Abstract: A video signal amplitude registration system for a television camera is provided in which the video amplitude of two or more related video signals derived from scanning a common reference are compared with a rising ramp voltage so as to generate a control voltage proportional to the misregistration of the video signal amplitudes at both the black and white signal levels.

Abstract: In a television signal synchronizer having a coherent memory, it is necessary to modify the writing of data into memory or the reading of data out of memory in order to provide field conversion. In the described apparatus, the reading out of data is always done according to a non-variant sequence determined by the local (studio) reference timing signals. In a first embodiment the read address generator signals are modified so as to read out the stored video signal in accordance with the non-variant write in sequence. In a second embodiment the write address generator signals are modified so as to position the incoming video signal into memory so that it is located in the proper memory position for the non-variant read out sequence.

Abstract: A synchronizing system is provided for synchronizing an oscillator having two or more substantially different frequencies, developed by division of the oscillator output frequency, from an external reference signal. The external reference is utilized as one input to a phase detector and to reset the divider. The divider is re-enabled by the external reference so that the next divider output is applied to the other input of the phase detector. The two inputs to the phase detector are now timed within a narrow range, which is within the pull-in range of the control loop, which minimizes the phase lock up time for synchronizing to the external reference.

Abstract: A reference signal generator is provided for generating the two subcarrier reference frequencies for the SECAM television system. A master oscillator generates the first subcarrier reference frequency which is coupled to a divider for obtaining the horizontal line rate. The horizontal line rate is multiplied and coupled to a mixer, where it is mixed with the first subcarrier to obtain sum and difference frequencies. A crystal filter coupled to the mixer extracts the second subcarrier, which is locked in frequency and phase relationship to the first subcarrier. The signal generator also contains provisions for synchronizing the subcarriers to an external horizontal system reference.

Abstract: A time base corrector for removing time base errors from video signal information of a type including synchronizing pulses is provided. A storage means in the form of a charge coupled device (CCD) has the video information coupled to its input. A start-stop oscillator in conjunction with a preset counter coupled to the storage means clocks the video information into the storage means so as to stop the clock when the input signal information has been transferred to the output terminal of the storage means. A local reference restarts the clock and the stored input signal information is clocked out in synchronism with the local reference.

Abstract: A repetitive cyclic test signal representing constant chrominance with changing phase, changing chrominance with constant phase, and changing chrominance with changing luminance is coupled through a television system under test to a vectorscope display device for measuring saturation, hue and luminance crosstalk within the television system.

Abstract: A sync regenerator is provided which regenerates synchronizing information signals having a varying amplitude and width by comparing the sync signals in a comparator circuit to which a source of reference potential is applied. The comparator output signal of fixed amplitude is pulse width detected and the value of the detector output voltage is coupled by a feedback circuit to the reference potential source to vary the reference potential so as to maintain the width of the comparator output signal constant. The regenerated sync output signal is of constant amplitude and constant width.

Abstract: A plurality of signal storage means are used to store, respectively, the peak signal value of the red, blue and green video signals of a color television camera for comparison against a predetermined signal level representing a desired combined signal condition, such as black. The peak values of the stored video signals are combined to ascertain the difference in peak signal amplitude between the red and green signals and the blue and green signals. Control signals developed from the difference signals adjust the respective red and blue channel signal levels so as to match the red and blue signal level to the green signal level to yield the desired combined signal condition.

Abstract: Apparatus for digitally processing a composite video signal recorded in PAL format for producing a continuous waveform at a four-line rate indicates at any four-frame reference time if the polarity of the subcarrier is in phase with a reference or inverted for matching the subcarrier phase of two PAL signals as required in electronic splicing of video tape recordings, in special effects switching, or mixing of PAL video signals.

Abstract: A plurality of comparators are used to compare the red, blue and green color signals of a color television camera against a first and second predetermined signal level threshold corresponding to selected values of grey scale. The outputs of the comparators are combined to ascertain the difference in signal amplitude between the red, blue and green signals with respect to the first and second predetermined signal thresholds which represent grey. If the amplitude deviation of the red, blue and green color signals is within the threshold limits, a control signal adjusts the gamma characteristics of the blue and red color channels to match the amplitude of the red and blue color signals to the amplitude of the green color signal to correct to grey. If the red, blue and green color signal deviation is without the threshold limits, the color signal is assumed correct and no adjustment is made.

Abstract: A video blanking circuit is provided which inserts a system blanking interval signal having controlled leading and trailing edges into a video signal. The blanking signal is combined with a clamped video signal in a first non-additive mixer which also provides a white clip level. The output of the first non-additive mixer is further coupled to a second non-additive mixer in which black level excursions are clipped so as to provide an output video signal having a proper system blanking interval into which synchronizing information may be added to complete the composite video waveform.

Abstract: A synchronizing generator is provided for synchronizing the composite video signal output of a television camera to an external television system reference represented by a source of reference signal including line and color reference signal components which are subject to variations in relative time and phasing. First and second phase-lock loops maintain independent synchronism of the line and color signal components of the composite video output to the line and color signal components of the source of reference signal.

Abstract: A system is provided for compensating for signal defects such as dropouts in recorded television signals. A recovered video signal is delayed for a period of substantially one scanning line, and the delayed signal is coupled to two channels, one for the luminance and scan synchronizing information and the other for the color information. The color information is phase-reversed each time it is delayed so as to provide a proper phase relationship when reinserting the delayed information into the signal path. The two channels are recombined to provide a compensating signal which is substituted for the original video signal during a dropout.

Abstract: A gamma circuit for developing a video output signal having a positive gamma coefficient from an input signal having a negative gamma coefficient includes a multiplier and amplifier which forms an electronic divider. Adjustable reference sources provide a means for varying the gamma of the circuit to correct an input signal gamma of -.35 to -1 to a positive gamma.

Abstract: Negative color film is processed in a color telecine camera by the selection of an optical filter which provides equal light transmission for the red and green colors so as to produce equal red and green video signals. The electrical gain of the blue channel is then increased to produce a blue video signal equal to the red and green video signals.

Abstract: A single pre-vertical sync pulse that repeats once each field and the line-by-line chroma phase information which exists in the form of the PAL square wave at one-half of the horizontal line frequency are combined in a novel circuit comprising a pair of J-K flip-flops to directly produce the complete Bruch blanking function in digital form for each field on an independent field-by-field basis.

Abstract: Apparatus is provided for controlling the phase and speed of a motor for driving the rotary magnetic heads of a video tape recorder. An output of a signal generator, for example, a sawtooth wave, having a frequency corresponding to the rotational speed of the motor is compared with an external reference signal, for example, a 60 Hertz power line signal. A difference in frequency generates a varying error voltage whose polarity is indicative of the error direction. Relatively large or prolonged frequency errors result in an error voltage waveform having an abrupt and relatively large change. This error voltage is differentiated to create relatively large pulses of polarity depending on the direction of the error voltage. The relatively large pulses either charge or discharge a capacitor, the output of which changes the current to the motor so as to reduce the relatively large frequency error to a range suitable for handling by a conventional combined position and velocity servo system.

Abstract: A system is provided for color correction of recorded television signals. The chroma signal is decoded to baseband using a reference subcarrier which has the same timing errors as the chroma signal. The stabilized baseband signal is remodulated onto a stable subcarrier and added back to luminance. The phase modulated subcarrier used for decoding is obtained from a phase modulator fed by reference subcarrier and modulated by the recorded signal burst phase error voltage. Provisions are made for processing signals recorded in NTSC or PAL format by converting the PAL alternate line burst switching to an unswitched NTSC format.

Abstract: An electronic signal mixer is provided for combining first and second signals by additively (or differentially) combining the first and second signals to provide a first output signal. The first and second signals are further combined in a multiplier circuit to provide an output signal which is a differential (or additive) combination of the first and second signals multiplied by a coefficient determined by a control voltage applied to the multiplier. The first combined signal and the product output of the multiplier are further combined to provide a resultant signal comprised of any proportionality of the first and second signals in accordance with the value of the control voltage.

Abstract: A video frequency amplifier is biased to provide output signals of a first magnitude. In response to the application of a predetermined control signal, the bias is altered so that output signals are provided of a second, different magnitude. When employed in communications systems of the type in which television images are "frozen" by a storage tube for subsequent transmission on an individual frame basis by a voice-quality telephone link, for example, and subsequently re-created, the control signal indicates whether the system and its storage tube are to operate either in the "transmit" or "receive" mode.