Hi, Thanks to all the posters for the good examples and info. There are lots of questions that could be asked about what constitutes a "strong" square wave (I think "strong" is probably NOT an official technical term
). (And certainly, one set of questions revolves around the ability to generate and render excellent rise times but I'll leave that for another post.)
I realize that there are many setup variables that can contribute to how waveforms render (generator equipment, cabling, termination impedance, scope capabilities, etc, etc.). My questions here are somewhat less about the equipment and setup - and more about how to read/interpret what is displayed.
Below are two examples: one from a Rigol DG1032Z and one from a Rigol DG1062Z - presumably similar other than bandwidth. Admittedly, they are each hooked to different scopes (the 1032 to a Rigol DS2022A and the 1062 to a LeCroy 7300A) and likely with different cables. Additionally, I could be wrong but I think the 1032 was probably terminated into 1 Mohm on the Rigol vs. 50 ohms on the LeCroy. (The bandwidth on a Rigol 2202 is typically 200MHz and I think it's 3GHz (with 20GSa/s!) on the LeCroy 7300 - big difference and probably there is a healthy difference in price too.)
Given all that my questions are about the level of detail seen on the two images. In particular, the images from the 1032 on the 2202 are pretty distinct (sharply detailed?). They show a pretty defined ringing at the tops and bottoms. The images from the 1062 on the 7300 don't seem to convey the ringing as distinctly. Perhaps there is less ringing shown on the 1062/7300 because of 1) the 50 ohm termination? (doubtful but maybe?), 2) the extra bandwidth of the 1062 vs. the 1032? (doubtful but maybe?), 3) better cabling?, or 4) the extra bandwidth and sampling of the 7300? (I don't know the specs on the display resolution - maybe that's better too on the 7300 but I'm betting it's the outstanding bandwidth and sampling of the 7300 that we are seeing), or 5) maybe it's something else? On a related observation, the tops and bottoms of the 1062/7300 combination appear much thicker than the tops and bottoms of the 1032/2202. Perhaps this is due to the ability of the 7300 to process and resolve (and ultimately display) noise more accurately beyond what the 2202 can resolve and display. Interestingly, the thicker tops and bottoms on the 7300 seem to be of an amplitude roughly similar to the ringing that is seen on the 2202. Perhaps that is why the ringing is not so evident on the 7300 (ie, the ringing is hidden in the noise)?
Net, net: which setup (the 1032/2022 or the 1062/7300) most accurately represents the phenomenon occurring? Is the waveform on 1032/2022 setup cleaner/more defined/more accurate or is it missing information that is being revealed by the 1062/7300 setup? I'm betting the difference is that the 2022 simply can't render the information as accurately as the 7300 but I'm curious to know...
Thanks, EF
PS, one other observation: the Rigol seems to use square divisions and the LeCroy uses rectangular divisions - a bit off topic but an observation...