AES E-Library

AES E-Library

New Understandings of the Use of Ferrites in the Prevention and Suppression of RF Interference to Audio Systems

Document Thumbnail

Building on the work of Muncy, [1] the author has shown that radio-frequency current on cable shields is often coupled to audio systems by two mechanisms – “the pin 1 problem” and shield-current-induced noise (SCIN). [2, 3, 4, 5] An improved equivalent circuit for a ferrite choke is developed that addresses both dimensional resonance within ferrites and the self resonance of inductors formed using those materials, then compared with measured data. Field tests show that chokes formed by passing signal cables through ferrite cores can significantly reduce current-coupled interference over the range of 500 kHz to 1,000 MHz. Guidelines are presented for diagnosing the causes of EMI from sources as diverse as AM broadcast transmitters and cell phones. Solutions are presented for use in new products and for RFI suppression in field installations.

AES Convention: Paper Number:
Publication Date:

Click to purchase paper as a non-member or login as an AES member. If your company or school subscribes to the E-Library then switch to the institutional version. If you are not an AES member and would like to subscribe to the E-Library then Join the AES!

This paper costs $33 for non-members and is free for AES members and E-Library subscribers.

Learn more about the AES E-Library

E-Library Location:

Start a discussion about this paper!

AES - Audio Engineering Society