how accurate are those 8.5 digit meters at 1MHz? I thought they were pretty much built for DC.
You might be interested in the 6.5 digit thermal RMS meter that HP made a while back. I don't know if it went up to 1MHz though.
Maybe you want to use a voltage divider connected to a thermal converter? 500ppm is 0.05 percent.
8.5 digit meter:
thermal converter:
Now, the tempco of the thermal converter is horrid, and the input impedance is 50ohm, but you have something better then 100ppm accuracy at 1MHz if the graph is to be trusted, with a 40V input max, while If I am reading correctly the 8.5 digit meter is only accurate to 1.5% at 1MHz, so 1500ppm?
maybe check spectral content first using a SA to see what kinda spread you got on the frequencies/crest then if its tonal you can trust the RMS converter as not averaging a buncha garbage.. oscilloscope wont provide enough resolution for you requirement, and probably wont detect the distortion that will effect your measurement right? But the thermal meter will just take everything into account, so you would need to filter it, but idk... and the thermal imposes its own time constant on the measurement, you would need to figure out the ramifications of this. I think you would need a 1MHz distortion meter to trust anything, the spectrum analyzer would just basically be useful to tell you that something is really wrong.. I think.. if you wanted 500ppm, I did not think about this that much though
but then you have to play thermal offset games at 2000ppm/degree C, so you need to calculate dissipation and prob calibrate out for temperature.............
and no idea on the HV side of shit
I consider an analog scope accurate to like 4%, digital maybe 2%? Are they better then that?
https://www.keysight.com/main/editorial.jspx?cc=US&lc=eng&ckey=806222&nid=-32453.753266&id=806222Not really, its 1.5 percent best bet, but its a scope, so I would multiply that times 1.5 since its not designed by voltnuts, plus it tells you nothing about the spread that might result from distortion along the frequency axis, its probably fairly linear if they can boast 1.5 though, but that's still pretty much killing your 500ppm, but your not getting anything more using a 8.5 digit meter vs a scope, unless your measuring the DC output of a thermal converter.. infact its less useful because you don't have any frequency data, can't see glitches and it requires alot of averaging,
8.5 digit meter offers a bit a piece of mind though in terms of how stable its gonna be compared to some lab scope that can be used for anything really
sounds like a pain in the ass measurement