Monopulse radar system

Claim 1

IN A COMBINATION AMPLITUDE-PHASE COMPARISON MONOPULSE RADAR SYSTEM HAVING MEANS RESPONSIVE TO DETECTED TARGET SIGNALS WHEREBY THERE IS PRODUCED A FIRST SUM AND A FIRST DIFFERENCE SIGNAL AT A FIRST PRESCRIBED INTERMEDIATE FREQUENCY, SAID DIFFERENCE SIGNAL HAVING A PRESCRIBED PHASE ANGLE WITH RESPECT TO SAID SUM SIGNAL WHICH IS A MEASURE OF THE DEVIATION OF THE TARGET FROM THE BORESIGHT AXIS OF THE SYSTEM, MEANS FOR DETECTING THE PHASE ANGLE COMPRISING: DISCRETE MEANS FOR CONVERTING SAID SUM SIGNAL AND SAID DIFFERENCE SIGNAL TO RESPECTIVE SECOND SUM IF AND SECOND DIFFERENCE IF SIGNALS SUCH THAT THE FREQUENCY OF SAID SECOND SUM SIGNAL AND THE FREQUENCY OF SAID SECOND DIFFERENCE SIGNAL DIFFER BY A PRESCRIBED AUTIO FREQUENCY, MEANS FOR GENERATING A SIGNAL AT SAID AUDIO FREQUENCY, MEANS FOR ADDITIVELY COMBINING SAID SECOND SUMAND SAID SECOND DIFFERENCE SIGNALS WHEREBY THERE IS PRODUCED A COMPONENT WHICH INCLUDES SAID SECOND SUM SIGNAL AND A DIFFERENCE SIGNAL AMPLITUDE MODULATED BY SAID AUDIO FREQUENCY, SAID MODULATED DIFFERENCE SIGNAL INCLUDING SAID PHASE ANGLE, AN AMPLIFIER RESPONSIVE TO THE OUTPUT OF SAID ADDITIVE MEANS FOR SIMULTANEOUSLY AMPLIFYING SAID SECOND SUM SIGNAL AND SAID AMPLITUDE MODULATED DIFFERENCE SIGNAL, MEANS RESPONSIVE TO THE OUTPUT OF SAID AMPLIFIER FOR RECOVERING THE ENVELOPE OF THE AMPLITUDE MODULATE DIFFERENCE SIGNAL WHEREBY THERE IS PRODUCED THE AUDIO FREQUENCY SIGNAL SHIFTED IN PHASE BY SAID PHASE ANGLE, AND MEANS FOR COMPARING SAID GENERATED AUDIO FREQUECY AND THE AUDIO FREQUECY SIGNAL INCLUDING SAID PHASE ANGLE WHEREBY SAID PHASE ANGLE IS DETECTED.