Research On MEMS-based Portable FTIR Acquisition System

In order to meet the need for fast,portable and efficient drug safety testing,a new FTIR portable spectrometer with high speed and portability,low latency and high accuracy is designed in this project.It meets the need for a real-time online portable spectrometer.The MEMS-based portable FTIR spectrometer designed in this project consists of an optical interferometer,an ADC acquisition backplane,and is equipped with the ZYNQ platform as the core processor.The main research of the thesis is carried out in three modules:Based on the prototype Michelson interferometer,a modified dual optical interferometer is built for this project.The interferometer light source consists of reference light and sample light,and a common MEMS micromirror is used to achieve simultaneous changes in the dual interference signals,and furthermore,simultaneous interference data are detected at the interferometer detector.The hardware requirements of the MEMS portable spectrometer are analysed,and the spectrometer hardware base board is drawn and machined and soldered using Altium.The DAC driver and amplifier circuit was designed to realise digital-toanalogue conversion and amplification,and to complete the low-frequency homogeneous driving of the MEMS micro-mirror;the ADC acquisition circuit was designed to carry out dual simultaneous acquisition of the sample light and the reference light,and to carry out the same signal processing for the two interfering lights to improve the SNR.The interferometric signal is processed in multiple stages according to the direction of the signal data stream,including I/V conversion,bandpass filtering,differential amplification and analogue-to-digital conversion.The acquired signal is finally sent to ZYNQ's EXIO.Combined with the development needs of the MEMS spectrometer,the ZYNQ-7000 of the ZYNQ platform is used to complete the logic control of the DAC and ADC of the spectrometer,to realise the MEMS micromirror drive and interferometric light acquisition,while for the acquired spectral data,certain data processing——de-DC,toe-cutting,FFT-is performed using the parallel high-speed advantage of the PL(FPGA)side.A custom IP was packaged with the spectrometer logic and loaded into the Block module together with Vivado's own IP,and the AXI protocol was used for high-speed interaction with the PS side.Finally,the whole system was debugged and sample tested to verify the functional requirements of the MEMS-based portable FTIR spectrometer designed in this project.The final realisation of the fast FTIR spectrometer reached a theoretical maximum resolution of 0.06cm-1 with a sampling accuracy of 16 bits and a sampling rate of 300 K.