Lock-in amplifier error prediction and correction in frequency sweep measurements.
This article proposes an analytical algorithm for predicting errors in lock-in amplifiers (LIAs) working with time-varying reference frequency. Furthermore, a simple method for correcting such errors is presented. The reference frequency can be swept in order to measure the frequency response of a system within a given spectrum. The continuous variation of the reference frequency produces a measurement error that depends on three factors: the sweep speed, the LIA low-pass filters, and the frequency response of the measured system. The proposed error prediction algorithm is based on the final value theorem of the Laplace transform. The correction method uses a double-sweep measurement. A mathematical analysis is presented and validated with computational simulations and experimental measurements.
Sonnaillon
Maximiliano Osvaldo
MO
Laboratorio de Cavitación y Biotecnología, San Carlos de Bariloche, Argentina. msonnaillon@ing.uncr.edu.ar
Bonetto
Fabian Jose
FJ
D000465:Algorithms; D000669:Amplifiers, Electronic; D008962:Models, Theoretical; D012680:Sensitivity and Specificity; D012815:Signal Processing, Computer-Assisted