Abstract: A television receiver system includes an HDTV tuner, and an NTSC tuner. In response to the entering of a channel number, a CHANNEL UP or CHANNEL DOWN command, or a channel label, in a channel selection mode, a controller searches a "paired channel" table for associated HDTV and NTSC channels. If an HDTV channel is associated with that channel number or channel label, the HDTV tuner is controlled to select the HDTV channel. If no HDTV channel is associated with that channel number or channel label, the NTSC tuner is controlled to select the corresponding NTSC channel. In another embodiment, the controller determines if HDTV signals are actually being received. If not, the controller causes the NTSC tuner to select the corresponding NTSC channel. In yet another embodiment, the "paired channel" data is sent via an Extended Data Services (EDS) transmission and automatically loaded into memory.

Abstract: A television receiver system having PIP capability includes two NTSC tuners and signal processing arrangements, and an HDTV tuner and signal processing arrangement. In order to accomplish a CHANNEL SWAP function, a controller searches a table for data indicative of pairing of NTSC channels and HDTV channels, the NTSC channel associated with the main channel HDTV source is tuned by the PIP NTSC tuner, and the HDTV channel associated with the PIP NTSC source is tuned by the HDTV tuner. If the inset image has no paired HDTV channel then the second NTSC tuner is controlled to select the channel formerly tuned by the PIP NTSC tuner.

Abstract: A video display has a first format display ratio. A mapping circuit maps an adjustable picture display are on the video display. A signal processor generates first and second video signals from input video signals having one of different format display ratios. A switching circuit selectively couples video signal sources as the input video signals. The signal processor can manipulate data from the input video signals by selective interpolation and cropping. A synchronizing circuit synchronizes the first and second signal processors with the mapping circuit. A selecting circuit selects as an output video signal between one of the first and second processed video signals and a combination of the first and second processed video signals. A control circuit controls the mapping circuit, the first and second signal processors and the selecting circuit to adjust in format display ratio and image aspect ratio each picture represented in the output video signal.

Abstract: An automatic kinescope bias (AKB) arrangement embodied in an integrated circuit (IC) includes circuitry for generating a timing signal during an AKB test interval, circuitry for generating a test signal in response to the timing signal, and circuitry including an output terminal for coupling the test signal to the kinescope. The AKB IC also includes an input terminal and a switching element coupled between the input terminal and the output terminal and responsive to the timing signal for selectively decoupling the input terminal from the output terminal. In a television system which includes a bias network which is coupled to the output of the video signal source and which inhibits the kinescope from being cutoff during the AKB test interval, the input terminal of the AKB IC is coupled to the output terminal of the video signal source. This allows the bias network to be decoupled from the display device during the AKB test interval, thereby preventing the bias network from affecting AKB operation.

Abstract: A display system controls vertical zoom and panning. A video display has a first format display ratio. A circuit, for example one generating a raster, maps on the video display an adjustable picture display area represented in a video signal having a vertical synchronizing component. The picture represented in the video signal has a second format display ratio. A vertical height control circuit, for example one controlling the vertical height of the raster by controlling the vertical deflection current, selectively enlarges the picture display area relative to the video display. A panning control circuit adjusts in phase a vertical blanking interval relative to the vertical synchronizing component to control which portion of the enlarged picture area is displayed and which portion is not displayed. The format display ratios can be the same or different, for example 16.times.9 for the video display and 4.times.3 for the picture, in the latter case.

Abstract: In beam scan velocity modulation (SVM) system for a television receiver, a video signal is applied to a differentiator followed by a limiting differential amplifier. A driver amplifier coupled to the limiting amplifier drives an output stage that supplies current to an SVM coil. Certain video signals with large high frequency content may tend to produce excessive dissipation in the devices of the output stage. To prevent this, a current source for the differential amplifier is controlled by a voltage which is a measure of the average current through the output stage. The magnitude of the current source is varied to thereby vary the peak-to-peak signal output from the limiting amplifier to prevent overdissipation of the output devices. The presence of random noise in the video signal can produce unwanted SVM operation which can impair the viewed image. The unwanted noise component in the video signal can be reduced in amplitude by coring. The coring is unaffected by the variable limiting.

Abstract: In a beam scan velocity modulation (SVM) system for a television receiver, a video signal is applied to a differentiator followed by a limiting differential amplifier. A driver amplifier coupled to the limiting amplifier drives an output stage that supplies current to an SVM coil. Certain video signals with large high frequency content may tend to produce excessive dissipation in the devices of the output stage. To prevent this, a current source for the differential amplifier is controlled by a voltage which is a measure of the average current through the output stage. The magnitude of the current source is varied to thereby vary the peak-to-peak signal output from the limiting amplifier to prevent overdissipation of the output devices. The driver amplifier performs a coring operation that is unaffected by the variable limiting.

Abstract: A convergence control system for a television apparatus, for example a projection television, comprises: a plurality of channels, each channel having a digital memory for storing a set of grid coordinate values defining a convergence correction grid; and, a pair of multiplying digital to analog converters for the grid coordinate values. A single circuit for generating sequential digital addresses is coupled to each of the channels for outputting the grid coordinate values from each of the digital memories to respective multiplying digital to analog converters of the channel. The values of respective horizontal grid lines are supplied to only one of the multiplying digital to analog coverters. A single waveform generator develops a pair of analog waveforms of complementary phase for modulating respective multiplying digital to analog converters of each pair in each channel. The sum of the modulating waveforms is constant.