EEVblog #396 - Bode Plotting on Your Osciloscope

[thefatmoop]

took me a while to get to this. If you have an arduino sitting around you can do the same with a 5$ dds module off ebay

http://reibot.org/2013/08/16/bode/

[st]

If they were ahead of the curve, they would have an option that properly did the bode plot including phase. Now, years later, they have pretty much missed the curve and hit the tree, since I still do not see that feature.

The comments about the low dynamic range operate under the assumption that attenuation must stay constant and you have only 8 bit to work with. That is not the case.

Check out the Analog Discovery. It does a very impressive (stepped) Bode plot, including phase, with fantastic dynamic range. You can use one channel as a reference to normalize the other.

ST

Agilent: lightyears ahead of the curve...

[Don.Milne]

Dave:

Is it possible to get a 'Bode-Like' Display on an Oscilloscope in the 'Frequency Domain', using an oscilloscope with a 'FFT' Math Function capability?. This would allow measurement of frequencies with respect to dB levels, as in similar plots on log-log or semi-log graphs.

[SteveLy]

@Don.Milne: You need a white noise source going into your filter and the output of the filter to the scope for FFT analysis. Power spectrum will show frequency response as square magnitude vs frequency. (But you won't get phase info using white noise.)