Abstract: A satellite receiver which is capable of being connected to different antenna assemblies which require different operating voltages, includes a switch mode power supply which supplies the different operating voltages. A microprocessor controls the duty cycle of the switch mode power supply to produce the different operating voltages in accordance with the required duty cycle. A memory stores values which define different duty cycles for each of the operating voltages and provides the values to the microprocessor.

Abstract: A television receiver displays characters within a box on a display screen wherein the normal picture is also displayed within the box. Circuitry in the receiver permits a display of the normal picture within the box for viewing the total picture while achieving good visibility of the characters within the box. The circuitry provided reduces the contrast of the picture within the box in relation to the contrast outside the box.

Abstract: Interference induced amplitude changes in the television signals received by a receiver which receives satellite signals are eliminated by delaying the signals for an integer multiple of the receiver line time and substituting the delayed signals for the undelayed signals for the duration of the amplitude changes.

Abstract: Automatic switching circuitry for processing input signals of more than one frequency, incorporating information for the derivation of one or more audio channels. The circuitry, including a selectively variable bandpass device, may be one of several values corresponding to the frequency of a input signal. A demultiplexing device is provided to apply a demultiplexing operation on signals output from the bandpass device, with a control logic monitoring the demultiplexing device to determine if a demultiplexing operation has been achieved, and instructing the selection of another value for the bandpass device if no demultiplexing operation was achieved for a given value of the bandpass device.

Abstract: A motor vehicle four-wheel-drive transmission employs an interwheel differential gear in a first axle, and solely viscous fluid coupling device in a second axle for differential transmission of drive to the road wheels of the second axle only when a speed-difference is established between the first and second road wheels, the two axles being mutually in direct driving connection through respective propeller shafts commonly driven by a change-speed box. In one arrangement of axle with a viscous fluid coupling device, a crown wheel is mounted co-axially on a housing of such coupling device from which nearside and offside half-shafts extend driven by separate sets of "inner" annular plates interleaved with those of an "outer" set of annular plates driven by the housing. In another similar arrangement, two separate viscous fluid couplings are used, the housings thereof being driven by a common crown wheel.

Abstract: In the recording of broadcast television text, the text is separated from the video signal and formed into blocks at slicer and then is fed into shift register. It is then taken out at a data rate lower than that when broadcast and coding is assigned to at least some of the blocks prior to recording onto a video cassette tape recorder. Retrieval and display incorporate similar functions in reverse order. In another embodiment data in block form is stored on a video disk for similar retrieval and display.

Abstract: In a circuit for indicating reception of stereo signals (for use in e.g. a radio tuner or television) audio signals prevailing in the left (L) and right (R) output channels are applied to respective limiting circuit and the output signals derived are fed to OR gate. When a monoaural signal is detected, the signals in the two output channels will be in coincidence and so the output from the exclusive OR gate remains low. When stereo signals are detected, however, a finite phase difference exists between the two signals and the output for the OR gate is correspondingly high. A Schmitt trigger drives an LED display whenever the output from the OR gate exceeds a preset threshold level to provide an indication that a stereo signal is being reproduced. A capacitor/resistor circuit imposes a time delay on level changes at gate so that the LED display remains illuminated, even during momentary interruptions of the audio signal.

Abstract: Viscous shear couplings for controlling the action of an interaxle or interwheel differential gear in a vehicle transmission are described. The couplings comprise a pack of interleaved annular plates which are free to float axially in an annular enclosure containing a viscous liquid. The enclosure incorporates a spring-loaded piston shiftable to vary the enclosure volume. The quantity of viscous liquid, in the range 85% to 100% of the minimum volume at ambient temperature, and the spring strength are chosen to give a predetermined pressure build-up within the enclosure with rise in temperature during shearing of the viscous liquid to tailor the torque-transmitting characteristics of the coupling to particular needs.

Abstract: A vehicle anti-skid braking system is described wherein the brake-applying effort of a driver on a hydraulic master cylinder is assisted or opposed by a reversible servo-booster in accordance with the instant condition of an anti-lock sensor and an associated switch-over valve means. The booster incorporates two shiftable diaphragm actuators only one of which operates to assist braking effort, but both of which operate to oppose braking effort thereby to reduce the possibility of a driver overriding anti-skid operation during "panic" braking. A modified system provides only a single diaphragm actuator for opposing a driver's braking effort under skid conditions.

Abstract: A control coupling in which an enclosure houses first and second sets of mutually interleaved elements in a viscous fluid. The first and second sets of elements are arranged for rotation about a common axis and for driving connection with first and second rotatable members respectively. The quantity of liquid within the enclosure and the construction of the enclosure are such that, at a predetermined working temperature of at least 100.degree. C, the pressure of the liquid in the enclosure rises substantially above ambient. At least one set of the elements is free to move in directions parallel to the common axis of rotation and at least one set of the elements is provided with facings of friction material.