Solid-state digital pressure transducer

Abstract

The solid-state digital transducer represents a new standard in precision pressure transduction for the next generation of airborne sensors. The pressure transducer produces pulse train outputs as a measure of pressure by developing strains in a silicon diaphragm which incorporates piezoresistive sensing elements. These elements are distributed resistance-capacitance (RC) networks which are diffused into a diaphragm surface as the control elements of phase shift oscillators. By this approach, a digital (frequency) signal generated at the source can be transmitted without noise and distance limitations and the need for precision analog to digital conversion is eliminated. The device exhibits advantages in the areas of reliability, accuracy, size and cost over present day analog devices. The solid-state digital pressure transducer is being developed to meet the requirements of supersonic and subsonic air data applications when coupled with a high-performance air data computer. This application requires low hysteresis with repeatability and stability which are the main features of the solid-state pressure transducer. Other possible applications are FM data acquisition systems and industrial robots.