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USB logic analyzer - what's the current "favorite" for ~150$? Hantek 4032L?
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toli:
SMB784, this device is not meeting my desired spec as I've described above. The 50MHz limitation isn't a function of sample rate for most devices, its about the speed of the comparator and timing constraints of the digital logic. Therefore its impossible to look at the maximum sample rate and understand what the maximum frequency it can sample will be. As I mentioned above, this model (the pro) is my plan B (or maybe C), since it isn't what I really want in a LA. Bang for bug isn't the parameter I'm looking for, I'm looking for something that can technically do what I want, which out of the devices I've seen so far only the Hantek can.
If I come to the conclusion I can't use the Hantek due to software limitation I'll get the DSlogic Pro, and live with the fact it can only due the more basic things I need. But so far it seems the Hantek isn't "dead" yet. Especially considering the SW will keep improving.

I'm still on the fence here though, the two users who have experience with this combo (abraxa and maginnovision) agreeing that it can do what I want, but if I understand correctly there are bugs at the moment that might make it a not so pleasant experience :)
SMB784:

--- Quote from: toli on July 06, 2018, 06:40:40 am ---SMB784, this device is not meeting my desired spec as I've described above. The 50MHz limitation isn't a function of sample rate for most devices, its about the speed of the comparator and timing constraints of the digital logic. Therefore its impossible to look at the maximum sample rate and understand what the maximum frequency it can sample will be. As I mentioned above, this model (the pro) is my plan B (or maybe C), since it isn't what I really want in a LA. Bang for bug isn't the parameter I'm looking for, I'm looking for something that can technically do what I want, which out of the devices I've seen so far only the Hantek can.
If I come to the conclusion I can't use the Hantek due to software limitation I'll get the DSlogic Pro, and live with the fact it can only due the more basic things I need. But so far it seems the Hantek isn't "dead" yet. Especially considering the SW will keep improving.

I'm still on the fence here though, the two users who have experience with this combo (abraxa and maginnovision) agreeing that it can do what I want, but if I understand correctly there are bugs at the moment that might make it a not so pleasant experience :)

--- End quote ---

The reason why I brought up the DSLogic pro is that I'm not convinced that it's limited to 50MHz. It has a Spartan 6 in it, and I don't see a reason why the comparator in the would be limited to the input Crystal frequency. These things are rated to much higher frequencies, and in order to generate a sampling clock of 400MS/s they must be capable of at least that frequency.  My bet is that the actual input bandwidth is higher than 50MHz, as the Nyquist frequency for a 400MHz sample clock is around 160MHz
toli:
Looks like you are right and it really does support higher BW. I've been watching videos from the OpenTechLab channel on youtube over the last few weeks, so today I've finally watched his review of the DSlogic Plus:
https://www.youtube.com/watch?time_continue=3&v=xZ5wKYnCNcs
Seems like the use of the coaxial leads and the way they implement the input stage really does give a significant advantage when it comes to high speed sampling.it really is very impressive that this small device can get to 200MHz input clock.

So this does make the option of getting the DSlogic plus (with the coaxial leads, no reason for me to keep twisting wires together if I don't have to, for 30$ its worth it :)) significantly more appealing than it was until this point. The number of boxes it doesn't tick in my desired spec just got smaller.

I'll try sending DreamSourceLab an email and ask them about the external clock mode. I'd like to understand if there are any other limitation to it and if the threshold voltage is indeed constant for 3.3V CMOS levels. If the threshold level is fixed this will be somewhat of a PITA for me to do this myself every time.
SMB784, do you have any way of feeding a clock into this pin and testing one (or both) of these parameters (maximum frequency it can run at, and threshold level adjustment support)?
SMB784:

--- Quote from: toli on July 06, 2018, 02:33:32 pm ---I'll try sending DreamSourceLab an email and ask them about the external clock mode. I'd like to understand if there are any other limitation to it and if the threshold voltage is indeed constant for 3.3V CMOS levels. If the threshold level is fixed this will be somewhat of a PITA for me to do this myself every time.

--- End quote ---

Judging by their spec sheet on their website tells me that the threshold is continuously variable between 0 and 5V, though I don't know how to do that yet.


--- Quote from: toli on July 06, 2018, 02:33:32 pm ---SMB784, do you have any way of feeding a clock into this pin and testing one (or both) of these parameters (maximum frequency it can run at, and threshold level adjustment support)?

--- End quote ---

I will see if I can get my hands on a >100 MHz square wave generator.  If not, then I dont think I can find something that I could use to test this :-/
toli:
Question is if this 0-5V range also holds for the CLK input vs just the 16 data channels. I think I've seen somewhere a mention that the CLK input is at 3.3V constant, but I can't seem to recall where it was.

BTW, you don't actually need >100MHz square wave to test these parameters. The threshold can be checked at low speed quite easily (and if I'm honest that's the more interesting parameter for me at the moment). For the maximum frequency test a sin wave will suffice. At these frequencies the rise time will limit square waves and they will look more like a sine anyway unless you take extra good care of the test setup. I've actually used sin wave input at 100MHz to the Cypress FX3 IC as a sampling clock because of a similar limitation, and its works like a charm with no issues at all (just add VDD/2 DC offset obviously :)).
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