A Low-Cost Circuit with Direct Digital Output for Pressure Measurement

A low-cost circuit with direct digital output for pressure measurement is presented. This circuit, with pulse width modulators and digital frequency differentiation, allows highly accurate and linear conversion of resistance deviation over time. Analytical expressions for system performance are obtained and verified experimentally. This alternative not only allows a can- cellation of temperature drifts but also the output shows good robustness and repeatability of pressure measurement.