We usually adopt DSP and ARM to perform signal collection and processing. However, functions of DSP and ARM largely depend on the software. Parameter modulation of the software must account for sampling time partly. Moreover, software can not control complex peripheral logic circuit very well. The above problems render DSP and ARM containing big flaws in high-speed data collection and processing. Field-programmable Gate Array (FPGA) possesses the characteristics of timeliness, controllability and rapid processing speed. The paper designed a new circuit based on FPGA to obtain high-speed signal, and utilized FFT IP core in FPGA to perform spectral analysis with the help of digital signals from the circuit. The paper introduced the design based on FPGA and verified that it possesses good performance according to actual experiments.