Date of Award
Spring 1978
Document Type
Thesis - Restricted
Degree Name
Master of Science (MS)
Department
Electrical and Computer Engineering
First Advisor
Ackmann, James
Second Advisor
Sances, Anthony
Third Advisor
Seitz, Martin
Abstract
Previous impedance studies in this laboratory used a four terminal measurement system at frequencies of 10 Hz to 100 KHz. Stray capacitance caused errors which necessitated calibration and correction of the data by substituting the load with a low capacitance known - value resistor and simulated electrode impedance before and after each study. In addition, load dependent phase shifts caused unpredictable errors that could not be corrected. The instrumentation system has been refined to greatly reduce these errors. Chapter I gives an overview of the previous impedance measurement techniques and their results. Chapter II discusses investigations of four constant current sources by bench studies and computer modeling to determine which design is least susceptible to stray capacitance and load dependent phase shifts. Chapter III reports the effects of stray capacitance between ground and the load and voltage leads, and describes circuits consisting of buffer amplifiers and shield drivers which were designed and constructed to reduce these effects. Chapter IV discusses the overall impedance system specifications. Chapter V presents several impedance studies on biologic specimens and compares them to the literature to demonstrate the improved measurement system. Concluding remarks and future recommendations are also presented.
Recommended Citation
King, Martin J., "A Four Terminal Instrumentation System for the Measurement of Complex Bioelectric Impedance" (1978). Master's Theses (1922-2009) Access restricted to Marquette Campus. 4910.
https://epublications.marquette.edu/theses/4910