Measurement and testing method for large telecommunications systems

Large telecommunication systems are assembled from independently operating sub-units and no two systems are identical. Each sub-unit has its own characteristic emission signature; these sub-units are coupled together with a multitude of differing cable types (screened and unscreened), and the whole system has an emission characteristic occupying a very wide frequency spectrum. Limitations within existing standards have been recognised and to cover the measurement of emissions from physically large telecommunication systems a draft standard has been developed. This draft has been accepted by European standards organisations as a proposed methodology for the testing of large telecommunication systems. Particular reference is made to the experience and preliminary results gained during the testing of a large telecommunications digital switching system on an open field site and measurements made in a shielded semianechoic chamber