Test Equipment: Oscillocopes

[TinselKoala]

Hmmm.... The "two lines" figure from MarkE looks to me like a little bit of phase difference in the two signals. At least that is what two signals with a slight bit of phase difference _should_ look like. But I agree, in a perfect world two perfectly in-phase and perfectly symmetrical square waves should produce two dots with a dim line connecting them or no line at all. A pair of in-phase sine wave signals will produce a more definite diagonal line. I think that the two lines that build up in MarkE's infinite persistence figure may indicate a slight bit of phase jitter or noise, possibly in the scope itself since the signals are coming from the same source, or an imperfection in the square wave signal.

My video demonstration using sine wave signals is here:

http://www.youtube.com/watch?v=mV1IHnIHaC8

[MarkE]

It is a slight asymmetry in the frequency response of the amplifiers.  The driving signal has a rise time that is faster than either amplifier can track.    If I drive with a signal that doesn't have such fast rise times, then I get the expected diagonal line seen below.

[TinselKoala]

Heh.... here are a couple of soundfiles to look at using X-Y mode....

http://frozenhaxor.pl/pliki/youscope.wav
http://frozenhaxor.pl/pliki/oscillofun.flac

Found these on a video demo here:
https://www.youtube.com/watch?v=3U7I3if3TtM

They display quite well on my Tek 2213a!

[Brian516]

So everything is looking pretty good so far. I'm not getting the diagonal line off the calibrator, but when I set it up off the calibrator with both traces overlapping, about 3 cycles on screen, and then switch to XY, I get two dots at very close to 45 degrees in the proper direction. When I invert Channel 2, it inverts the diagonal properly. See the pictures below.
I ran the same test using the two original Tek probes I have (the 6062A I rebuilt, and the 6065A that the scope came with) and the 6065A is acting up a little. I'd like to be able to use it with the 6062A when I need a pair of high quality probes, so if it's something fixable I'd like to try and fix it. I made a vid of the calibrator sq wave to X-Y with those probes and showed what the issue is with the probe.  If it's too much of a pain to remedy I'll just set it aside for some other time.

I'm about to run both pairs of probes using the sine wave to make sure I get the actual line, play with the phase settings, and then check out the links that TK posted and have a little fun with it.
I got a little carried away getting my mini-lab set up or I'd have already done all this testing. But hey, at least I'm about ready to populate it, run a 110V dedicated line to it (all that I have there for now is an old ungrounded outlet!!) and set up some lighting..

http://i1081.photobucket.com/albums/j347/Brian_Bloom/CAM00224x_zpsmipym7fq.jpg
http://i1081.photobucket.com/albums/j347/Brian_Bloom/CAM00222x_zpsfa467i5m.jpg
http://i1081.photobucket.com/albums/j347/Brian_Bloom/CAM00223x_zpsvwlcd5pg.jpg

Vid should be done uploading shortly:
https://www.youtube.com/watch?v=msbXPU_l_aw

[Brian516]

How are you able to upload a pic to the OU server as an attachment and it show up as a link instead of the picture?   I guess my method works fine, but I'd still like to know. Is it just the type of file you are attaching? Is it that if it's not a jpg  or gif file, it displays as a link?
I mean, I like not having to click on a link and all that to see a picture, but in these forums it's better to have links instead of the pic, especially if there are multiple. Saves from having to load page after page just to go a few posts back or forward.

Brian