Circuit for detecting the frequency difference of simultaneously applied alternatingcurrent signals as a direct current signal

Claim 1

A FREQUENCY DISCRIMINATOR COMPRISING: FIRST AND SECOND INPUT MEANS FOR RECEIVING A FIRST AND A SECOND ALTERNATING CURRENT SIGNAL, RESPECTIVELY; FIRST AND SECOND OUTPUT TERMINALS; FIRST AND SECOND LOAD MEANS COUPLED IN SERIES BETWEEN THE FIRST AND SECOND OUTPUT TERMINALS; MEANS COUPLED TO THE FIRST INPUT MEANS FOR LIMITING THE AMPLITUDE OF THE FIRST ALTERNATING CURRENT SIGNAL RELATIVE TO A REFERENCE POTENTIAL; MEANS COUPLED TO THE SECOND INPUT MEANS FOR LIMITING THE AMPLITUDE OF THE SECOND ALTERNATING CURRENT SIGNAL RELATIVE TO THE REFERENCE POTENTIAL; A FIRST CAPACITOR COUPLED TO THE FIRST INPUT MEANS; A SECOND CAPACITOR COUPLED TO THE SECOND INPUT MEANS; A FIRST UNIDIRECTIONAL CURRENT CONDUCTIVE DEVICE COUPLED BETWEEN THE FIRST CAPACITOR AND A JUNCTION OF THE FIRST AND SECOND LOAD MEANS; A SECOND UNIDIRECTIONAL CURRENT CONDUCTIVE DEVICE COUPLED BETWEEN THE FIRST CAPACITOR AND THE FIRST OUTPUT TERMINAL, THE FIRST AND SECOND UNIDIRECTIONAL CURRENT CONDUCTIVE DEVICES BEING POLED IN OPPOSITE DIRECTIONS RELATIVE TO THE FIRST CAPACITOR; MEANS DEFINING AN ALTERNATING CURRENT PATH TO A SOURCE OF THE REFERENCE POTENTIAL COUPLED TO THE FIRST OUTPUT TERMINAL; A THIRD UNIDIRECTIONAL CURRENT CONDUCTIVE DEVICE COUPLED BETWEEN THE SECOND CAPACITOR AND THE JUNCTION OF THE FIRST AND SECOND LOAD MEANS; A FOURTH UNIDIRECTIONAL CURRENT CONDUCTIVE DEVICE COUPLED BETWEEN THE SECOND CAPACITOR AND THE SECOND OUTPUT TERMINAL, THE THIRD AND FOURTH UNIDIRECTIONAL CURRENT CONDUCTIVE DEVICES BEING POLED IN OPPOSITE DIRECTIONS RELATIVE TO THE SECOND CAPACITOR; AND MEANS DEFINING AN ALTERNATING CURRENT PATH TO THE SOURCE OF REFERENCE POTENTIAL COUPLED TO THE SECOND OUTPUT TERMINAL.