Publication Date


Document Type


First Advisor

Haji-Sheikh, Michael J.

Degree Name

M.S. (Master of Science)

Legacy Department

Department of Electrical Engineering


Engineering; Electrical engineering; Time-domain reflectometry--Research; Electromagnetic measurements--Research; Liquid level indicators--Research; Liquids--Measurement--Research


The present research is related to the Time Domain Reflectometer (TDR) level measurement device capable of generating and receiving electromagnetic waves. The primary objective is to measure the height of water in a tank and design an efficient measuring device. The TDR is based on the reflection mechanism, in which the time delay between the transmitted and reflected signals helps to determine the distance from the source to the surface of water, which is later used to deduce the height of water in the tank. The TDR is built using a 74AC14 IC, which is capable of producing pulse signals with very low rising and falling time that provide greater accuracy. Thus, the generated pulse signals are transmitted into the probe inserted in a tank. The total time taken by the probe to travel the path to and fro is found out, which in return helps in calculating the height of the liquid in the tank. The functioning of the proposed TDR circuit and the bi-axial probe is also tested in the laboratory.


Advisors: Michael J. Haji-Sheikh.||Committee members: Martin Kocanda; Mansour Tahernezhadi.


61 pages




Northern Illinois University

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