EMI filters in wireless applications

摘要

Successfully passing the electromagnetic interference (EMI) tests required by organizations such as the U.S. FCC usually requires the correct usage of EMI filters, key elements for meeting noise immunity, and generated-radiation levels. Cell phones and wireless LANs using protocols such as GSM phone bands (800-, 900-, and 1,900-MHz range) and Bluetooth and wireless LAN 802.11b (2.4 GHz) can radiate excessive EMI from cables connected to accessory ports as well as receiving unwanted RF through those same ports.