Test Equipment: Oscillocopes

[TinselKoala]

TK,

Do you know if AUTO on Brian's TEK allows the scope to free run (display a trace) in the absence of a trigger (signal input)?

If so, he might be more comfortable using that mode instead of NORM.

PW

Yes, I believe it does.


Meanwhile, scoposcopy fans... check out Jerobeam Fenderson's website. Scroll down about half-way. See anything familiar?   

http://www.jerobeamfenderson.net/

[Brian516]

PW,
that's most definitely good to know.  I'll remember that for the next time I set up an audio system.

That's great! It's actually one of the best displays of that file I've seen! This is actually the first time I've been able to see the full  A T O M D E L T A letters so clearly, even if they are upside down (instead of sideways?)  You could try inverting CH2 and see if the letters show right-side up!

Clearly there is nothing wrong with the major sections of the scope: input and display. I doubt that there will be any issues with timebase or trigger either.

You've got the L and R channels going to the wrong scope channels is all, just swap them and you'll see the display rotate 90 degrees to conform to what is usually seen. But before you do that try inverting CH2 !

I will most definitely try both right after I get this post typed up and see if I can get them to display right side up!  If I can, I'll make another vid of it.  I can actually make it look even sharper if I run it without an audio output.  Seems I got a good scope! Must have been very well taken care of by the power company that had it for a while, and then when they got rid of it, it was rarely ever used at all from what I was told.

Brian, in the earlier video you are puzzled by the fact that at one point the scope still showed a horizontal line when you had no signal from the laptop going to it. Later on, the screen blanked when you had no signal. What was the scope control that you adjusted between those incidents? The scope's Trigger Level control. 
When it didn't blank, you had the trigger level set so precisely that it responded to the inevitable tiny noise left on the signal and showed you the baseline. Moving the control a tiny fraction either way would have caused the screen to blank. When you reset the trigger level later on, you didn't hit this exact setting, so when you turned off the signal from the soundcard the screen blanked as you expected it to. That all actually indicates _great_ trigger performance from a very sensitive trigger circuit.

Yep!  I realized that afterwards, and noticed that when the trigger is set in a certain range, it is EXTREMELY sensitive.  In that range, even lightly bumping the table, or setting something down will make it trigger.

TK,

Do you know if AUTO on Brian's TEK allows the scope to free run (display a trace) in the absence of a trigger (signal input)?

If so, he might be more comfortable using that mode instead of NORM.

PW

Yes, it most certainly does.  Isn't it a good idea to keep it on NORM and get used to adjusting the tigger level?  I'm sure there will also be some applications from time to time where I would want it on AUTO, so I will also set it on AUTO and repeat whatever process I had just done with it on NORM, that way I know what to expect with both.

Meanwhile, scoposcopy fans... check out Jerobeam Fenderson's website. Scroll down about half-way. See anything familiar?   

http://www.jerobeamfenderson.net/

It's allllmost my scope!  that's the B model, though. Wonder what the difference is other than the button setup... looks like it's got a few extra knobs as well.

[TinselKoala]

What I usually do is to use Auto to set up baselines (channel input coupling to Ground) and V/div settings (input coupling to DC or AC coupled) and trigger slope (rising or falling edge) , then once I know I can get the trace at the proper vertical scale, I switch to Normal and use the trigger level knob to get a triggered trace when the signal of interest is applied. Then when I'm not probing anything the screen blanks. When I apply the signal the screen wakes up and shows the trace.

[Brian516]

That's great! It's actually one of the best displays of that file I've seen! This is actually the first time I've been able to see the full  A T O M D E L T A letters so clearly, even if they are upside down (instead of sideways?)  You could try inverting CH2 and see if the letters show right-side up!

Clearly there is nothing wrong with the major sections of the scope: input and display. I doubt that there will be any issues with timebase or trigger either.

You've got the L and R channels going to the wrong scope channels is all, just swap them and you'll see the display rotate 90 degrees to conform to what is usually seen. But before you do that try inverting CH2 !

!!!!!!!!!!!!!!!!!!!!!!!     

https://www.youtube.com/watch?v=bOPaevLfGnc

I am downloading Ubuntu ISO for the desktop, and decided to do a search for Linux Oscilloscope and Function Generator, and found this:

http://www.filebuzz.com/findsoftware/Linux_Function_Generator_Sound_Card/1.html

click on the Oscilloscope and read the features of that!   Not bad for $25, and the multiInstrument version has everything for $50.  I may try and get that at some point if I'm able to get 2 input channels going via soundcard, and don't end up finding something similar for free. That's after I get some real hardware of course...

[Brian516]

What I usually do is to use Auto to set up baselines (channel input coupling to Ground) and V/div settings (input coupling to DC or AC coupled) and trigger slope (rising or falling edge) , then once I know I can get the trace at the proper vertical scale, I switch to Normal and use the trigger level knob to get a triggered trace when the signal of interest is applied. Then when I'm not probing anything the screen blanks. When I apply the signal the screen wakes up and shows the trace.

good stuff. I'll try to get in the habit of doing that.