PC as a scope

Ryssen · 1st January 2004, 02:30 PM

Can I use my PC as a scope,how?

mercator · 1st January 2004, 02:43 PM

Here is one using a sound card for the input:
http://polly.phys.msu.su/~zeld/oscill.html

For a more diy approach, try
http://www.ee.washington.edu/consele...nal/scope1.htm

I tried to do this about ten years ago with limited success, probably because of the slow processor and limited resolution of the sound card. I expect with a modern setup you should get fairly decent performance.

Dave

Happy New Year!

wintermute · 2nd January 2004, 09:35 AM

I've been successfully using mine.

I have an athalon 2Ghz machine with an audigy II ZS sound card.

I also made a preamp to put before the sound card, which has switchable attenuation/gain of .01 .1 / 1 10. Got it from Jaycar was an Electronics Australia design. http://www1.jaycar.com.au/productVie...=&SUBCATID=432

Note that I changed the opamp to a better one which also required increasing the power supply (I used a 12V SLA battery). You definitely want something like this if you are going to be measuring any largeish voltages, or you will likely fry your sound card. (don't try anything above about 3V without it!).

I have been using TrueRTA (the free version) and it is pretty good as long as you are measuring freqencies below about 10Khz. I think this is a limitation with the software or possibly my graphics card (Geforce II GTS). Basically if measuring a sine wave (which has been output by the sound card) over 10Khz, the displayed waveform looks more and more distorted (more like a triangle wave when getting to around 15Khz, and virtually unrecogisable at 20Khz).

One thing it is useless for is testing whether or not your amp is oscillating supersonically

definitely only usefull in the audible range.

Here are some links to threads where I have posted CRO screenshots, when testing my amp.

http://www.diyaudio.com/forums/showt...705#post248705

http://www.diyaudio.com/forums/showt...873#post286873

and finally (if there wasn't enough already

) a link to the rmaa tests I did on the soundcard and the soundcard preamp.

http://home.swiftdsl.com.au/~tonywww...mpare_MKII.htm

Note I haven't tracked down where the 50Hz spike comes from when testing with rmaa but its not there when using as a scope!

Tony.

Wes Marquenie · 2nd January 2004, 09:50 AM

http://www.bitscope.com/

1st January 2004, 02:30 PM	#1
Ryssen diyAudio Member Join Date: Dec 2003 Location: Sweden--> Here	PC as a scope Can I use my PC as a scope,how?

2nd January 2004, 09:35 AM	#3
wintermute just another diyAudio Moderator Join Date: Aug 2003 Location: Sydney Blog Entries: 22	yes with limitations I've been successfully using mine. I have an athalon 2Ghz machine with an audigy II ZS sound card. I also made a preamp to put before the sound card, which has switchable attenuation/gain of .01 .1 / 1 10. Got it from Jaycar was an Electronics Australia design. http://www1.jaycar.com.au/productVie...=&SUBCATID=432 Note that I changed the opamp to a better one which also required increasing the power supply (I used a 12V SLA battery). You definitely want something like this if you are going to be measuring any largeish voltages, or you will likely fry your sound card. (don't try anything above about 3V without it!). I have been using TrueRTA (the free version) and it is pretty good as long as you are measuring freqencies below about 10Khz. I think this is a limitation with the software or possibly my graphics card (Geforce II GTS). Basically if measuring a sine wave (which has been output by the sound card) over 10Khz, the displayed waveform looks more and more distorted (more like a triangle wave when getting to around 15Khz, and virtually unrecogisable at 20Khz). One thing it is useless for is testing whether or not your amp is oscillating supersonically definitely only usefull in the audible range. Here are some links to threads where I have posted CRO screenshots, when testing my amp. http://www.diyaudio.com/forums/showt...705#post248705 http://www.diyaudio.com/forums/showt...873#post286873 and finally (if there wasn't enough already ) a link to the rmaa tests I did on the soundcard and the soundcard preamp. http://home.swiftdsl.com.au/~tonywww...mpare_MKII.htm Note I haven't tracked down where the 50Hz spike comes from when testing with rmaa but its not there when using as a scope! Tony. __________________ Any intelligence I may appear to have is purely artificial! Some of my photos

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1st January 2004, 02:43 PM	#2
mercator diyAudio Member Join Date: Feb 2003 Location: Calgary	Here is one using a sound card for the input: http://polly.phys.msu.su/~zeld/oscill.html For a more diy approach, try http://www.ee.washington.edu/consele...nal/scope1.htm I tried to do this about ten years ago with limited success, probably because of the slow processor and limited resolution of the sound card. I expect with a modern setup you should get fairly decent performance. Dave Happy New Year!

2nd January 2004, 09:50 AM	#4
Wes Marquenie diyAudio Member Join Date: Jan 2003 Location: Enschede	http://www.bitscope.com/

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