Radar receiver

In a semiactive radar guidance system for a guided missile, such missile carrying a monopulse receiver to convert echo signals to tracking signals and a rear receiver responsive to signals coming directly from a radar transmitter to provide a local oscillator signal that is offset in frequency by a predetermined amount from the frequency of the signals from a radar transmitter, the improvement comprising:

• (a) first downconversion means for providing, in response to the echo signals and a first local oscillator signal, first I.F. signals in the monopulse receiver and, also in response to signals coming directly from the radar transmitter and the first local oscillator signal, first I.F. signals in the rear receiver;
• (b) second downconversion means, responsive to the first I.F. signals in the rear receiver and to a second local oscillator signal, for providing a second local oscillator signal to downconvert the first I.F. signals in the monopulse receiver to second I.F. signals;
• and
• (c) automatic frequency control means for maintaining a fixed offset of the second local oscillator signal from the frequency of the first I.F. signals input into the second downconversion means.