Aircraft control apparatus and difference amplifier therefor

Claim 1

IN A CONTROL SYSTEM FOR AN AIRCRAFT, THE COMBINATION COMPRISING: ATTITUDE REFERNCE MEANS; MEANS FOR PRODUCING A FIRST CURRENT SIGNAL INDICATIVE OF THE ATTITUDE OF THE AIRCRAFT WITH RESPECT TO SAID REFERENCE MEANS; MEANS FOR PRODUCING A SECOND CURRENT SIGNAL INDICATIVE OF THE TIME RATE OF CHANGE OF THE ATTITUDE OF THE AIRCRAFT WITH RESPECT TO SAID REFERENCE MEANS; A HIGH GAIN, ELECTRONIC, DIFFERENCE AMPLIFIER HAVING FIRST AND SECOND INPUT AND OUTPUT TERMINALS; A FIRST IMPEDANCE NETWORK CONNECTED BETWEEN THE FIRST INPUT TERMINAL OF SAID AMPLIFIER AND A SIGNAL GROUND, SAID NETWORK COMPRISING TWO IMPEDANCE DEVICES CONNECTED IN SERIES WITH A COMMON TERMINAL BETWEEN THE DEVICES; A SECOND IMPEDANCE NETWORK CONNECTED BETWEEN THE SECOND INPUT TERMINAL OF SAID AMPLIFIER AND SIGNAL GROUND; MEANS CONNECTED FROM THE OUTPUT TERMINALS OF SAID AMPLIFIER TO SAID FIRST AND SECOND NETWORKS, FOR SUPPLYING ELECTRICAL NEGATIVE FEEDBACK; MEANS FOR APPLYING SAID FIRST SIGNAL TO THE COMMON TERMINAL OF SAID FIRST NETWORK; MEANS FOR APPLYING SAID SECOND SIGNAL TO THE FIRST INPUT TERMINAL OF SAID AMPLIFIER; SERVO MEANS HAVING FIRST AND SECOND ELECTRICAL INPUT TERMINALS AND A MECHANICAL OUTPUT SHAFT; MEANS CONNECTING THE FIRST AND SECOND OUTPUT TERMINALS OF SAID AMPLIFIER TO FIRST AND SECOND INPUT TERMINALS RESPECTIVELY OF SAID SERVO MEANS, SAID AMPLIFIER PROVIDING A VOLTAGE SIGNAL TO SAID SERVO MEANS; ATTITUDE CHANGING MEANS MECHANICALLY COUPLED TO THE AIRCRAFT; AND MEANS MECHANICALLY COUPLING THE SHAFT OF SAID SERVO MEANS TO SAID ATTITUDE CHANGING MEANS.