Code-Division-Multiplexed Electrical Impedance Tomography Spectroscopy |
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Authors: | McEwan A. Tapson J. van Schaik A. Holder D.S. |
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Affiliation: | Dept. of Med. Phys. & Bioeng., Univ. Coll. London, London, UK; |
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Abstract: | Electrical impedance tomography uses multiple impedance measurements to image the internal conductivity of an object, such as the human body. Code-division multiplexing is proposed as a new method that can provide simultaneous impedance measurements of the multiple channels. Code division provides clear advantages of a wide frequency range at reduced cost and reduced complexity of sources. A potential drawback is the lack of perfectly orthogonal code sets. This caused an increase of 0.62% in root-mean-square spectral error when two codes were used to record two impedance channels simultaneously on a low-pass filter network. The method described provides images and spectra which are equivalent to the conventional time-multiplexed method, with increases in frequency resolution and measurement speed which may be of benefit in some applications of electrical impedance tomography spectroscopy. |
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