Abstract: A horizontal sync separator that is capable of operating with horizontal sync signals of differing durations. A monostable is operated by the leading inverted negative edge of the horizontal sync pulse and generates a minimum duration horizontal pulse. The minimum duration horizontal pulse is applied along with the inverted negative horizontal pulse to an OR gate which outputs the longer of the two pulses. The arrangement assures proper video clamping during the horizontal back porch interval.

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 receiver for receiving a cable and terrestrial digital signals of differing VSB modes where the data levels of the various signals have a desired relationship that enables simple data level slicing and error determination. Some of the signals have sync levels that do not conform to the desired relationship and the receiver includes a comb filter for reducing interference when receiving an 8VSB terrestrial signal. The mode of the received signal is determined and a correction factor is applied to the syncs of the signals as needed to reestablish the desired relationship. Operation of the comb filter results in additional levels and a disruption of the desired relationship. For such cases, the comb filtered data levels are modified to make them a subset of the VSB 16 data levels. The modifications are accomplished in feedback paths of the phase tracker after the circuit equalizer and do not affect the data levels passed to the next stage.

Abstract: A web television includes (i) a display, (ii) an internet module for supporting internet communications between the web television and internet content providers, (iii) a PIP module for providing a PIP area of the display, (iv) a video processor module for supplying video to the display, (v) an audio processor module for supplying audio to a speaker of the web television, (vi) an video/audio switch for switching outputs from a tuner of the web television and from the internet module between the PIP module, the video processor, and the audio processor, (vii) a television controller, and (viii) a two-way communication bus interconnecting the internet module, the PIP module, the video processor module, the audio processor module. The television controller controls the internet module, the PIP module, the video processor module, the audio processor module, and the video/audio switch so as to selectively display the internet communications and television signals on the display.

Abstract: A FPLL has an I, a Q and a third multiplier, with the I multiplier supplying demodulated signals to a limiter and the Q multiplier supplying signals to a loop filter. A VCO and phase shift circuit supply quadrature signals to the I and Q multipliers. The analog input signal is applied to the I multiplier and to the third multiplier. The third multiplier, which is located in an AC path in the loop to avoid the effects of offsets due to stray DC voltages and currents, is also supplied with the digital output of the limiter. The third multiplier supplies its output to the Q multiplier.

Abstract: A double conversion tuner includes a first filter that is relatively flat over a 6 MHz band at 920 MHz. A pair of series-parallel resonant circuits form notch filters that operate on the downconverted signals to economically produce a 6 MHz frequency response at 44 MHz that has excellent adjacent channel and other signal rejection.

Abstract: A method for assembling data by sorting and filtering new data records and old data records, such as data records that an Electronic Program Guide data provider typically transmits to a head end of a cable television system. New incoming data records are combined with existing stored data records to form combined data records. Each of the data records is assigned an array index value. The combined data records are then sorted into one field of multiple fields. Within each field, each sorted data record is compared with other sorted data records and any conflicting data record is removed. The remaining non-conflicting data records are compared within each field and exact duplicate data records are removed from each corresponding field. The remaining processed data records are compared within each field and any older difference duplicate data record is removed. The filtered data records are then transmitted to a database.

Abstract: A digital television receiver includes a filter for minimizing NTSC interference with a received signal having a constant symbol rate. An equalizer has two one symbol delays for each tap. A filtered and a non-filtered version of the received signal are applied to a multiplexer at the input of the equalizer, which is operated at twice the symbol rate. The outputs of the multipliers in the equalizer are combined and applied to a demultiplexer. The filtered and non-filtered equalized signals are compared and a selection as to which of the filtered or non-filtered received signals is to be processed is made based upon the comparison.

Abstract: A television receiver with PIP circuitry provides a snapshot feature for freezing the main video display in the PIP display inset by operation of a special key on a remote control keypad. With the television receiver operating normally (PIP deactivated), one operation of the special key switches the main video signal to the PIP input and freezes the PIP display in its largest size and in the position it occupied the last time PIP was activated. A video message informs the viewer that a snapshot feature is operational. A subsequent operation of the special key switches the PIP signal to the PIP circuitry and unfreezes the display as in normal PIP operation. A further operation of the special key deactivates the PIP circuitry.

Abstract: A telephone line access arrangement for a telephone instrument and a modem gives priority to the telephone instrument in all instances. A microprocessor controls the modem and receives an input signal that is indicative of the existence of an off hook state for the telephone instrument. Logic device generates the input signal based upon the different electrical conditions characterizing the telephone instrument and the modem.

Abstract: In a synchronous code division multiple access (SCDMA) system, a set of substantially orthogonal code words is selected such that each code word in the set of substantially orthogonal code words is minimally correlated with a channel characteristic such as noise. When a station transmits a data signal, it multiplies the data signal by its assigned code word in order to produce a spread data signal. The spread data signal is transmitted over the channel of the SCDMA system.

Abstract: A communication system has a plurality of stations which communicate data in a data frame having a plurality of slots, wherein the plurality of slots are new message minislots NMS, expansion minislots EMS, and data slots DS. A master station determines a range parameter R which is based upon a number of slave stations transmitting reservation requests in a data frame. The master station also determines a parameter MAP according to a number of reservation requests in a queue waiting to be processed by the master station. The parameter MAP defines the new message minislots, the expansion minislots, and the data slots in an upstream data frame. The master station transmits the range parameter R and the parameter MAP to a plurality of slave stations. Each slave station independently determines a random transmission parameter RN.

Abstract: A selective RF circuit for a double conversion tuner includes three double tuned bandpass circuits, each of which is tunable over approximately one-third of the tuning range. Switching diodes are used at the input and the output of each of the bandpass sections for selectively activating one of the bandpass sections and deactivating the remaining ones in response to a bandswitching signal. Operational amplifiers or other devices supply the input and output switching diodes by providing a current sink for the active bandpass and current sources for the inactive bandpasses.

Abstract: A two piece plastic lens for a large screen projection system in which the two lens elements are formed with similar curves. The lens is supported at its peripheral edge by a flexible strip having a T-cross section that fits into a matching groove in a frame or on the housing. The curved lens elements tend not to separate with temperature changes and the like and focus and display quality are maintained.

Abstract: Accelerated thermal upshock rates in the exhaust cycle of a CRT envelope are attained for CRTs, and especially a tension mask CRT having a shadow mask-supporting rail frame affixed to a flat, skirtless front panel. The corner walls of the CRT funnel are made with thinner walls to provide an increased compliance of the normally very rigid corners of the funnel-to-panel seal area. Panel-fracturing stresses generated in the funnel-to-panel seal area corners during upshock are thus alleviated allowing for faster CRT throughput during manufacture.

Abstract: An in-line electron gun includes a main lens having G3 and G4 three aperture electrodes and corresponding chain link (extended aperture) electrodes. The outer apertures in each of the G3 and G4 electrodes are barrel shaped and the middle aperture is elliptical. This construction maximizes the aperture area. The spacings between the G3 and G4 electrodes and their corresponding chain link electrodes are maximized within the existing size constraints of the gun. The combined effect weakens the electric field of the main lens which reduces spherical aberration.

Abstract: In a contention resolution system for use in connection with transmitting and receiving data over a communication medium, a first station determines a contention based variable E for a future upstream data frame. The variable E indicates a number of resolution slots (i) which result from expansion of a contention slot of a previous upstream data frame containing contention between the second station and other stations, and (ii) within which previously contending data may be re-transmitted by the second station. The first station inserts the variable E in a downstream data frame for transmission over the communication medium to the second station. The second station receives the variable E from the downstream data frame. The second station randomly selects one of the E resolution slots, and the second station inserts the previously contending data in the randomly selected resolution slot for re-transmission in an upstream data frame.

Abstract: VSB data is transmitted in a frame which includes a frame sync, a segment sync, a mode control, and a plurality of data symbols. The mode control indicates the number of modulation levels of the data symbols and includes 2-level symbols forming the following byte: PABCPABC. P is a parity bit, and ABC represents a selected one of a plurality of data constellations defining the modulation levels of the data symbols.