Analog lock-in amplifier design using subsampling for accuracy enhancement in GMI sensor applications
Fecha
2023Versión
Acceso abierto / Sarbide irekia
Tipo
Artículo / Artikulua
Versión
Versión publicada / Argitaratu den bertsioa
Identificador del proyecto
Impacto
|
10.3390/s23010057
Resumen
A frequency downscaling technique for enhancing the accuracy of analog lock-in amplifier
(LIA) architectures in giant magneto-impedance (GMI) sensor applications is presented in this
paper. As a proof of concept, the proposed method is applied to two different LIA topologies using,
respectively, analog and switching-based multiplication for phase-sensitive detection. Specifically, the
operati ...
[++]
A frequency downscaling technique for enhancing the accuracy of analog lock-in amplifier
(LIA) architectures in giant magneto-impedance (GMI) sensor applications is presented in this
paper. As a proof of concept, the proposed method is applied to two different LIA topologies using,
respectively, analog and switching-based multiplication for phase-sensitive detection. Specifically, the
operation frequency of both the input and the reference signals of the phase-sensitive detector (PSD)
block of the LIA is reduced through a subsampling process using sample-and-hold (SH) circuits. A
frequency downscaling from 200 kHz, which is the optimal operating frequency of the employed
GMI sensor, to 1 kHz has been performed. In this way, the proposed technique exploits the inherent
advantages of analog signal multiplication at low frequencies, while the principle of operation of the
PSD remains unaltered. The circuits were assembled using discrete components, and the frequency
downscaling proposal was experimentally validated by comparing the measurement accuracy with
the equivalent conventional circuits. The experimental results revealed that the error in the signal
magnitude measurements was reduced by a factor of 8 in the case of the analog multipliers and by a
factor of 21 when a PSD based on switched multipliers was used. The error in-phase detection using
a two-phase LIA was also reduced by more than 25%. [--]
Materias
Lock-in amplifier,
Phase-sensitive detector,
GMI sensor,
Subsampling,
Sample-and-hold
Editor
MDPI
Publicado en
Sensors 2023, 23, 57
Departamento
Universidad Pública de Navarra. Departamento de Ciencias /
Nafarroako Unibertsitate Publikoa. Zientziak Saila /
Universidad Pública de Navarra/Nafarroako Unibertsitate Publikoa. Institute of Smart Cities - ISC /
Universidad Pública de Navarra/Nafarroako Unibertsitate Publikoa. Institute for Advanced Materials and Mathematics - INAMAT2
Versión del editor
Entidades Financiadoras
This work has been supported by Grant PID2019-107258RB-C32 funded by the Spanish
Ministerio de Ciencia e Innovación (MCIN/AEI/10.13039/501100011033), and by the project
PJUPNA2005 funded by the Public University of Navarre.