Date of Award

Spring 1989

Degree Type

Thesis - Restricted

Degree Name

Master of Science (MS)


Biomedical Engineering

First Advisor

Battocletti, Joseph H.

Second Advisor

Ackmann, James J.

Third Advisor

Jeutter, Dean C.


Physiological signals are often buried in noise. In order to improve the signal-to-noise ratio, the signals are averaged. Signals obtained from the following devices are averaged in this thesis: photo-electric plethysmograph, doppler flowmeter, NMR blood flowmeter, electrocardiograph, and a pump system simulating blood flow on the extracorporeal electromagnetic flowmeter. Since these signals depend on the heart rate and the heart rate of a healthy individual varies even at rest, the signal averaged waveform becomes dispersed. Dispersion in this thesis refers to the broadening of the averaged waveform due to a variable heart rate. Dispersion of the above signals is illustrated and discussed in this thesis. A model of the phenomenon of dispersion of the NMR blood flow pulse is developed using a triphasic flow pulse. Finally, the signal-to-noise improvement is evaluated for the model signal.



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