Development of a High-Performance Data Acquisition and Processing System Based on System-on-Module and Field-Programmable Gate Array for Portable and Embeddable Optical Instruments

Highly integrated data acquisition and processing (DAQP) systems play an important role in promoting the miniaturization of high-performance optical instruments. Currently, such systems are mainly based on digital signal processors or advanced reduced instruction-set compute machines, which have the advantages of low-power consumption and embedded integration, but still face certain limitations in processor performance, interface capacity, and edge computing capabilities. In this work, we report the development of a novel DAQP system based on a system-on-module and field-programmable gate array architecture, which combines the functionalities of signal generation, high-speed data acquisition, and lock-in amplifier (LIA). It had two signal generation channels with a maximum output frequency of 125 million samples/s, four signal acquisition channels with a maximum sampling rate of 65 million samples/s, and a four-channel digital LIA (DLIA) with a demodulation frequency range from dc to 5 MHz. By using the exponential moving average (EMA) filtering algorithm in DLIA, the compilation resource consumption of the filter was reduced. When the modulation frequency was set to 20 kHz and the input voltage range was set to ±1 V, the measured input-referred noise of the DLIA was about 39 nV/ $\surd $ Hz. In order to verify the high-speed acquisition and modulation demodulation functions of the DAQP system, it was applied to amplitude modulation cavity-enhanced absorption spectroscopy, achieving portable and high-precision NO2 measurements and providing an effective means for the miniaturization of optical instruments.