An arrangement for eliminating offset errors in a power control circuit of a pulsed transmitter final amplifier

摘要

A high frequency power amplifier (10) amplifies periodic signals in the form of HF bursts. The power output of the amplifier is adjusted by a control loop (20) which produces a control signal in response to a comparison made between a set-point value (BV) and the actual power output (Put) of the amplifier and applies the signal to the power amplifier. The control loop includes a differential amplifier (25). A correction circuit (40) measures the output voltage of the differential amplifier over a time period (t1 to t2 ) prior to each HF burst and stores in a memory (C) a magnitude proportional to this output voltage. During the following HF burst, this magnitude is used to introduce into the control loop a correction magnitude (Ukorr) for correction of offset voltages (Uoff) occurring in the control loop.