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Solving the EMI Problem for Audio Sub-Section in Small Boxes

IP.com Disclosure Number: IPCOM000123924D
Original Publication Date: 1999-Jul-01
Included in the Prior Art Database: 2005-Apr-05
Document File: 1 page(s) / 25K

Publishing Venue

IBM

Related People

Gupta, S: AUTHOR

Abstract

Disclosed is a method for Solving the EMI problem for Audio sub-section in Small Boxes. In small boxes like a Network computer box, Audio becomes a large source of EMI and difficult to solve. Grounding is very critical in audio sub-section for Audio quality. So in the large boxes this problem is not very severe. In a large box it is possible to connect the audio ground to the digital ground through a filter (sometimes just a short) and keep it isolated from the chassis ground without having much EMI problems. In the small boxes keeping chassis ground isolated from the Audio ground makes EMI a big problem. This invention solves this problem with very small cost.

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Solving the EMI Problem for Audio Sub-Section in Small Boxes

   Disclosed is a method for Solving the EMI problem for
Audio sub-section in Small Boxes.  In small boxes like a Network
computer box, Audio becomes a large source of EMI and difficult to
solve.  Grounding is very critical in audio sub-section for Audio
quality.  So in the large boxes this problem is not very severe.  In
a large box it is possible to connect the audio ground to the digital
ground through a filter (sometimes just a short) and keep it isolated
from the chassis ground without having much EMI problems.  In the
small boxes keeping chassis ground isolated from the Audio ground
makes EMI a big problem.  This invention solves this problem with
very small cost.

   In case of a small box, isolate the audio ground from
the digital ground and connect it to Chassis ground through a
filter.  This filter design depends on the nature of the box.  In
general a ferite in series with a capacitor works fine.  By doing
this, ground loops are avoided, and it improves audio quality, and at
the same time connect the chassis ground to the audio ground through
the filter to solve the EMI problems.