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if the PN measurements also use some kind of averaging of measurement points – thus somehow allowing for “timing instability” to appear in practice – even if the PN measurement looks fine?
We don’t believe, BTW the topic is enough complex, so it’s a little difficult to explain the working principle of the Timepod and other PN measurements tool operating in the same manner.
Just a quick explanation from a downloadable paper
“… high-speed, high-resolution analog-to-digital conversion (ADC) devices that sample the RF
reference and signal inputs, fast in-phase and quadrature digital down conversion, low pass filtration,
decimation and other digital signal processing, including the arctangent calculation of phase and FFT spectral
analysis, along with dual-channel cross-correlation to cancel internal noise.”
Good papers about phase noise measurement can be found at rubiola.org