Standards
EU standard 55022
(CISPR22)
As/NZ standard 3548
Limits and methods of measurement of radio interference characteristics of information technology equipment.
Procedures are given for the measurement of the levels of spurious signals generated by the ITE and limits are specified for the frequency range 0.15 MHz to 1 000 MHz for both Class A and Class B equipment.
ITE equipment is equipment designed for the purpose of:
(a) receiving data from an external source;
(b) performing some processing functions on the received data (such as computation, data transformation, filing, sorting, storage, transfer of data);
(c) providing a data output (either to other equipment or by the reproduction of data or images).
Classification:
Class A equipment is ITE which satisfies the class A interference limits but does not satisfy the class B limits. Class A equipment may be used in commercial and industrial establishments, but not in domestic establishments or in residential areas.
Class B equipment is generally not subject to restrictions on use and may be used in domestic establishments.
Radiated:
Requires the use of a broadband antenna to measure the level of RF energy radiated from the product into ‘space’. Ideally an Open Area Test Site (OATS) or equivalent should be used. Uncalibrated test sites will require the use of an ERS to quantify test site distortion. Frequency range 30MHz to 1000MHz.
Conducted:
The RF conducted back down the mains lead is measured preferably with a LISN (Line Impedance Stabilisation Network), or alternatively with a voltage probe if a LISN is not suitable, and from other terminals with a voltage probe. Frequency range 150KHz to 30MHz.
The signals from the antenna, LISN or voltage probe are all analysed in a CISPR16 EMC analyser.
A comprehensive range of alternative LISNs for up to 150A rating and 3 phases are available. If applicable, a voltage probe can be supplied in place of the LISN. ...RFG-5BC
Recommended option: RF910 pre-selector. Essential if the EUT generates broadband noise (e.g. variable speed motors, motors with commutators, power controllers, phase angle controllers) ...add -R
RF200 broadband antenna
ERS
LISN
Voltage probe (PLIP)
RF910 automatic pre-selector
RF800 Band B filter
Note The above is for guidance only. Refer to the published standard for definitive details, exclusions and exceptions and detailed test technique.
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LAPLACE INSTRUMENTS LTD |
Tel: + 44 (0)1263 515160 Fax: + 44 (0)1263 512532 E-mail:tech@laplace.co.uk |
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