Abstract: An average beam current limiter for a kinescope responsive to video signals coupled to the kinescope via a signal transmission channel comprises a source of control signals representative of average current drawn by the kinescope. When average beam current exceeds a predetermined threshold level by an amount within a first range of beam current, a corresponding control signal is coupled to the signal transmission channel to vary the D.C. content of the video signal in a direction to limit beam current above the threshold level within the first range. When beam current exceeds the threshold level by a relatively greater amount within a second range of current, a corresponding control signal serves to vary the peak amplitude of the video signal to limit beam current within the second range.

Abstract: A controlled oscillator comprises an amplifier including an active device, a filter network arranged in a feedback loop of the amplifier for providing regenerative feedback to sustain oscillation of the amplifier, and a source of control signals. A common load network is provided for oscillatory signals produced by the amplifier and for the control signals, and is coupled to the filter network. The common load network comprises amplifying means having a low input impedance relative to an impedance presented to the oscillatory and control signals by parasitic capacitances which may be associated with respective output terminals of the active device and the source of control signals.

Abstract: An automatic gain controlled chrominance signal amplifier system for a color television receiver is arranged to process composite chrominance signals having burst and image-representative components. First, second and third amplifier stages are provided for amplifying the image-representative components. The first amplifier also amplifies burst components and is gain controlled in a first closed loop arrangement to maintain a substantially constant amplitude for the burst component and to thereby maintain an appropriate gain for image components. The second and third amplifiers are coupled to the output of the first amplifier. The output of the second amplifier is coupled to a chrominance signal overload detector arranged to respond to image-representative signal components having peak amplitudes greater than a predetermined level.

Abstract: A video amplifier circuit for combining chrominance and luminance signal components and for supplying resultant color representative signals to an image reproducing cathode ray tube comprises first, second and third transistors direct current coupled in series relation with a load circuit across an operating voltage (B+) supply. The first and second transistors are of one conductivity (NPN) while the third is of opposite conductivity (PNP). Luminance signals, which are direct current coupled to the third transistor (a voltage follower), are converted by means of a drive control resistor to provide luminance current drive to the other series connected transistors. Chrominance signals are direct current coupled to the control (base) electrode of the first transistor which operates in conjunction with the second transistor as a cascode voltage amplifier for chrominance signal components.

Abstract: A controllable phase shifting circuit suitable for providing tint control in a color television system comprises first and second differential amplifiers, each providing antiphase outputs and supplied respectively with first and second alternating color reference signals which are in a first predetermined (e.g., quadrature) phase relation. A third signal, which is a fractional part of one of the first two signals, is combined with the other of the first two signals at its respective amplifier input to produce a fourth signal with a phase different from that of the first, second or third signals. A third amplifier provides differential gain control inputs to the first and second amplifiers. A combining circuit sums relatively in-phase or antiphase output signal components from the first and second amplifiers to produce an output signal with a desired phase (e.g., flesh tone phase).

Abstract: A chroma-burst separator and amplifier suitable for use in the chrominance channel of a color television receiver includes a differential amplifier for supplying antiphase composite chrominance signals including burst and chroma signal components to first and second gating circuits, respectively. The first and second gating circuits conduct in complementary fashion in response to keying pulses coincident with the burst and chroma signal intervals for providing separated antiphase burst and antiphase chroma output signals each with differential direct potentials which remain substantially constant and equal throughout the chroma and burst intervals.

Abstract: An electrical signal multiplier comprises a pair of signal transmission gates each including a pair of parallel coupled, opposite conductivity field effect transistors. An input signal which, for example, is to be demodulated, is applied in balanced, push-pull relation to each of the transmission gates, respectively. Balanced push-pull reference switching signals render the transmission gates conductive and non-conductive, in complementary fashion, during alternate switching intervals. Output (demodulated) signals are provided alternately at signal outputs of the transmission gates.

Abstract: A controlled oscillator suitable for construction largely in integrated circuit form includes an oscillating amplifier stage and a regenerative feedback loop including a resonant frequency determining element coupled to the amplifier stage for providing an oscillatory reference signal. A phase shift network is provided outside the loop for shifting the phase of the oscillatory signal a predetermined amount. A control circuit which is supplied with the phase shifted oscillatory signal to produce anti-phase signal outputs is responsive to control signal representative of the phase and/or frequency of a predetermined reference signal for selecting portions of the anti-phase output signals. A combining network sums the oscillatory signal and the selected portions from the control circuit to produce a combined signal with a resultant phase which is supplied to the oscillating amplifier stage for maintaining the oscillatory signal in desired relation with the reference signal.

Abstract: An integratable bias circuit for semiconductor junction diodes of the type exhibiting junction capacitance when reverse biased by suitable applied voltages includes a source of fixed bias reference voltage applied to the diode junction. The reference voltage is selected less than the reverse conduction breakdown voltage of the diode junction to prevent diode operation beyond its reverse breakdown potential while also reliably determining the junction capacitance.

Abstract: An integratable third harmonic signal generator includes a signal multiplier coupled to a source of alternating input signal, for providing a first output signal proportional to the input signal raised to the third power. The first output signal includes a first harmonic component and a third harmonic component each proportional to the input signal. Means are also included for deriving, from the input signal, a second output signal in predetermined magnitude and polarity relation with the first harmonic component. The first and second output signals are combined to cancel the first harmonic component and thereby provide a third output signal proportional to the third harmonic component of the input signal substantially devoid of any first harmonic component.

Abstract: A signal amplifier is supplied with input signals at its base electrode and also is supplied at its emitter with quiescent operating current from a current source. Amplified output signals developed at the collector of the amplifier are coupled to a transistor-diode current splitter. The relative division of current in the splitter is controlled by coupling a variable direct current supply to the diode. The latter supply comprises a source of direct voltage, a variable resistive voltage divider coupled across the voltage source, and the combination of a voltage follower stage, a first series resistor coupled between the resistive divider and the input of the voltage follower and a second resistor coupled between the output of the follower and the diode. Gain controlled push-pull output signals may be provided by differentially coupling a second amplifier device to the first and coupling the output of a second current splitter to the second amplifier.

Abstract: Hue correction apparatus of the general type described in U.S. Pat. No. 3,663,744 is provided. Chrominance signals are monitored on a dynamic basis and the phase of a color subcarrier reference signal is automatically altered when the chrominance signals are in the vicinity of the flesh tone (+I) axis. The phase of the reference subcarrier is altered, making use of a wide bandwidth phase detector, by controllably adding a portion of an amplitude limited chrominance signal to the subcarrier so as to shift the subcarrier phase towards the phase of the chrominance signal. The range of angles and response of the apparatus is restricted by means of an offset bias control coupled to the chrominance signal adder circuits. Green and blue tones are relatively unaffected by the system operation. Good transient response of the correction apparatus is provided at sharp color transitions.

Abstract: A signal amplifier is supplied with input signals at its base electrode and also is supplied at its emitter with quiescent operating current from a current source. Amplified output signals developed at the collector of the amplifier are coupled to a transistor-diode current splitter. The relative division of current in the splitter is controlled by coupling a variable direct current supply to the diode. The latter supply comprises a source of direct voltage, a variable, resistive voltage divider coupled across the voltage source, and the combination of a voltage follower stage and a series resistor coupled between the resistive divider and the diode. Gain controlled push-pull output signals may be provided by differentially coupling a second amplifier device to the first and coupling the output of a second current splitter to the second amplifier. The second current splitter is then also controlled by the same current source as the first.