Products > Test Equipment
PicoScope 2000
MrW0lf:
PicoScope 2408B FREQUENCY COUNTING ACCURACY
This scope has sample jitter spec of 3ps RMS typical and supports 20GSa/s ETS. So I started getting ideas about pushing it much further than default 4-digit frequency reading.
After initial tests it was clear that in MHz range ETS is best option. You need both very high sampling rate, and at least 10k points for stats. Accessing extra accuracy goes like this:
1) apply standard counter for "sanity check"
2) make math channel counter "freq(A)", apply DC Average to it.
Suppose reading is 119.6MHz on both counters.
3) make second counter "freq(A) - 119E+6", apply DC Average to it.
Then you can read MHz part of reading from 1/2 and kHz part from 3.
Sadly no femtosecond-accuracy and guaranteed 6-digit reading. Worst error 1.165ps in this test making it typically 5-digit accurate. It's not a FemtoScope after all :'( Will do separate test for sub-MHz range and get my missing digits from there...
Think math channel (or even standard reading) digit count should made configurable in settings, so volt/timing nuts could access it without so much trouble...
Note that "standard error" means error for reading using standard counter func:
MrW0lf:
PicoScope 2408B MICROPHONICS
Dave brought up microphonics issue with some scopes:
Did turn on ChA, ChB. Channels unterminated. Tuned trigger to barely rise from noise.
Tapping on table: no result
Tapping box by hand: no result
Tapping box with pen: no result
Strong blow directly above channels with pen: result
So for any practical intents and purposes - think no problem. Seems that effect has nothing to do with caps in this case. Purely "electron inertia" in conductive parts.
Now I have buy it new probe or something... Poor little thing never understood why such beatings :'(
MrW0lf:
Had no time to roll review further but find interesting stuff time to time... So far been using 12Mbit/s USB isolator when working on "nasties" but this or similar could prove useful as well:
https://www.meilhaus.de/en/promo-ranger2201.htm
alank2:
Excellent review MrW0lf. I was going to do a picoscope review as well, and I may still someday, but you outdid me in your testing by far. Good job! I have a 2205A and a 2207B, and while the 2205A exceeds it specs, the 2207B exceeds them much further like you 2208B does. I'm going to sell some equipment and get a 2407B as well so I have a 4 channel model. One thing I really like about the picoscope software is the custom probe option. I can setup a custom probe for my small PDI 60A two range clamp or the pintek DP-25 differential probe and you can even define the ranges so you can know when you are over range for the probe even if the scope isn't over range.
MrW0lf:
Thanks :) Feel free to add some chapter here if like. I decided to check hardware first because if thats no good - little point to dig into software features. But luckily hardware is well engineered so software feature testing has green light. Had some other matters that stalled review progress but think time to resume. Currently found offline postprocessing feature on saved data very useful. Will post couple words about it soon.
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