Abstract: A frequency detector of a phase-lock-loop circuit is used for measuring a frequency error between a frequency of an output signal of an oscillator and a frequency of a synchronizing signal. When the frequency error in each of 32 periods of the synchronizing signal exceeds a predetermined magnitude, the phase-lock-loop circuits begins operating in a coarse frequency correction mode. As long as the 32 periods have not lapsed, the phase-lock-loop circuit operates in an idle mode of operation and the oscillator is not corrected. As a result, during vertical retrace, when equalizing pulses occur, the phase-lock-loop circuit is not disturbed by a large frequency error.

Abstract: A phase-locked-loop circuit includes an oscillator having switched capacitors that are selectively coupled to a positive feedback path of the oscillator in a coarse frequency error correction mode of operation. When the frequency error is small, the circuit operates in a fine error correction mode without varying the selection of the switched reactive elements.

Abstract: In a phase-lock-loop circuit a frequency detector measures a frequency error between an oscillatory signal and a synchronizing signal in alternate horizontal line periods for generating a frequency error indicative signal. The frequency error indicative signal is applied to an oscillator for correcting the frequency error in other alternate horizontal line periods in a manner to prevent frequency error measurement and correction from occurring in the same horizontal line period.

Abstract: A phase detector of a phase-lock-loop circuit measures a phase error between an output signal of an oscillator and a synchronizing signal. When a difference between the phase error that is measured in a pair of horizontal line periods exceeds a first magnitude, that is indicative of phase error inconsistency, the phase of the oscillator output signal is not corrected and the phase-lock-loop circuit operates in an idle mode of operation.

Abstract: An acoustic transducer which can be made small in size, i.e., in width, length and thickness, so as to fit into a credit card size package. The transducer comprises a flat frame having an opening therethrough. A pair of diaphragms of a piezoelectric plastic material extend across the opening in the frame along opposite sides of the frame. The diaphragms are stretched in at least one direction and are bonded to the frame under tension in the direction of the stretch. The diaphragms are bonded together at a position within the opening in the frame. The diaphragms are coated in both surfaces with conductive metal films. The inner metal films on the diaphragms which are opposed to each other are electrically connected together and the outer metal films are electrically connected together.

Abstract: To improve the bandwidth of a display driver stage in a wideband video signal processing and display system, the output of a display driver amplifier is coupled to a display device via a transmission line having an unterminated output end, a misterminated source end to develop a negative non-zero source reflection coefficient, and a phase delay within a given range.

Abstract: A brightness control circuit in a video signal processing system includes an amplifier and an adjustable brightness control coupled to the amplifier input, which also receives keying pulses via a resistor-capacitor input circuit. Output pulses from the amplifier exhibit a brightness determinative amplitude related to the setting of the brightness control. To maintain a substantially constant waveshape for the output pulses as the brightness control is adjusted, a shaping capacitor is coupled between the input and output of the amplifier.

Abstract: A method and associated apparatus are disclosed for facilitating the service adjustment of the blanking current levels of a kinescope in a color television receiver, when video signals are decoupled from the kinescope and kinescope vertical scanning is disabled in a service operating mode of the receiver. In the service mode, a grid electrode of the kinescope is forward biased during a monitoring interval to produce a kinescope cathode output voltage proportional to the kinescope blanking current level. A sample of the cathode output voltage is compared with reference voltages for providing plural output signals representative of high, low and correct cathode blanking current levels relative to a desired current level. The output signals energize plural display devices for indicating whether the blanking current is high, low, or correct with respect to the desired current level. If necessary, the kinescope bias is adjusted until the display devices indicate that the desired blanking current level is obtained.

Abstract: Circuit to apply an offset voltage to be added to a charge storage signal depositing a charge on a radially swept charge storage surface so that the charge storage signal is a minimum at the center of the surface and a maximum at the outer edges of the sweep. This reduces or eliminates the charge integration in the area where the sweep lines converge.

Abstract: A video frequency amplifier is biased to provide output signals of a first magnitude. In response to the application of a predetermined control signal, the bias is altered so that output signals are provided of a second, different magnitude. When employed in communications systems of the type in which television images are "frozen" by a storage tube for subsequent transmission on an individual frame basis by a voice-quality telephone link, for example, and subsequently re-created, the control signal indicates whether the system and its storage tube are to operate either in the "transmit" or "receive" mode.