About Picos' Sampling Rate

[balnazzar]

The scope takes in a fast burst of data from the A2D to RAM.
Then sends it to PC via USB (speed at whatever standard is used 2.0 etc)
Then scope takes in another sample etc.
So however slow USB is it will still work.
Obviously too slow will delay display on screen.

It's 480 Mbps. Should be enough for streaming *buffered* pairs (time, amp)...

[wasedadoc]

The scope takes in a fast burst of data from the A2D to RAM.
Then sends it to PC via USB (speed at whatever standard is used 2.0 etc)
Then scope takes in another sample etc.
So however slow USB is it will still work.
Obviously too slow will delay display on screen.

It's 480 Mbps. Should be enough for streaming *buffered* pairs (time, amp)...

No, that is the theoretical maximum rate.  See the reply by Peter Hand at https://www.quora.com/What-is-the-transfer-rate-of-a-standard-USB-2-0-device for explanation of why the actual sustained rate is usually less.

[bdunham7]

It's 480 Mbps. Should be enough for streaming *buffered* pairs (time, amp)...

At what rate?

[jasonRF]

If you are holding out for 4 channels then you will probably need to wait a long time, or be willing to spend a lot of money.  Are you keeping all of these devices you are buying, or returning some?   Because sds1104x-e + AD2 + 2205a = a hefty sum of money.   

By the way, I do not think Picoscopes support SCPI. 

I will post my project when it is in a little better shape.  I need to redo the hardware design and clean up the script.   It will probably take 4+ weeks, since my job is taking up most of my time at the moment.  I am making it truly bare-bones, for the purpose of sharing something simple that actually works.  The script uses standard Fourier analysis to extract just the frequency of interest, and also adjusts the vertical setting for each frequency to maximize dynamic range. Others that have more microcontroller and python experience can add bells and whistles (lcd front-panel on generator, GUI for software, etc).   This is my first project using either, and I am not actually doing anything with the arduino beyond using a few commands from a library I downloaded.    I may eventually pick up a cheap SCPI-compatible scope (maybe vds1022i) to see if I can make that work as well.  Just for fun.   

Jason

I'm returning both the Siggy and the AD2 (both of them = 1000 bucks). My budget is limited to that sum.
I'm returning the Siglent because I like the scope very much, but I just cannot concentrate with its acoustical noise. And I'm returning the AD2 because I like the software but the instrument itself is quite limited. Great for some specific stuff, not so for other tasks. So that leaves me with the VDS1022i that is surprisingly decent for the price (and has much more sensitivity than the ad2) but cannot bode plot.. Once I saw the post about bode plotting with an external generator, I thought to buy the 2205A for 200$ so to have a pro tempore cheap bode plot device until I find a decent scope for 1 grand maximum.  In your opinion, will its amount of memory be sufficient for doing FRA with an external generator?

Wasn't aware that Picos don't support SCPI  I'll do some experiments with the 1022i and let you know, though.

Thanks!

One thing that would be interesting for you to do is measure the channel-to-channel crosstalk on the vds1022i.  The specs are pretty poor at 40:1, compared to 200:1 for the Pico.  If it really is just 40:1 then that will limit the ability of the owon to do Bode plotting.  In practice I get much better than 200:1 on the 2204a although I have never measured it directly.  The owon might similarly exceed the spec. 

If the vds1022 has sufficiently low crosstalk, then if I were you I would try to get Bode plotting working on the vds1022i before buying a 2205a.   Especially since the scope hardware on the two models has similar capability in some ways.  The vds1022i has a little better sensitivity and the 2205a has a little more memory.   Of course the software is the big difference.   

I can post a draft of my script and the hardware by next weekend if you want to see if you can modify it to work with the vds1022i.   A quick and dirty approach might be to use the nice python API that florentbr wrote for the vds1022i. 

Jason

yes, if you can post a draft, it would be great. Even if it's still rough, just to get the idea! Thanks.

Just posted a draft on the projects board.

[euzer]

Interesting information to know. We have a 2205A with 16kS memory. I'd be interested to know if there is any open SDK based streaming application(s)/implementation out there that I could use rather than PicoScope's V7 block mode. I can't find a download of V6 on the PicoScope site. I can't see in V7.1.29.19560 that the streaming functionality has been reintroduced.

For my application a couple of weeks ago I would have liked to capture around 10sec of serial data an decode the 1,200 Baud data, but the resolution just wasn't up to it at the sample rate. It just about worked at a 1s capture window. It's a shame that streaming has been nobbled. It seems a big step up in memory (x 2k) to 32MS when going from the 25MHz to 50MHz (2000B?) model.

Thanks

[Antonio90]

If you need/want realtime streaming to a computer the ThunderScope might work. It is designed to stream the full 1GS/s to the pc via Thunderbolt/PCIe, using the RAM as acquisition memory.

Allegedly, the crowdfunding will start this month. https://www.crowdsupply.com/eevengers/thunderscope

[euzer]

Thanks. We have a DreamSourceLab logic analyser which streams well and hoped the PicoScope would function similarly.