Products > Test Equipment
Oscilloscope Bode Plot Speed Comparison
<< < (5/8) > >>
nctnico:

--- Quote from: jasonRF on June 23, 2023, 12:25:27 pm ---Unless you know the gory details of how the scope is doing the analysis, these will all be apples to emu comparisons. 

--- End quote ---
Logic dictates that every FRA implementation uses narrow bandwidth filtering aka selective frequency detection. Otherwise any DUT other than a simple RC filter will give false readings.
jasonRF:

--- Quote from: nctnico on June 23, 2023, 04:51:01 pm ---
--- Quote from: jasonRF on June 23, 2023, 12:25:27 pm ---Unless you know the gory details of how the scope is doing the analysis, these will all be apples to emu comparisons. 

--- End quote ---
Logic dictates that every FRA implementation uses narrow bandwidth filtering aka selective frequency detection. Otherwise any DUT other than a simple RC filter will give false readings.

--- End quote ---
Agreed, but even in this framework you can adjust parameters that can change the time dramatically by changing how “narrow” you desire, determining how much averaging you need, etc.  Of course some measures of performance will also change with these decisions  (dynamic range, immunity to noise, phase estimate accuracy, etc).    With the picoscope  example, with 1% resolution bandwidth (at least 100 cycles) it takes < a minute.   Requiring at least 10 Hz absolute resolution takes about 10 times as long.  I would call both “narrow”, but they do not yield identical performance.   

Jason
mawyatt:
Had a few moments late last night and decided to give the PicoScope 4262 a try, this has 16 bit ADCs and a high quality built-in AWG, however the AWG is limited too <20KHz, and the scope to <5MHz.

The FRA software for the PicoScopes was created by Aaron Hexamer, we are using version 0.7.3b (need to look for a later version if available). This is quite a nice implementation by Aaron, and definitely utilizing a Frequency Selective sampling scheme, with various parameters controlling such available to the user.

The only criticism of this software is the lack of a linear frequency scale, however the hardware (4262) has very limited AWG frequency range of <20KHz, so the ability to work with an external AWG would be nice.

We conjured up a Peltz Oscillator at ~10KHz for the Bode plot of the Injected Oscillator. After some fiddling around with the various parameters working with a Noise Rejection BW of 3Hz with high levels of oversampling and Noise Rejection parameter, this was very slow but produced some outstanding results  :-+

This morning we decided to try the Analog Discovery 2, only to "Discover" that we couldn't download the basic scope operating software for either a Mac nor PC after jumping thru a bunch of hoops and getting an "access denied error messages" when attempting the download from a Mac or PC. This sent us searching for an answer on their user site, only to find nothing specific regarding such, which then required site registration and a very unusual method of verification which employs getting various letters from certain words and then added another with other letters which we failed to understand or execute properly, after several failed attempts finally getting thru. So not very impressed with Diligent so far :--

If we get the AD2 working we'll attempt a Bode plot of the mentioned oscillator.

Best,
Fungus:

--- Quote from: mawyatt on June 24, 2023, 04:11:46 pm ---...this was very slow but produced some outstanding results  :-+

--- End quote ---

All this test gear but no stopwatch or enough disk space for a screenshot?
2N3055:

--- Quote from: Fungus on June 24, 2023, 04:48:42 pm ---
--- Quote from: mawyatt on June 24, 2023, 04:11:46 pm ---...this was very slow but produced some outstanding results  :-+

--- End quote ---

All this test gear but no stopwatch or enough disk space for a screenshot?

--- End quote ---

No need to be disrespectful and rude...
Navigation
Message Index
Next page
Previous page
There was an error while thanking
Thanking...

Go to full version
Powered by SMFPacks Advanced Attachments Uploader Mod