CISPR22-compliant emissions testing

Schaffner EMC Ltd has developed a complete solution for fully CISPR22-compliant measurements based on its SCR3500 series of measuring receivers.

Schaffner EMC Ltd has developed a complete solution for fully CISPR22-compliant measurements based on its SCR3500 series of measuring receivers.

The latest revision of CISPR22 (EN55022) came into force on the 1st January 2001.

It contains a new requirement for designers and manufacturers of any equipment with a telecomms function to test all telecomms ports for RF emissions in the range 150kHz to 30MHz.

Because of the wide range of cables and connectors employed and the sensitivity of the equipment to changes in cable characteristics, several different test methods are defined by the standard, each with its own connection hardware.

The new CISPR22 solution includes both a capacitive voltage probe and a current sensing probe, which are ideal for site testing and commissioning of equipment.

But the workhorse is a newly developed impedance stabilisation network (ISN) which is used on single or dual symmetric wire pairs by applying a longitudinal conversion loss.

Three different sets of values across the frequency range are defined by the standard, and so each ISN comes with a set of adapter units designed to provide the three defined LCLs: 80/55, 60/35 and 50/25dB.

Sets are available for a range of different connector types, such as RJ11 and RJ45, and custom standards can be supported on request.

The ISNs are supplied fully calibrated complete with measured curves for LCL and common-mode impedance.

Also, as an added bonus, the ISN can be used as a fully compliant CDN for immunity testing of telecomms cables.

Launched last year, the SCR3500 receiver range comprises two models: the SCR3501 covering the frequency range from 9kHz to 1GHz, and the SCR3502 with an extended range from 9kHz to 2.75GHz to include mobile telephony and microwave heating applications in addition to covering a wider range for spurious emissions.

Back to top