Abstract: A signal processor responsive to a video input signal provides a first video output signal linearly related to the input signal and a second video output signal non-linearly related to the video input signal. A first combining circuit combines the first and second video output signals in predetermined proportions to provide a third video output signal having both linear and non-linear components. A second combining means combines the second and third video output signals in proportions determined by an average picture level (APL) representative control signal to provide a processed video output signal having enhanced contrast for all values of the average picture level of displayed images.

Abstract: A so-called "V.sub.BE multiplier" circuit is used to temperature compensate a semiconductor device with respect to both short term self-heating effects and long term ambient temperature effects. The compensation circuit includes a transistor with a base, an emitter coupled to an operating potential, and a collector coupled to an operating potential. First and second resistors are respectively coupled across the base-emitter and collector-base junctions of the transistor. The values of the resistors as chosen so that a voltage derived from the collector-emitter path of the transistor and applied to the semiconductor device exhibits a temperature coefficient which substantially matches the temperature coefficient of the semiconductor device.

Abstract: A synchronizing pulse separator for a video apparatus provides horizontal and vertical synchronizing pulses from a composite video signal. The sync separator incorporates a compensation circuit that achieves noise immune operation with composite video signals that provide progressive field display and consequently lack synchronization equalizing pulses. The compensation circuit maintains a sufficient bias level on the sync separator transistor during the vertical blanking interval to prevent premature triggering of the vertical deflection circuit due to noise.

Abstract: Apparatus for compensating a temperature dependent operating characteristic of a semiconductor device includes a compensation circuit which exhibits an electrical time constant closely approximating a thermal time constant of the semiconductor device. A control voltage exhibiting the electrical time constant is applied to the semiconductor device with a sense for substantially negating temperature dependent deviations of the operating characteristic of the semiconductor device.

Abstract: A video output amplifier has an output terminal coupled to a signal input electrode of a kinescope. A signal limiting circuit coupled to the output terminal limits the magnitude of large video output signals to prevent saturation of the video output amplifier. The limiting circuit includes a resistor and a limiting diode coupled from the output terminal to a bias potential.

Abstract: A television receiver responsive to a broadcast television signal in a normal operating mode includes a television signal channel with high frequency peaking circuits, followed by a display driver to which an auxiliary video signal may be applied. A low pass filter is connected between the output of the television signal channel and the display driver, which exhibits a wide bandwidth when the receiver is intended to display auxiliary video information. The bandwidth of the low pass filter is inversely related to the bandwidth of the driver such that the low pass filter exhibits a narrow bandwidth relative to the bandwidth of a wideband display driver. In addition, the low pass filter exhibits a trapping characteristic at the second harmonic frequency of the chrominance signal in a color television receiver.

Abstract: In a luminance channel of a color television receiver, a luminance signal is conveyed to the input of a delay line via first and second series connected source resistors. A series tuned trap tuned to the chrominance subcarrier frequency is coupled between the junction of the first and second resistors and a point of reference potential. The coaction of the first and second source resistors and the trap results in a significant reduction in frequency dependent source impedance variations at the input of the delay line.

Abstract: A television receiver responsive to broadcast television signals in a normal operating mode includes a video channel with high frequency peaking circuits, followed by a wideband display driver to which auxiliary R, G, B color image signals are applied in an auxiliary operating mode of the receiver. A low pass filter restricts the high frequency response of the video channel in the normal mode so that the combination of the high frequency peaking circuits and the wideband display driver does not result in a condition of excessive signal bandwidth and attendant unwanted spurious high frequency signal effects.

Abstract: In a television receiver with a kinescope driver stage for providing video drive signals to an image displaying kinescope, a control circuit couples an auxiliary character information signal to a reference input of the driver stage, separate from a source of reference bias potential also coupled to the reference input of the driver stage. The intensity of displayed character information is related to the control circuit biasing, which is derived from a pre-existing local source of alternating current signal.