Rca Inc.

Rca Licensing Corporation

James H Wharton

Jack E James

Lawrence E Smith

John Gordon Amery

Peter D Osman

A video apparatus capable of operating at different line deflection frequencies incorporates a CRT electron gun assembly heater supply voltage circuit that maintains a constant rms voltage level independent of the line deflection frequency. The heater supply includes a transformer winding located on the line deflection driver transformer. The duty cycle of the developed AC voltage waveform remains substantially constant independent of the line deflection frequency, so that the AC voltage may be applied to the heater circuit.

CRT filament supply for multiple frequency video apparatus

A deflection circuit for a video apparatus that operates at multiple line rate deflection frequencies includes an S-shaping correction circuit that provides proper S-shaping of the line deflection current at any of the video apparatus line rate operating frequencies. A first S-shaping capacitor is in series with the deflection winding and also in series with a transformer primary winding. The transformer secondary winding is coupled to one or more capacitors. The secondary winding side capacitors are coupled to the secondary winding circuit in response to a line rate frequency indicative signal in order to form a series combination of the primary and secondary side capacitors. The effective capacitance of the secondary side capacitor is then equal to the actual capacitance value increased by a factor determined by the transformer secondary to primary winding turns ratio.

Linearity correction for multiple frequency video apparatus

A deflection circuit for a video apparatus is capable of operating at different horizontal rate frequencies in response to the incoming video information rate. In one embodiment, the deflection oscillator input voltage is varied in a cyclical manner to vary the oscillator frequency. When the oscillator frequency corresponds to the frequency of the incoming video information, the input voltage is maintained to maintain the desired oscillator frequency. In an alternate embodiment, a frequency to voltage converter generates the desired oscillator input voltage in response to the incoming video information rate.

Multiple frequency horizontal oscillator for video apparatus

A power supply for a video display apparatus includes circuitry that produces a pulse width modulated signal in response to the selected horizontal deflection rate. The pulse width modulated signal controls the switching of an FET through a transformer to provide a load circuit operating voltage representative of the deflection frequency. A turn-off signal for the FET is provided to a turn-off transistor from the primary winding of the transformer to insure rapid turn off of the FET.

Power supply drive circuit improvement

In a deflection circuit that operates in any scan frequency selected from a plurality of frequencies, the supply voltage that is DC-coupled to a first terminal of a trace capacitor is increased when the scan frequency increases. The deflection circuit includes a diode modulator that is controlled by a modulation voltage having an AC component voltage that varies at a vertical rate. The increase in the supply voltage causes an increase in a DC component voltage of the modulation voltage that is coupled to a second terminal of the trace capacitor such that the voltage in the trace capacitor increases in the same proportion as the supply voltage. The proportional increase in the trace capacitor voltage maintains the raster width unchanged when the scan frequency increases.

Raster width correction apparatus for multi scan frequency monitors

A regulating switched mode power supply for a video display apparatus provides electrical isolation between the load circuits and the AC line. A power transformer incorporates a regulator winding referenced to AC line ground potential. First and second feedback circuits develop first and second feedback signal components that are applied to a regulator control circuit which controls the conduction of the power supply switching transistor. The two feedback circuits have different time constants to accurately monitor load circuit loading conditions in order to maintain load circuit voltage level regulation.

Dual feedback switching power supply regulator for isolated chassis

In a video monitor for display alphanumeric data on a kinescope display screen, a kinescope driver transistor receives binary video data signals at a low impedance emitter input electrode and provides high level video data output signals to the kinescope from a collector output electrode. A source of adjustable control voltage is coupled to the base electrode of the driver transistor for varying the intensity of the data display.

Video data display driver stage

The format of two audio input signals, which may be of either matrixed form wherein each signal comprises two common components or of unmatrixed form wherein each signal comprises a respective independent component, is determined by applying the signals to a first network circuit which linearly combines the signals to produce a resultant audio output signal exhibiting a null condition when the input signals are of matrixed form and a non-null condition when the input signals are of unmatrixed form. A null detector responsive to the resultant signal supplies a control signal to a second decoder matrix which decodes the matrixed signals to independent form and couples the decoded signals to respective first and second output terminals when the null condition is detected and which couples the unmatrixed input signals to respective ones of the first and second output terminals when the non-null condition is detected.

Stereophonic bilingual signal processor

Selected fields of a redundant field slow motion video tape reproduced video signal are stored in a memory at a given clock rate and recovered from the memory at a clock rate inversely proportional to the number of times each field is repeated so as to produce a non-redundant video output signal of reduced bandwidth yet processing the full informational content of the original video signal. The original signal normally exhibits an ordered color field sequence but is subject to anomalous variations from time to time which causes anomalous variation of the chrominance-burst phase relationship of the video output signal. A detector, responsive to a change of a parameter of the video input signal, detects the anomalous variations of the chrominance-burst phase relationship and produces a control signal that is applied to a circuit which effectively reverses the phase relationship of the chrominance and color burst components of the video output signal of the memory when the control signal is present.

Video disc slow down processor with reverse color detector/corrector

In video recording apparatus a luminance signal is doubly preemphasized by a cascade connection of two networks prior to clipping and application to a frequency modulator. One network has a non-linear phase characteristic and an amplitude response which increases by a predetermined amount over a lower portion of the luminance band and is substantially constant otherwise. The other network has a substantially linear phase response, and a rising amplitude response within the upper portion of the luminance band. The relative amplitude responses of the networks are in a predetermined relationship such that the combination exhibits a frequency dependent variation dominated by the one network over the lower portion of the luminance band and dominated by the other network over the upper portion of the luminance band whereby the luminance signal receives an increase in preemphasis over both portions of its bandwidth and clipping distortion under transient signal conditions is reduced. In video reproducer apparatus, a combination of deemphasis networks imparts a complementary deemphasis characteristic to the preemphasized luminance signal thereby effecting a signal-to-noise ratio enhancement.

Video disc systems with plural preemphasis/deemphasis networks

A video disc player includes color burst responsive processing circuitry. A burst killer effectively removes burst from the player output when reproducing monochrome program material whereby an improved quality monochrome picture may be obtained from a color television monitor which may be used with the player. The burst killer is controlled on a field-by-field basis in response to an analog or digital signal manifestation of the reproduced video signal whereby the burst killer is automatically enabled and disabled during reproduction of mixed monochrome-color program material.

Video disc player with burst remover

A composite video signal is separated into luminance and chrominance components which are processed in separate channels having transfer functions which differ in terms of frequency response and large signal amplitude response. The luminance channel subjects the luminance signal to high frequency preemphasis and to hard limiting or clipping at predetermined fixed levels. The chrominance channel exhibits a substantially uniform amplitude response and a variable compression characteristic dependent upon the chrominance signal level, a sum of chrominance and processed luminance signals or a composite output signal formed by a sum of processed chrominance and processed luminance signals. The composite signal is suitable for application to a picture carrier frequency modulator whereby an FM signal is produced suitable for video disc or tape recording and in which a tendency for luminance-chrominance crosstalk or interference is minimized.

Video processor employing variable amplitude compression of the

The luminance component of a video signal subject to overshoot is preemphasized and clipped prior to application as a modulating signal to a frequency modulator. Overshoot of the luminance signal, which tends to cause clipping distortion of the modulating signal is minimized by generating a compensating signal representative of the horizontal detail component of the luminance signal. The luminance signal is delayed relative to the compensating signal and subtractively combined therewith prior to application to the clipping circuitry such that the resultant modulating signal exhibits preshoot and reduced overshoot thereby minimizing the clipping distortion. Compensation is effectively disabled for luminance signal overshoots below the clipping level by means of an adjustable coring circuit in the compensating signal path whereby luminance signals exhibiting overshoot below the clipping level are not distorted by the compensating signal.

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Indianapolis, IN, United States of America

James H Wharton