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A New Integrated Front-End for a Noninvasive Brain Imaging System Based on Near-Infrared Spectroreflectometry.
- Source :
-
IEEE Transactions on Circuits & Systems. Part I: Regular Papers . Dec2005, Vol. 52 Issue 12, p2663-2671. 9p. - Publication Year :
- 2005
-
Abstract
- In this paper, we present a fully integrated front-end of a portable spectroreflectometry-based brain imaging system dedicated for acquisition of modulated optical signals at a frequency of 1 Hz to 25 kHz. The proposed front-end preamplifier is composed of a photodetector, a transimpedance preamplifier, a two-stage voltage amplifier and a mixer. Strict constraints regarding noise thus have to be considered. The preamplifier consists of a transimpedance block featuring a 95-dBΩ gain and an average input current noise density at the frequency of interest of approximately 3 pA/√Hz. Each of the two subsequent voltage amplifiers allows the user to obtain an additional 25-dB gain. Considering the tuning capabilities and the losses due to the filters and the nonideal buffers, the proposed front-end allows us to obtain a total gain up to 145 dB. The back-end of the amplification chain is composed of a mixer which is used to produce a continuous voltage proportional to the amplitude of the input optical signals. All those features were integrated using CMOS 0.18-μm technology and the experimental results are in agreement with the initial design requirements. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 15498328
- Volume :
- 52
- Issue :
- 12
- Database :
- Academic Search Index
- Journal :
- IEEE Transactions on Circuits & Systems. Part I: Regular Papers
- Publication Type :
- Periodical
- Accession number :
- 19253287
- Full Text :
- https://doi.org/10.1109/TCSI.2005.857920