Resonance bridge or frequency discriminator circuit and sensing system

Claim 1

A FREQUENCY DISCRIMINATING RESONANT BRIDGE CIRCUIT COMPRISING: A FIRST TERMINAL ADAPTED FOR CONNECTION TO A SOURCE OF ALTERNATING FREQUENCY SIGNALS; A SECOND TERMINAL; A FIRST RESISTOR CONNECTED BETWEEN SAID FIRST AND SECOND TERMINALS; A FIRST CAPACITOR CONNECTED TO SAID SECOND TERMINALS; A THIRD TERMINAL; A SECOND RESISTOR CONNECTED BETWEEN SAID FIRST AND THIRD TERMINALS; A SECOND CAPACITOR CONNECTED TO SAID THIRD TERMINALS; A FOURTH TERMINAL; A THIRD RESISTOR AND A FIRST DIODE CONNECTED IN SERIES BETWEEN SAID SECOND AND SAID FOURTH TERMINALS; A FOURTH RESISTOR AND A SECOND DIODE CONNECTED IN SERIES BETWEEN SAID THIRD AND FOURTH TERMINALS;