[1] EE6350 Lecture Notes.
[2] New JRC introduces a reflective optical sensor the NJL5501R well suitable for Pulse Oximeter and Heart rate monitor..
[3] John Allen, Photoplethysmography and its application in clinical physiological measurement, Physiol. Meas. 28, 2007.
[4] P.E. Allen, CMOS Analog Circuit Design, Chapter 8: Comparators.
[5] Alex K. Y. Wong, Kong-Pang Pun, Yuan-Ting Zhang, and Ka Nang Leung,A Low-Power CMOS Front-End for Photoplethysmographic Signal Acquisition With Robust DC Photocurrent Rejection".