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GW Instek AFG-2225 vs Rigol DG4102

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jpb:

--- Quote from: JuanPC on June 12, 2013, 12:03:13 am ---True Bandwidth is determined by RiseTimes, a faster rise time means true Higher Bandwidth,
for example Agilent has maximum 30Mhz, but a Rise Time of 8.4ns,
but Rigol DG4162 160Mhz also has a <8ns RiseTime, usually a true 150Mhz scope has <2.3ns RiseTimes, at 100MHz has <3.5ns, 350MHz 1ns, 500MHz 700ps, or 0.7ns, that means to see a 40ps Jitter is impossible with a 500MHz scope.

--- End quote ---
Whether or not you can see 40psecs of jitter on a 500MHz scope I would have thought was dependent on the trigger jitter and timebase accuracy rather than the scope rise time. For example, my scope is only 350MHz BW with 1nsec rise time but in equivalent time sampling mode it goes up to 100GS/s which implies that it can place time points within 10 psecs. For a 500MHz scope the fastest timebase is 500ps/div and each division is 50 pixels so each pixel is 10psecs. 40psecs of jitter would mean that the line would be thickened to around 4 pixels which should be visible. It wouldn't be a very accurate measurement of course!

JuanPC:

--- Quote from: jpb on August 01, 2013, 01:48:55 pm ---
--- Quote from: JuanPC on June 12, 2013, 12:03:13 am ---True Bandwidth is determined by RiseTimes, a faster rise time means true Higher Bandwidth,
for example Agilent has maximum 30Mhz, but a Rise Time of 8.4ns,
but Rigol DG4162 160Mhz also has a <8ns RiseTime, usually a true 150Mhz scope has <2.3ns RiseTimes, at 100MHz has <3.5ns, 350MHz 1ns, 500MHz 700ps, or 0.7ns, that means to see a 40ps Jitter is impossible with a 500MHz scope.

--- End quote ---
Whether or not you can see 40psecs of jitter on a 500MHz scope I would have thought was dependent on the trigger jitter and timebase accuracy rather than the scope rise time. For example, my scope is only 350MHz BW with 1nsec rise time but in equivalent time sampling mode it goes up to 100GS/s which implies that it can place time points within 10 psecs. For a 500MHz scope the fastest timebase is 500ps/div and each division is 50 pixels so each pixel is 10psecs. 40psecs of jitter would mean that the line would be thickened to around 4 pixels which should be visible. It wouldn't be a very accurate measurement of course!

--- End quote ---

It's imposible to explain all in 3 lines, but Yes, in DSO the Sampling also does affect, 5GSa/s RealTime has 200ps per division, if designed properly.
40ps It's also imposible to see with a 5GSa/s RT scope.
Equivalent Sampling mode is like Image interpolation....
If i have a 320x240 pixel image and upsample to 4k, is not the same as if taken at 4k, or more and downsample.
Equivalent Sampling is good if the Real Time is good.
But also wfm/s affect.
100GS/s EquivalentSampling is useless if RealTime is 500MS/s or less, for jitter measurements.

I had a 1GS/s RT 100Mhz scope with 25GS/s ES and to see 700ps from my soundcard s/pdif was imposiblle, infinite persistance and all.
The funny thing is, if loudspeakers are good enough most people can hear 700ps very easy when compared to another more stable clock,.

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