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ElectroMagnetic Interfernce Conducted Noise Mode Analysis Simplified and Auto System

IP.com Disclosure Number: IPCOM000113475D
Original Publication Date: 1994-Aug-01
Included in the Prior Art Database: 2005-Mar-27
Document File: 2 page(s) / 50K

Publishing Venue

IBM

Related People

Fujio, S: AUTHOR [+2]

Abstract

The present invention relates to an simplified but useful tool for ElectroMagnetic Interference (EMI) conducted noise mode analysis. The tool concerned with the invention comprises conventional instruments, and means for adding or subtracting noise voltage by utilizing mutual coupling with looped wires. It can divide noise into common and normal mode parts simultaneously.

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ElectroMagnetic Interfernce Conducted Noise Mode Analysis Simplified
and Auto System

      The present invention relates to an simplified but useful tool
for ElectroMagnetic Interference (EMI) conducted noise mode analysis.
The tool concerned with the invention comprises conventional
instruments, and means for adding or subtracting noise voltage by
utilizing mutual coupling with looped wires.  It can divide noise
into common and normal mode parts simultaneously.

      Fig. 1 shows a block diagram of typical conducted noise
measuring system.  Computer system (1) to be tested is connected to
the power (3) through line impedance stabilization network (2) which
extracts the noise on line (Va) and neutral (Vb) power line.  To
divide noise into common and normal mode, four current probes are
coupled with two looped wires (8) as depicted in Fig. 2.  Two of the
current probes (4),(6) are to inject the noise (Va), (Vb) onto the
looped wire (8).  Other two of them (5), (7) are to pick up noise
from the wire.  One of the looped wire is routed to add the injected
noise to obtain the common mode part (Vc), and the other is routed to
subtract them to obtain the normal mode part (Vn).

      As this tool can output the two mode of noise simultaneously
without using any switches, it is suitable to apply it to
automatically measuring and analyzing system.