Root cause is the conductor of electromagnetic interference voltages or currents of change, namely, greater DV/DT or di/dt.DV/DT, or di/dt to the conductor to produce electromagnetic radiation. On one hand, you can take advantage of this feature to implement a specific functionality, such as wireless communications, radar and other features, on the other hand, electronic equipment while at work, the conductor of the DV/DT or di/dt will produce associated with electromagnetic radiation. Both subjective and for what purpose, and objective of electromagnetic pollution on the environment. There are factories and enterprises in the production process will often have some large equipment (motors, inverters) frequent switching, they also may cause capacitive, inductive interference, will also affect the normal display or acquisition instrumentation. All occasions with mutations of voltage and current, and certainly the presence of electromagnetic interference. Digital pulse circuit is a typical interference sources, along with the wide use of electronic technology, electromagnetic pollution will become more and more serious.