학술논문
Acquisition of Fetal Magnetocardiograms in an Unshielded Hospital Setting
Document Type
Periodical
Source
IEEE Transactions on Applied Superconductivity IEEE Trans. Appl. Supercond. Applied Superconductivity, IEEE Transactions on. 17(2):823-826 Jun, 2007
Subject
Language
ISSN
1051-8223
1558-2515
2378-7074
1558-2515
2378-7074
Abstract
The acquisition of fetal magnetocardiographic signals in various noisy environments is studied, and improvement in the signal-to-noise ratio (SNR) of weak biomagnetic signals is investigated for various noise levels and gradiometer implementations. There is a consistent improvement in the SNR as fetal gestation age (GA) increases. The SNR in unshielded environment is shown to be acceptable over a wide range of GA values when using the second-order gradiometers with a field balance ${\rm C}_{\rm B}=5\times 10^{-4}$ and a gradient balance ${\rm C}_{{\rm G}1}=5\times 10^{-3}$ or better. It is also shown that the optimal gradiometer baseline length strongly depends on the ambient noise level and the overall gradiometer balance. Shorter ($≪$80 mm) baselines are preferred only when using highly balanced gradiometers in a very high noise environments.