PC based oscilloscope

[satdaveuk]

Hi 6666
A problem you may experience using Mic input of a pc is its low impedance so try this out, Its a simple FET follower which will attenuate automatically by a factor of 30, it has high input impedance and low output impedance which will match your PC sound cards, should do the job nicely .

Regards

[6666]

Hi Dave
Thanks for the cct, I have only been using Line In
as it will tolerate a higher input level.
Cheers

[mohandes]

do you think my friend 6666 is it ok?http://yveslebrac.blogspot.com/2008/...-galaxy.htmlif it is well tell to us to make thatthanks

[mohandes]

hi please hek that

[6666]

do you think my friend 6666 is it ok?http://yveslebrac.blogspot.com/2008/...-galaxy.htmlif it is well tell to us to make thatthanks

Hi
I am not sure what the waveform is
can you please tell me where you are measuring that wave form ?

In the small amount of testing I have done with PC based
programs and comparing waveforms with my real CRO
the sound card software is limited, it seems to like square or sine waves
but when it comes to short pulses like in a PI
it does not work very well.

[mohandes]

Hi
I am not sure what the waveform is
can you please tell me where you are measuring that wave form ?

In the small amount of testing I have done with PC based
programs and comparing waveforms with my real CRO
the sound card software is limited, it seems to like square or sine waves
but when it comes to short pulses like in a PI
it does not work very well.

hi
thanks , i have more scope program that we can make but dont know work for pi ?
if you agree put them here?

[mohandes]

hi friend 6666
http://www.hlachini.com/Projects/PC-...silloscope.htm
this is scope that work in Turbo C.
will work this for pi detector

[6666]

Hi Mohandes
the problem is
its very hard to answer that question as I dont have a unit I can test on the bench
and compare to a real CRO.

[mohandes]

ok
but my means do you think it is good for pi or no
merci

[Davor]

It must have sub microsecond sampling, otherwise it is useless.

[ODM]

Frankly it looks useless for MD purposes. It only has the means for determining amplitude of a signal (by full wave rectifier) and zero crossings. Zero crossings are timed by parallel port input, so the precision and speed is very limited.

A sound card input would work better, but still usually be too slow unless you're building a low frequency detector. Even then, it'd be hard to trace fast glitches, and depending on experience and layout of your build, those are likely to happen.

Unfortunately, if you need to do fast oscilloscope measurements, the only solution is to get a real oscilloscope.

Beware, "Pocket scopes" on ebay are lousy as far as bandwidth goes. You can't do 1MHz bandwidth by 1MSa/s. Some scopes do display far more than their samplerate would comfortably allow, but it's just a "best guess" reconstruction. Same applies with equivalent time measurements. Beware of glitches, be sure your signal is indeed repetitive!

[mohandes]

ok
thanks ODM and davor

who have real scope for measure pi detector by computer??

[Davor]

That would require an external sampling and processing unit, but at that prices you will get a better second hand analogue cathode ray oscilloscope. Check http://www.picotech.com/oscilloscope.html for ideas