Variably adjustable attenuator

摘要

For a variably adjustable attenuator having PIN diodes arranged in a T circuit, a largely constant standing wave ratio which is low over the entire range of attenuation can be achieved in that a control current for the series elements and a control current for the shunt elements is generated from a common control signal via two function generators, the first control current for the series diodes falling exponentially and the control current for the shunt diodes increasing exponentially with increasing attenuation. A preferred circuit for the function generators and a configuration of such an attenuator which is distinguished by particularly low interference due to crosstalk and intermodulation are specified.