A field programmable gate array-based ultrasonic spectrometer

This paper describes a novel architecture for a low-voltage ultrasonic data acquisition system intended for process monitoring of liquid chemicals in an industrial context. The system is appropriate for operations in hazardous environments where limits are imposed on the working voltage levels of equipment, due to potential fire or explosion hazards. High SNRs in the captured signal records were achieved using 1 V Golay complementary sequences combined with cross-correlation for signal detection, all of which were implemented on a single-field programmable gate array chip. The system has an operating bandwidth of 40 MHz and a dynamic range at the receiver of 2 Vp-p with a resolution of 14 bits. Theoretical and practical design criteria are examined to optimize received signal SNR and data acquisition rate whilst minimizing hardware complexity. The system was implemented using a reconfigurable hardware platform of relatively low cost, providing a basis for developing more powerful and robust systems in future. Experiments show that the performance of the system is equivalent to that of a conventional high-voltage pulse-transmission system.