Abstract: An X-radiation protection circuit in a television receiver is responsive to both high voltage and high beam current conditions. A first detector is interconnected with an electron beam power source and monitors the beam current therefrom. The first detector produces a first voltage proportional in magnitude to the electron beam current. A second detector monitors a high voltage transformer that produces a potential for operating on the electron beam and the second detector produces a second voltage that is proportional in magnitude to the high voltage potential. A monitoring circuit constantly monitors both the first and second voltages and produces a trigger signal whenever the additive sum of the first and second voltages exceeds a selected magnitude. In this manner, a trigger signal indicates an excessively high combination of electron beam current and high voltage. This circuit is constantly responsive to both high voltage and electron beam current.

Abstract: An interrupt circuit monitors a television audio demodulator or an external video input circuit and interrupts the video signal to CRT and the audio signal to television speaker(s) whenever a lost signal condition is detected. In the preferred embodiment, a lost signal condition is detected by monitoring the voltage level of the signal from the audio demodulator or the external video input circuit and generating a detect signal whenever the voltage exceeds a predetermined threshold. When a television signal is lost, both the audio demodulator signal and the external video signal constitute a noise signal that has a voltage amplitude that is greater than the normal operating range of either of these two signals. In the preferred embodiment, when a detect signal is produced, both the video signal to the CRT and the audio signal to the television speaker(s) are interrupted and alternate video and audio signals are provided to the CRT and speaker(s) by a microprocessor.

Abstract: Color distortion created in non-standard decoding matrices is corrected by sensing potential differences between hue representative signals and applying correction potentials representative of these potential differences to color representative signals experiencing the greatest distortion.

Abstract: A liquid-tight seal is achieved in a two-part transformer casing by use of a U-shaped channel in the main body of the casing, the U-shaped channel being formed on one side by a rigid joint member and, on the other side, by a flexible member. Both members are molded in a single unit with the main casing, but the flexible member has a decreased cross-section relative to that of the rigid member. The cover for the casing has a lip extending into the U-shaped channel. The lip is wedge-shaped, having a minimum cross-sectional area at its furthest projection into the U. At its other extremity, the cross-sectional height of the lip slightly exceeds the perpendicular distance between the flexible and rigid members. A rectangular cross-sectional part of the lip immediately adjacent to the cover provides a contact surface for the flexible member, while the rigid member makes contact with the wedge-shaped portion over a greater area.

Abstract: A signal processor useful for a non-integer scan rate conversion and non-integer sampling rate conversion, applies multiplicative factors to a multiplicity of initial data elements which are then summed to obtain a data element at the new sampling or scanning rate. Each multiplicative factor is a function of the conversion factor, the multiplied initial data element, and the data element of the converted sampling or scanning rate. This procedure utilizes all the data elements in the initial sequences and establishes a converted sampling or scanning rate with a significant reduction of processing steps.

Abstract: A remote controlled radio frequency receiver. A modulated carrier having a frequency F1 containing remote control data is received in a radio frequency receiver having a local oscillator and demodulator. The data contained in the received carrier is produced as digital data. A microprocessor executes commands represented by the digital data. The radio receiver frequency receiver is tuned by a frequency synthesizer which is incremented by a microprocessor to tune a frequency band containing the modulated carrier. A non-volatile memory is provided for storing the value of a carrier frequency, and the value of an access signal in the event a carrier transmitter fails to produce the modulated carrier containing the needed remote control data.

Abstract: In a circuit arrangement for optionally connecting the outputs of a plurality of signal sources which produce signals consisting of d.c. and a.c. components to an input of a signal sink, an interference-free switching is accomplished by providing that all the signals supplied by the signal sources from their outputs.

Abstract: a Fresnel lens for use in rear projection screens wherein said lens has a plurality of facets facing away from the light source and each of said facets has an optimal riser angle, said riser angle varying from the center to the outer edge of said lens as a function of the focal length the refractive index, the angular subtense of the exit pupil and the radial distance from the center of the lens, thereby improving the efficiency of the Fresnel lens.

Abstract: A system for processing coded information is disclosed. A receiver receives coded information from a source. The receiver is equipped with a decoder and a real time clock. The coded information is decoded only when the time signal from the real time clock is within a given time interval. The coded information contains a source time signal and a time interval signal. A means for comparing the source time signal with the real time signal determines if the real time is within the time interval, and, if it is, a means for decoding will decode the coded information.

Abstract: For enhancing the contrast of a picture on a projection screen derived from a liquid crystal display, the analyzer which is normally part of the liquid display unit is incorporated either in front of or in back of the screen relative to the viewing area or may constitute a layer between the front and rear portion of the screen. In any of these positions, the presence of the analyzer will result in darker dark portions and therefore in enhanced contrast. When used in front of the screen relative to the viewing area, protection of the lenticular surface also results.

Abstract: Method for extracting a contrasting object in a digital image. The method estimates a threshold S.sub.1 for each picture element, corresponding to a background estimation threshold representing an image contrast. A local contrast function GR(i,j) is determined as a recursive gradient proportional to the difference between the average of a video signal on the line of each picture element, and a function of the averages of the estimated background contrasts and picture elements located on an identical line or a previous line. Using the local contrast function, an estimated background value for each element is determined by comparing the contrast function to the threshold. The difference is taken between the video signal and the estimated background. The result of this difference is compared to a second decision threshold to determine whether or not the picture element belongs to the contrasting object.

Abstract: A digital television processing section capable of picture enhancement, progressive scanning, and multiple picture-in-picture processing is provided. The preferred digital television processing section preferably comprises a picture enhancement processor (PEP), a progressive scan processor, a picture in picture processor, at least one multiplexing means, and a common memory means. The PEP broadly comprises a parameter control means, a memory input select means, and mixer for obtaining current video data, delayed video data from the common memory, and control information from the control means, and for processing the obtained data and information to provide a signal to the progressive scan processor. In various modes of operation, the mixer also provides the signal to the memory input select means which forwards the information to the common memory. The common memory is used as a field delay device and feeds a delayed signal forward to the progressive scan processor.

Abstract: In a radio receiver which can be switched between at least two waveranges, the coil winding (33) of the oscillator circuit (31) has a further coil winding (36) inductively coupled to it with which a capacitor (37) is arranged in parallel for limiting the waverange comprising the higher frequencies. In the case of reception of the waverange comprising the lower frequencies this capacitor (37) is effectively arranged as a padding capacitor in series with the set of plates (34) of the variable capacitor in the oscillator circuit (31) while simultaneously the further coil winding (36) is effectively arranged in series with the coil winding (33) of the oscillator circuit (31) for the purpose of extending the range and a further capacitor (38) is effectively arranged in parallel with the set of plates (34) of a variable capacitor in the oscillator circuit (31), for the purpose of shifting the waverange of higher frequencies to the waverange of lower frequencies.

Abstract: A conventional peaking signal derived by delaying the incoming video or luminance signal first by one horizontal line delay and then by a second horizontal line delay is modified by multiplication with an adaptive factor. The adaptive factor is derived by first taking the difference between the incoming signal and the twice delayed signal, then deriving the magnitude or the square of this difference and multiplying this by a factor K empirically derived for the particular display device. The resultant signal is then subtracted from unity. This yields the factor by which the conventional peaking signal is multiplied. The conventional signal multiplied by this factor constitutes the final peaking signal which is added to the 1H delayed luminance signal to yield the desired peaked luminance signal.

Abstract: A drive apparatus for an optical disc read system. An interface is provided to a host controller for reading out data on a compact disc. The read out data is converted from parallel to serial format, and transmitted with a clock stream to the host controller. Host controller commands are transmitted to the drive apparatus which recognizes the command as either allowable or non-allowable. The interface provides signalling to the host controller of drive error conditions, spin up/non-spin up conditions, and non-allowable command situations for the controller.

Abstract: A modular coupling unit which functions as an interface between a communication unit or peripheral apparatus and the communication network includes a code word signal generator for generating a unique address code which is representative of the geographical location in which the relevant coupling unit is "permanently" included in the communication network. This signal generator is and continues to be energized as soon as and for so long as a communication unit or peripheral apparatus is and has been connected to the coupling unit. The address codes generated in bursts by such a generator are transferred via a connecting cable between the relevant communication unit and the coupling unit to this communication unit. The relevant address code is stored in the coupling unit. On request and within the time regime holding for the communication network, the address code is read and transferred to a diagnostic module via the communication network.

Abstract: An amplifier circuit whose input stage (1) has a variable gain and a DC voltage level on its load resistor (Rc), which is stabilized with the aid of means comprising a DC current generator (S), which varies contrary to the average output current of this input stage (1) and which for this purpose supplies a complementary current (I.sub.2) on this load resistor (Rc).The stabilizing means furthermore comprise a high gain differential amplifier (A) of which an input (15) is connected to the active terminal (11) of the load resistor (Rc) and whose output signal is used for the current generator control (S) via a low-pass filter (F) such that that complementary current (I.sub.2) is applied as negative feedback to the input (15) of the differential amplifier (A). An automatic gain control device which utilizes this amplifier circuit is also shown.

Abstract: A method and a system for radio direction-finding by measuring the Time of Arrival (ToA) of the leading edge of signals from a distant source at two relatively closely spaced receiving elements. In order to give a good degree of immunity to multipath, the times at which the instantaneous detected amplitudes of the received signals first exceed a minimal threshold value such that received signals can be satisfactorily distinguished from noise is measured in such a manner that the measured time is not affected by multipath which involves more than a few meters additional path length for the indirect, delayed signal. A suitable timing circuit is disclosed.By making ToA measurements on three coplanar, non-collinear receivers, directions of incidence in three dimensions can be determined.A method and a system using both ToA and phase-difference measurements can provide the accuracy of interferometry but be simpler and cheaper.

Abstract: A pixel rounding method and circuit for bit-map graphics displays. The pixel codes are divided into two groups "high" and "low", and pixels with "high" groups codes are rounded against pixels with "low" group codes. The rounding can be prerounding or postrounding and involves extending a rounded pixel partway into the adjacent (preceding or succeeding) pixel position. Rounding decisions are made by detecting diagonal relationships of "high" and "low" group codes in blocks in four pixel codes. A rounding circuit receives a pixel code stream and produces a version thereof which is delayed by one pixel period. In accordance with the rounding decisions, the original and delayed pixel code streams are selectively switched each half pixel period to provide a resultant pixel code stream which is used to generate the display.

Abstract: A high definition television signal having 525 lines per frame, a sequential scan, and 59.94 frames per second is encoded into a time multiplex signal for transmission. The encoder drops alternate line, but creates line difference signals which allow reconstruction of the dropped lines at the receiver. The line difference signals are time compressed, while the luminance signals of the alternate, transmitted lines are time expanded. The encoder can accept programs from any one of a plurality of program originators, as long as the frame and line rates are multiples of one another. The time multiplex signal carries luminance and chrominance components in each line, but update signals such as high frequency luminance, high frequency chrominance and the line difference signals in a predetermined pattern in sequential frames.