Automatic gain control ratio circuit

Claim 1

IN COMBINATION WITH A SCANNING RADAR OF THE MONOPULSE TYPE INCLUDING AN ANTENNA SYSTEM FOR PERIODICALLY RADIATING ELECTROMAGNETIC PULSE ENERGY IN THE FORM OF A DIRECTIONAL BEAM AT A GIVEN PULSE REPETITION RATE AND FOR PICKING UP PULSE ECHOES REFLECTED FROM TARGETS WITHIN SAID BEAM ON WHICH THE RADIATED PULSE ENERGY IMPINGES, AND ASSOCIATED MEANS FOR DERIVING REFERENCE SUM AND ERROR DIFFERENCE INTERMEDIATE FREQUENCY SIGNALS FROM SAID ECHO PULSE RECEIVED DURING EACH PULSE REPETITION PERIOD: AN AUTOMATIC GAIN CONTROL RATIO CIRCUIT FOR OBTAINING IN RESPONSE TO EACH RECEIVED ECHO PULSE AND ELECTRICAL CORRECTION SIGNAL WHICH IS ACCURATELY PROPORTIONAL TO THE RATIO OF THE DIFFERENCE TO THE SUM INTERMEDIATE FREQUENCY SIGNALS DERIVED FROM THAT PULSE AND PROVIDES A MEASURE OF THE POSITION, INCLUDING BOTH RANGE AND ANGLE WITH RESPECT TO THE CENTER AXIS OF THE RADIATED BEAM, OF THE TARGET PRODUCING THAT ECHO PULSE, WITH RESPECT TO THE ANTENNA SYSTEM, SAID RATIO CIRCUIT COMPRISING TWO TRANSMISSION CHANNELS EACH INCLUDING A SUBSTANTIALLY IDENTICAL VARIABLE GAIN AMPLIFIER, FOR RESPECTIVELY AMPLIFYING EACH SET OF DERIVED SUM AND DIFFERENCE INTERMEDIATE FRQUENCY SIGNALS; MEANS FOR RECTIFYING THE AMPLIFIED VOLTAGE OUTPUT OF THE SUM INTERMIDATE FREQUENCY AMPLIFIER CHANNEL; A SOURCE OF NEGATIVE REFERENCE VOLTAGE OF PREDETERMINED CONSTANT VALUE; A SIGNAL ADDITION CIRCUIT FOR ADDING THE RECTIFIER VOLTAGE OUTPUT OF THE SUM AMPLIFIER CHANNEL TO THE REFERENCE VOLTAGE FROM SAID SOURCE TO PRODUCE AN AUTOMATIC GAIN CONTROL VOLTAGE OF AMPLITUDE PROPORTIONAL TO THE SUM OF THE ADDED VOLTAGES; AN INTEGRATING LOOP CIRCUIT FOR APPLYING EACH PRODUCED AUTOMATIC GAIN CONTROL VOLTAGE DEGENERATIVELY TO THE AMPLIFIERS IN BOTH SAID CHANNELS TO ADJUST THEIR GAINS IN ACCORDANCE WITH THE AMPLITUDE OF THE APPIED VOLTAGE, SAID LOOP CIRCUIT INCLUDING MEANS FOR IMPROVING THE ACCURACY OF THE RATIO ERROR SIGNAL APPEARING IN THE OUTPUT OF SAID DIFFERENCE AMPLIFIER CHANNEL, COMPRISING A DELAY LINE IN THE PATH OF THE FEEDBACK AUTOMATIC GAIN CONTROL VOLTAGE, HAVING A TOTAL DELAY TIME EQUAL TO THE LENGTH OF A PULSE REPETITION PERIOD.