Pressure analog generating equipment

Claim 1

CIRCUITRY FOR SELECTIVELY DEVELOPING FLUID PRESSURE OUTPUTS INDICATIVE OF STATIC AND RAMP CONDITIONS FOR AIRCRAFT COMPRISING A FEED-BACK AMPLIFIER, MEANS FOR PRODUCING PRESSURE CONDITIONS ABOVE ATMOSPHERIC, MEANS TO PRODUCE PRESSURE BELOW ATMOSPHERIC, AN ELECTRO-PNEUMATIC VALVE CONNECED TO EACH OF THE PRESSURE PRODUCING MEANS, AN OUTPUT TUBE CONNECTED TO SAID VALVE SO THAT A PRESSURE IS PRODUCED WHICH IS THE OUTPUT PRESSURE DIFFERENTIAL, MEANS TO CONTROL THE ELECTROPNEUMATIC VALVE FROM SAID AMPLIFIER TO ESTABLISH THE PRESSURE DIFFERENTIAL IN THE OUTPUT TUBE AS DEVELOPED FROM EACH OF SAID PRESSURE DIFFERENTIAL PRODUCING MEANS, A BRIDGE CIRCUIT, MEANS TO CONNECT THE INPUT CIRCUIT OF THE AMPLIFIER ACROSS ONE OF THE BRIDGE DIAGONALS TO DETERMINE THE CURRENT FLOWING THROUGH SAID AMPLIFIER IN ACCORDANCE WITH THE BALANCED AND UNBALANCED CONDITION OF THE SAID BRIDGE CIRCUIT, FLUID TRANSDUCER MEANS CONNECTED TO RECEIVE A FLUID INPUT PRESSURE CORRESPONDING TO THAT AVAILABLE IN THE OUTPUT TUBE FROM SAID VALVE, MEANS CONTROLLED BY SAID TRANSDUCER FOR RETURNING THE BRIDGE CIRCUIT TO A BALANCED STATE IN ITS STATIC OPERATIONAL MODE AND THEREBY REDUCE THE AMPLIFIER INPUT TO SUBSTANTIALLY A ZERO VALUE, SWITCH MEANS FOR TRANSFORMING THE BRIDGE CIRCUIT FROM A STATIC TO A RAMP CONDITION AND REMOVING THE OUTPUT EFFECT OF THE FLUID TRANSDUCER ON THE AMPLIFIER INPUT DURING A RAMP CONDITION OF OPERATION, AND MEANS FOR APPLYING A CONTROLLABLE INPUT SIGNAL OF SELECTED POLARITY TO THE AMPLIFIER FOR PRODUCING CHANGING AMPLIFIER OUTPUTS AND RESULTANT PRESSURE CHANGES IN THE OUTPUT OF THE ELECTRO-PNEUMATIC VALVE DURING A CONTROLLABLE STATE OF OPERATION INDICATIVE OF RAMP CONDITIONS.