Document Type
Thesis
Date of Award
5-31-1988
Degree Name
Master of Science in Biomedical Engineering - (M.S.)
Department
Biomedical Engineering Committee
First Advisor
Peter Engler
Second Advisor
Chung H. Lu
Abstract
A reliable non-invasive tracking of the fetal heart rate from the maternal abdominal surface could be of significant diagnostic importance in the monitoring of pregnancies, not only for fetal heart rate assessment, but also for the observation of congenital cardiac malformations and transient difficulties during labor. Further, the fetal heart rate recording may be used to assess fetal heart rate variability in the antepartum period of gestation when it is not possible to obtain a fetal scalp lead electrocardiogram.
There are several methods being used to detect the fetal heart rate. Phonocardiography, abdominal electrocardiography and ultrasound cardiography are the three most commonly used techniques for external fetal cardiography. This thesis describes an application of adaptive signal processing to fetal phonocardiography for detecting fetal heart signals from maternal abdominal recordings. The method uses a "primary" input containing the mother's as well as fetal's heart sound signal and a "reference" input containing only the mother's heart sound signal correlated in some unknown way with the primary signal. The reference input is adaptively filtered and subtracted from the primary input to obtain the signal estimate of the fetal heart sound. Adaptive filtering before subtraction permits the treatment of inputs that are both deterministic or stochastic, stationary or nonstationary. Wiener solutions are developed to describe asymptotic adaptive performance and output signal-to-noise ratio for stationary stochastic inputs, including single and multiple reference inputs. These solutions show that when the reference input is free of signal and certain other conditions are met, noise in the primary input can essentially be eliminated without signal distortion.
Recommended Citation
Lin, Jeng-Kwan, "Fetal phonocardiography" (1988). Theses. 3142.
https://digitalcommons.njit.edu/theses/3142
