Measure Frequency Response of a Filter

[osterchrisi]

Hi there!

I have a question concerning an analog filter I want to make. I'm quite into electronics and want to design a filter now. I should be able to measure the frequency response somehow to check out the results of my filter in a good way - besides my ears of course
Does it make sense to simply send white noise through the filter, record that through my soundcard and look at it with a FFT-Analysis? Or better record a sinewave through it and look at a FFT-Analysis later?
Does anyone have experience with that?

Thanks for you answers!

[spm_gl]

I would test it with white noise, pink noise and a slow sine sweep. You could use something like Jaaa and Japa to create the test signal and display the results. Try to use a decent sound card though, otherwise your measurement will be tainted by the noise of the cards input. But also check with an analog oscilloscope whether you have high frequency oscillations or weird noise. And be proud of yourself if everything works and sounds well.

[osterchrisi]

Ok, good. I was thinking about Japa too, could you possibly explain the store function to me if you know how that works? I have an oscilloscope too but not the storage-type so I don't really know how to use that for measuring a frequency response... But of course I can seek for weird noises inside my circuit...

Thanks for your answer!

[spm_gl]

The storage function is pretty cool. For example, you could measure the response with pink noise, press ->x under "Store A", then measure with white noise, and have the older measurement displayed by pressing the X at the bottom next to "Mem".
If you store the second measurement under Y by pressing ->y under "Store A", you can display the difference between the two by pressing X/Y next to "Mem".

[Capoeira]

I would use qloud for a sweep. for white and pink noise you could use Audacity, too

[Capoeira]

I would use qloud for a sweep. for white and pink noise you could use Audacity, too

there is also Aliki now: http://www.kokkinizita.net/linuxaudio/

[osterchrisi]

Cool! Figured it out, I think it's enough for me like this, great!
Thank you very much!