Abstract: A surge protector for alternating current service includes at least an incoming hot line and a neutral line, but usually includes an incoming hot line, an incoming neutral line and a safety ground line. The surge protector has an input transformer and a series connected transformer with input connection to the input transformer secondary winding, and connected in series to a non-linear surge suppression circuit, and therefore has a gross output connection to the non-linear surge suppression circuit, and a low impedance input to the secondary winding of the series connected transformer from the non-linear surge suppression circuit, and has a surge cancelled hot line output connection.

Abstract: A surge protector for alternating current service includes at least an incoming hot line and a neutral line, but usually includes an incoming hot line, an incoming neutral line and a safety ground line. The surge protector has a series connected transformer with input connection to the incoming hot line, and connected in series to a non-linear surge suppression circuit, and therefore has a gross output connection to the non-linear surge suppression circuit, and a low impedance input to the secondary winding of the series connected transformer from the non-linear surge suppression circuit, and has a surge cancelled hot line output connection. The surge protector is for single or three phase service.

Abstract: The present invention is directed to a wide input voltage range surge suppressor. It includes a series circuit for attachment to an upstream AC power input, and to a downstream load. There is a nonlinear low pass L-C filter having an inductor (and in some preferred embodiments, a low Q linear inductor) and a diode bridge, wherein the diode bridge includes at least one large value capacitor. There are two or three electrolytic capacitors of the nonlinear low pass L-C filter diode bridge in preferred embodiments. There is also a two section high pass filter connected to the electrolytic capacitor. This two section high pass filter has at least two diversely rated capacitors and at least three diversely rated resistors. A voltage offset diode is connected to the two section high pass filter and at least one electronic switch is connected to the voltage offset diode, with at least one capacitor connected to the electronic switch. The electronic switch is preferably a silicon controlled rectifier (SCR) switch.

Abstract: The present invention is directed to a wide input voltage range surge suppressor. It includes a series circuit for attachment to an upstream AC power input, and to a downstream load. There is a nonlinear low pass L-C filter having an inductor (and in some preferred embodiments, a low Q linear inductor) and a diode bridge, wherein the diode bridge includes at least one large value capacitor. There are two or three electrolytic capacitors of the nonlinear low pass L-C filter diode bridge in preferred embodiments. There is also a two section high pass filter connected to the electrolytic capacitor. This two section high pass filter has at least two diversely rated capacitors and at least three diversely rated resistors. A voltage offset diode is connected to the two section high pass filter and at least one electronic switch is connected to the voltage offset diode, with at least one capacitor connected to the electronic switch. The electronic switch is preferably a silicon controlled rectifier (SCR) switch.

Abstract: In a television system including a source of an intermediate frequency (IF) signal, which signal includes an IF picture carrier amplitude modulated with video information, synchronous demodulator means responds to the IF signal, for providing an in-phase first output video signal that has both luminance and chrominance components, and for providing a quadrature-phase second output video signal that has a chrominance component but substantially no luminance component. Chroma circuitry is responsive to the quadrature-phase second output video signal for generating first and second color-difference signals.

Abstract: An oscillator, constructed partially within the confines of a monolithic integrated circuit, includes a differential-input, differential-output, differential amplifier within the monolithic integrated circuit. First and second resistive potential dividers located within the monolithic integrated circuit respectively divide the potentials appearing at the first and second output terminals of the differential amplifier in a predetermined ratio for respective application to the first and second input terminals of the differential amplifier, thereby respectively completing first and second direct-coupled regenerative feedback connections. An inductor located outside the monolithic integrated circuit is connected between the first and second input terminals of the differential amplifier and is anti-resonated by one or more capacitors, which may be located inside or outside the monolithic integrated circuit.

Abstract: In a television system including a source of an intermediate frequency (IF) signal, which signal includes an IF picture carrier amplitude modulated with video information, synchronous demodulator means responds to the IF signal, for providing an in-phase first output video signal that has both luminance and chrominance components, and for providing a quadrature-phase second output video signal that has a chrominance component but substantially no luminance component. Chroma circuitry is responsive to the quadrature-phase second output video signal for generating first and second color-difference signals.

Abstract: A high-performance television receiver synchronously detects the picture IF signal. A synchronous impulse noise in the IF signal generates either positive-going noise or negative-going noise in the video signal supplied from a synchronous video detector, which noise is subsequently replaced by a value of video signal occurring previous to the impulse noise in the following manner. The video signal contaminated with impulse noise is supplied as input signal both to an impulse noise detector and to a delay line. The output signal from the delay line, delayed by about 240 ns, is supplied as the signal for tracking by a track-and-hold circuit. The detected impulse noise signal is used to actuate the hold condition in the track-and-hold circuit. By stretching the pulse from the impulse noise detector for the 600-800 ns duration overlapping the duration of most impulse noise, the track-and-hold circuit replaces most impulse noise with previously stored values of the delayed video signal.

Abstract: A high-performance television receiver synchronously detects the picture IF signal. A synchronous impulse noise in the IF signal generates either positive-going noise or negative-going noise in the video signal supplied from a synchronous video detector, which noise is subsequently replaced by a value of video signal ocurring previous to the impulse noise in the following manner. The video signal contaminated with impulse noise is supplied as input signal both to an impulse noise detector and to a delay line. The output signal from the delay line, delayed by about 240 ns, is supplied as the signal for tracking by a track-and-hold circuit. The detected impulse noise signal is used to actuate the hold condition in the track-and-hold circuit. By stretching the pulse from the impulse noise detector for the 600-800 ns duration overlapping the duration of most impulse noise, the track-and-hold circuit replaces most impulse noise with previously stored values of the delayed video signal.

Abstract: A surface-acoustical-wave (SAW) or other lumped intermediate-frequency amplifier filter is followed by an IF amplifier chain and a second detector constructed within the confines of a monolithic integrated circuit. The IF amplifier chain includes three emitter-coupled differential amplifiers, each exhibiting up to about twentyfold voltage gain, cascaded one after the other. Provision is made for automatically controlling the voltage gain of the first two emitter-coupled differential amplifiers. Common-collector amplifiers are used to buffer the application of the balanced output signals from each of the emitter-coupled differential amplifiers to the succeeding emitter-coupled differential amplifier or second detector. Balanced current responses to the direct bias potentials on which the balanced signals supplied to the second detector are respectively superposed, are extracted by lowpass filtering that is on-chip and does not use off-chip IF bypass capacitors.

Abstract: In a television receiver a downconverter responding to a selected television signal respectively supplies its first and second output signals as the input signals of first and second IF amplifiers, respectively. The downconverter includes a local oscillator for generating oscillations at a frequency controlled in response to the AFT signal. The first IF amplifier includes a first adjacent-channel sound carrier trap, in consequence whereof the first-IF-amplifier response is substantially reduced for the downconverted picture carrier, and an in-channel sound carrier trap. Responsive to the first-IF-amplifier response, a video detector generates a composite video signal in which sound beats are suppressed to relatively low level by the first adjacent-channel sound carrier trap.

Abstract: Variable-gain amplifier stages, such as may be used in a television receiver intermediate-frequency (IF) amplifier, each comprise a pair of transistors connected as an emitter-coupled differential amplifier with resistive collector loads. An electrically controlled conductance is connected between the collector electrodes of the transistors, to shunt the resistive collector loads in controllable amount to set the voltage gain of the stage. The electrically controlled conductance in each variable-gain amplifier stage is constructed so as not to change the DC operating conditions of the emitter-coupled differential amplifier and its resistive collector loads with variation in the conductance of the electrically controlled conductance. Front end portions of television receivers or video tape recorders are described each of which uses separate intermediate-frequency (IF) amplifiers for the FM sound carrier and vestigial-AM picture carrier.

Abstract: In TV receiving apparatus, a first IF amplifier chain comprises a first gain-controlled amplifier followed in cascade connection by a second gain-controlled amplifier, and a second IF amplifier chain comprises a third gain-controlled amplifier followed in cascade connection by a fourth gain-controlled amplifier. The second and fourth gain-controlled amplifiers are controlled similarly by an AGC signal, and the first and third gain-controlled amplifiers are controlled similarly by that AGC signal delayed in similar amounts. An RF amplifier is gain-controlled responsive to that AGC signal delayed even more, and a downconverter supplies first detector response to amplified RF, which first detector response is applied to the first and second IF amplifier chains by respective frequency-selective filters. The first IF amplifier response is downconverted to generate sound IF. The second IF amplifier response is detected to recover video signal.

Abstract: A surge suppressor comprises a first series circuit having a first inductance and a first alternating voltage limiter, including at least a first capacitance and a bidirectionally conductive rectifying circuit for charging the first capacitance, coupled between first and second input terminals for limiting surge currents and voltage excursions coupled to first and second load output terminals. The first alternating voltage limiter further comprises a sensing circuit for sensing at least one of the charging current supplied to and the voltage developed across the first capacitance. An auxiliary energy storage circuit and a normally open switching device responsive to the sensing circuit are provided for coupling the auxiliary energy storage circuit across the first capacitance during high energy surge conditions.

Abstract: A surge suppressor for repeatedly protecting a load against surges occurring on A-C power mains from lightning surges or the like comprises a first series circuit having a first inductance and a first alternating voltage limiter, including at least a first capacitance and a bidirectionally conductive rectifier circuit, coupled between first and second input terminals. The first inductance conducts substantially all of the current supplied from the A-C power mains. A second series circuit comprising a second inductance and second alternating voltage limiter, including at least a second capacitance and a second bidirectionally conductive rectifier circuit, is coupled across the first alternating voltage limiter and is coupled to first and second output terminals.

Abstract: An integrated circuit overload protection device is used to protect a bipolar transistor used in the common emitter configuration. The protective device comprises a bipolar transistor of opposite type to the protected amplifying transistor. The protective transistor is connected with its base to the collector of the amplifying transistor and with its collector connected to the terminal of the power supply which is not connected to a terminal of the load resistor of the protected device. The emitter of the protective device is preferably connected to the base of the protected device through a protective resistor. Inputs to the protected transistor are provided at the interconnection of the emitter of the protected device with one terminal of the protective resistor.

Abstract: The composite video signal input to the voltage comparator of a TV receiver AGC system is subjected to the filtering action of a low pass filter for noise suppression purposes. A wideband signal path, bypassing the low pass filter, is enabled during trailing edges of noise impulses exceeding the normal sync peak level, in order to substantially preclude delay of the fall of said trailing edges.

Abstract: Television receiver employs a synchronous video detector system, and includes an AFT detector responsive to carrier waves supplied by reference amplifier of synchronous detector system. A peak detector, independent of the synchronous video detector and the receiver's automatic gain control system, is responsive to the output of the receiver's IF amplifier, and supplies an output to a voltage comparator. When the comparison indicates the IF output swing exceeds a threshold value, the AFT detector is disabled to avoid an AFT "lockout" condition.

Abstract: A gain-controlled amplifier is provided, including first and second common emitter-coupled amplifying transistors for receiving differential input signals. The emitter circuits of the amplifying transistors include first and second controlled resistance devices, having base electrodes coupled to each other and to a source of gain-control potential, collector electrodes coupled to a source of reference potential, and respective emitter electrodes coupled to respective emitter electrodes of the amplifying transistors. Each of the controlled resistance devices includes a region of high resistivity (intrinsic) semiconductor material between the base and emitter electrodes, which gives the base-to-emitter junction of the device a PIN diode-like characteristic. The application of a gain-control potential to the bases of the devices may be used to vary both the small base-to-emitter current and the relatively larger emitter-to-collector current in the devices.

Abstract: Sync-positive and sync-negative video signals appearing across load resistors of synchronous video detector employing array of NPN transistors are coupled via respective voltage dividers to complementary inputs of differential amplifier employing NPN transistors. Signals appearing across load resistor of amplifier are coupled via an active filter to video signal output terminal. Detector load circuits, amplifier load circuit, and active filter each provide high frequency roll off with break point lying between desired video passband and second subharmonic of picture carrier intermediate frequency. Active filter provides response boost within high end of video passband, and response null in vicinity of picture carrier intermediate frequency. Level shift circuit utilizes series resistance of active filter. Differential amplifier has current source responsive to amplifier output to avoid cut off of amplifier transistor receiving sync-negative drive.