Rearrangeable and exchangeable optical module with system-on-chip for wearable functional near-infrared spectroscopy system

Tsukasa Funane, Takashi Numata, Hiroki Sato, Shinsuke Hiraizumi, Yuichi Hasegawa, Hidenobu Kuwabara, Kiyoshi Hasegawa, Masashi Kiguchi

Research output: Contribution to journalArticlepeer-review

5 Citations (Scopus)


We developed a system-on-chip (SoC)-incorporated light-emitting diode (LED) and avalanche photodiode (APD) modules to improve the usability and flexibility of a fiberless wearable functional near-infrared spectroscopy (fNIRS) system. The SoC has a microprocessing unit and programmable circuits. The time division method and the lock-in method were used for separately detecting signals from different positions and signals of different wavelengths, respectively. Each module autonomously works for this time-divided-lock-in measurement with a high sensitivity for haired regions. By supplying +3.3V of power and base and data clocks, the LED module emits both 730- and 855-nm wavelengths of light, amplitudes of which are modulated in each lock-in frequency generated from the base clock, and the APD module provides the lock-in detected signals synchronizing with the data clock. The SoC provided many functions, including automatic-power-control of the LED, automatic judgment of detected power level, and automatic-gain-control of the programmable gain amplifier. The number and the arrangement of modules can be adaptively changed by connecting this exchangeable modules in a daisy chain and setting the parameters dependent on the probing position. Therefore, users can configure a variety of arrangements (single- or multidistance combinations) of them with this module-based system.

Original languageEnglish
Article number011007
Issue number1
Publication statusPublished - 2018 Jan 1
Externally publishedYes


  • functional near-infrared spectroscopy
  • module-based system
  • system-on-chip
  • wearable

ASJC Scopus subject areas

  • Neuroscience (miscellaneous)
  • Radiological and Ultrasound Technology
  • Radiology Nuclear Medicine and imaging


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