Abstract: A transceiver has bidirectional internal interface lines which can be connected to a baseband circuit. The transceiver is switchable by the baseband circuit between a transmission mode and a reception mode. The internal interface lines are connected to at least one quadrature modulator which in the transmission mode is connected to the interface lines, and to a quadrature demodulator which in the reception mode is connected to the interface lines. In the alternative, the demodulator is set to high impedance in the transmission mode and the modulator is set to high impedance in the reception mode.

Abstract: An amplifier array having digitally adjustable total gain and being constructed of a multiplicity of switchable individual amplifiers, includes at least two parallel, selectively triggerable gain paths having input and output sides. Each of the gain paths has an input amplifier and a switching amplifier being connected downstream of the input amplifier and being switchable in stages. A multiplexer has inputs connected to the output side of the gain paths and has an output. An amplifier array input is connected to the input side of the gain paths and an amplifier array output is formed by the output of the multiplexer. In a mobile radio receiver having the amplifier array, a total gain of the amplifier array is adjusted for setting an output signal of the mobile radio receiver at a constant level.

Abstract: 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.

Abstract: A bipolar semiconductor circuit arrangement with transistors of one conduction type having a differential amplifier stage formed by a first and a second transistor with collectors coupled back crosswise to bases thereof and with emitters thereof connected to terminal of a current source having another terminal which is at supply potential, the first and second transistors having a collector circuit wherein a respective resistance is connected includes a pair of control transistors having collector-emitter paths connected between the respective resistances and the collectors of the first and second transistors of the differential amplifier stage, the control transistors having respective base terminals serving as a source of complimentary input signals, and having respective collectors connected to a source of complementary output signals.