Good Cheap (or Free) PC oscilloscope program?

[Analog]

Was wondering what those of you use. I have a young learner that can't afford a scope, and I thought he could use a PC oscilloscope program as an introductory way to look at waveforms in the time domain. If you have any experience with such, please post. He wants to first just look at his guitar pickups on a scope, so is there one that maybe uses the mic input on a PC as the analog input? Thanks.

 

[Torben]

There are a few. Two that were brought up recently are for Windows (you didn't say what OS you are interested in. . .?):

http://www.sillanumsoft.org/ (My favourite)
**broken link removed**

If you're using Linux, you can try XOscope: http://xoscope.sourceforge.net

Note that most PC soundcards are AC coupled so you can't measure DC. For something like a guitar pickup it should be fine. You'd also be limited to whatever the card can handle, probably a max. frequency of ~22kHz. Which you won't see from your guitar anyway, so it won't be a problem.

If you're planning on putting anything into the mic or line in on a soundcard over a volt or so, you probably should build something like this http://xoscope.sourceforge.net/hardware/hardware.html to protect your card.


Torben

 

[walshlg]

wow that's great thanks! How low a frequency can you use successfully? I also see that there is a signal generator in the program too, can you use that and the scope program at the same time? Any idea what the output goes to with a surround sound gaming sound card?

 

[Torben]

wow that's great thanks! How low a frequency can you use successfully? I also see that there is a signal generator in the program too, can you use that and the scope program at the same time?

Yes, you can. At least in VA. I imagine most softscopes which include a signal generator would support this, as the feature would otherwise be much less useful. I can't swear to it, though. I know VA supports using both at the same time.

Any idea what the output goes to with a surround sound gaming sound card?

Try the headphone output--presumably it's only got two channels. Otherwise it depends on your card driver and how you configure VA. I suspect it defaults to the first two outputs.


Torben

[Edit--I forgot about the frequency question: I'm not 100% sure but since it's just AC-coupled I would suspect that you could go down below 1Hz. I've never tested the limit, though.]

 

[Hero999]

Assuming it's AC coupled, I would have thought 20Hz is probably a more sensible limit. Somehow I can't see them oversizing those AC coupling capacitors too much as it would be a waste of money.

 

[Torben]

Assuming it's AC coupled, I would have thought 20Hz is probably a more sensible limit. Somehow I can't see them oversizing those AC coupling capacitors too much as it would be a waste of money.

Yeah, that does make more sense, doesn't it?


Torben

 

[Analog]

Very nice, thanks for the links.