Two frequency pulse radar - has bistable switch and coincidence circuit to compare transmitted and received pulses

The pulse radar appts. which transmits trains of pulses having two different repetition rates f1 and f2 (with f1 f2) which serve for removal of ambiguity, includes a bistable switching stage (1) which alternately switches a test pulse through frequencies f1 and f2, together with a coincidence circuit arrangement 3, 4) which compares a delayed echo pulse with the output signals of the bistable switching stage, to form a selction criterion. The time delay interval (tau 1) of the echo pulse depends on the output and input cycle time of the echo and test pulses. The bistable switching circuit may be controlled by the leading edge of the test pulse. The switching arrangement ensures a suitable relationship between the noise and effective power.