A design of multi-frequency and multi-channel weak signal data acquisition system based on DSP and FPGA

In order to extract the multi-frequency weak logging signal at µ V level from the strong background noise, a multi-frequency and multi-channel weak signal data acquisition system based on digital signal processor(DSP) and field programmable gate array(FPGA) is presented. The system took Analog Device's Digital Signal Processor ADSP21992 as a core and Actel's FPGA as a interface chip and realized the real-time acquisition of the multi-frequency and multi-channel weak signal by designing the low-noise pre-amplifier and filer circuits, the analog to digital circuits and the peripheral interface circuits communicating via control area network(CAN) bus. Experimental results show the system can well extract the multi-frequency weak signal about 4 µ V from the strong background noise as well as ensure the high-speed synchronous sample of wide band signal, raising sample efficiency and data reliability.