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Siglent SDS6000A DSO's 500MHz-2GHz

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2N3055:

--- Quote from: randomOracle on August 30, 2022, 03:16:17 am ---
--- Quote from: 2N3055 on August 29, 2022, 07:19:22 am ---You didn't read that bottleneck in standard desktop scopes is not the interface itself but system throughput.

--- End quote ---

let me explain:
- instead of heaving this loop(arming - trigger - fetch data)
you do this:
- arm - measure sequence - fetch sequence
so you save many-times over the "fetch data" command which is only issued once and then a big chunk of data is fetched that includes multiple measurements. this is independent of the scope bandwidth and already saves you a lot of communication which otherwise slows down the scope.

so you use a crappy scope and flood it with arm-trigger-fetch messages to fetch small chunks. no surprise that bandwidth goes down and I'm not arguing against that.
the better approach is to fetch large chunks of data as this increases the payload size relative to the protocol overhead (cf. link to LeCroy document). this improves system throughput a lot, even on crappy scopes because this type of load they can handle much better.

next thing: the SDS6000A _already has_ USB3 on the front for mouse/flash drive ... so clearly the system should be able to sustain USB3 speeds. so why not have USB3 to connect to the computer? your system bandwidth argument is illogical in the sense that for a scope that has USB3, it should be able to sustain the speed of it, too. If not, clearly, the designers made a mistake. Which is my whole point here: they simply "forgot" to include USB3 on the back and this is what I complain about here. You may disagree and that is totally fine since apparently it is not something you need. If others need that, you should be fair to accept that, too.


--- Quote from: 2N3055 on August 29, 2022, 07:19:22 am ---You didn't read that Siglent has scope platform (in China only at this moment) that is rack mount, up to 512 channels combined system to achieve exactly this type of application you're doing. And other manufacturers too. There are also dedicated acquisition cards etc etc...

--- End quote ---

Do I care about a device that is in China and cannot be bought by me? If this is internally based on the SDS6000A platform (which to a certain degree seems to be the case, based on the SDS6000L product number), then this further supports the fact that this is a pure marketing decision: they want to sell the SDS6000L with synchronization ... and not muddy the water by having the SDS6000A also offering this feature. I'm looking forward to tear-downs of both scopes and then we will know. Of course, this was their decision right from the start when they did the design. I'm fully aware how products like this are made and that this is a complex process. However, this is something they generally can do (SDS5000X, SDS6000L) and the extra dollars spent would not hurt much on a per unit basis (again: assuming they would have considered that in the design process).

Long story short: USB3 on the back and the synchronization was missed and/or a pure marketing decision. Not necessarily for technical reasons. This is truly sad. Siglent makes great hardware but with this one, they fell short of my expectations. But seems like people on this forum can't accept a good rant.


--- Quote from: 2N3055 on August 29, 2022, 07:19:22 am ---[...]

--- End quote ---

There was simply too much finger-pointing and bold font in the remainder of your post that I will ignore this part.

--- End quote ---

We seem to have problem in communication here.

You do grab sequence and then transfer data to PC. That is best way, I agree.
Data transfer to PC is not very fast on OS level (let's call it that). Because general purpose scopes are not servers and it is not optimized for that.

As for USB, there is some confusion about that.  Front USB ports and USB port in the back are not the same.  With USB an equipment can be either host or peripheral . Your PC is host device, USB stick is peripheral.  Scope connected to PC is a peripheral device, like USB stick.
Different direction than those ports in the front of scope where scope is a PC.

And while USB 3 and 4 are coming for free courtesy of CPU chipset on motherboard,  an additional special peripheral controller needs to be added to CPU bus to add USB peripheral direction. And these are not so mainstream as you think.  And way you connect it is not so easy or fast, because many embedded CPU platforms usually don't have super fast CPU busses exposed .

As a data point, Signal Hound BB60C USB3 spectrum analyzer uses Cypress (same as Picoscope 3000D series) USB3 chip and achieves max throughput of 160 MB/s. But that is because internal FPGA is wired directly to USB3 controller and is doing nothing except that, namely just trying to shovel data directly to PC. With same chip Picoscope 300D achieves fraction of that speed, because it has to do other stuff (BB60C does al data crunching on PC while Picoscope does bunch of data processing internally before). BB60C is quite a different architecture to a general purpose scope.

So adding a USB3 would have been done at additional cost of different computing platform, and additional computing resources just for USB3 peripheral part. That I tried to explain, most of the users don't use scope as you do. So scope platform would be much more expensive to 100% of users because of 1% of potential users... At one point you need to make a business (not marketing) decision. and that is all. One device cannot do all. Even without artificial market segmentation decisions.

It was not "removed on purpose because of marketing".   SDS6000A as a platform predates SDS6000L for maybe 2 years.  Rack mount data acquisition version was made later, to serve that market.   Your conclusion on this is simply wrong. I know it for a fact. As you said, some of us do have a bit "deeper" knowledge on this topic, not just speculations.

As a final note I was not "finger pointing". Quite the opposite, I wanted to make sure it is clear that I understand that you have specific need (that is not really mainstream use of scope in a big picture) and that I understand that, but that does not give you right to proclaim "professional or not" based on specific feature set features. There are many, very professional, scopes from many tier A manufacturers that also have low data throughput to PC and no REF IN and that does not make them unprofessional. Just not good for your use. Which is unfortunate but it is what it is.

I will reiterate: for your use a Picoscope 6000E series would be a better match. You would have better control of scope from your software, and throughput on these is quite respectable. They were made for this kind of application.

So I confirm your proposition that Picoscope 6000E would be better choice for you, based on your use case, I corrected some of your wrong facts, and explained why some of your statements are wrong, hoping there will be some learning experience to someone.
You basically got free scope application engineer consultation for free. Why am I suddenly a bad guy?


luudee:
Hi Guys,


I have a liberated SDS5000X. Overall, I love the scope.

But there is one thing that really bothers me a lot, to a point
where I want to throw the scope in the bin:

The CPU is incredibly slow. Sometimes the UI freezes for a few
second. Often it fails to decode long streams of SPI data, etc.


So, my question is this: Does the SDS6000 have a faster CPU ?
More memory (for the CPU to work with) ?

Do you know what FPGA the SDS5000X uses vs the SDS6000 ?

And finally, can the SDS6000 liberated the same way as the
SDS5000X ?


Many thanks,
luudee

tautech:

--- Quote from: luudee on October 09, 2022, 12:33:59 pm ---I have a liberated SDS5000X. Overall, I love the scope.

But there is one thing that really bothers me a lot, to a point
where I want to throw the scope in the bin:

The CPU is incredibly slow. Sometimes the UI freezes for a few
second. Often it fails to decode long streams of SPI data, etc.

--- End quote ---
Have you tried a factory Default to delete any previous hidden settings ?
New firmware coming soon that hopefully can address some issues.


--- Quote ---So, my question is this: Does the SDS6000 have a faster CPU ?
More memory (for the CPU to work with) ?

Do you know what FPGA the SDS5000X uses vs the SDS6000 ?
--- End quote ---
I had both for a while and didn't notice any significant differences in operation/performance.
Are you on the latest V0.9.7R2 firmware ?

--- Quote ---And finally, can the SDS6000 liberated
--- End quote ---

Yes

--- Quote ---the same way as the SDS5000X ?
--- End quote ---
No.

luudee:

--- Quote from: tautech on October 09, 2022, 07:24:20 pm ---...
I had both for a while and didn't notice any significant differences in operation/performance.
Are you on the latest V0.9.7R2 firmware ?


--- End quote ---


Hi Rob,


yeah I bet, but did you try to do real work, with a busy set up ? :-)

Try running all 4 analog channels,
two digital busses, one of the busses being decoded (SPI)
and also use the zoom mode ...

It will be slower than my grandmother trying to cross the street !


Yes, I do have the latest firmware, and did a factory reset as well ...


Cheers,
luudee

JPortici:

--- Quote from: luudee on October 10, 2022, 07:19:21 am ---yeah I bet, but did you try to do real work, with a busy set up ? :-)

--- End quote ---

I do :)
Yes, the ui gets slowed down, about as much as in any scope i've ever used (beside keysight for the obvious reasons, but i'll take everything more this scope has over ui speed when doing lots of stuff).
When i have busy setups i stop acquisition after i have acquired what i want to look at. Scope in stop mode is much more responsive for obvious reasons. Then there's the history mode to look back at previous acquisitions.
Or if things must run, once it's set up and i let it run it's as responsive as ever

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