Deutsche Thomson-brandt Gmbh

Thomson Consumer Electronics S.a.

Gerhard Maier

Bertram Fischer

Joachim Lange

Masahiro Fujimoto

David Harrison

Veit Armbruster

Erich Geiger

Erich Kirschner

Betram Fischer

A lens having a variable index of refraction and a point of symmetry is fabricated from a plurality of substantially identically shaped parts. Each of the parts is pyramidal in configuration and has a base and a plurality of sides extending from the base to an apex. Each of the parts has a coefficient of refraction which varies from the base to the apex.

Lenses with a variable refraction index

A printed circuit board includes an oscillator and a modulator. The oscillator includes a first printed inductor and a capacitive diode which are printed on one side of the printed circuit board. The modulator includes a second printed inductor coupled to the first printed inductor and printed on the same side of the printed circuit board as the oscillator. A conductive surface at a reference potential is arranged the other side of the printed circuit board and in the vicinity of the oscillator and the modulator and electrically coupled to the oscillator and the modulator using conductive through holes.

Oscillator and modulator arrangements on a circuit board

Method for fabricating a lens having a variable refractive index

A circuit arrangement for switching-through (transit switching) of RF-signals is provided. The signals from several RF-signal sources are switched via controlled diode paths wherein capacitance diodes are used for achieving a high value of decoupling between sources in the unenergized state.

Circuit arrangement for switching of RF signals

A circuit for generating a cut-off voltage for the switching diodes in a high frequency filter by rectifying the output signal of an oscillator includes a first diode which has a low threshold voltage and which rectifies the output signal to apply the cut-off voltage to the switching diodes in a first mode of operation. A second diode, having a low resistance, is parallel to the first diode and by-passes the first diode in a second mode of operation.

Circuit arrangement for generating an inverse voltage for switching

A circuit arrangement for distributing an antenna signal to input terminals of two appliances. One of these appliances is connected to a variable frequency modulator. An attenuating filter stage is connected between a pre-amplifier and the input of the appliance that is connected to the modulator. The pre-amplifier receives and amplifies the antenna signal. The attenuating filter stage is a frequency trap which has a trapping frequency that is identical to the modulator frequency and is synchronized with tuning of the modulator frequency. The attenuating filter stage, furthermore, is always exactly tuned to the frequency of the modulator and has a tuned frequency that is always aligned in parallel to the frequency of an oscillator in the modulator, so that modulation is not present.

Circuit arrangement for distributing an antenna signal to two appliances

The individual radio frequency filters are balanced successively by application of an auxiliary frequency at the antenna input. The auxiliary frequency is disposed between the frequency of the picture carrier and the sound carrier of the selected channel. The resulting intermediate frequency is disposed in the intermediate frequency region between the picture and sound intermediate frequency. The measurement voltage is picked up at the automatic gain control output of the radio frequency amplifier. The reference circuit is switched with regard to its frequency to the intermediate frequency during the balancing. The capacitance at the automatic gain control output is decreased during that time.

Automatic balancing system for communications receiver apparatus

The present invention provides a radio frequency device circuit arrangement with a UHF and VHF receiver part of a television set, which television set has a single base circuit board frame construction. The board has a soldering side and a component side. A rectangular box frame with a separating wall is attached to the board on the component side. Two subcircuit module boards are attached to circuit board frame and cooperate with the box frame to form the RF circuit arrangement.

Radio frequency device circuit arrangement

Audible antenna alignment apparatus

Tuning system for television sets

A mixer circuit with a conventional very high frequency circuit for the reception of color television bands I and III, which is connected dependent on the band and which is provided with an NPN transistor. The NPN transistor operates via a collector resistor onto a two circuit band filter. Moire interferences in the band I region expanded for CATV are avoided by having the mixer current used to 0.3 to 0.6 mA via a counter coupling resistor disposed between base and hot end of the resistor 4. Thus the self-interference in band I is reduced by a value of about 60 dB. In case of band III operation the corresponding switching voltage is fed via a series connection of a diode 6 and a resistor 5 to the base and thus the base level is lifted up to higher mixing current, since in band III self-interferences cannot occur in the case of the presence of signals.

VHF mixer circuit with band dependent switching

A receiver stage for radio or television receiver. A single case enclosing a device comprises inside a tuner, an intermediate frequency amplifier connected to the tuner, a demodulator connected to the intermediate frequency amplifier, and a phase locked loop provision connected to the tunner. The joint case allows joint shielding of all components with shield plates mounted inside the case, avoids unreliable plug connections and reduces the production cost of radio and television receiver sets.

Receiver stage for radio or television receiver

A method and apparatus is provided for the tuning of the resonant circuits of a communications receiver. The frequency f.sub.D is generated with an additional oscillator, which frequency is then mixed with the receiver oscillator frequency, of which three frequencies fo, fo+f.sub.D, fo-f.sub.D are formed and are applied to the antenna output. The frequency f.sub.D, which is evaluated as a narrow band, is generated by mixing at the intermediate frequency output. A maximum balancing is provided over all high-frequency circuits. The acceptor circuits are tuned to fo and fo+f.sub.D (N+5, N+11) for obtaining maximum damping of the oscillator frequency and of the mirror frequency, where N+5 and N+11 represent mirror frequencies.

Tuning of a resonant circuit in a communications receiver

A circuit is provided for the measurement and recognition of maximum or minimum voltages coming for example from a frequency selective measurement objective and in particular from an electronic filter. A fixed measurement frequency is fed to the measurement object. The measurement object is balanced by a stepwise change of a tuning voltage. The output voltage generated by the measurement object is fed to a switch after rectification and amplification, which switch is clocked with a clock signal. The output voltages of the switch are fed to an intermediate storage. The output voltages of the intermediate storage are supplied to a differential amplifier via an intermediate switch actuated by a control clock cycle. If the output voltage reaches an extremum such as a maximum then the stepwise change of the tuning voltage is interrupted. The value determined for the tuning voltage is stored in a memory such as a random access memory, the contents of which represents the optimum for the tuning of the measurement object such as for example the filter.

Circuit for the determination of voltage extrema

An input circuit is provided for a television receiver for amplifying and transforming the input signals into an intermediate frequency signal. The output of the mixers is fed via intermediate-frequency bandpass filters to respective decoupling diodes, which are switched on depending on the selected receiver frequency range. The output of the decoupling diodes is fed to an impedance transformer such as an emitter follower and its output in turn is entered into an intermediate-frequency amplifier.

Growing community of inventors

Dauchingen, Germany

Gerhard Maier