Abstract: A testing arrangement tests an MPEG video decoder that decodes frames of digital video data. The testing arrangement receives a data message containing a plurality of test frames and a reference checksum for each test frame. A checksum calculator calculates a calculated checksum for each test frame as decoded by the MPEG video decoder. A comparator compares each calculated checksum to its corresponding reference checksum, and determines whether the MPEG video decoder has properly decoded the test frames based upon results of the comparison.
Abstract: A circuit for developing correction signals for on-line controlling a precorrection arrangement in an HDTV 8VSB digital signal transmitter. The transmitted signal is sampled, sorted, smoothed and sliced to determine the symbol amplitude levels of the transmitted multilevel symbols. The centers of the sliced clusters of sampled symbol levels are used to determine the symbol amplitude levels. Correction signals for compensating the precorrection arrangement are developed based upon the determined symbol levels and the known symbol levels.
Abstract: A web television includes a display, a tuner, an internet module, and a PIP module. The tuner is arranged to select television video for display on the display and to select television audio for display by a speaker of the web television. The internet module is arranged to supply internet video for display on the display and to supply internet audio for display by the speaker of the web television, and the internet video and audio are derived from internet communications between the web television and internet content providers. The PIP module is arranged to provide a PIP area within a main area of the display. The internet video and the television video may be swapped between the PIP area and the main area of the display, and the speaker of the web television may be swapped between the internet audio and the television audio.
Abstract: A packet token generator is arranged to generate A packet tokens and B packet tokens according to the following equation:
where a1=a2+1 and b=1 or 0, where a1, a2, b, c1, c2, and d are parameters supplied to the packet token generator, where one of the A packet tokens and the B packet tokens are generated every a reference clock cycles, and where the other of the A packet tokens and the B packet tokens are generated every &agr;+1 reference clock cycles.
Abstract: A frame to field converter includes a converter memory and an address generator. The address generator is arranged to repetitively generate a set of line selecting address sequences and to sequentially apply the addresses of successive ones of the line selecting address sequences to the converter memory. Each line selecting address sequence has a first portion of addresses and a second portion of addresses, and no address is repeated in the first portion of each line selecting address sequence. In response to these line selecting addresses, a first group of lines is written into the converter memory in frame order, and the first group of lines is subsequently read out of the converter memory in field order as a second group of lines is written into the converter memory in frame order.
Abstract: A linear filter for use in 8 MHZ television broadcast systems is provided having a frequency response which includes a notch corresponding to a television picture carrier fpix, a notch corresponding to approximately a television color subcarrier fcs, and a notch corresponding to approximately a television sound carrier fs. Accordingly, the linear filter substantially reduces co-channel interference in a digital signal received by a digital television.
Abstract: An HDTV receiver includes an AGC system that develops an RF AGC voltage that is derived on an analog basis and an IF AGC voltage that is derived on a digital basis. The digital voltage is developed from an error signal that comprises the most significant bits of a continuously operated large accumulator that is supplied with the algebraically combined output of the digital signal and an AGC reference number.
Abstract: A receiver receives a signal which contains a code vector. The code vector is a member of a predetermined set of code vectors. The code vectors may be Kerdock code vectors. The receiver produces a transform, such as a Walsh transform, of the received signal. The transform contains a coefficient corresponding to each of at least some of the code vectors of the predetermined set of code vectors. The receiver determines data elements transmitted as the received code vector based upon the magnitudes of the coefficients of the transform. When plural code vectors are transmitted, the receiver determines data elements transmitted as a first code vector based upon the magnitudes of the coefficients of the transform, subtracts the first code vector from the received signal, produces a new transform of the subtraction results, and determines data elements transmitted as another code vector based upon the magnitudes of the coefficients of the new transform, and so on.
Abstract: A data server includes an SCSI disk that stores data and an SCSI bus that is connected to the SCSI disk and that is arranged to transfer the data from the SCSI disk. An SCSI bus adapter is connected to the SCSI bus and initiates the transfer of the data from the SCSI disk. A host computer controls the SCSI bus adapter. An application is also connected to the SCSI bus. The application switches control of the SCSI bus from the SCSI bus adapter to the application, and the application controls the rate at which data is transferred from the SCSI disk to the application.
Abstract: An institutional television receiver includes parental content controls for selectively blocking television signals based upon encoded ratings therein. The television receiver is coupled to a control center via a communications path. User preferences regarding the parental content controls are set, enabled, and disabled from the control center. User commands are supplied from the television receiver to the control center which, in turn, sends appropriate commands back to the receiver for controlling it.
Abstract: A television receiver has a surfing feature that provides one or more of a plurality of surfing groups for enabling tuning, with up/dn keys, only among designated surf channels in the selected one of the surfing groups. Certain ones of the receivable television signals are designated as memory channels and enable conventional sequential tuning with up/dn keys when the surfing feature is disabled. A surf key on a remote control transmitter or an on-screen cursor controls activation and deactivation of the surfing feature and selection of the surfing groups. An EAROM has bits that may be set to store memory channels, surfing groups and surf channels within the surfing groups.
Abstract: A data server includes an SCSI disk, an SCSI bus connected to the SCSI disk, an SCSI bus adapter connected to the SCSI bus, a host computer arranged to control the SCSI bus adapter, and an application connected directly to the SCSI bus. The application is arranged to receive data transferred over the SCSI bus and to control the transfer of the data from the SCSI disk. The application includes a token generator that generates tokens. The application is arranged to transfer data from the SCSI disk to an output if a token is generated substantially coincidental to a data request and to transfer null data from the SCSI disk to the output if a token is not generated substantially coincidental to a data request. The tokens are spread so as to reduce data rate jitter that would otherwise be caused by the null data.
Abstract: A combined VHF/UHF active antenna, suitable for indoor use, includes a common element that serves as a reflector for UHF signals and as a director for VHF signals. The VHF element is bent upon itself to permit its packaging as a consumer product accessory.
Abstract: A reference signal source produces a substantially distortion free reference signal which is supplied to a demodulator that is arranged to demodulate the substantially distortion free reference signal. A calibration filter and an equalizer are included downstream of the demodulator. A controller sets the calibration filter to initially pass the reference signal to the equalizer without substantial change to the reference signal. The controller subsequently calibrates the calibration filter in accordance with the demodulator caused distortion reduced by the equalizer.
Abstract: An indoor antenna for a UHF and higher frequency receiver has a plurality of polygon shaped conductive elements spaced apart from each other in a three dimensional arrangement. The signals from each pair of elements are combined through adjustable phase and attenuation networks and the combined signal is supplied to the input of a receiver that includes evaluation circuitry for optimizing the response of the antenna system when subjected to multipath conditions. A plurality of sets of random adjustment values are initially applied to the phase and attenuation networks and the antenna response over the signal band is monitored. The set of random values that exhibits the least deviation from the optimum antenna response over the received frequency band is used as the starting point for an optimization program for the calculation of further adjustments to the individual phase and attenuation networks to optimize the antenna response over the received signal band.
Abstract: A high definition television tuner includes a frequency compensated PI type PIN diode attenuator with the current through the series diode controlled separately from the current through the shunt diodes. A look-up table contains information that correlates the selected RF frequency and the desired AGC level with input data for two D/A converters. A microprocessor controls the D/A digital data, which is based upon information provided by a digital signal processing circuit. In one embodiment of the invention, the look-up table is connected between a D/A converter and a microprocessor and the microprocessor controls the look-up table for supplying the digital data to the D/A converters. In another embodiment, the microprocessor, after receiving the desired AGC level information, first interrogates the look-up table, then supplies the digital data to the D/A converter based.
Abstract: A multi brand remote control transmitter includes a programmable memory for configuring the transmitter to transmit the IR control codes for a plurality of controllable devices of different manufacturers, each of which is identified by series of digits. Provision is made for recovering the series of digits from the programmed transmitter by a series of keyboard operations. The digits are read out by flashing an LED that corresponds to the controllable device.
Abstract: A vibration isolating mounting system for a tuner comprises a frame including a base portion having four upstanding angled members overlying the base portion. A tuner is mounted on a circuit board that includes four keyhole-shaped outwardly extending edge slots that are aligned with similar slots in the angled members and in the base portion. Four grommet-like elements cooperate with the edge slots to resiliently suspend the circuit board and tuner intermediate the angled members and the base portion.
Abstract: A method and apparatus for power tuning a terminal of a bi-directional communications system, such as a cable television plant. An iterative or cycle method is used to achieve a proper terminal transmitter power level at a remote terminal. A polling signal is transmitted in a downstream direction from a controller to the terminal. If the controller receives a status signal which is transmitted upstream from the terminal, then the controller compares a received power level measured at a head end against a predetermined range of acceptable power levels. If the power level is outside of the predetermined range, then the controller calculates and transmits a terminal transmitter power level in a downstream direction to the terminal. The iterative or cyclic method repeats until the received power level is within the predetermined range.
October 8, 1997
Date of Patent:
August 29, 2000
Zenith Electronics Corporation
Mack S. Daily, Thomas M. Johnson, Thomas E. Pennacchia
Abstract: A television signal transmission signal comprises a suppressed carrier, VSB signal having respective Nyquist slopes at the lower and upper edges of a 6 MHz television channel, the center frequency of the Nyquist slope at the lower edge of the channel being substantially coincident with the frequency of the suppressed carrier, and a pilot signal in quadrature relation with the suppressed carrier. The suppressed carrier is modulated by an N-level digitally encoded signal having a sample rate fs substantially equal to three times the NTSC color subcarrier frequency, with the frequency of the color subcarrier being less than the co-channel NTSC picture carrier by an amount equal to about fs/12. The received signal is demodulated by a synchronous detector in response to the received pilot signal and interfering NTSC beat components are attenuated by a linear filter having notches at fs/12, 5fs/12 and fs/2.
February 9, 1994
Date of Patent:
December 19, 2000
Zenith Electronics Corporation
Richard W. Citta, Dennis M. Mutzabaugh, Gary J. Sgrignoli