A frequency-sensing readout using piezoelectric sensors for sensing of physiological signals

Dilpreet Singh Buxi, Jean-Michel Redoute, Mehmet Rasit Yuce

Research output: Chapter in Book/Report/Conference proceedingConference PaperResearchpeer-review


Together with a charge or voltage amplifier, piezoelectric sensors are commonly used to pick up physiological vibrations from the body. As an alternative to chopper or auto-zero amplifiers, frequency sensing is known in literature to provide advantages of noise immunity, interfacing to digital readout systems as well as tunable range of sensing. A frequency-sensing readout circuit for sensing low voltage signals from piezoelectric sensors is successfully developed and tested in this work. The output voltage of a piezoelectric sensor is fed to a varactor, which is part of an Colpitts LC oscillator. The oscillation frequency is converted into a voltage using a phase locked loop. The circuit is compared to a reference design in terms of linearity, noise and transfer function. The readout has a input-referred noise voltage of 2.24μV/√Hz and consumes 15 mA at 5V supply. Arterial pulse wave signals and the cardiac vibrations from the chest are measured from one subject to show the proof of concept of the proposed readout. The results of this work are intended to contribute towards alternative low noise analog front end designs for piezoelectric sensors.

Original languageEnglish
Title of host publication2014 36th Annual International Conference of the IEEE Engineering in Medicine and Biology Society
EditorsJeff Duerk, Jim Ji
Place of PublicationPiscataway NJ USA
PublisherIEEE, Institute of Electrical and Electronics Engineers
Number of pages4
ISBN (Electronic)9781424479290
ISBN (Print)9781424479276
Publication statusPublished - 2 Nov 2014
EventInternational Conference of the IEEE Engineering in Medicine and Biology Society 2014 - Sheraton Chicago Hotel and Towers, Chicago, United States of America
Duration: 26 Aug 201430 Aug 2014
Conference number: 36th
https://ieeexplore-ieee-org.ezproxy.lib.monash.edu.au/xpl/conhome/6923026/proceeding (Proceedings)
https://web.archive.org/web/20140331105330/http://embc.embs.org/2014/?page_id=120 (Website)


ConferenceInternational Conference of the IEEE Engineering in Medicine and Biology Society 2014
Abbreviated titleEMBC 2014
CountryUnited States of America
Internet address

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