The Model 451 excites the transducer according to user set parameters for voltage and frequency. A variable gain differential amplifier receives the resulting signal which is then coupled to a synchronous detector, user controlled four-step filter, analog-to-digital converter, and micro-controller. Here, all functions from arithmetic calculations, to front-panel data and menu displays, to user interface operations are controlled. In parallel, the displacement data is calculated and coupled to the front panel for display. Finally, a digital-to-analog converter and output analog stages produce the desired analog output signal. The display indicates both the analog voltage and the actual transducer displacement. Settings, maintained in non-volatile memory, are entered into the Model 451 using the front panel controls.