Our most frequently requested new feature is here at last! PicoScope can now plot a spectrum with a log frequency axis. With both axes set to "Logarithmic", the result is a Bode magnitude plot. You can adjust the number of decades between 1 and 6.
Here's what happened when we plotted the output of our PicoScope 3206B's built-in signal generator set to "white noise", with X and Y axes set to "logarithmic" under the Spectrum Options:
Remember: you can download PicoScope 6.10.2 Beta and try out the new features in Demo mode, even if you don't own a PicoScope device (yet).
I notice that you also now have filtering which includes band pass. Can that be linked to the log frequency axis so that it is a tracking filter? And also link it to the sine generator? (This would enable feedback loop analysis.)
What I miss though in this Beta is the 200kHz hardware filter setting for 4262. Hope you get that back soon. It's also missing in the latest version. R6.9.14. but is there in R6.6.57.
Also it would be nice with better control of Y axis scaling in spectrum mode. Being able to freely chose upper limit, lower limit, range, exact number of dB or V per div.
Regarding the missing hardware 200kHz filter setting that is missing,
this issue has been fixed and will be available in a later release.
It is possible by using a maths channel that you could create your own upper and lower limit.
Unfortunately at this moment it is not possible to choose the per div.
Please note that the values to select in the math channel wizard will not be in dbu and you will have to calculate backwards to get the dbu value you want.
I tested the feature yesterday and it works nice. But I would like to mention one point. Using the internal wave form generator of 4262 it is not optimal to have a sweep increment which is linear and the frequency spectrum axis is log! It should not be so complicated to change the sweep increment to something like number of increments per decade or something similar.
I was happy to learn that the latest Picoscope 6 allows for the analog hardware lowpass filter at 200kHz to be used as well as the log axis for frequency in spectrum mode.
I was less happy to learn that on two installations on two different machines Pico 6.10.16 gives very sluggish response when moving the rulers. Stopping aquisition removes this problem.
Both installations are on Mac with Bootcamp and Windows 7.
One installation is on a macbook pro running Bootcamp with Win 7 and OSX 10.6.8 and on that one I also have problems with Pico changing bandwith in spectrum mode when I change some other FFT parameter. Very annoying as I have to start/stop aquisition or change back manually. If I have a 20kHz or 50kHz bandwith in the spectrum view, Pico changes to 5MHz.
If memory serves me the sluggish ruler response is primarly in spectrum mode and with a large FFT number (which equals slow update rate) the "sluggishness" is worse, to the point that it's not really useable.
I'll try to add a more specific and detailed description later but still wanted to get this info to you now.
The processing required to produce the fft will be taking time away from updating the display, the display would generally not need updating until the new spectrum is ready. The more detail in the fft the slower the response will be.
I would like to poin again the attention to a new feature for log sweep mode or decade sweep mode with number of points per decade or octave. The current linear mode is not correct for 20Hz to 20 kHz. I always se a bump to the lower part in spectrum view peak hold. I used the procedure from the video channels. I think the number of sweep points in the lower part is too few in the FFT integration. It should not be that hard to program this like always the samd number o sweep points per decade?