Abstract: First and second amplifiers are coupled together to provide complementary output signals at respective output terminals in response to application of operating potentials to first and second supply terminals of each amplifier and application of an input signal to at least the first amplifier. A switching circuit, responsive to a first level of a tri-state control signal supplied thereto, applies the operating potentials individually to the first and second supply terminals of each amplifier and concurrently couples the input signal to the input of the first amplifier and, responsive to a second level of the tri-state control signal, isolates all of the amplifier supply terminals and decouples the input signal. Transient disturbances are minimized by AC coupling the input signal and applying a common mode signal from a common mode source to the AC coupling, to a reference input of each amplifier and to the output terminal of each amplifier.

Abstract: An M-bit digital signal, the most significant bit (MSB) thereof and an integer K are added to produce a sum which is truncated by N least significant bits to provide a symmetrically rounded bit-reduced digital output signal. The MSB may be applied in true or complemented form to the adder for selecting wide or narrow rounding modes having different numbers of output zeros disposed about a point of symmetry for a given input signal change. Advantageously, undesirable direct current (DC) shifts due to least significant bit (LSB) reduction in digital video, audio or similar applications are prevented.

Abstract: A first pixel of a given field is compared with second and third vertically aligned pixels of corresponding horizontal position of an adjacent field to produce, for each first pixel, a pixel difference signal having a value of zero if the value of the first pixel is intermediate the values of the second and third pixels, the difference signal otherwise having a value equal to the absolute value of a difference between the value of the first pixel and the value of one of the second and third pixels having a value closest to that of first pixel. The pixel difference signals are accumulated over a predetermined portion of one field period of the video signal to provide a field difference signal which is analyzed by a group of five correlators for patterns characteristic of 2-2 pull-down or 3-2 pull-down film mode sources. Flags are produced for identifying film mode operation and for identifying which of the adjacent fields to use in subsequent video processing such as de-interlacing or flicker reduction.

Abstract: A caller ID system is disclosed in which a prescaler is coupled between a source of a caller ID signal and a caller ID receiver, and a processor is coupled to the caller ID receiver. The prescaler is responsive to the processor for scaling the caller ID signal.

Abstract: A more rapid charging of an integrating capacitor of a PLL is provided when large frequency changes are desired. In one embodiment, the phase locked loop (PLL) circuit sinks or sources current to charge or discharge the integrating capacitor. A threshold voltage proportional to a current through the capacitor turns on an augmenting circuit which sinks or sources more current of the proper polarity to the integrating capacitor from an external source until a PLL lock is achieved. Once the lock is achieved, if a small correction current is required by the PLL, the small correction current is below a threshold required to actuate the augmenting circuit, and the PLL loop behaves in the usual manner as if the augmenting circuit were not present. In another embodiment, the integrating capacitor is reduced in value by switchably connecting a second capacitor in series with the integrating capacitor so that the total reduced capacitance of reduced value can be charged more quickly.

Abstract: A television system for receiving a plurality of television programs includes a programming unit for causing the television system to receive and record a particular television show aired on a given channel, at a particular time and date in accordance with schedule data entered by a user. The television system includes a controller for generating the on-screen displays in response to user-entered data. Upon completion of a programming entry, the controller causes a display of a substantially grammatically correct sentence summarizing the entered programming instructions and acting as a confirmation screen. In one embodiment, the confirmation screen is interactive in that certain variables within the sentence may be modified by the user to change the sense of the sentence, and thus to modify the programming instructions.

Abstract: A complementary push-pull emitter follower amplifier is coupled between the output of a high voltage driver amplifier and the cathode of a kinescope for reducing the effective capacitance presented to the driver amplifier that is attributable to the kinescope cathode, socket, spark gaps and related stray capacitances. A secondary undesired capacitance loading of the amplifier attributable to the collector to base capacitances of the follower amplifier is effectively reduced by regulating the collector emitter voltages of the push-pull follower output transistors at respective substantially constant values thereby improving parameters such as the slew rate and bandwidth of the overall video display system.

Abstract: The invention concerns an arrangement including a microprocessor controller, PROM memory, and a digital to analog converter (DAC) arrangement for generating a plurality of control voltages for trimming respective ones of a plurality of varactor controlled tunable filters. The controller couples digital control signals to the respective DACs which generate respective analog control voltages which are applied to the respective tunable filters. A tuning voltage generated by a closed control loop, such as phased locked loop also under the control of the controller, is combined with the output control voltages generated by the respective DAC's in a resistance divider arrangement.

Abstract: A color interpolation circuit allows information uniquely identifying one of six colors to be stored by using only two binary bits of memory storage, and allows information uniquely identifying one of 120 colors to be stored by using only four binary bits of memory storage. This is accomplished by storing only the foreground, edge, and background colors (i.e., herein referred to as "independent" colors), and an "interpolate operator" code, and by providing circuitry to properly interpret and process the interpolate operator code to generate "intermediate colors". This permits a 33% reduction of memory size and reduces the "fetch speed" requirements of associated on-screen display (OSD) scan converter circuitry.

Abstract: The present infra-red remote control transmitter understands external formats, and those with toggle-bits and different carrier frequency ranges, and transmits signals in these data formats to the appropriate devices, with or without a toggle-bit. The remote control receives and transmits infra-red formats and comprises an infra-red receiver with a microprocessor and/or with two carrier frequency oscillators to generate two modulation frequencies, in which case it is provided with two infra-red receivers. An externally formatted data word with toggle-bits is subjected, after being read at least twice, to a comparison inside the microprocessor, from which the presence of toggle-bits, their number, position and the carrier frequency of the data word are found.

Abstract: A system for receiving a radio signal representing a radio program comprises at least first and second radio receiver units. Each receiver unit receives the radio signal at a respective frequency and produces a respective radio program signal. All of the radio program signals represent the same radio program. A decoder decodes a control signal, such as an RDS signal, from each of the radio program signals. A control device processes the control signals to determine the delay between the radio program signals. The control device uses the delay information to modify a a variable delay in the signal path of at least one radio program signal until the radio program signals are synchronized. The synchronized radio program signals are combined, e.g., by fading the signals together, to produce a resultant radio program signal.

Abstract: An auxiliary video information decoder for extracting an auxiliary video information signal from a video signal includes a data slicer and apparatus for adjusting the slicing level of the data slicer. The slicing level is adjusted rapidly until a reference component of the auxiliary information signal is detected during a display interval of the video signal in which auxiliary video information is expected to occur. A count is incremented after display intervals in which the reference component is detected and is decremented after display intervals in which the reference component is not detected. Slicing level adjustment ceases while the count is at least a predetermined number. The apparatus rapidly adapts the slicing level to long-term video signal amplitude changes of significant magnitude (e.g. following a channel change) and maintains a constant slicing level when transient variations occur in the video signal amplitude.

Abstract: A video clock input signal is applied to a delay line comprising a cascade connection of a plurality of delay elements formed in an integrated circuit for providing a plurality of delayed clock signals at respective taps of the delay line. A selection circuit, responsive to a horizontal synchronizing signal supplied thereto, couples a selected one of the taps to an output for providing a delayed output clock signal that is edge-aligned with the synchronizing signal. For reducing the number of taps required to provide a given minimum delay step resolution and a given minimum total delay for delay elements which may vary in delay, from one integrated circuit to another, the taps are spaced one element apart for a first group of the delay elements and are spaced more than one element apart for at least one second group of the elements.

Abstract: The present invention relates to a method of enhancing the noise Immunity of a phase-locked loop. The phase-locked loop includes a comparator and apparatus for inhibiting the action of the comparator on the phase-locked loop. According to the method, the inhibition is lifted during a main time window resulting from the intersection of a first time window derived from the input signal of the phase-locked loop, and of a second time window derived from the loop-return signal.

Abstract: A system for processing auxiliary video signals provides for decoding an extended data services signal in line 21 of field 2. Extended data services provide a general purpose video system information and control capability in addition to basic closed caption operation. Extended data services information is arranged in packets of data. Each packet provides information regarding current of future video programs, the source of the video program, and miscellaneous information such as time of day. The extended data services data may be decoded to control the operation of a video system including a videocassette recorder (VCR) and a television receiver.

Abstract: Program related data contained in the broadcast signal of an advertisement for a future television show are evaluated and compared with the current TV set tuning when a LEARN button on a remote control is pressed. A VCR tunes to the present TV channel and stores the program related data for the future television show. The apparatus also ensures that a program to be recorded will start and end at the right time and that broadcast advertisements will be skipped during recording, are disclosed.

Abstract: A tuner of for a digital satellite television receiver comprises a single conversion stage which produces an IF signal at a low enough frequency to permit a SAW filter to be used to perform symbol shaping as well as the normal IF filtering function. The local oscillator is controlled by a phase locked loop tuning control IC normally used to control the local oscillator of a tuner of a conventional broadcast or cable television receiver. In an exemplary embodiment for tuning RF signals provided by a block converter in the 950 to 1450 mHz frequency range, the IF has a center frequency of 140 mHz.

Abstract: A shield assembly for installation on a portion of a printed circuit board is presented. The shield (16) assembly includes shield mounted on the component mounting side of the printed circuit board and has a plurality of support projections (30) inserted through apertures of the printed circuit board to the conductor side where they are mechanically secured and electrically connected to a reference potential. A first shield cover (22) is mounted to the shield at a peripheral edge distal of the printed circuit board. A second shield cover (34) is disposed at the conductor side of the printed circuit board. The second shield cover (34) is provided with two pluralities of protrusions (32, 42). The first plurality of protrusions (32) extends through apertures in the printed circuit board to engage the body of the shield. The second plurality of protrusions (42) engages respective support projections (30) of the shield.

Abstract: In a projection television system, a blue phosphor roll-off compensation network is included in the emitter circuit of a common emitter configured transistor comprising the driver amplifier for the blue cathode ray tube. The roll-off compensation network includes a voltage divider connected between the emitter of the common emitter configured transistor and a source of a bias voltage, and a second transistor having its base connected to a point within the voltage divider and its collector-emitter path connected in series with a gain changing resistor between the emitter of the common emitter configured transistor and the source of the variable bias voltage. The voltage divider determines the level of drive current at which the second transistor is rendered conductive and thereby the point at which roll-off compensation is applied. The gain changing resistor determines the amount of compensation.

Abstract: A television system for receiving a plurality of digitally-encoded television programs includes circuitry for selecting a particular digital data transmission channel from a plurality of digital data transmission channels containing a desired digitally-encoded television program in response to a control signal, at least one of the data transmission channels also including television program schedule data. The system also includes user-operable data entry circuitry for entering data, and a controller for generating the above-noted control signal in response to user-entered data. The controller selects a virtual channel from a plurality of virtual channels in response to user-entered data, each virtual channel being subject to reassignment to a different one of said a plurality of digital data transmission channels, the television program schedule data defining the relationship of each of the television programs to respective ones of the plurality of digital data transmission channels.