AD630 Lock-In Amplifier Circuit for Weak Signal

Abstract:

Lock-in amplifying (LIA) is one of important techniques of picking up weak signals buried in the noise, and is the core component of Tunable Diode Laser Absorption Spectroscopy (TDLAS) technology. Then we design a small size, dual phase lock-in amplifier (LIA) integrated circuit. This paper is based on the phase-sensitive detector AD630, together with the phase-locked loop (PLL) circuit (74HC4046) and the active filter (MAX275) the value of Q and the center frequency of which could be adjusted. The output signals were collected by A/D converter and dedicated high-resolution data acquisition card. The range of frequency is 500Hz-100 kHz, the dynamic range of acquisition signal is greater than 100dB, the signal-to-noise ratio is up to 60dB, and the overall area of circuit is only 14cm × 14.8cm. Experiments show that the design meets the requirements of integration into the system.

• Periodical: Advanced Materials Research (Volumes 482-484)
• Pages: 975-980
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.482-484.975
• Online since: February 2012
• Authors: Yan Li Liu, Rui Zhang
• Keywords: AD630, Lock-in Amplifying (LIA), Phase Sensitive Detector, Weak Signal Detection

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