Evaluation and Improvement of the Reproducibility of CISPR 25 ALSE Test Method

The reproducibility of the Absorber Lined Shielded Enclosure (ALSE) radiated emission test method, defined in the standard CISPR 25, is evaluated through an interlaboratory comparison (ILC). The ILC started on September 2016 and concluded on February 2017. Nineteen data sets have been received and analyzed. The investigated frequency range is from 1 MHz to 1000 MHz. The most critical (worst reproducibility) frequency range is the one from 10 MHz to 50 MHz where the robust (outlier-resistant) standard deviation of the measured values is comprised between 5 dB and 8 dB. In the frequency range from 50 MHz to 1000 MHz the robust standard deviation is comprised between 2 dB and 3 dB. The main causes of non-reproducibility are identified and test setup adjustments aimed at improving the reproducibility are proposed.