Multi Modulation Frequency fNIRS (mFD-fNIRS)
Definition: Frequency Domain measurements are typically taken at a single modulation frequency. The three measured signals from these measurements are the direct current amplitude, alternating current amplitude, and phase. These signals have a modulation frequency dependence. Multi Modulation Frequency fNIRS (mFD-fNIRS) combines multiple measurements of FD-fNIRS at different modulation frequencies, either simultaneously or by repeated measurements, each at a discrete modulation frequency. The measurements at discrete modulation frequencies are then used simultaneously for spectroscopic or tomographic reconstruction of optical properties. In current literature, the frequencies typically range from tens of MHz to 1000 MHz and have been shown to increase localization and better image resolution compared to single modulation frequency FD-fNIRS.
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References: https://doi.org/10.1364/BOE.435913https://doi.org/10.1364/BOE.467614
https://doi.org/10.1117/1.NPh.8.4.045002
Related terms: Frequency Domain, Modulation Frequency