Browse Prior Art Database

Dual-In-Line Ferrite Attenuator Assembly

IP.com Disclosure Number: IPCOM000060430D
Original Publication Date: 1986-Apr-01
Included in the Prior Art Database: 2005-Mar-08
Document File: 2 page(s) / 52K

Publishing Venue

IBM

Related People

Newell, DC: AUTHOR

Abstract

This article describes a modularized packaging of ferrite attenuation components for insertion on printed circuit cards and/or boards as a deterrent to external leakage of high frequency components of 30-300 MHz. Existing personal computers have crystals and oscillators that radiate harmonic frequencies. When an output cable is attached to a printed circuit card and then connected to an external unit, these frequencies will radiate causing special connectors or other devices to be attached to the cable or connector to prevent escapement of these frequencies. In order to suppress EMC (electromagnetic compatibility) emissions, several techniques are available to designers. Some choose to install a ferrite bead within a cable to suppress emissions. Other designers install other protective means.

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Dual-In-Line Ferrite Attenuator Assembly

This article describes a modularized packaging of ferrite attenuation components for insertion on printed circuit cards and/or boards as a deterrent to external leakage of high frequency components of 30-300 MHz. Existing personal computers have crystals and oscillators that radiate harmonic frequencies. When an output cable is attached to a printed circuit card and then connected to an external unit, these frequencies will radiate causing special connectors or other devices to be attached to the cable or connector to prevent escapement of these frequencies. In order to suppress EMC (electromagnetic compatibility) emissions, several techniques are available to designers. Some choose to install a ferrite bead within a cable to suppress emissions. Other designers install other protective means. In the packaging disclosed herein, the specific ferrite beads were selected to provide the maximum attenuation at frequencies of concern to FCC class B environments. The package provides ten lines of input/output attenuation easily installed on future printed circuit boards eliminating special connectors and allowing any style connector to be used, e.g., phone jacks. The ferrite bead assembly is illustrated in the drawings. Fig. 1 shows an upper plastic enclosure, and Fig. 2 shows the lower plastic pre-drilled frame of the compression bit heat seal assembly. Five ferrite beads have two wires threaded through pre-drilled holes in the b...