Patents Represented by Attorney William H. Meagher
  • Patent number: 4276566
    Abstract: In a television receiver comprising a video output stage for supplying amplified image representative video signals to a color kinescope, a signal clipping network is included for inhibiting video signal amplitude transitions otherwise capable of inducing radio frequency interference (RFI) by causing the video output stages to change between saturated and nonsaturated conductive states. The network is disposed in a low level video signal processing channel of the receiver, and serves to clip peak transient signal amplitude excursions likely to induce RFI in the video output stage. The clipping network exhibits a "floating" clipping level to account for variations in the black reference level of the video signal, and therefore variations in the peak level of transients likely to induce RFI, due to unit-to-unit tolerance variations of preceding signal processing circuits.
    Type: Grant
    Filed: August 10, 1979
    Date of Patent: June 30, 1981
    Assignee: RCA Corporation
    Inventor: Robert P. Parker
  • Patent number: 4275362
    Abstract: A gain controlled amplifier is provided which is capable of handling a wide range of input signal levels without the need for input signal attenuation. A transistor is arranged in a common emitter amplifier configuration and includes a PIN diode as a controllable impedance in the emitter circuit. An input signal and a gain control voltage are applied at the base of the transistor. As the input signal level increases, the gain control voltage is decreased, causing an increase in the substantially resistive impedance of the PIN diode, which bears a constant relationship to the decreasing gain control voltage (i.e., a linear relationship on a semilog plot). The gain of the transistor amplifier is thereby reduced. At high input signal levels, the impedance of the PIN diode comprises a large resistive component in parallel with a large reactive (i.e., small capacitive) component at the emitter of the transistor, thereby affording substantial gain reduction.
    Type: Grant
    Filed: March 16, 1979
    Date of Patent: June 23, 1981
    Assignee: RCA Corporation
    Inventor: Jack R. Harford
  • Patent number: 4272778
    Abstract: A first resistive current path is DC connected between respective output terminals of push-pull color demodulator. A second resistive current path is DC connected between respective output terminals of a second push-pull color demodulator. An output color-difference signal is formed by a differential amplifier having one input DC connected to an asymmetrically positioned point in first resistive current path, and a second input DC connected to an asymmetrically positioned point in second resistive current path. Output color-difference signal corresponds to a combination of the demodulated signals, with a polarity relationship and magnitude ratio determined by the asymmetry of positioning of the takeoff points in the respective current paths. Output quiescent voltage is independent of the asymmetry of positioning of the takeoff points.
    Type: Grant
    Filed: March 3, 1980
    Date of Patent: June 9, 1981
    Assignee: RCA Corporation
    Inventors: Leopold A. Harwood, Robert L. Shanley, II
  • Patent number: 4263567
    Abstract: In a VCO, the switching of capacitor charge control circuits between capacitor charging and discharging states is rendered responsive to the current demand of a first FET monitoring the potential across the capacitor. The source-drain path of a second FET, variable in conductivity in response to an external frequency control signal, is connected in the source circuit of the first FET, in parallel with the source-drain path of a third FET. The third FET is non-conductive during operation in the capacitor charging state, but is strongly conductive during operation in the capacitor discharging state. As a consequence, the threshold potential at which switching to the capacitor discharging state occurs varies in accordance with the control signal, while the threshold potential at which switching to the capacitor charging state occurs does not so vary.
    Type: Grant
    Filed: May 11, 1979
    Date of Patent: April 21, 1981
    Assignee: RCA Corporation
    Inventor: Brian Astle
  • Patent number: 4263610
    Abstract: A circuit for generating a composite keying signal comprises a burst gate circuit and a voltage translating network in a color television receiver also including keyed signal processing circuits and means for deriving horizontal and vertical blanking signals and a horizontal sync signal from a composite color television signal containing a color burst component. The burst gate circuit responds to the horizontal sync signal to develop a burst gate pulse encompassing the burst interval. A voltage level developed by the translating network in response to the horizontal and vertical blanking signals is combined with the burst gate pulse to produce a composite keying signal. The composite keying signal comprises a first pulse component of a desired level as determined by the translating network and ocurring during the blanking intervals, and a second pulse cmponent as provided from the burst gate circuit, superimposed on the first pulse and encompassing the burst interval.
    Type: Grant
    Filed: January 18, 1980
    Date of Patent: April 21, 1981
    Assignee: RCA Corporation
    Inventors: Robert L. Shanley, II, Leopold A. Harwood, Erwin J. Wittmann
  • Patent number: 4263622
    Abstract: Apparatus is disclosed in a video signal processing system for automatically controlling the blanking (black) current level of an image reproducing kinescope having cathode and grid intensity control electrodes. During measuring intervals when cathode blanking current is to be monitored, a fixed voltage is applied to the cathode over the entire measuring interval, and a locally generated auxiliary signal is applied to the grid electrode during a portion of the measuring interval. A version of the grid signal appears as a cathode output signal proportional to the level of cathode blanking current conduction. A voltage responsive sensing network coupled to the cathode provides an output difference voltage proportional to the difference in cathode current conducted over the measuring interval. This voltage is utilized to modify the cathode bias in a direction to produce the desired cathode blanking current level at or in the vicinity of kinescope cut-off.
    Type: Grant
    Filed: January 7, 1980
    Date of Patent: April 21, 1981
    Assignee: RCA Corporation
    Inventor: Werner Hinn
  • Patent number: 4263608
    Abstract: In a SECAM-PAL transcoder, color-difference signals, sequentially recovered from received SECAM signals by a single FM discriminator, are supplied via a first emitter-follower to a first modulating signal input terminal of a balanced modulator, which develops a quasi-PAL signal output using PAL subcarrier frequency oscillations. A DC potential, supplied to a second modulating signal input terminal of the modulator via a second emitter-follower, matches discriminator output level under no-color signal conditions. A third emitter-follower, responsive to a blanking waveform, effects cutoff of the first emitter-follower during blanking periods and delivers elevated blanking pedestal to the first terminal. A fourth emitter-follower, responsive to the same blanking waveform, effects cutoff of the second emitter-follower during blanking periods and delivers matching blanking pedestal to the second terminal.
    Type: Grant
    Filed: December 26, 1979
    Date of Patent: April 21, 1981
    Assignee: RCA Corporation
    Inventor: Werner Hinn
  • Patent number: 4263565
    Abstract: A limiter includes an amplifying stage with its operating point determined by a bias voltage developed across a capacitance associated with a charging path and a discharging path. With alternate disabling and enabling of one of the paths controlled by a switching device with a duty cycle reflective of the limiter output duty cycle, the average potential across the capacitance varies in accordance with changes in the duty cycle of the limiter output. The variation sense is selected such that the resultant alterations of the operating point oppose deviations of the duty cycle from a chosen norm (e.g., 50%).
    Type: Grant
    Filed: April 27, 1979
    Date of Patent: April 21, 1981
    Assignee: RCA Corporation
    Inventor: Brian Astle
  • Patent number: 4261017
    Abstract: An electron beam influencing apparatus comprises a deflection yoke which incorporates a kinescope neck-embracing collar which extends from the rear of the yoke. The collar extends over a portion of a slidably mounted sleeve. Permanent magnet neck components are rotationally mounted to the sliding sleeve. The collar and sleeve are formed so that the yoke and collar rotates independently of the sleeve, but longitudinal movement of the yoke and collar will cause longitudinal movement of the sleeve also. A single clamp is used to secure the collar and sleeve to the tube neck. The collar may be attached to a yoke adjustment plate which allows pivotal or transverse yoke motion while maintaining stationary positioning of the adjustment plate.
    Type: Grant
    Filed: December 27, 1979
    Date of Patent: April 7, 1981
    Assignee: RCA Corporation
    Inventor: Tom W. Branton
  • Patent number: 4261013
    Abstract: An apparatus for locating the position of the horizontal centerline on the display screen of a television kinescope comprises two screen edge sensors disposed at the top and bottom of the display screen. The edge sensors are mounted on a vertically movable member at a separation equal to the vertical dimension of the display screen. Each edge sensor comprises a light source for directing a beam of light at the kinescope along a first light path and a detector for sensing the different amount of radiation returned from the display screen and the adjacent reflective aluminum coating along a second light path. The sensors are moved until the detector outputs are equal, indicating the sensor is located at similar positions with respect to the top and bottom screen edges. The mid-point between the sensor is then the location of the horizontal centerline of the display screen.
    Type: Grant
    Filed: December 27, 1979
    Date of Patent: April 7, 1981
    Assignee: RCA Corporation
    Inventors: Marinus Van Renseen, Myron H. Wardell, Jr.
  • Patent number: 4260956
    Abstract: A biasing circuit is provided for stabilizing the gain of a transistor amplifier against variations in temperature. The amplifier includes an input terminal and a transistor having a base-to-emitter junction coupled between the input terminal and the second terminal of a two-terminal source of supply potential. The biasing circuit is coupled between the two supply terminals and includes a resistor coupled to the first terminal, a semiconductor rectifying junction coupled between the input terminal of the amplifier and the second supply terminal, and the parallel combination of the collector-to-emitter path of a second transistor and a voltage divider coupled between the resistor and the rectifying junction. The base of the second transistor is coupled to an intermediate tap of the voltage divider. As the temperature of the circuit increases, the g.sub.m of the amplifying transistor decreases.
    Type: Grant
    Filed: March 16, 1979
    Date of Patent: April 7, 1981
    Assignee: RCA Corporation
    Inventor: Jack R. Harford
  • Patent number: 4254365
    Abstract: A side pincushion corrected deflection circuit for a television receiver includes a deflection winding, a trace capacitor and a first switch for generating scanning current in the deflection winding. A modulator circuit includes a modulator inductor, a modulator capacitance and a second switch for generating a sawtooth modulator current in the inductor. The trace and modulator capacitors are charged from a voltage source through a flyback transformer winding. Reflected load currents from other television receiver circuits also flow in the flyback transformer winding. A transistor stage in the modulator circuit shunts current away from the modulator capacitor to control the modulator and trace capacitor voltages. A vertical rate bias voltage is applied to the transistor stage and varies the shunt current at the vertical rate to provide side pincushion correction. The transistor stage is operated in an open loop manner with no voltage feedback of the modulator capacitor voltage.
    Type: Grant
    Filed: October 1, 1979
    Date of Patent: March 3, 1981
    Assignee: RCA Corporation
    Inventor: Peter R. Knight
  • Patent number: 4254447
    Abstract: An integrated circuit heat dissipator is provided which will additionally hold the integrated circuit in a printed circuit board prior to soldering. The heat dissipator is comprised of a single elastic piece of metallic material having oppositely facing sides joined by a fold at the top. A tab is located at the bottom of each of the sides which is suitable for insertion into a printed circuit board. The tabs have a width which allows them to contact only the heat-conducting pins of the integrated circuit. The heat dissipator is mounted adjacent to the integrated circuit with one of the tabs contacting the heat-conducting pins. The elastic material gives the heat dissipator a spring-like property which causes the tabs to press outwardly from each other when inserted in a board so as to fixedly hold the heat dissipator and the integrated circuit in the printed circuit board prior to soldering.
    Type: Grant
    Filed: April 10, 1979
    Date of Patent: March 3, 1981
    Assignee: RCA Corporation
    Inventor: Patrick D. Griffis
  • Patent number: 4254366
    Abstract: Serially coupled first and second capacitors are charged from a DC source of unregulated input voltage through the primary winding of a flyback transformer of a horizontal deflection circuit. The voltage across the first capacitor is established as the voltage difference between the input voltage and the voltage across the second capacitor. The first capacitor functions as a trace capacitor for a horizontal deflection winding. A switch couples a trace voltage to the horizontal deflection winding to generate a trace deflection current. The switch also couples a first winding of a saturable reactor to the second capacitor to provide a capacitor discharge current path. A bias current flowing in a second winding of the saturable reactor varies the effective inductance of the first winding in response to energy level changes in the deflection circuit to control the voltage across the second capacitor.
    Type: Grant
    Filed: September 6, 1979
    Date of Patent: March 3, 1981
    Assignee: RCA Corporation
    Inventor: Walter Truskalo
  • Patent number: 4254436
    Abstract: A noise cancellation circuit is provided for cancelling impulse noise in a composite video signal. A composite video signal which may be contaminated with impulse noise is coupled to a noise inverter and an active filter. The noise inverter generates an inverted noise pulse for each noise pulse in the composite video signal which exceeds a predetermined threshold level. The active filter delays the composite video signal and combines the delayed video signal with the inverted noise pulses, resulting in cancellation of the impulse noise. The noise-free video signal is amplified by the active filter for subsequent signal processing. The threshold level of the noise inverter varies in response to the signal level at the output of the active filter. The active filter utilizes a feedback capacitor to delay the video signal and to improve the transition time of the leading edges of synchronizing signal components of the video signal.
    Type: Grant
    Filed: August 18, 1978
    Date of Patent: March 3, 1981
    Assignee: RCA Corporation
    Inventor: Jack R. Harford
  • Patent number: 4253077
    Abstract: A deflection adjustment device for a television deflection yoke and kinescope comprises a pair of magnetically permeable tabs adapted for linear movement along the kinescope minor axis. Means are provided for translating the rotary motion of a yoke adjustment machine into the desired linear tab travel. The tabs are moved in equal amounts, either toward or away from the yoke axis, to maintain the tabs equidistant from the yoke axis in order to correct coma errors.
    Type: Grant
    Filed: October 30, 1979
    Date of Patent: February 24, 1981
    Assignee: RCA Corporation
    Inventor: Myron H. Wardell, Jr.
  • Patent number: 4253121
    Abstract: An automatic kinescope beam current limiter in a television receiver comprises a sensing network for deriving a signal representative of average and peak beam current demand directly from the video signal cathode current of the kinescope, and a control circuit responsive to the derived signal. When excessive average beam current is sensed, the control circuit supplies a control voltage for modifying the D.C. level (brightness level) of the video signal in a direction to limit beam current demand over a first range of average beam currents, and subsequently supplies a control voltage for reducing the peak amplitude (contrast level) of the video signal to limit beam currents over a second range of relatively greater average beam currents.
    Type: Grant
    Filed: September 11, 1979
    Date of Patent: February 24, 1981
    Assignee: RCA Corporation
    Inventor: Leslie R. Avery
  • Patent number: 4253110
    Abstract: An automatic kinescope beam current limiter for a television receiver comprises a source of signal representative of kinescope beam current conduction, a first transistor responsive to the representative signal over first, second and third ranges of excessive beam currents above a threshold level, and a second transistor. A first control signal derived from the first transistor modifies the video signal peak-to-peak amplitude (contrast level) when beam currents above the threshold level occur. The output of the first transistor is selectively coupled to an input of the second transistor when beam currents beyond the first range occur. A second control signal derived from the second transistor modifies the video signal D.C. component (brightness level) to limit beam currents beyond the first range, whereby both the peak amplitude and D.C. components are modified over the second range.
    Type: Grant
    Filed: December 14, 1979
    Date of Patent: February 24, 1981
    Assignee: RCA Corporation
    Inventors: Leopold A. Harwood, Erwin J. Wittmann, Robert L. Shanley, II
  • Patent number: 4251756
    Abstract: First and second capacitors are charged from a DC source of unregulated input voltage through the primary winding of a flyback transformer of a horizontal deflection circuit. The average voltage across the first capacitor is established as the voltage difference between the input voltage and the average voltage across the second capacitor. The first capacitor functions as a trace capacitor for a horizontal deflection winding. A switch applies a trace voltage to the horizontal deflection winding to generate a trace deflection current. The switch also applies the voltages developed across the second capacitor and across a flyback transformer secondary winding to a regulator inductance to control the flow of current in the second capacitor. The current flowing through the inductance is varied in order to control the voltage across the second capacitor for regulating a selected deflection circuit quantity.
    Type: Grant
    Filed: September 6, 1979
    Date of Patent: February 17, 1981
    Assignee: RCA Corporation
    Inventor: Donald H. Willis
  • Patent number: 4250521
    Abstract: A video signal dropout compensator stores information from at least one incoming television line which is represented by a plurality of samples of combined liminance and chrominance signal components. The samples occur at a rate equal to four times the chrominance subcarrier frequency. When a signal dropout is detected in one or more of the samples, a replacement sample is generated using samples from at least one adjacent television line. The value of the sample on the adjacent line at the horizontal location, corresponding to the dropout sample, is subtracted from the sum of the samples before and after this corresponding location sample. The resultant value gives a dropout replacement sample with proper chrominance phase having a close approximation of the correct luminance value.
    Type: Grant
    Filed: July 19, 1979
    Date of Patent: February 10, 1981
    Assignee: RCA Corporation
    Inventor: David I. Wright