Abstract: Band limited standard video signals are sampled with line coupled sampling clock pulses. The sampling clock pulses are shifted from field to field by one-half a sampling interval. The sampling clock pulse rate is twice the frequency at the center of the Nyquist edge of the transmission channel. The received signal is sampled in synchronism, line coupled and offset from field to field. A video memory records the sampled values and furnishes them to the monitor at twice the sampling frequency and without flicker as a full frame. The video playback takes place at twice the line frequency or alternatively with the same line frequency and synchronous spot wobbling.

Abstract: A remote control circuit which operates on a frequency basis and essentially with analog signals. The remote control circuit includes at the transmitting end a controlled oscillator, a frequency/direct signal converter and a comparator connected together into a frequency control loop. A transmitter is also provided which is fed by the oscillator of the control loop. A control path including a frequency signal source and a frequency/direct signal converter is provided at the transmitting end and receives its input signal from the frequency signal source. The converter of the control path is connected with the one input of the comparator of the control circuit. At the receiving end there is provided an amplifier, a frequency/direct signal converter and an evaluation circuit.

Abstract: A semi-conductor laser comprising a crystal having a sequence of layers forming a heterostructure diode and which includes a laser active zone interposed between a pair of semiconductor layers. Each of these semi-conductor layers has a band gap which is greater than that of the layers within the laser active zone. The laser active zone includes a first semiconductor layer having a given band gap, and at least second and third semiconductor layers each having a band gap which is greater than that of the first layer. The first layer is contiguous with and interposed between semiconductor layers each having a band gap which is greater than that of said first layer and forms a pn-junction with one of those contiguous layers. A strip-shaped region of a uniform conductivity type diffused from the surface of the crystal penetrates into at least one layer of the laser active zone but does not penetrate into the first layer.

Abstract: A method of embedding semiconductor components in plastics comprising inserting components into the plastics material and thereafter hardening the plastics material by irradiation with high energy beams.

Abstract: A method for transmitting data between at least one central office and a plurality of mobile radio stations via a relay station by a time multiplex transmission procedure in which signals are transmitted in a succession of time frames structure and the central office transmits on a first frequency to all mobile radio stations via the relay station, which method includes:causing the central office to periodically transmit different messages at arbitrarily selected times, which messages include routine inquiry messages directed to each mobile station in sequence during each time frame;causing each mobile station to respond to an inquiry message by transmitting a selected short message on a second frequency;causing a selected mobile station to transmit data to the central office by transmitting to the central office an announcement of the intent to transmit data during a first time frame, causing the central office to set aside reception capacity for the data in a time frame following the first time frame, and t

Abstract: An H.F. broadband amplifier comprises a transistorized differential amplifier input stage the potential of which is set by a voltage divider circuit, and an additional transistor for attenuating a.c. signals present at the input of the amplifier in its turned off stage, the emitter-collector parts of the additional transistor being connected into a collector current circuit of a transistor of the differential amplifier, and the base of the additional transistor being operated in base connection, and switched to a reference potential of low resistence in HF terms to reduce the capacitative coupling between input, and output of the amplifier circuit.

Abstract: In a two-band compander pre-emphasis is carried out during compression and de-emphasis during expansion in the lower frequency range. Noise suppression is improved by this measure.

Abstract: A dc/dc converter for controlling the current through a load which comprises a switching transistor having its emitter-collector circuit coupled between an input voltage source and the load. A control transformer having first, second and third electromagnetically coupled windings is also provided, the second winding of the transformer being electrically connected between the base and emitter of the switching transistor. A control switching logic circuit selectively generates pulses for determining the beginning and the end of the conducting period of the switching transistor, and a control circuit coupled to the logic circuit selectively short circuits the third winding thereby reducing the voltage across the second winding and driving the switching transistor into its non-conducting state.

Abstract: A device for centering a record disc with respect to a turntable, in which the disc is successively radially centered and axially positioned relative to the turntable, which device includes a centering shaft engageable with the disc to effect preliminary radial centering thereof, is additionally provided with further radial centering elements mounted to engage a disc after it has engaged the shaft and to undergo yieldable movement relative to the turntable in the axial direction of the disc under the influence of its engagement with the disc for effecting final radial centering of the disc, and a magnetic attracting unit operatively associated with the disc and the turntable for axially positioning the disc after it has been finally radially centered.

Abstract: In the transmission of information in first and second carrier frequency systems occupying the same frequency bands and each composed of a succession of channel carriers having different respective frequencies, each channel carrier defining a respective transmission channel and being modulated with a premodulation carrier itself modulated with information to be transmitted in its associated channel, at least one channel of the first system is switched into a selected channel of the second system by shifting the frequency of the modulated channel carrier of the one channel of the first system with the aid of an unmodulated channel carrier, filtering the channel to be switched through out of the shifted signal by means of a bypass filter, and converting the filtered-out channel to the frequency of the selected channel of the second system with the aid of a carrier at the frequency of a selected channel carrier of the first system.

Abstract: In a digital tuning system for a radio receiver, which system includes a station memory having a plurality of memory locations for storing digit representations identifying respective broadcast frequencies to be received, a plurality of station selector elements each connected to be actuatable for addressing a respective memory location to cause the tuning system to tune the receiver to the station identified by the representations stored in the addressed memory location, a plurality of band selector elements each connected to be actuatable for causing the receiver to be tuned within a respective signal band, and components operable for continuously varying the receiving frequency to which the receiver is tuned, the station memory is provided with a plurality of additional memory locations and each band selector element is connected to address, upon being actuated, a respective additional memory location to cause the tuning system to tune the receiver to the station identified by representations stored in the

Abstract: In a modulation and demodulation system for converting a binary sequence composed of a succession of bits, each having a value of "1" or "0", occurring in successive bit intervals, into a transmitted signal containing a representation of each bit, by representing a bit of one value as a change in the level of the transmitted signal at a time corresponding to the middle of the associated bit interval, and representing a bit of the other value as a change in the level of the transmitted signal at a time corresponding to the end of the associated bit interval if a further bit of the other value follows, transmitted signal level changes associated with the bits of the other value are in part suppressed for causing the time period between level changes in the transmitted signal to be no longer than the period of more than two consecutive level changes at intervals equal to each bit interval and associated with the bits of the other value.

Abstract: An electrode system comprises two discs or plates forming an anode and a cathode, each of the discs or plates having a structure of parallel ridges and grooves on at least one of the main surfaces, the discs or plates being assembled together with their structures facing and orientated so that the ridges on one disc or plate cross the ridges on the other disc or plate and a membrane is located between the structured surfaces of the discs or plates so as to be abutted on both sides by the ridges thereof and form the grooves between the ridges into chambers on each side of the membrane.

Abstract: A composite semiconductor/glass material comprising at least one semiconductor layer permanently connected to a plate shaped glass substrate, the doping of the semiconductor layer rising from a minimum at its surface away from the glass substrate to a maximum adjacent the glass substrate.

Abstract: In a method for producing an electrophotographic recording material composed of a dual layer of amorphous and crystallized selenium applied to an electrically conductive substrate, tellurium is vapor-deposited in a vacuum onto the surface of the conductive substrate to a layer thickness of about 0.5 to about 5 nanometers to form a tellurium layer, and selenium is vapor-deposited onto the tellurium layer to a layer thickness of about 20 to about 100 microns to form the dual layer of amorphous and crystallized selenium.

Abstract: A four-port network for separating signals comprised of two doubly polarized frequency bands for an antenna feeder system in directional or satellite radio operation, wherein a first polarization converter for converting linear polarization to circular polarization, and vice versa, is designed for the lowest inherent ellipticity in the lower frequency band and is connected ahead of a symmetric polarization filter for the lower frequency band, and a second polarization converter which compensates the remaining ellipticity in the upper frequency band is connected between the symmetrical polarization filter and a further polarization filter for the upper frequency band.

Abstract: A circuit for producing a frequency dependent output signal in response to two a.c. input signals, including a converter unit connected to receive the two a.c. input signals for furnishing an output signal having a d.c. component which varies in dependence on changes in the value of a relationship between the frequencies of the two a.c. input signals, and a frequency generator connected to the converter unit for producing an a.c. output signal whose frequency is a function of the value of such d.c. component.

Abstract: A solar cell comprises a semiconductor body with a p-n-junction, a metallized area on the light receiving surface of the semiconductor body, a connection or contact area on the light receiving surface, a reflection reducing layer completely covering the metallized area and the connection or contact area and a further contact on the rear face. A metal connector is fixed to the connection or contact area by placing the connector against the reflection reducing layer and conductively connecting the connector to the connection area while concurrently eliminating the reflection reducing layer from that area.

Abstract: In a tuning circuit for tuning a receiver to a desired broadcast frequency, which tuning circuit includes a source of counting pulses indicating the magnitude of the change in the frequency value to which the circuit is to be tuned, a counter connected to receive the counting pulses and to assume a count state representative of the broadcast frequency to which the circuit is to be tuned, and a timing member for producing a tuning signal having a value determinative of the frequency to which the circuit is tuned during a tuning operation, the timing member is provided with a unit connected to the source of counting pulses for deriving a control signal representative of the frequency of the pulses, and a unit connected for varying the tuning signal in accordance with the control signal in such a manner that as the frequency of the counting pulses increases, the rate of change of the frequency to which the circuit is tuned is increased.

Abstract: A non-inverting amplifier circuit having input and output terminals wherein the input impedance between the input terminal and a reference point is relatively low. The circuit comprises a first amplifier having a non-inverting input coupled to the input terminal, an inverting input, and an output coupled to the output terminal. A second amplifier is also provided, the second amplifier having a non-inverting input, an inverting input coupled to the output of the first amplifier and an output coupled to the non-inverting input of the first amplifier.