Lock-in-amplifiers are used in many applications for signal processing and offer the ability to discriminate high levels of noise. While these instruments are very powerful and offer many features, they are not portable and are expensive. An economical and easy to use alternative circuit is presented which incorporates pre-amplification, reference, and synchronous detection on one circuit board. The design can be used in laboratory or process control situations where its small size and low cost are advantageous. The circuit was successfully applied to moderate and high level signals as seen in flame infrared emission detection and in a portable radiometer for rocket plume studies.
Mofidi, Mokhtar; Hudson, M. Keith; Cole, Reagan; and Wilson, James D.
"Simple Synchronous Detector for Spectroscopic Studies,"
Journal of the Arkansas Academy of Science: Vol. 45
, Article 21.
Available at: http://scholarworks.uark.edu/jaas/vol45/iss1/21