The electromagnetic radiation will result in information leakage being recovered when computers work. This article presents a high-speed real-time data acquisition system based on peripheral component interconnect (PCI) bus and field programmable gate array (FPGA) for sampling electromagnetic radiation caused by video signal. The hardware design and controlling flow of each module are introduced in detail. The sampling rate can reach 64 Msps and system transfers speed can be up to 128 Mb/s by using time interleaving, which increases the overall sampling speed of a system by operating two data converters in parallel.