SELT (Single Ended) and DELT (Double Ended) measurements are functionalities defined in the ITU standards. Sophisticated algorithms and Spectrum Analysis based on the signal levels in each bin are providing more detailed information on the line and the presence of noise which is possible with the latest generation of DSL chipsets. However this approach is not adequate for measuring noise like REIN (Repetitive Electrical Impulse Noises) and other equivalent disturbers that have become a major concern of the Service Providers because of the dramatic effect on services like IPTV and Gaming.
Noise is a permanent headache for the Service Provider who wants to deliver a consistently high level of quality at best possible data rate. Sparnex Instruments added functionality to the ICXACT to allow for spectrum measurement of these types of signals with an Impairement Sampler™ that is configurable for amplitude, duration and frequency. 24 hour tests on existing lines with high impedance probes permits for chasing specific noises on the wireline even when they are not present very often.
Special Noise Finder™ software will screen the measured data for the type of noise masks that are programmed, and will give an accurate picture of the noise present on the subscriber line under test during and after a measurement campaign. If the laboratory is equipped with the ANG product range and the Noise Creation™ software as well as the Noise Import™ software it is possible to regenerate these noises for DSL modem, DSLAM and chipset performance test purposes.
Check also the ICXACT for more information.