Abstract: Switches are cascaded for improved off-state attenuation. The first switch of the cascade comprises an L-type attenuator with series branch including a resistor and a shunt branch including a Zener diode. A bias network coupled to the attenuator and to the second switch of the cascade connection controls the diode bias for operation at a specific forward conduction when the second switch is open and for operation at a specific reverse bias condition when the second switch is closed for causing the attenuator to provide the plural functions of (1) enhancing the switch off-state attenuation, (2) providing over-voltage and overcurrent protection for input transients of either polarity and (3) providing a predetermined output DC level when the second switch is on for establishing the DC bias of a subsequent circuit, such as an amplifier, the DC bias so supplied being in a tracking relationship with DC power supplied to the subsequent circuit.

Abstract: A television receiver includes a kinescope spot burn protection circuit comprising a capacitor coupled between a source of blanking signal and a control grid of the kinescope for applying negative grid cut-off bias to the kinescope in response to the blanking signal. The amplifier is of the cascode type having a minimum output voltage for peak white levels of a video signal applied to the cathode. The protection circuit includes a potential divider for biasing the kinescope at a positive voltage level related to the minimum output voltage of the amplifier during normal operation of the receiver to maximize the brightness of displayed images.

Abstract: A color television receiver includes a comb filter having luminance and chrominance outputs coupled to respective inputs of a display processor. A signal source provides composite and non-composite color video signals for display. A switching circuit having a first operating mode for coupling the composite video signal to an input of the comb filter for enabling display thereof by said display processor. The switching circuit has a second operating mode for coupling the luminance component of the non-composite video signal to the input of the comb filter and for concurrently coupling the chrominance component of the non-composite video signal to the chrominance output of the comb filter for facilitating display of the non-composite video signal by said display processor.

Abstract: A video source is coupled to a display processor by a circuit path including a comb filter and a luminance signal delay line and including a comb filter amplitude correction circuit. Circuit means in the path prevents impedance variations of the correction circuit from causing reflections in the delay line thereby preventing image blur due to such reflections. In a preferred embodiment this feature is provided using existing receiver circuitry thereby providing the further technical and economic advantage of improved reliability and providing a cost reduction.

Abstract: An auxiliary video input terminal (S-terminal) couples luminance and chrominance input signals to respective inputs of peaking circuits in the display processor of a receiver. The chrominance input signal is subjected to pre-distortion (de-peaking) to correct for sideband amplitude distortion in the chrominance peaking filter of the receiver thereby preventing color distortion in displayed images. The luminance signal is subjected to additional peaking at a frequency greater than the characteristic peaking frequency of the luminance peaking filter thereby enhancing the sharpness of wideband luminance input signals displayed by the receiver.

Abstract: An auxiliary video input terminal (S-terminal) couples luminance and chrominance input signals to respective inputs of peaking circuits in the display processor of a receiver. The chrominance input signal is subjected to pre-distortion (de-peaking) to correct for sideband amplitude distortion in the chrominance peaking filter of the receiver thereby preventing color distortion in displayed images. The luminance signal is subjected to additional peaking at a frequency greater than the characteristic peaking frequency of the luminance peaking filter thereby enhancing the sharpness of wideband luminance input signals displayed by the receiver.

Abstract: An auxiliary video input terminal (S-terminal) couples luminance and chrominance input signals to respective inputs of peaking circuits in the display processor of a receiver. The chrominance input signal is subjected to pre-distortion (de-peaking) to correct for sideband amplitude distortion in the chrominance peaking filter of the receiver thereby preventing color distortion in displayed images. The luminance signal is subjected to additional peaking at a frequency greater than the characteristic peaking frequency of the luminance peaking filter thereby enhancing the sharpness of wideband luminance input signals displayed by the receiver.

Abstract: A component audio/video system includes a system controller having an input/output port adapted for connection via a bidirectional data bus to a plurality of peripheral audio/video devices. At times determined by a system master clock the controller transmits, via the bidirectional bus, user programmed sequences of commands at user specified times to user selected peripheral devices for controlling the operating modes thereof. After transmission of a command of a sequence, the controller monitors the bus to detect a received return status message from the selected device and in response to the received message selectively (1) re-transmits the last command, (2) interrupts the transmission and (3) transmits a further command in the sequence whereby a number of individual devices may be controlled by a single master clock and the possiblility of conflict between a currently transmitted command and a current device operating mode is minimized.

Abstract: High voltage capacitors particularly suited for a BiCMOS process are formed in conjunction with prior art low voltage capacitors. In a first embodiment of a high voltage capacitor, an N+ region (66) is used as a first plate of the capacitor. The thermal gate oxice layer (48) used in conjunction with the MOS transistors (22,24) is also grown over the N+ region (66). Since the thermal oxide growth over the N+ region is accelerated, a thicker oxide region will be formed. A polysilicon plate (70) is formed over the thick oxide region (68) at the same time the first plate (12) of the low voltage capacitor (10) is formed. Alternatively, a nitride layer (18) may be formed over the thick oxide layer (68). The nitride layer (18) is also used in the formation of a low voltage capacitor (10).

Abstract: A phase-locked loop circuit having a charge pump and a voltage controlled oscillator which includes a phase/frequency comparator having a single circuit for operating in phase or frequency modes and which uses the discharge signal from the oscillator flip flop to trigger resetting of the input flip flop and which uses a one-shot in the phase compare mode for high frequency operation.

Abstract: A dropping resistor and a pair of differential current steering pairs coupled to the resistor with each operable to draw and cease drawing current through the resistor in response to associated corresponding input signals. An integrator is coupled through an emitter follower to one end of the resistor for integrating the current due to the difference in voltage from that voltage established when only one of the pair draws current through the resistor. Preferably the resistor is integrated on a semiconductor chip together with the remainder of the charge pump and integrator circuitry.

Abstract: An oscillator circuit having a coil and capacitor tank circuit, a clamp resistor connected at one end to the coil and a switch coupled to the clamp resistor and coil. The switch is operative to close in response to a first input logic clamp signal and shunt the coil with an impedance that causes the oscillation to stop quickly. In response to removal of the input logic clamp signal the tank circuit starts to oscillate from a known state. Preferably the clamp resistor has a value which equalizes the tank currents for the clamped and peak unclamped states.

Abstract: A folded cascode amplifier with rail-to-rail common-mode range utilizes a fully differential input with two sets of input common source amplifier devices to allow rail-to-rail common-mode range. The first set of devices utilizes N-channel transistors (28) and (32) to provide operation in one direction and P-channel transistors (38) and (42) to allow operation in the other direction. Two common gate amplifier output legs are provided for generating a differential voltage between an output node (50) and an output node (48) in a cascode configuration. A feedback circuit is provided for maintaining node (50) at analog ground over the full common-mode range of the input voltage. The feedback circuit utilizes a current source with transistors (88) and (90) and a differentially configured set of transistors (80) and (82) to control a feedback transistor (86).

Abstract: Disclosed is a small-area solid state driver (30) adapted for switching high voltages. The driver (30) includes a DMOS device (48) driving a bipolar SCR (58). A SCR NPN transistor (54) and PNP transistor (56) are parasitic in nature, thus reducing the wafer area of the driver (30). The SCR (58) provides current sink capabilities to the driver output (60). Current source capabilities are provided by a substrate input terminal (50) which is connected to the output (60) by diodes (84, 86). A third input (52) allows the SCR (58) to be disabled.

Abstract: A voltage controlled oscillator circuit of a type having a tank circuit for generating oscillations which includes a means for establishing a fixed bias voltage with respect to ground at a bias end of said tank circuit, means for drawing current from an a.c. end of said tank so as to control the tank gain, and an AGC capacitor. A constant current source is coupled to the AGC capacitor for supplying it with a constant charging current. Means are provided for discharging the AGC capacitor at a voltage level determined by a ratio of resistors and a transistor emitter-base ratio.

Abstract: A technician set-up unit is described for cable television converter installation and address assignment, and a method for using the unit with an addressable television converter. The set-up unit and method permits address assignments to be made in a convenient and easy manner by the CATV operator, thus avoiding address assignment during manufacture. The technician set-up unit, which is portable, forms a hardware link between the converter and addressing computer. Using the technician set-up unit as an intermediary device, data can be downloaded to the converter by the addressing computer to define the converter address and to establish the appropriate level of service. The benefit of the invention also permits the technician set-up unit to verify proper converter installation.

Abstract: A diode network includes a series branch coupled between two signal ports and a shunt branch coupled between a node in the series branch and ground and connected in parallel with a transistor of a latching circuit that is further coupled to supply forward bias to the shunt branch and reverse bias to the series branch when the transistor is conductive for blocking RF signal flow between the ports. The bias applied to the branches is reversed when the latch transistor is non-conductive thereby enabling RF signal flow between the ports. The transistor provides plural functions of establishing positive feedback for the latch, supplying forward and reverse bias to the shunt and series branches, respectively, and enhancing the attenuation of the shunt branch when conductive.

Abstract: An amplifier applies turn-on bias to the gate electrode of an output field-effect transistor in response to a first level of an input signal applied to the amplifier. A switched power source supplies operating current to the amplifier for developing the turn-on bias when the amplifier input signal is at the first level. A feedback-controlled bypass circuit diverts a portion of the operating current from the amplifier during an initial turn-on period and gradually reduces the magnitude of the diverted operating current as the output transistor turns on thereby producing a "soft" turn-on of the output transistor so as to minimize a potential for creating radio frequency interference in nearby RFI sensitive devices such as the tuner in a television or radio receiver. Complementary circuits include dual current supply and diversion circuits providing controlled rise and fall times for complementary field-effect output transistors.

Abstract: A field transfer imager is erased after every field transfer, prior to a new field of pixels-descriptive charge packet being accumulated in the successive charge transfer stages of the charge transfer channels of the image register. The image register is operated to supply a field of "null" charge packets for each field of pixel-descriptive charge packets it supplies. The "null" charge packets and pixel-descriptive charge packets are temporarily stored in respective field storage registers, and converted a line at a time to serial format for sensing. The resulting "null" samples and pixel-descriptive samples are differentially combined to provide pixel-descriptive samples with suppressed dark current ramp components and, assuming field-rate shuttering of the imager is not used, with suppressed transfer smear components.

Abstract: A compressor compresses the edges of a wide screen image to provide a compressed wide screen video signal which may be displayed on a conventional 4:3 aspect ratio receiver with the compressed edge portions largely hidden from view because of receiver overscan. Complementary edge expansion restores the compressed signal to its original form for display by a wide screen receiver. The relative proportions of compression applied to the left and right edges of the wide screen images are varied to reduce the appearance of edge distortion in the compressed signal when displayed on a standard aspect ratio receiver and to reduce the appearance of loss of edge resolution in the expanded signal when displayed on a wide screen receiver.