Abstract: A translator demodulates a received digital television signal so as to produce a digital data stream, a symbol clock, and a byte clock, wherein the symbol clock and the byte clock are corrupted by phase noise. The digital data stream is written into a buffer in response to the corrupted byte clock. The corrupted symbol clock is applied to a frequency/phase locked loop having a narrowband loop filter. The frequency/phase locked loop produces a regenerated symbol clock having substantially no phase noise. The digital data stream is read from the buffer in response to the regenerated symbol clock. The digital data stream read from the buffer and the regenerated symbol clock are applied to a modulator for re-broadcasting of the received digital television signal.

Abstract: A translator demodulates a received digital television signal so as to produce a digital data stream, a symbol clock, and a byte clock, wherein the symbol clock and the byte clock are corrupted by phase noise. The digital data stream is written into a buffer in response to the corrupted byte clock. The corrupted symbol clock is applied to a frequency/phase locked loop having a narrowband loop filter. The frequency/phase locked loop produces a regenerated symbol clock having substantially no phase noise. The digital data stream is read from the buffer in response to the regenerated symbol clock. The digital data stream read from the buffer and the regenerated symbol clock are applied to a modulator for re-broadcasting of the received digital television signal.

Abstract: A multiple frequency horizontal scan system includes a scan frequency compensation system which detects horizontal scan frequency changes by frequency detecting the horizontal sync pulses. A frequency responsive switching system couples the appropriate reactive components to the horizontal defection yoke and horizontal output transformer in response to sync pulse frequency. The system further supplies alternative voltages for the scan system operating supply in response to horizontal sync pulse frequency. In addition, the system provides a convenient source of frequency dependent switching signal which may be utilized to operate additional auxiliary elements in response to changes of horizontal scan system frequency.

Abstract: A display monitor includes a conventional cathode ray tube display together with conventional display drive circuitry. Vertical and horizontal deflection systems are operative to provide raster scanning of the cathode ray tube. High voltage apparatus produce the required CRT beam accelerating potential. A scan modulator is coupled to the horizontal deflection system and is operative to provide stable control of the amplitude of horizontal deflection signal. A modulator drive control responds to the amplitude of horizontal deflection signal and produces a control signal utilized by the modulator in maintaining stable horizontal scan amplitude. A scan selection network is coupled to the modulator drive control to selectively alter the operating point of the scan modulator and thereby produce different scan widths for normal and expanded view operation.

Abstract: A display monitor includes a conventional CRT and associated display drive circuitry together with conventional horizontal and vertical deflection systems. A high voltage system is operated in response to the horizontal deflection system to produce a CRT accelerating potential. A display size control responds to changes of high voltage system current to produce an error signal which is used to produce compensating amplitude changes of vertical and horizontal deflection currents in order to maintain substantially constant image size.

Abstract: A display monitor includes a conventional cathode ray tube display and display drive. A conventional horizontal deflection system and high voltage system are operable to provide horizontal scan of the cathode ray tube and a high voltage potential therefor. A vertical deflection system suitable for multiple frequency and normal or expanded modes of operation includes a vertical oscillator and vertical amplifier driving a vertical deflection yoke. A sample of the vertical deflection signal is detected by an amplitude detector and compared to a reference amplitude to produce an error signal operative upon the vertical scan system. Individual reference voltages corresponding to normal and expanded modes of operation are selectively coupleable to the reference voltage portion of the system by a selector switch.

Abstract: A regulator for compensating for the IR drop of a rectifier coupled between the secondary winding of a transformer and a load circuit includes a pass transistor connected between the load circuit and the rectifier. A DC reference voltage is developed by a circuit connected across the secondary winding that is not subject to current fluctuations. A differential amplifier is supplied with the reference voltage as one input and the load voltage as another input. The output of the differential amplifier controls the conductivity of the pass transistor. A current limiting transistor is included in the base circuit of the pass transistor and, in turn, is controlled by another differential amplifier supplied with potentials representative of the IR drop across the rectifier. A shut down transistor is provided for cutting of the pass transistor in the event the load circuit voltage drops below a predetermined level.

Abstract: A CRT video display includes a horizontal oscillator for producing a variable rate horizontal scan control signal in response to different resolution modes of operation. A horizontal output signal is produced in response to the variable rate horizontal scan control signal and a B+ voltage. The pulse amplitude of the horizontal output signal is maintained constant in response to changes in the rate of the horizontal scan control signal by appropriately adjusting the B+ voltage, whereby the high voltage and horizontal raster size of the display are maintained constant despite variations in the horizontal scan control signal which accommodate different resolution modes of operation.

Abstract: Circuitry is described for driving the primary winding of a horizontal output transformer without the use of a conventional drive transformer. The horizontal output transistor is coupled to a tap on the output transformer and is switched off and on to excite the transformer. The horizontal output transistor is driven, in turn, by a driver transistor whose collector is also coupled to a tap on the output transformer such that adequate power is derived from the transformer to drive the output transistor into saturation. The driver transistor receives horizontal scan rate pulse from input circuitry which is preferably adapted to provide a path to ground for stored charges in the output transistor so that it may be rapidly turned fully off when a scan pulse terminates.

Abstract: A balanced, constant current power supply having two rectifying bridges coupled in parallel is energized by an AC source for generating a plurality of DC output voltages. The parallel arrangement of diode rectifying bridges permits the use of low cost, polar electrolytic capacitors in the power supply and results in a balanced circuit capable of generating a plurality of parallel DC outputs. The AC-driven, DC power supply of the present invention operates without a transformer and, in combination with a plurality of shunt regulators, is capable of providing a plurality of well-regulated DC output voltages.

Abstract: An electronic switch is provided for use in a battery-powered portable television receiver which eliminates power supply current drain when the television receiver is turned off. Coupled transistors are rendered conductive by means of either a clock or a manually switched input signal to provide a direct voltage battery output to television receiver circuitry. Also disclosed in an electronic switch combination for selectively controlling the audio output for the entire television receiver either manually or automatically.

Abstract: Video display distortion in a television receiver introduced by input voltage excursions is compensated for by a voltage regulation circuit which tracks the changing input line voltage while automatically switching to an active filter mode once the line voltage has decreased to a predetermined level. This permits the removal of AC transients from the fluctuating input signal and avoids display degradation resulting therefrom.

Abstract: A rechargeable battery provides a source of operating potential for an electronic circuit load. An operator controlled on-off switch connects the battery to a relay, and through the normally open relay contacts, to the electronic circuit. The relay winding is returned to ground through a capacitor. When the switch is closed the relay is momentarily energized by the current which charges the capacitor. A transistor has its collector-emitter path in parallel with the capacitor and its base coupled to the movable tap on a voltage divider connected across the load. In the absence of a low voltage condition across the load, the transistor conducts maintaining relay closure for normal circuit operation.