A novel DSP-based LVDT signal conditioner

A novel signal conditioning system for linear variable differential transfo rmers (LVDTs) is presented. This system considers the signals involved in t he operation of the LVDT to be analogous to a double sideband suppressed ca rrier AM (DSBSC-AM) communication system, where the position information is akin to the signal to be transmitted and the input sine wave excitation to the LVDT is akin to the carrier wave. Signal conditioning is achieved thro ugh a modified digital signal processor-based Costas receiver. This system has better dynamic response than existing solutions and better noise reject ion than commercially available solutions. Static testing of the system usi ng both 4-wire and 5-wire LVDTs verifies that the conditioner meets or exce eds the linearity performance of existing signal conditioning systems over the full-scale operating range. In addition, this system requires no phase compensation network or manual tuning.