Siemens Aktiengesellschaft

Infineon Technologies Ag

Werner Veit

Josef Fenk

Robert-Grant Irvine

Martin Simon

Stefan Beyer

Bruno Scheckel

Helmut Herrmann

Peter Sehrig

Jean Wilwert

A circuit configuration for direction modulation contains an oscillator, whose output signal is split into quadrature components for modulation with a useful signal. A frequency shifting circuit has the effect that that the output frequency and the frequency of the oscillator are fractional rational multiples with respect to one another. The circuit contains a phase shifter for generating first further quadrature components and also a divider for generating second further quadrature components. The quadrature components are mixed with one another. As a result of the frequency offset, the oscillation frequency of the oscillator is shifted to outside the useful frequency band. Remodulation effects do not influence the adjacent channels. The circuit can be realized simply and cost-effectively and, in particular, requires only one oscillator.

Circuit configuration for direct modulation

A circuit configuration for generating an output signal orthogonal to an input signal includes a delay device having an input to which an input signal is applied, an output at which an output signal is available, and a control input for controlling a time lag. A multiplier device has inputs being coupled to the input and the output of the delay device and has an output. A device for low-pass filtering is connected between the output of the multiplier device and the control input of the delay device.

CIRCUIT CONFIGURATIONS HAVING A DELAY DEVICE, A MULTIPLIER, FILTER AND/OR A MASTER-SLAVE FLIP-FLOP FOR GENERATING: AN OUTPUT SIGNAL BEING ORTHOGONAL TO AN INPUT SIGNAL, AN OUTPUT SIGNAL HAVING A FREQUENCY BEING DOUBLE THAT OF AN INPUT SIGNAL, OR TWO OUTPUT SIGNALS BEING ORTHOGONAL TO ONE ANOTHER

The circuit for combined operation of a mobile radio with GMSK and 8-PSK modulation includes a transmission PLL for GMSK operation, and a direct modulator for 8-PSK operation. A transmission oscillator in the transmission PLL is also used as a synthesizer oscillator for the direct modulator. The modulation in the transmission PLL is suppressed for this purpose. The circuit allows cost-effective implementation while retaining the advantages of a transmission PLL.

Modulator circuit configuration

An integrated circuit configuration for generating a reference current by bipolar technology includes a transistor of one conduction type having a control terminal being acted upon by a reference voltage and having a load path. An externally connectable resistor is to be connected between the load path of the transistor and a reference potential. A current mirror configuration has an input side connected between the load path of the transistor and a supply voltage source and has an output for picking up a reference current.

Circut configuration for generating a reference current

An operational amplifier includes a symmetrical end stage being formed of emitter followers. The end stage has output terminals forming outputs of the operational amplifier and has input terminals. A voltage divider is connected between the output terminals of the end stage and has a tap. A first differential amplifier stage has input terminals forming symmetrical inputs of the operational amplifier and has output terminals each being coupled to a respective one of the input terminals of the end stage. Loads each terminate a respective one of the output terminals of the first differential amplifier stage. Two second parallel-connected differential amplifier stages each have a first input terminal connected to a reference potential, a second input terminal connected to the tap of the voltage divider, and an output terminal each being coupled to a respective one of the loads.

Operational amplifier with high common mode rejection

A integratable transmitter/receiver configuration for higher frequencies includes a reception path mixer multiplying a reception signal and a carrier frequency signal with one another. A controlled first intermediate frequency oscillator can be turned off by a switch control signal and has a frequency range being reversible by a first range control signal. A demodulator is connected downstream of the reception path mixer and receives the output signal of the first intermediate frequency oscillator both directly and phase-displaced by 90.degree.. A phase detector device is connected downstream of and controls the first intermediate frequency oscillator, and has a frequency range being reversible by a second range control signal. A controlled second intermediate frequency oscillator is connected parallel to the first intermediate frequency oscillator and can be turned on by the switch control signal. A transmission path mixer has one input being connected to the outputs of the first and second intermediate frequency oscillators and has another input receiving the carrier frequency signal. A modulator is connected downstream of the transmission path mixer, receives an input signal, and supplies a transmission signal.

Transmitter/receiver configuration for higher frequencies

A circuit configuration includes a limiter amplifier having n series-connected limiter stages. The limiter stages are alternatingly direct-current coupled and alternating-current coupled. A detector circuit is connected to the limiter amplifier.

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Unterhaching, Germany

Werner Veit