Title :
Influence Analysis of Sensor´s Nonlinearity on Output of Lock-in Amplifier
Author :
Feng, Zhihua ; Liu, Rilong ; Yang, Dengfeng ; Kong, Fanrang
Author_Institution :
Dept. of Precision Instrum. & Precision Machinery, Univ. of Sci. & Technol. of China, Anhui
Abstract :
Generally the lock-in amplifier (LIA) can be used to detect very weak signal. This is based on the fact that any signal with a different frequency from that of the LIA´s reference signal will result in zero output. However, if the signal is measured by a sensor with some nonlinearity, the LIA indeed yields some mixed output that comes from the correlation between the measured signal and reference signal. This paper presents a theoretical analysis on the output of LIA. Furthermore, based on analysis results, a curve fitting method of measuring the sensor´s dynamic and tiny nonlinearity is provided. Experimental results verify that it is a useful measurement method when the accuracy is focused on
Keywords :
amplifiers; curve fitting; electric sensing devices; curve fitting; lock-in amplifier; reference signal; sensor nonlinearity; Curve fitting; Dielectric liquids; Frequency measurement; Low pass filters; Noise measurement; Pollution measurement; RF signals; Radiofrequency amplifiers; Sensor phenomena and characterization; Signal to noise ratio; Lock-in Amplifier; nonlinearity; sensor;
Conference_Titel :
Instrumentation and Measurement Technology Conference, 2005. IMTC 2005. Proceedings of the IEEE
Conference_Location :
Ottawa, Ont.
Print_ISBN :
0-7803-8879-8
DOI :
10.1109/IMTC.2005.1604469
