title: A simplified digital lock-in amplifier for the scanning grating spectrometer.
abstract: For the common measurement and control system of a scanning grating spectrometer, the use of an analog lock-in amplifier requires complex circuitry and sophisticated debugging, whereas the use of a digital lock-in amplifier places a high demand on the calculation capability and storage space. In this paper, a simplified digital lock-in amplifier based on averaging the absolute values within a complete period is presented and applied to a scanning grating spectrometer. The simplified digital lock-in amplifier was implemented on a low-cost microcontroller without multipliers, and got rid of the reference signal and specific configuration of the sampling frequency. Two positive zero-crossing detections were used to lock the phase of the measured signal. However, measurement method errors were introduced by the following factors: frequency fluctuation, sampling interval, and integer restriction of the sampling number. The theoretical calculation and experimental results of the signal-to-noise ratio of the proposed measurement method were 2055 and 2403, respectively.
authors.affiliation: College of Instrumentation and Electrical Engineering, Jilin University, 130021 Changchun, China.
authors.forename: Jingru
authors.identifier: 0000000296472744
authors.initials: J
authors.lastname: Wang
authors.affiliation: College of Instrumentation and Electrical Engineering, Jilin University, 130021 Changchun, China.
authors.forename: Zhihong
authors.initials: Z
authors.lastname: Wang
authors.affiliation: College of Instrumentation and Electrical Engineering, Jilin University, 130021 Changchun, China.
authors.forename: Xufei
authors.initials: X
authors.lastname: Ji
authors.affiliation: College of Instrumentation and Electrical Engineering, Jilin University, 130021 Changchun, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Liu
authors.affiliation: College of Instrumentation and Electrical Engineering, Jilin University, 130021 Changchun, China.
authors.forename: Guangda
authors.initials: G
authors.lastname: Liu