Thomson Consumer Electronics Inc.

Rca Inc.

Rca Licensing Corporation

Thomson Licensing S.a.

Other

Thomson Licensing

William A Lagoni

Robert Lawrence O'Brien

Ronald Thomas Keen

Isaac M Bell

Roger L Lineberry

Robert Preston Parker

Mark Francis Rumreich

Todd J Christopher

Max Ward Muterspaugh

Robert L Shanley, Ii

James Russell Bergen

Jack S Fuhrer

Enrique Rodriguez-Cavazos

Dalton H Pritchard

Dal Frank Griepentrog

Thomas D Gurley

Gregory George Tamer

Thomas D Yost

Robert D Altmanshofer

Wayne E Harlan

Charles M White

Walter E Sepp

Dennis Ronald McCarthy

Charles B Neal

Karl R Koblitz

Albert P Pica

Abraham E Rindal

Joseph Peter Bingham

Charles Michael White

Gary A Whitledge

James B Webb

A color television receiver system processes color difference signals for providing tint control while maintaining uniform color amplitude with respect to changes in hue shift angle. The color difference signals are modified as a function of each other and as a function of a hue shift angle to produce modified color difference signals. A color difference signal [B-Y] is supplied as a first input to multipliers Mand M. Another color difference signal [R-Y] is supplied as a first input to another pair of multipliers Mand M. A control signal generator produces output signals sin &#x3b8; and cos &#x3b8; where &#x3b8; is the hue shift angle. The sin &#x3b8; signal is supplied as a second input to multipliers Mand Mwhile the cos &#x3b8; signal is supplied as a second input to multipliers Mand M. The outputs of Mand Mare added in an adder Ato produce a modified output [R-Y]'. Similarly, the output of multiplier Mis provided as a positive input to adder Awhereas the output of multiplier Mis provided as a negative input to adder Ato produce a modified color difference signal [B-Y]&#x2032;. The modified color difference signals [R-Y]&#x2032; and [B-Y]&#x2032; represent a color vector having an amplitude A that remains substantially constant over a relatively wide range of hue shift angles &#x3b8;.

Color difference hue control system

An emitter follower amplifier is coupled between the output of a high voltage video amplifier and the cathode of a kinescope for reducing the effective capacitance presented to the video amplifier that is attributable to the kinescope cathode, socket, spark gaps, and related stray capacitances. A secondary undesired capacitance loading of the video amplifier is effectively reduced by regulating the collector-emitter voltages of the emitter follower output transistors at substantially constant values thereby improving parameters such as slew rate and bandwidth of the overall video display system. Nonlinear circuitry in the follower circuit facilitates accurate AKB current sensing and provides simplification of the voltage regulation circuitry. White limiting circuitry is included within the video amplifier for reducing excess peak white drive that results in objectionable smears. Black limiting circuitry within the video amplifier is also provided to prevent the collapse of the collector-emitter voltage of the push-pull follower output transistor. The heat sink capacitance of the video amplifier output transistor is screened out via bootstrapping.

Display driver apparatus

A television receiver includes telephone network interface circuitry which allows the receiver to receive and process Caller-ID signals for display during the ringing period of the telephone set. The television receiver also includes circuitry which allows a list of priority callers to be entered. In this way, the incoming Caller-ID codes are compared to the telephone numbers of the priority callers. Upon detection, the Caller-ID information of a priority caller is displayed on screen during television viewing. The telephone numbers of those callers not listed as priority callers are not displayed during the ringing period of the telephone. Both displayed and non-displayed telephone numbers which correspond to unanswered telephone calls are stored in a Caller-ID list for display at the user's convenience. In this way, the user is able to enter data to select beforehand which calling telephone numbers are permitted to interrupt his or her television show by displaying Caller-ID information on the screen.

Television receiver having a user-editable telephone system caller-ID

A projection television system includes an automatic contrast control section for controlling the amplitude of the luminance signal in response to the peak value of a luminance-representative image component signal in order to prevent white-spot blooming. Circuitry is provided for deactivating the automatic contrast control section when a user sets the contrast control level above a given threshold level, e.g., corresponding to the maximum contrast control level. As a result white-spot blooming is inhibited in order to ensure sharp images for a contrast control range below the given threshold level while allowing maximum white image components to be produced (at the expense of white spot blooming) when the contrast control level is set above the threshold level, depending on the preference of the user.

Video system including apparatus for deactivating an automatic control

A VCR or laserdisc player includes circuitry for detecting a code provided by VCR tapes, tape cassettes, or laser videodiscs, which indicates that the material recorded on the videotape or videodisc has been recorded in a compressed fashion to enable proper playback on a 16.times.9 television receiver. In response to detection of this code, the VCR or laserdisc player applies a DC signal to the chrominance output terminal of its S-Video connector. Circuitry in the television receiver detects the DC signal on the chrominance terminal of its S-Video input connector, and controls a wide-screen processor to expand the image by displaying it over the entire width of the 16.times.9 display screen.

Apparatus for use in a VCR or laserdisc player for providing a signal

A differential current source (50) provides first and second complementary output currents (I1, I2) responsive to a video input signal (S1) which are coupled via respective load networks (52,54) to a common supply terminal (22) and develop first and second complementary video output signals (V1,V2). A first output circuit (56) applies the first output signal to a first output terminal (16) via a voltage follower transistor (Q6) and applies the second output signal to the first output terminal via a current source transistor (Q8). A second output terminal (18) is similarly driven by a second voltage follower transistor (Q5) and a second current source transistor (Q7), all transistors being of the same conductivity type. A tri-state control circuit (Q1,Q2) coupled to the differential current source enables the differential current source in a first operating mode to produce the first and second complementary currents whereby push pull output signals are produced at the output terminals. In a second operating mode, the tri-state control circuit forces the complementary currents to zero whereby the common supply terminal (22) applies turn-off bias via the two load networks to the control electrodes of all of the output transistors thereby 'tri-stating' (isolating) the output terminals. Advantageously, in the tri-state mode, there is zero quiescent power dissipation in the output circuits, the load networks, the differential current source and the tri-state control circuit.

Tri-state video differential driver

A television receiver embodying the invention includes a plurality of luminance signal sources, each capacitively coupled to an input of a luminance signal selection switch and each capacitor being coupled to a respective clamp circuit with each clamp circuit having a reference voltage input coupled to a common reference voltage source. A sync separator is provided having a first input coupled to receive the output of luminance signal selection switch and a second input coupled to a source of reference potential derived from said reference voltage source. Advantageously, the overall number of clamp circuits is minimized by merging the sync separator circuit with the input signal selection clamping circuit.

Multi-input television receiver with combined clamping and synchronizing

A video signal to be processed is applied to a non-linear processor having an adjustable gain responsive to a control signal over at least one portion of the amplitude range of the video input signal. A sampling circuit, responsive to the video signal, generates video samples related to the video signal. A control circuit, responsive to the video samples, generates the control signal in accordance with the number of samples in at least a given amplitude range thereby controlling the percentage of samples of a given range in displayed images. Plural control and sampling circuits may be included provide control for white stretch processing, black stretch processing and video mid-point processing for enhancing contrast through out the entire video signal range.

Non-linear contrast control apparatus with pixel distribution

A clamp system for use in a television receiver having tuner and auxiliary video sources, comprises an IF AGC and video detector circuit having an AGC reference voltage input and an auxiliary video input signal clamp circuit having a reference voltage input. The detector circuit and the clamp circuit are each formed on a common integrated circuit along with a video switch for selecting video signals provided by said detector and clamp circuits. The integrated circuit further includes a reference voltage source and a bias generator for deriving the AGC reference voltage and the auxiliary input signal clamp voltage from the common source.

Video processing circuit with IF AGC loop, auxiliary video clamp and

A video input signal to be displayed is applied to an offset clamp circuit which effects a DC offset of blanking and active video portions of each video line. The DC offset or shift is of an amount and in a polarity sense to place the black level of the active portion of an NTSC color standard signal at a level corresponding to blanking level of the NTSC color standard. Advantageously, subsequent clamping at the shifted level enables contrast control without altering the black level of displayed images.

Television receiver with luminance signal clamped offset and re-clamped

A luminance signal filter for use in a multi-source television receiver, includes a tunable filter responsive to a bandwidth control input signal for determining the bandwidth of luminance signals applied to said filter and a variable delay circuit inversely responsive to said bandwidth control input signal for providing a substantially uniform overall delay for said luminance signal filter.

Variable bandwidth luminance filter with commonly tuned delay and

In a TV system which includes an autopix feedback loop limiting the range over which the contrast can be controlled, there is included means for generating a non-linear contrast control voltage as a function of customer control settings in order to extend the range over which the customer can control the contrast.

Non-linear customer contrast control for a color television with autopix

A fixed filter determines a lower portion of the amplitude characteristic of a chrominance signal sideband correction filter. A variable filter determines the upper portion of the amplitude characteristic. A control signal tunes the variable filter for providing a symmetrical response for video signals having balanced color sidebands and tunes the variable filter for providing an asymmetrical response for video signals having unbalanced sidebands.

Television receiver with switchable chrominance signal filter

Video signal processing circuit including a source of composite luminance signals having image-representative components separated by regularly recurring synchronizing signal components; keyed clamp and signal clipping circuit coupled to the luminance signal source and responsive to back porch keying pulses for clamping a back porch interval of the composite luminance signal to a predetermined direct voltage level, the keyed clamp and signal clipping circuit further including a voltage sensitive signal clipping circuit responsive to the direct voltage level and to the clamped composite luminance signals for removing synchronizing signal components from the composite components; chrominance signal processing circuit for demodulating a color subcarrier signal to produce a plurality of color difference signals; a source of keying pulses recurring during the synchronizing signal interval; and a plurality of keyed clamp circuits each responsive to the synchronizing signal interval keying pulses and individually responsive separately to one of the demodulated color difference signals and the image-representative luminance signal for clamping each of the color difference and image-representative luminance signals to a common voltage reference level.

Video signal processing circuits

Two transistors are operated individually as emitter follower buffer amplifiers for R-Y and B-Y input signals and are operated together as an inverting summing matrix for deriving a G-Y output signal from the R-Y and B-Y input signals. All three output signals are 'buffered' (i.e., provided by low impedance sources) and are subject to substantially equal delays. Advantageously, the circuit implementation requires only two transistors and three resistors to provide output signals which are (1) buffered, (2) matrixed and (3) delay compensated and which features improved reliability (due to reduced 'parts count') and an economic implementation of the buffering, delay compensation and matrixing functions.

Growing community of inventors

Indianapolis, IN, United States of America

William A Lagoni