66
Broadband Powerline Communications Networks
in CISPR 22 had defined limits for the conducted and radiated emissions from ITEs and
served as the basis for the major national standards.
The second important standardization subcommittee of the IEC is the Technical Com-
mittee 77 (TC 77), also referred to as IEC TC 77 and it plays a complementary role to
the CISPR. It was created in 1973, to be responsible, together with other committees to
some extent, for Basic EMC standards that have general application and for Generic EMC
standards, in which the stated requirements can be fully or partially respected; [IEC01].
It also allows a systematic approach for classifying the EM phenomena. The study of
the EMS of electrical equipment and articulation of measurement methods, as well as the
compilation of recommendations and standards for this domain of EMC, has been the
specialty of IEC subcommittee TC 65.
Regional Organizations
In the United States, the Federal Communications Commission (FCC) is the governmental
agency that is responsible for the frequency planning and interference control. Most of
the time, the FCC is considered a regional organization rather than a national organiza-
tion. The FCC has regulations covering the limitation of emissions from a wide range
of products; among these the FCC Part 15 standards are applied to all digital equipment.
These FCC regulations impose two different emission limits, measured at different dis-
tances from the device. The applicable limit depends on the environment in which the
equipment will operate. Class A equipment is designed for use in commercial or indus-
trial applications. Class B defines limits to be applied to equipment for use at home or in
residential premises. The FCC does not specify the shielding effectiveness but regulates
the EM emissions for both classes A and B. For each class, FCC defines the limits of
the radiated field strength in the spectrum 30 MHz to 1 GHz and the voltage limit of the
conducted disturbances in the frequency band 450 kHz to 30 MHz.
In Europe and in the framework of the "Comit´e de Coordination Europ´een des Normes
Electriques pour le March´e Commun" (CENELCOM), or European coordination com-
mittee of electrical standards in the European Common Market, a decision was taken
to establish a Common Standardization Committee for creating a standard for electri-
cal equipment emission limits. The Common Standardization Committee was founded
in 1970 and immediately linked itself with representatives of electrical energy suppli-
ers and electrical household appliances manufacturers. The Common European Market
was enlarged in 1973 and with it CENELCOM was reorganized under the name CEN-
ELEC, for "Comit´e Europ´een de Normalization Electrotechnique", or European electrical
standardization committee. There are series of European EMC standards for various
types of specific equipment, such as information technology, but there are also gen-
eral emission (EN 50081) and immunity standards, which apply in the absence of specific
standards; [Moly97].
National Regulators
The Radiocommunications Agency is an Executive Agency of the UK's Department of
Trade and Industry. It is responsible for the management of the nonmilitary radio spectrum in
the United Kingdom, which involves international representation, commissioning research,
allocating spectrum and licensing its use, and keeping the radio spectrum clean; [Stro01].
In Germany and after the liberalization of the postal and telecommunications markets, the