Gain monitoring system for a heightfinding radar

Claim 1

IN A GAIN MONITORING SYSTEM FOR A MULTI-CHANNEL RECEIVING SYSTEM, SAID GAIN MONITORING SYSTEM INCLUDING A PILOT PULSE GENERATOR MEANS PRODUCING RECURRENT PULSEMODULATED PILOT SIGNALS TO BE RECEIVED BY EACH CHANNEL OF SAID MULTI-CHANNEL RECEIVING SYSTEM, MEANS FOR COMPARING THE GRAINS OF ADJACENT CHANNELS OF SAID MULTI-CHANNEL RECEIVING SYSTEM, COMPRISING IN COMBINATION, SWITCHING MEANS COUPLED BETWEEN SAID PILOT PULSE GENERATOR MEANS AND SAID MULTI-CHANNEL RECEIVING SYSTEM FOR RECURRENTLY ACTIVATING A FIRST PAIR OF ADJACENT CHANNELS DURING FIRST MONITORING INTERVALS, EACH OF SAID FIRST PAIR OF ADJACENT CHANNELS PRODUCING RECURRENT OUTPUT PULSES, COMPUTER MEANS COUPLED TO THE OUTPUT OF SAID RECEIVING SYSTEM AND RESPONSIVE TO THE OUTPUT PULSES DURING SAID FIRST MONITORING INTERVALS FOR PRODUCING RECURRENT VIDEO OUTPUT PULSES WHOSE MAGNITUDE VARIES ACCORDING TO THE RADIO OF THE VOLTAGE GAINS OF SAID FIRST PAIR OF ADJACENT CHANNELS, THE MAGNITUDE OF SAID VIDEO OUTPUT PULSES HAVING A PREDETERMINED VALUE WHEN THE GAINS OF SAID FIRST PAIR OF ADJACENT CHANNELS ARE EQUAL, REFERENCE GENERATOR MEANS COUPLED TO SAID SWITCHING MEANS FOR PRODUCING A RECURRENT REFERENCE VOLTAGE, THE MAGNITUDE OF SAID REFERENCE VOLTAGE HAVING A FIXED VALUE EQUAL TO THE PREDETERMINED VALUE OF SAID VIDEO OUTPUT PULSES FROM SAID COMPUTER MEANS WHEN THE GAINS OF SAID PAIR OF ADJACENT CHANNELS ARE EQUAL, AND INDICATOR MEANS COUPLED TO THE OUTPUT OF SAID COMPUTER MEANS AND TO THE OUTPUT OF SAID REFERENCE GENERATOR MEANS FOR INDICATING THE DIFFERENCE BETWEEN SAID VIDEO OUTPUT PULSES FROM SAID COMPUTER MEANS AND SAID RECURRENT REFERENCE VOLTAGE.