I was googling for a formula to transform the dbc/Hz value given in data sheets for VNA, spectrum analyzers and VCO is often given in dBc/Hz with offset. Now looking up research papers about future oscillator devices based on new nanophysical effects, the physical oscillator is often measured with a spectrum analyzer and the linewidth (f/delta_f) is given)
Is there any calculable link between both measures to see how well such devices compare to state of the art oscillators? Only very seldom a dBc/Hz value is given in research papers, as the measure makes less sense without a given standard carrier frequency and offset. The linewidth is more a physical than a technical measure and makes different published devices better to compare. Is this reasoning correct or is it also that to define the dBc/Hz measure you need a very accurate spectrum analyzer while the linewidth can be deduced basically from a plotted graph?
Is there a way to transform the dBc/Hz of a standard VNA @ 100 MHz being around 110-120 to a linewidth. I need a value here or order of magnitude. I also read here, the dbc/Hz of a function/waveform generator is often better than that of a spectrum analyzer, so determining it this way is also no option?
Thanks for your advise and time