Thermionic square law indicating device wherein cathode power dissipation is maintained constant to provide an indication of the magnitude of the unknown signal

Claim 1

A SQUARE LAW INDICATOR COMPRISING: A SOURCE OF AN INPUT SIGNAL OF RELATIVELY VERY HIGH FREQUENCY; A D.-C. POTENTIAL SOURCE; A REFERENCE POTENTIAL; A CIRCUIT INTERRUPTER DEVICE HAVING TWO EXTERNAL CONNECTIONS AND OPERATING AT RELATIVELY VERY LOW FREQUENCY; POTENTIOMETER MEANS HAVING TWO ENDS AND A POSITIONABLE TAP, ONE OF SAID ENDS BEING CONNECTED TO SAID REFERENCE POTENTIAL, THE OTHER OF SAID ENDS BEING COUPLED TO SAID SOURCE OF D.-C. POTENTIAL AND SAID POSITIONABLE TAP BEING JOINTLY COUPLED TO SAID INPUT SIGNAL SOURCE AND ONE EXTERNAL CONNECTION OF SAID CIRCUIT INTERRUPTER DEVICE; A DIODE HAVING A PLATE AND A DIRECTLY HEATED CATHODE, SAID PLATE AND CATHODE BEING CONNECTED IN CIRCUIT TO BE BIASED BY SAID SOURCE OF D.-C. POTENTIAL SO THAT SAID DIODE CONDUCTS IN THE TEMPERATURE LIMITED MODE AND SAID CATHODE BEING FURTHER COUPLED IN SERIES CIRCUIT BETWEEN THE OTHER EXTERNAL CONNECTION OF SAID CIRCUIT INTERRUPTER DEVICE AND SAID REFERENCE POTENTIAL; FREQUENCY SENSITIVE SERVO MEANS RESPONSIVE SUBSTANTIALLY ONLY TO ENERGY OF SAID RELATIVELY VERY LOW FREQUENCY AND CONNECTED BETWEEN SAID DIODE PLATE AND SAID POTENTIOMETER MEANS POSITIONABLE TAP TO POSITION SAID TAP SO THAT THE HEATING POWER DISSIPATED BY SAID CATHODE IS MAINTAINED CONSTANT AND AN INDICATOR CONNECTED TO SAID POTENTIOMETER MEANS POTIONABLE TAP WHEREBY THE POSITION OF SAID TAP, AND THE INDICATION OF SAID INDICATOR, IS PROPORTIONAL TO THE SQUARE OF SAID INPUT SIGNAL.