Digital demodulation using I/Q signals and optical phase control applied to a vibrometer
journal contribution
posted on 2020-06-10, 11:23 authored by Ángel Manuel Gálvez-Límaco, José Henrique Galeti, Emílio Carlos Nelli Silva, Ricardo Tokio Higuti, Michael J. Connelly, Cláudio KitanoAn efficient and cost effective optical phase detection vibrometer based on a modified closed loop homodyne Michelson interferometer is presented. Real-time phase demodulation is carried out, using an embedded platform that performs data acquisition, signal processing, PI (proportional-integral) control and the generation of signals that drive the electrooptic Pockels cell phase shifter and the piezoelectric actuator under test. Two phase quadrature signals are generated from a single interferometric output, using the interleaving action, in alternation, of a digitally generated modulating signal, and then the wellknown differential-cross-multiplication technique is applied to perform the computation of the phase shift of interest. The quadrature condition is reached using the PI loop based on an error signal obtained from a Lissajous figure derived from out-of-phase signals. The vibrometer is capable of measuring nanometric displacements, and is simple, inexpensive, accurate, immune to fading and self-consistent. The new method was used to determine the displacement frequency response curves of two prototypes of multi-actuated flextensional piezoelectric actuators. Measurements were made between 500 Hz and 15 kHz, and the results agreed with those obtained by the standard SCM-Signal Coincidence Method.
History
Publication
IEEE Sensors Journal; 20 (19), pp. 11313-11325Publisher
IEEE Computer SocietyNote
peer-reviewedOther Funding information
CNPq (Conselho Nacional de Desenvolvimento Científico e Tecnológico – www.cnpq.br), CAPES Foundation, Ministry of Education of BrazilRights
© 2020 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.Language
EnglishUsage metrics
Categories
No categories selectedLicence
Exports
RefWorks
BibTeX
Ref. manager
Endnote
DataCite
NLM
DC