Siglent SDS12102X-E CAN Eres filter time constants

[klaff]

Playing with the Eres function on the scope.  Plumbed the Trig Out signal into Channel 1 (via 10x probe and nifty probe-BNC adapter) and grabbed images looking at that signal with Normal acquisition, and with Eres set to 0.5, 1, 1.5, 2, 2.5, and 3 bits of "enhancement".  Eres mode and zooming are mutually exclusive, which rules out Eres as useful for much work, IMO.  Looks like bandwidth at 1 GSa/s and 3 bits Eres is around 7.5 MHz, 2.5 bits 15 MHz, 2 bits 30 MHz, 1.5 bits 60 MHz, 1 bit 120 MHz.

Adding a capture with 20 MHz bandwidth setting for comparison.

[klaff]

Looked at the CSV files to see if the "enhanced bits" are available, but it appears they are not.  The scope appears to be scaled (as I think rf-loop has stated here before) such that the 256 levels of the 8-bit A2D are mapped to 10.24 divisions or 25 levels per division, and the number of levels found in the file doesn't change between Normal Acquisition and Eres.

[rf-loop]

It follow this principle:

http://cdn.teledynelecroy.com/files/appnotes/an_006a.pdf

Small note: Your conclusion about frequency response is  somewhat suspicious. Why? Because  true effective risetime in scope input BNC center tap is really undefined. But of course, naturally , due to simple math, every "half bit" reduce BW to half. 
Also it need remember that system rise time (what you see finally in scope screen) follow this principle SQR (( trise1 ^2) + ( trise2 ^2 )).

But anyhow thanks about this example.

[klaff]

I already read that, having seen where you posted it previously, thanks!

I agree that my bandwidth values should not be taken as precise values but as rough approximations. Neither the Eres shapes nor the 20 MHz BW filter are the gaussian shape that the famous bandwidth equation (.35 = Tr*BW) is derived from.  I was mainly just looking out of curiosity; I'm not sure what I would use the Eres feature for, especially since you can't get at the higher resolution data!

On the other hand, I am very pleased with the serial decoder functionality.  I captured 280 ms of CAN bus traffic and could scroll through a list of the 800 or so transactions that my system did in that time. If I pan the zoomed view, the highlighted line in the list follows along! Neat!

On the other (third?) hand, I have found a few little bugs and quirks and managed to get it to lock up once.

So far I give it a B+, or maybe an A- if one reminds me that not too much cash left my wallet.