Development of LVDT Signal Conditioner Using Waveguide Acoustic Resonance Tube

A novel signal conditioning technique for Linear Variable Differential Transformers (LVDT) is presented. This technique considers the usage of waveguide acoustic resonance tube as signal conditioner. The induced voltages of the LVDT coils are converted into sound waves by loudspeakers, and then the waves are traveling within a resonance tube in a force mode of operation, where the position information of the core is presented as a signal acquired by microphone placed in the opposite side of the resonance tube. Signal measurement and processing is achieved utilizing LabVIEW software. A plot which illustrates a relationship between the core position and the measured voltages via sound card is obtained by measuring the amplitude, frequency and phase of the acquired signal.