Abstract: A circuit has two amplifiers each of which have different transfer functions. Means are shown for switching between them. The output signal can be a matrixed or non-matrixed color signal, or a gamma or non-gamma corrected signal. The amplifiers can be differential amplifiers.

Abstract: A transmitter has a dynamic compressor provided with a dynamic control device and a compression rectifier fed by the signals to be transmitted, whose output signal controls the dynamic control device via a threshold device and also comprises a signal source which supplies a pilot signal, the signal to be transmitted and the pilot signal being fed to the input of the dynamic control device.

Abstract: A circuit for converting into an FDM format spatially separated signalling signals and pilot signals, comprises a digital filter bank for converting the signals into the FDM format. A receiver for separating the signalling signals and pilot signals from the FDM signal comprises another digital filter bank for producing baseband signals. These filter banks have a transfer characteristic formed by a number of passband curves which are derived from the characteristic of a selected low-pass filter.

Abstract: A transmission system for the coded transmission of information signals in which the transmitter and receiver comprise a dynamic control circuit, in which a signal generator is included for supplying a dynamic control signal.When a pulse train analyzer which analyzes the transmitted pulse train delivers a series of one-pulses, an exponential variation of the dynamic control signal is obtained by actuating a feedback circuit which applies the dynamic control signal to the input of the signal generator.

Abstract: Transmission system for signal transmission by means of compressed delta modulation provided with leaking integrators in the delta modulator and demodulator, the leaking integrator in the modulator being connected in series with the capacitor of large capacitance between the terminals of a signal source having controlled current sources for reducing the noise and distortion produced by the modulator.

Abstract: Cross-correlation arrangement for determining the presence or absence of a signal x.sub.2 (t) of known frequency in an unknown signal x.sub.1 (t) if this signal x.sub.2 (t) is present for at least a period of time .tau..sub.o with an unknown starting instant. An auxiliary signal a.sub.1 (t) is added to the signal x.sub.2 (t). The sum signal is converted into one-bit code words s(nT) which are multiplied in at least a first correlation channel by one-bit code words y.sub.per (kT) which are stored in a storage medium having at least N/2 addressable storage locations. The code words y.sub.per (kT) are elements of a series {y.sub.per (kT)} which is formed by the code words which occur in a predetermined time interval having a length NT and which are of a non-periodical signal of the form sign [x.sub.2 (t) + a.sub.2 (t)]. The product code words obtained are added together in an integrator. This integrator is read each time after a time interval NT and reset.

Abstract: A facsimile system including a picture pick-up arrangement in which the picture information to be transmitted is processed in separate groups of picture elements. The information of a first number of adjacent lines and a second number of adjacent picture elements is applied to a picture element comparison circuit. When only white information occurs in a group of picture elements thus formed this picture element group is represented by a logical 1. When there is black information in the picture element group an instantaneous derived code signal is formed with a logical 0 followed by a number of bits suitable for picture element coding. A considerable bit reduction is the result as compared with a one-bit representation per picture element. A specific choice of a clock pulse frequency results in a simple signal coding.

Abstract: Indicated as hybrid D-PCM a new transmission system is given which is based on differential pulse code modulation (DPCM) with signal compression at the transmitter end and signal expansion at the receiver end.In the transmitter defined auxiliary information is fed to the DPCM code groups to obtain composite code groups, while in the receiver a local auxiliary signal derived from a reconstruction device is subtracted in a separating device from the received composite signal. With a particularly simple construction hybrid D-PCM is distinguished as compared with DPCM by effective perturbation reduction, in addition to which a pulse can be saved in the transmitted code groups.

Abstract: An amplifier circuit for high frequency signals, particularly for cable distribution systems, comprising at least a first transistor controlled at its base electrode by a signal source, and a difference amplifier in which the distortion produced across the base-emitter junction of the said transistor is eliminated in a simple manner by means of feerforward control.

Abstract: A line deflection circuit in a television display apparatus. Between the parallel diode and the chassis there is a series arrangement of a first winding and a capacitor, a second winding being included between the switch and the voltage supply source. A diode is connected to a point of the first and to a point of the second winding and conducts in the retrace period of the deflection current. By adjusting the conduction time of the switch a trace voltage can be obtained which exceeds the supply voltage so that the circuit is suitable for battery supply.

Abstract: Switching system for an automatic telecommunication exchange with space- and time division multiplex. A two-stage switching network is described which, from the traffic-technical point of view is the equivalent of a single switching matrix. The switching network is divided into two stages in such a way that the crosstalk is reduced. The two stages are interconnected via time division multiplex intermediate lines. The intermediate lines which are not used for connection at any moment are grounded. Controlling the crosspoints does not require more routing memories as for a single switching matrix having the same number of inputs and outputs.

Abstract: A switch for a varicap tuner has a differential amplifier. A feedback circuit comprising a current mirror and a feedback amplifier ensures equal current flow in the difference amplifier transistors, and thereby ensures temperature compensation.

Abstract: A signal consisting of square pulses is applied to an FSK transmitter and is transformed into a control signal consisting of substantially symmetrical trapezoidal pulses. This control signal is applied on the one hand to a gyrator oscillator modulator to generate an FSK signal and on the other hand to a conversion device which converts the control signal into a direct voltage signal the direct voltage value of which shows a positive pulsatory variation each time during the occurrence of the edges of the trapezoidal pulses of the control signal. Said direct voltage signal is used to subsequently modulate the FSK signal in an amplitude modulator. The amplitude-modulator FSK signal may now be applied directly as a modulation signal to a carrier modulator without the intermediary of a band-pass filter.

Abstract: A color televison display device including a cathode-ray tube whose neck supports a system of deflection coils which causes isotropic astigmatic errors upon deflection. This is eliminated with the aid of a quadripolar field to which end four windings are wound preferably as four toroid windings on the core of the deflection coil system at the area of the deflection plane. The windings are arranged pairwise opposite to each other and this in such a manner that two windings are exactly located in the gaps of the field deflection coils and the two other windings are shifted 90.degree. in the tangential direction. Parabola currents which may have the line frequency and/or the field frequency must flow through the four windings.

Abstract: The low-voltage winding of a line transformer consists of a foil winding. In order to tune the line transformer to the third or the fifth harmonic, the coupling factor is adjusted by sliding the high-voltage winding with respect to the low-voltage winding. The length of the leg of the core whereabout the low-voltage winding and the high-voltage winding are arranged substantially exceeds the width of the low-voltage winding. The high-voltage winding can be partly slid beyond the head face of the low-voltage winding, with the result that the coupling factor is reduced.

Abstract: System for the vocoder transmission of speech signal with reduced bandwidth. The speech signal is split into a low-frequency part and a high-frequency part. The high-frequency part is subdivided into a number of sub-bands and for each sub-band a control signal with reduced bandwidth is transmitted. A control signal is representative for the ratio between the energy in the sub-band of the speech signal and the energy in the corresponding sub-band of a reference signal with high-frequency components, which is produced from the low-frequency part of the speech signal.

Abstract: FM-radio receiver having an audio amplifier stage, provided with switching means, and a squelch circuit which is coupled to the output of the receiver demodulator, this squelch circuit comprising two circuits which are constructed in such a manner that one circuit produces at an early stage an output signal when co-channel interference occurs whereas the other circuit produces an output signal which controls said switching means and which occurs only at an impermissible signal/noise ratio and/or an impermissible degree of co-channel interference.

Abstract: A transmission of a binary signal which transmission is immune to interference is obtained by transmitting the bits of the binary signal by means of a frequency-modulated signal in which a cycles of a first frequency f.sub.1 are followed by b cycles of a second frequency f.sub.2 for a binary zero value and b cycles of the first frequency f.sub.1 are followed by a cycles of the second frequency f.sub.2 for a binary one value.

Abstract: Radio frequency signal distribution device for use in a distribution system for VHF and UHF signals, which device comprises an input terminal, an output terminal and a signal transmission line connected between the input terminal and the output terminal, which signal transmission line is provided with a plurality of directional couplers which are connected in series for the radio frequency signal on the signal transmission line, each directional coupler comprising a coupling loop as well as a tap-off terminal which is connected to the coupling loop, which coupling loop has an electrical length of a quarter of the wavelength of a frequency in the TV UHF range, which signal distribution device can supply signals to some dozens of subscribers within a radius of 80 to 100 m which signals satisfy the requirements imposed in practice as regards the signal level within given frequency bands.

Abstract: A protection circuit for a subscriber's telephone set which comprises a resistor applied in series with the subscriber's line to which resistor a threshold device is connected in parallel, a network being provided which comprises the control input and which is connected between the subscribers' lines while the output of the threshold device is connected to the control input to switch the normally high impedance to a low impedance when the threshold voltage of the threshold device is exceeded by the voltage across the resistor.