TY - JOUR
T1 - Digital Demodulation Using I/Q Signals and Optical Phase Control Applied to a Vibrometer
AU - Galvez-Limaco, Angel Manuel
AU - Galeti, Jose Henrique
AU - Silva, Emilio Carlos Nelli
AU - Higuti, Ricardo Tokio
AU - Connelly, Michael J.
AU - Kitano, Claudio
N1 - Publisher Copyright:
© 2001-2012 IEEE.
PY - 2020/10/1
Y1 - 2020/10/1
N2 - An 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 well-known 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.
AB - An 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 well-known 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.
KW - metrology
KW - Optical interferometry
KW - piezoelectric transducers
KW - signal processing
UR - http://www.scopus.com/inward/record.url?scp=85091042036&partnerID=8YFLogxK
U2 - 10.1109/JSEN.2020.2997900
DO - 10.1109/JSEN.2020.2997900
M3 - Article
AN - SCOPUS:85091042036
SN - 1530-437X
VL - 20
SP - 11313
EP - 11325
JO - IEEE Sensors Journal
JF - IEEE Sensors Journal
IS - 19
M1 - 9102231
ER -