0000000000512337
AUTHOR
Yannick Gruson
Cross-Spectrum PM Noise Measurement, Thermal Energy, and Metamaterial Filters.
International audience; Virtually all commercial instruments for the measurement of the oscillator PM noise make use of the crossspectrum method (arXiv:1004.5539 [physics.ins-det], 2010). High sensitivity is achieved by correlation and averaging on two equal channels, which measure the same input, and reject the background of the instrument.We show that a systematic error is always present if the thermal energy of the input power splitter is not accounted for. Such error can result in noise underestimation up to a few decibels in the lowest-noise quartz oscillators, and in an invalid measurement in the case of cryogenic oscillators. As another alarming fact, the presence of metamaterial com…
Artifacts and Errors in Cross-Spectrum Phase Noise Measurements : Invited lecture
Inserting an attenuator between the oscillator under test and the phase noise analyzer, one expects that the white phase noise increases monotonically with the attenuation. By contrast, we observe that with some oscillators the white noise has sharp minimum for a given value of the attenuation, which clearly indicates problem. With other oscillators, it increases monotonically with the attenuation, but the values are not consistent with the thermal energy introduced by the attenuator. In both cases artifacts are present, which takes the form of a sharp notch in the spectrum, occurring where the white FM noise crosses the white PM noise. Such anomalous behavior is the tip of the iceberg, and…