A simple microcontroller based digital lock-in amplifier for the detection of low level optical signals

Dorrington, Adrian A.; Künnemeyer, Rainer

doi:10.1109/DELTA.2002.994680

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Dorrington, A. A. & Künnemeyer, R. (2002). A simple microcontroller based digital lock-in amplifier for the detection of low level optical signals. In Proceedings of the First IEEE International Workshop on Electronic Design, Test and Applications (DELTA ‘02), Christchurch, New Zealand, January 29-31 2002 (pp.486-488). Washington, DC, USA: IEEE computer society.

Permanent Research Commons link: https://hdl.handle.net/10289/3215

Abstract

Traditionally digital lock-in amplifiers sample the input signal at a rate much higher than the lock-in reference frequency and perform the lock-in algorithm with high-speed processors. We present a small and simple digital lock-in amplifier that uses a 20 bit current integrating analogue-to-digital converter interfaced to a microcontroller. The sample rate is set to twice the reference frequency placing the sampled lock-in signal at the Niquest frequency allowing the lock-in procedure to be performed with one simple algorithm. This algorithm consists of a spectral inversion technique integrated into a highly optimised low-pass filter. We demonstrate a system with a dynamic range of 103dB recovering signals up to 85dB below the interference.

Date

2002

Type

Conference Contribution

Publisher

IEEE computer society

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©2002 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.

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