An Experimental Investigation on a Liquid Fluidic Frequency Demodulating Circuit

Abstract

This study deals with a frequency demodulating circuit using water as a working fluid. In constructing a liquid frequency demodulating circuit, some improvements on the dynamic characteristics of the fluidic element and the construction of the circuit were carried out to solve the problem which will occur as compared with the pneumatic one. Two methods by use of electro-viscous fluid. Another is a mechanical method with the use of a vibrator. In a liquid a-c fluidics, the upper limit of frequency response is an important factor. In this circuit, the phase discriminator showed a frequency response as large as 140 Hz. By using beat frequency technique, this frequency demodulating circuit was operated at about 700 Hz by the electrically controlled method and at about 400 Hz by the mechanical method.