An EMI measurement system based on near-field grid scanning

At present, most of the electromagnetic interference (EMI) test systems describe radiation with a spectrogram of a single point. This paper proposed a grid scan algorithm to help system give a colourful spatial distribution of spectrum. On the LabWindows/CVI platform, an EMI detecting system, combined with near-field probes, spectrum analyzer, USB-GPIB, USB-DAQ and PC, is integrated. Using the VISA (Virtual Instrumentation Software Architecture), the system accomplished the instrument control. NI-DAQmx and related corrections help system realize the data acquisition. The experimental results show that the system can give a fine spectrogram of a high accuracy, and a spatial distribution graph which can reflect the radiation vividly. It is proved that the system has a practical and popularization value, especially in the EMI detection of act equipment.