by Bart Caswell
In 2013 and 2014, the U.S. Army Primary Standards Laboratory piloted a six-laboratory intercomparison (ILC) of phase noise measurements using a Fluke 9640A-LPN signal generator as the test article. The article was tested at 0.5 GHz, 1 GHz, and 4 GHz at offset frequencies of 10 Hz, 100 Hz, 1 kHz, 10 kHz, 100 kHz, 1 MHz, and 10 MHz. The National Institute of Standards and Technology (NIST) provided the phase noise measurements to which the measurements of the other participating laboratories were compared. The only issue encountered during the ILC was a small spur at 1 GHz and 10 MHz offset. Since it only affected one lab and the spur’s effect was known, it was still included in the results. Only one laboratory had one averaged reading with a normalized error greater than one.