| 摘要 |
<p>An apparatus (102) is adapted to detect the linear extension (position), velocity and acceleration of a hydraulic cylinder (108). The hydraulic cylinder (108) defines a variable length coaxial resonant cavity (112). Under the control of a controller (228), an RF transmitting section (114) and an RF receiving section (116) are used to determine the resonant frequency of the cavity. The receiving section includes a comparator circuit for increasing the sensor's sensitivity and eliminating spurious detections of the cylinder's resonant frequency. The linear extension of the cylinder (108) is determined as a function of the resonant frequency.</p> |
