Patent ID: 8538731

Claim:
An apparatus for reading analog signals comprising: a measurement and control system; a physical wire connection attached to the measurement and control system; a plurality of passive sensors including at least three sensors defining a nonlinear circuit connected to the measurement and control system through the physical wire connection, wherein the physical wire connection is made with only two wires and the measurement and control system is configured to receive analog signals through the two wires from the at least three sensors; and a generator for selectively activating each of the plurality of passive sensors to selectively acquire an analog signal from at least one of the plurality of passive sensors, said measurement and control system being configured to individually analyze analog signals from each of the plurality of passive sensors by measuring electrical parameters of the nonlinear circuit and by calculating an impedance contribution of the at least one of the plurality of sensors, said impedance contribution representing the analog signal from the at least one of the plurality of passive sensors.