Siemens Aktiengesellschaft

Siegfried Ganser

Josef Fenk

A low-noise amplifier stage with reversible amplification includes a first series circuit of load paths of two transistors which is connected through a resistor to ground. A second series circuit or n series circuits of load paths of two transistors is likewise connected through a resistor to ground and is connected parallel to the first series circuit. Parallel-connected collectors of the first transistors of the series circuits are connected through an oscillator circuit to a supply voltage terminal. Two reference voltage sources are provided for supplying a first reference voltage to base terminals of the first transistors of the series circuits and for supplying a second reference voltage to base terminals of the second transistors of the series circuits. A reversing device connects a node point of the load paths of the transistors of the second series circuit to a supply voltage terminal as a function of a control signal.

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Munich, Georgia

Siegfried Ganser