R. m. s. meter circuit using linear resistors and voltage biased diodes to approximate the square law characteristic

Claim 1

A TRUE R.M.S METER CIRCUIT FOR MEASURING A.C. OR D.C. COMPRISING A FULL WAVE RECTIFIER FOR RECEIVING AN ELECTRICAL INPUT SIGNAL TO BE MEASURED, A CAPACITOR RESISTIVELY COUPLED IN SERIES WITH A RESISTOR ACROSS THE OUTPUT OF SAID FULL WAVE RECTIFIER, MEANS FOR MAINTAINING THE CHARGE ON SAID CAPACITOR AT A LEVEL PROPORTIONAL TO THE R.M.S VALUE OF SAID ELECTRICAL INPUT SIGNAL, SAID CHARGE MAINTAINING MEANS INCLUDING A PAIR OF VOLTAGE DIVIDERS CONNECTED ACROSS THE OUTPUT OF SAID RECTIFIER AND A PAIR OF DIODES CONNECTED IN SERIES IN OPPOSED RELATIONSHIP BETWEEN A TAP ON ONE OF SAID DIVIDERS AND A TAP ON THE OTHER OF SAID DIVIDERS, THE JUNCTION BETWEEN SAID DIODES BEING CONNECTED TO THE JUNCTION BETWEEN SAID RESISTOR AND SAID CAPACITOR, EACH OF SAID DIODES BEING FORWARD BIASED BY THE VOLTAGE DIVIDER WITH WHICH IT IS MOST CLOSELY CONNECTED TO CONDUCT AT A DIFFERENT POINT ON THE INPUT SIGNAL CYCLE TO MAINTAIN THE CHARGE ON SAID CAPACITOR AT A VAUE THAT IS PROPORTIONAL TO THE R.M.S VALUE OF SAID ELECTGRICAL INPUT SIGNAL, AND A D.C. METER CIRCUIT COUPLED IN PARALLEL WITH SAID CAPACITOR FOR MEASURING THE POTENTIAL THEREON THEREBY PRODUCING A TRUE MEASURE OF THE R.M.S VALUE OF SAID ELECTRICAL INPUT SIGNAL.