Description of a digital AC ratiometric sensor conditioner

Ratiometric transducers such as strain gauge bridge transducers are commonly excited with AC sinusoidal waveforms. The transducer output must be amplified, demodulated and filtered in the process known as “sensor conditioning”. Traditionally, sensor conditioning is accomplished using analog components for the functions of demodulation, zero suppression, ranging and filtering. An alternative is to sample and digitize the transducer output as close to the transducer as possible, replacing the analog signal conditioning functions with digital processing. This article describes the design of a sensor conditioner that implements AC excitation synthesis and signal conditioning using the digital signal processing techniques