Radio frequency linear position sensor using two subsequent harmonics

Reference Number: N 01-03

Inventors: Bitar, Ali A.

Owner: NISTAC

USPTO Link: 5241278

Invention Summary

An apparatus is adapted to detect the linear extension of a hydraulic cylinder. The hydraulic cylinder defines a variable length coaxial resonant cavity. Under the control of a controller, a transmitting section and a receiving section are used to determine the linear extension of the hydraulic cylinder. The controller detects two subsequent harmonics of the resonant frequency and responsively determines the resonant frequency. The linear extension is determined as a function of the resonant frequency.