Abstract: An integrated voltage-controllable RF-signal attenuator having a pair of signal input terminals and a pair of signal output terminals, comprising a first signal transmission path connected between a signal input terminal and a signal output terminal, which attenuator includes a first pair of PIN-diodes which are arranged in series opposition and which have a RF-signal impedance which is variable by passing a variable forward bias current through them, and a signal discharge path connected between the signal input terminals, said discharge path comprising a second pair of PIN-diodes arranged in series opposition, which attenuator also includes a special circuit of pairs of PIN-diodes, arranged in series opposition, by means of which the distortions can be kept lower within the normal attenuation range than is possible with the known attenuators which are provided with the same pairs of PIN-diodes, arranged in series opposition.

Abstract: A color television system for transmitting a color television signal, specifically for recording on and subsequently reproducing from a record carrier. The color television signal to be transmitted contains a first carrier which is frequency-modulated with the luminance information and a second carrier which is modulated with the chrominance information, whose frequency lies between zero and the first-order lower side band of the modulated first carrier which corresponds to the highest modulation frequency. Said second carrier does not have a fixed frequency, but is locked to the instantaneous frequency of the modulated first carrier by a constant integral ratio. Depending on the characteristics of the transmission medium and the signal processing equipment said ratio is preferably two or three.

Abstract: A color television display device in which, in order to eliminate given convergence errors, the line deflection coils are shaped so that the axes of the two gaps between these coils intersect the horizontal symmetry plane of the display tube, the one axis extending from the top to the bottom, viewed from the rear in the forward direction, while the other axis extends from the bottom to the top.

Abstract: A deflection coil for a cathode ray tube having spaced apart first and second coil sections with longitudinally extending winding elements, wherein said elements each define a first portion formed with a given winding density and a second end portion thereof being formed with a lesser winding density, said portions of given and lesser winding density of both coil sections being respectively arranged at corresponding ends of said coil.

Abstract: A chroma-keyer is for a coded color video signal without decoding to color signals taking place. The chrominance signals component is filtered from the coded color video signal and added to a combination of gating stages switching in accordance with an adjusted chromaticity point and a color synchronization signal, which, after adjustable Schmitt triggers and flip flops, provides an output switching signal for chroma-keying.

Abstract: A deflection system for a color television display tube having saddle-shaped line deflection coils. For the correction of remaining convergence errors in the corners of the display screen a bend is provided in the boundary between the active parts of each of the line deflection coils and the coil window, so that the window is locally widened.

Abstract: A combined police and fire alarm system has provision for voice communication between street corner boxes and a central station via existing telegraphic cables. The boxes automatically transmit identification signals to the central station upon being activated. The central station can check out the boxes by causing them to transmit their identification signals and an audio test signal.

Abstract: Through a provision of a bias voltage, with the aid of a diode to the base of a transistor of a complementary pair, which transistor is controlled via a small capacitance, a video output amplifier having a very slight dissipation can be obtained.

Abstract: Facsimile transmission can be effected in a conventional television system by means of code words which occur in a television line period in a field blanking interval. Transmission in the UHF band does not give rise to specific problems, but transmission in the VHF band does, in particular in that pulse disturbances occur. The influence of these disturbances can be eliminated by transmitting the same facsimile information during two (or more) successive line periods. The receiver is provided with a circuit which includes three delay devices, one having a delay time equal to a line period and the other two having delay times equal to at least the duration of a facsimile code word. The pulse disturbance is detected by means of a superposition stage and a signal detector, and the undisturbed code word is supplied via a change-over stage to a storage stage.

Abstract: A speech bandwidth compression system uses a first set of filters to separate the speech signal into baseband (300-800 hz) and highband (800-3200 hz) signals. The baseband (first formant or fundamental pitch frequency) is transmitted directly, and is also rectified to form harmonics which are mixed with the highband signals in a second set of (paired digital) filters which form sine and cosine forms (amplitude and phase information) of the harmonic components, which are then multiplexed for transmission to a receiver which provides the corresponding bandwidth expansion system to reconstruct the original speech signal.

Abstract: A video processing circuit features direct current coupled circuits. This reduces streaking errors and lowers the power dissipation required.

Abstract: A circuit in a color television receiver for generating a correction current of field frequency for a quadripolar winding which is positioned on the core of the deflection coil. The circuit is in series with the deflection coil and constitutes a bridge circuit with diodes and resistors. A resistor is included in one diagonal branch and the winding in the other.

Abstract: In a television receiver including a line frequency switched supply voltage circuit and a line deflection circuit in which a first loop is constituted by a winding of the voltage circuit, a winding of the second circuit, a capacitor and a diode. A second loop comprises the control means of the line deflection switch and windings coupled to the above-mentioned windings.

Abstract: A push-pull B-stage in IC is arranged with an additional transistor in such a manner that one transistor in the IC and the additional transistor together constitute a new push-pull amplifier while the transistor in the IC is loaded to a higher extent and the other final stage transistor in the IC only serves as a driver for the additional transistor.

Abstract: A switched-mode power supply provided with a control stage and a switching stage coupled by means of a transformer. The collector of an additional transistor is connected to the transformer. In this manner the ratio of the collector current to the base current of the switching transistor can assume a predetermined value, for example a constant value whatever the value of the mains voltage applied to the power supply.

Abstract: The invention relates to an oscillator having a positive feedback amplifier circuit the gain of which is controlled in direct opposite relationship to the amplitude of the oscillatory voltage produced by the oscillator and is especially useful for crystal controlled oscillators. The controlled feedback amplifier comprises a differential amplifier one branch of which feeds a rectifier producing the control voltage and the other branch of which acts as the controlled feedback amplifier.

Abstract: A color television display tube comprising at least eight correction coils, arranged in one plane about the tube neck, for controlling the static convergence and possibly other aspects such as color purity.

Abstract: A network has a transformer coupled open-circuit stable negative impedance. A positive impedance is included in the network as a shunt impedance, so as to thereby render the network both open-circuit stable as well as short-circuit stable.

Abstract: Transmission system for transmitting signals modulating a carrier between two main stations via parallel coaxial lines the inner conductors and the non-earthed outer conductors of which are connected to the earthed main stations via capacitors. The main stations contain low-frequency signal sources which in parallel with direct-current supply sources are connected to the supply current loop for the repeaters included in the coaxial lines. The low-frequency cross-talk due to the low-frequency signals is suppressed by means of compensating circuits.

Abstract: A degaussing circuit, for example for a color television receiver, in which the degaussing coil is in series with a PTC-thermistor and in which the series arrangement thus formed is in parallel across a second PTC thermistor and across an a.c. voltage source, for example the supply mains. The thermistors are thermically coupled.