Arrangement for stabilising the frequency of a pulsed IMPATT oscillator

摘要

This oscillator is used as transmitting oscillator in a transmitting/receiving device, particularly in a radar sensor, in which received signals are mixed down to an intermediate frequency by means of the frequency-stabilised signal of a local oscillator in a receiving mixer. The transmitting signal generated by the IMPATT oscillator (Imp. Osz.) partly crosses over into the receiver circuit where an IF signal is generated at the output of the receiving mixer (Mischer). The IF signal is conducted via a low-noise preamplifier, on the one hand to a high-pass filter and on the other hand to a low-pass filter. The passband characteristic of high-pass and low-pass filter is selected in such a manner that it in each case covers the top and bottom boundary area of the IF band width. A pulse-shaped control signal present at the output of one of the two filters (high-pass filter, low-pass filter) when the actual IF frequency is too high or too low is supplied to a controller which corrects the basic setting of a modulator (Imp.-Mod.) allocated to the IMPATT oscillator (Imp. Osz.). <IMAGE>