comprises a capacitor connector between the collector and the output terminal, a diode connected between the emitter and the output terminal, and a resistor network for biasing the diode to adjust the conductivity of the diode.

Phase shifting circuit utilizing a transistor, a capacitor, and a diode

Composite sync is separated from a video signal and integrated in order to produce a vertical control pulse. This pulse is then applied to the input of a one-shot multivibrator which provides an output essentially equal in duration to the time from the end of vertical sync to the start of the active picture, blanking the entire vertical interval with the exception of the vertical sync pulses. Optionally, a second one-shot multivibrator may be triggered at the horizontal sync rate and used to inhibit blanking during the times corresponding to equalizing, horizontal sync and color burst in order to preserve these legitimate parts of the signal. The first one-shot multivibrator may be replaced by a counter which counts at the horizontal rate and is reset by the vertical pulse. An increase in accuracy allows blanking of the period just before the vertical sync. Also, video presence may be sensed with a simple low-pass filter and CMOS gate and used to apply power to the main processing circuitry thus extending battery life. Blanking may be achieved by the use of a FET which simply shorts the video to signal ground during periods when blanking is desired.

Circuitry for removing information from, or modifying information in,

A video effects generator consists of two major components: an electronic video switch and a waveform generator. The switch can give either sharp or soft edges, fade in or out or fade between the two inputs. This switch is driven by a waveform generator to provide switching at a line rate, field rate or both. Effects result when two video sources are alternately selected within the time of one field.

Video switcher/effects generator

A circuit for splitting a video signal into a chroma signal and a luminance signal comprises a resistor and a bandpass filter connected to the resistor. The bandpass filter passes a frequency component at the frequency of the color pilot burst. A chroma switch receives the frequency component passed by the bandpass filter, and is provided with a feedback transistor for reducing the input impedance of the chroma switch.

Combined video processing circuit and image enhancer

A video effects generator consists of two major components: an electronic video switch and a waveform generator. The switch can give either sharp or soft edges, fade in or out or fade bewteen the two inputs. This switch is driven by a waveform generator to provide switching at a line rate, field rate or both. Effects result when two video sources are alternately selected within the time of one field.

A video processing circuit separates chrominance and luminance signals and processes the same separately from synchronizing information whereby the video signal may be reformed with a selected video level, selected color saturation, and selected chroma hue. The synchronizing information is not reprocessed, but is coupled through the circuit and the other video signal portions are adjusted relative thereto.

A detail enhancing circuit for use with video tape recorders recovers or separates detail from the overall video signal and adds amplified detail back into the video signal. The luminance signal is differentiated and high amplitude transitions are clamped, leaving the detail information.

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Portland, OR, United States of America

James A Karlock