Abstract: HF mixer for changing the frequency of an alternating voltage input signal at the circuit input to an output signal supplied at the circuit output, with an input signal source for generating the alternating voltage input signal and a local oscillator for providing a heterodyne signal. The mixing stage has two transistors complementary to one another, and connected as base grounded circuits or gate grounded circuits, connected in parallel for the alternating voltage input signal. The two transistors are connected to the local oscillator in such a way that they are equidirectionally driven by the heterodyne signal, so that both transistors change simultaneously to the blocked or conductive state.

Abstract: HF mixing stage in the form of a common-base circuit including: two bipolar amplifying transistors; two switching stages each assigned to an amplifying transistor and each having two emitter-coupled bipolar switching transistors and with two signal sources which supply the bases of the switching transistors with superimposed signals; two nodes at which the emitters of the switching transistors are connected to the collector of the associated amplifying transistor; two further output nodes at which the collectors of each of two switching transistors in different switching stages are connected together; circuit elements for electrical isolation through which the emitters of the amplifying transistors are connected together; an input signal source with associated internal resistor of which the one terminal is connected via the circuit input to the circuit elements for electrical isolation and the other terminal is connected to reference potential and whose signal is to be transposed into another frequency range

Abstract: An HF mixer stage having a common base circuit comprises an amplifier stage having two amplifier transistors, a switching stage with two transistor pairs each having two emitter-coupled switching transistors, and a switching circuit connected to the switching transistors; the switching transistors of a transistor pair are connected to the collector of the associated amplifier transistor, the bases of the switching transistors are subjected to a heterodyne signal. In accordance with the invention, the two amplifier transistors are of the opposite conductivity type, the emitters of the amplifier transistors are connected to the circuit input, and the two switching transistors of a transistor pair are of the same conductivity type as the associated amplifier transistors.

Abstract: A system for regulating the transfer impedance of a plurality of current-to-voltage converters to a substantially equal value includes a reference voltage source and a reference impedance for providing a reference current. A reference current-to-voltage converter is responsive to the reference current and provides an output voltage. A comparator is responsive to the reference voltage and the output voltage and provides a control signal to the reference current-to-voltage converter and to all the other current-to-voltage converters to maintain the transfer impedance of all the current-to-voltage converters constant.

Abstract: An amplifier stage for use with low-resistance AC voltage sources has first and second complimentary transistors, each having a control terminal, a current input terminal and a current output terminal. The transistors are connected together at a first junction point, a current terminal of the second complementary transistor being connected at the first junction point to a corresponding current terminal of the first complimentary transistor. The respective other corresponding current terminals of the transistors are connected to respective opposite poles of a direct current supply, so that the first transistor, the second transistor, and the direct current supply form a series connection providing a common quiescent current to the transistors. The transistors are each provided with a respective separate direct current operating voltage at a respective control terminal.

Abstract: In a radio receiver in accordance with the heterodyne principle or with the homodyne principle, two additional transmission channels are provided for interference suppression. The two additional transmission channels have a different degree of distortion. Either mixing with a heterodyne oscillator signal takes place in each of the two transmission channels and the resultant intermediate frequency signals or baseband signals are added in phase opposition to give a sum signal, or the output signals of the two additional transmission channels are added in phase opposition to give a sum signal and the resultant sum signal is mixed with a heterodyne oscillator signal to give an intermediate frequency signal or baseband signal. The signals obtained after addition and mixing and derived from the output signals of the two additional transmission channels are frequency-selected and demodulated, and the demodulated signal is used for gain control.

Abstract: In a circuit array for setting the operating point of a first transistor. A current-inverting circuit (current mirror circuit) has a pinch resistor connected in series with the base-emitter path of another transistor within the current inverting circuit. The current inverting circuit supplies the current-inverting base current of the first transistor.

Abstract: In a circuit array for setting the operating point of a first transistor. A current-inverting circuit (current mirror circuit) has a pinch resistor connected in series with the base-emitter path of another transistor within the current inverting circuit. The current inverting circuit supplies the current-inverting base current of the first transistor.

Abstract: In a controllable amplifier circuit with an amplifier transistor a further transistor is provided that, when actuated under control conditions, deprives the amplifier transistor of at least a part of the input signal.

Abstract: In an integrated circuit arrangement with a protective arrangement at least partially integrated into it and protecting the integrated circuit arrangement from high-energy electrical faults, the protective arrangement has an ohmic resistance in the form of one or more resistance areas that is designed so as to absorb a major proportion of the energy from electrical faults in the event of limit loads and distribute the heat generated within it by the energy absorption over a surface of the protective arrangement such that the protective arrangement affected by the heat energy of the ohmic resistance is not thermally overloaded. Furthermore, the protective arrangement has a voltage-limiting element or several voltage-limiting elements to limit the interference voltage.

Abstract: In an amplifier comprising an amplifier transistor and a tunable selection circuit with a coil, a further coil is arranged between the collector of the amplifier transistor and the supply voltage source and is inductively coupled with the coil of the tunable selection circuit.

Abstract: In a radio receiver in which the received signal is converted by mixing into an intermediate frequency signal and/or a baseband signal, and in which an apparatus is provided which generates an intermediate frequency signal and/or baseband signal and derives therefrom a control signal for suppression or reduction of interfering disturbances, the signal fed to the apparatus is distorted in the apparatus in such a way that the signal distortion effected in the apparatus is greater than the distortion to which the signal fed to the receiver is subjected in the receiving section of the receiver.

Abstract: In a radio receiver in which the received signal is converted by mixing into an intermediate frequency signal and/or a baseband signal, the degree of distortion of received disturbance signals in the receiver is temporarily changed and a recognition circuit is used which recognizes from the change in the signal gaining demodulation, caused by the change in the degree of distortion, whether the receiver is receiving spurious interference signals falling into the useful channel, and which, in the event of such a disturbance signal reception, initiates a suppression or reduction of the spurious interference signals.

Abstract: A signal input circuit composed of a control member, such as a PIN diode, for controllable attenuation of an input signal, and reactances for selection of the input signal, wherein the signal frequency current is regulated by the control member such that the operating power required by the input circuit remains constant to the greatest possible degree in spite of the regulation.

Abstract: In a mixer stage comprising a transistor for mixing, with the input signal and/or the oscillator signal being fed inductively to the mixing transistor, there is provided for inductively coupling the mixer transistor to the corresponding filter a coil which is magnetically coupled to this filter. The inductivity of the coupling coil is of such dimensions that the source impedance controlling the transistor to a greater than the input impedance of the mixer transistor when the filter is aligned.

Abstract: The present invention relates to a band gap circuit for providing an integral multiplication of an elementary band gap voltage. The circuit comprises a first transistor having its base connected to its collector via a resistor, a second transistor which is connected at its base to the collector of the first transistor, and a third transistor which is connected at its base to the collector of the second transistor, with the emitters of the three transistors being connected to one pole of a supply source. A fourth transistor is provided in emitter follower configuration and connected between the emitter of the fourth transistor and a connection point, is a series connection comprising at least one resistor and at least one diode.

Abstract: An integrated amplifier circuit comprising an amplifier transistor connected in a common base configuration with its base zone being connected via an integrated capacitance to the semiconductor substrate of the integrated circuit so as to connect (short circuit ) the base zone to the semiconductor substrate at the operating frequency of the amplifier.

Abstract: An integrated amplifier circuit which includes a semiconductor substrate, an amplifier transistor fabricated on the substrate, and an RC network fabricated on the substrate to suppress undesired, self-excited oscillations, the RC network being connected between the base of the transistor and the substrate.

Abstract: In a circuit for transforming direct-current signals whose output signal is dependent on the input signal, the temperature variation of the output signal is adjustable, and two transistors whose base-emitter sections exhibit an appropriate voltage difference are provided for control of the temperature variation of the output current.

Abstract: In a selective amplifier stage with a frequency-selective input filter to which there is coupled inductively an amplifier transistor, there is provided for the inductive coupling of the amplifier transistor to the filter a coil which is magnetically coupled to the coil of the input filter. The coupling coil is of such dimensions that when the input filter is aligned to maximum amplification of the stage, the source impedance driving the transistor is greater than the input impedance of the amplifier transistor.