What is EMI/EMC?
EMI/EMC is the acronym of ElectroMagnetic
Its concern is the ability of electronic equipment to work
satisfactorily in the electromagnetic environment (immunity)
without introducing intolerable electromagnetic interference
to that environment (emission).
Computer screen distortion caused by your
cellular phone, cross-talk between phone lines, and electrostatic
discharge (ESD) are some examples of EMI problems.
EMC is concerned with the generation, transmission
and reception of electromagnetic energy. These three aspects
of the EMC problem form the basic framework of any EMC design.
A source (also referred to as an emitter) produces the emission,
and a transfer or coupling path transfers the emission energy
to a receptor (receiver), where it is processed, resulting
in either desired or undesired behavior. Interference occurs
if the received energy causes the receptor to behave in an
Importance of EMC
EMC has become increasingly important recently
because of its wide ranging industrial and more general societal
(for instance medical) implications. Meeting EMC standards
is a basic requirement for any electrical and electronical
device before placement on the market. EMC problems are thus
main concerns of the telecommunication, electronics, automobile
There are four types of EMC test: radiated
emission, radiated immunity, conducted emisssion and conducted
The radiated emission test system includes
equipment under test (EUT), an antenna and the signal analysis
device. The induced voltage from antenna is measured and the
data is used to calculate the field strength by antenna factor.
An immunity test, requires an electromagnetic
source to generate the desired environment. This source is
linked to the EUT either by radiated or by conducted method.
Additionally, a monitor is required to know if the EUT is