Products > Test Equipment

Siglent SDS2000 new V2 Firmware

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nctnico:
Still not going to return it? You have not gotten to protocol decoding yet...
BTW: did you try to move the digital channels? In an ancient firmware version you could move the digital channels individually.

TheDefpom:
One thing I wish the firmware did is to not give a false impression of accuracy on the frequency display, it should reduce the number of digits to remove the trailing zeros, which make it look like it has a precise reading, when in fact it does not!

Maybe a way of adjusting the accuracy of the display could be added to the firmware also, to allow for the reference oscillator not being exactly on frequency, a calibration point, so it can be compensated for to give correct frequency display, at the moment it is of little use to me because it is so far out of accuracy.

Performa01:

--- Quote from: nctnico on December 20, 2015, 10:39:21 pm ---Still not going to return it?

--- End quote ---

Not me! ;)

In general it’s a great DSO already, with exceptional low noise and a rock solid trigger system.

Granted, there is a number of bugs yet, but none of them is a show-stopper and I’m positive they’ll be fixed eventually.

Average acquisition mode suffers from the memory limitation, but then again, for the price I paid for the SDS2304, I might have got a WaveAce 2024 at best, where apart from the lower bandwidth and it’s not being an MSO, I wouldn’t have had to worry about memory limitations in certain acquisition modes, as there are generally not more than 12kpts per channel available...

Eres is even worse, as it doesn’t even do what it promises, but then again, how many scopes in this class do have a useful resolution enhancement in the first place?

FFT isn’t terribly useful, but this is also not uncommon in this class and quite obviously only manufacturers who offer scopes with 12 or more bits (where FFT starts to make really sense) go to the effort to implement it in a way such as to get the most out of it.

Only real annoyance is the trigger frequency counter, as it is low resolution, inaccurate and unreliable all at the same time. Where are the days, when we had analogue scopes with a Y-output, where we could hook up the frequency counter that had the resolution and accuracy that we needed for our task?



--- Quote from: nctnico on December 20, 2015, 10:39:21 pm ---BTW: did you try to move the digital channels? In an ancient firmware version you could move the digital channels individually.

--- End quote ---

You are perfectly right – the bug I’ve observed is just about the initialization as it seems. Arranging the channels manually works, and even a nice auto arrangement (just as I’d have expected it right from the start and as it was in previous FW version) can be had by just one push on the position knob.



--- Quote from: nctnico on December 20, 2015, 10:39:21 pm ---You have not gotten to protocol decoding yet...

--- End quote ---

Hopefully I will get to test the digital channels anytime soon. But what I can tell already, in principle everything seems to work – also parallel and serial decoding.

Performa01:
Pass Fail Mode

This is an extremely valuable feature for finding anomalies in a signal – if it’s properly implemented, that is. On some scopes, the pass/fail test is dog slow and finding a glitch could take forever. So let’s see what the SDS2000 has to offer in this regard…

For this test, I use a basic square wave at 1MHz, 50% duty cycle, about 2.6Vpp amplitude and 12ns transition time for both edges. The automatic measurements indicate slower transition times, most likely because the signal generator doesn’t quite meet its specs at full amplitude of 10Vpp into 50 ohms and my test setup eats up a little speed too, with a total of 2 metres coaxial cable and a homebrew power-splitter (which is also the reason why only a fraction of the original amplitude makes it to the scope input).

Acquisition mode is peak detect and display type is dots (Waveform)




Now it’s time to prepare the mask for the test. I set the tolerances to 0.16 divisions for both x and y direction, that corresponds to 16ns and 80mV, or +/- 8ns and +/- 40mV, to be precise (Mask)



Please ignore the numbers in the Total/Pass/Fail display on the top right corner – these are just old values that will only be reset when a new test is started – which makes sense of course.

Now we can run the test for the first time – and nothing happens, other than the Total and Pass numbers count up at a rate of about 38000/s, which is – what do you know – exactly the waveform update rate for this setting. The Fail count stays at zero, as is expected for stable and undisturbed waveform.

Now we can make the waveform faulty – for instance by changing the square to a sine – but I didn’t want to be that uninspired. Instead I changed the rise time from 12 to 24ns on the signal generator, thus making sure the rising edge would violate the horizontal tolerance window by a few nanoseconds. I ran the test for 60 seconds, and sure enough, the result met all my expectations (Pass_Fail_SlowRise_60s)



The test ran 38000 times per second, resulting in a total of 2284039 inspected waveforms – and none of them passes the test. In other words, the SDS2000 generated some 38000 errors every second, which is quite impressive.

What is the real detection rate then? At 1MHz, we get one million faulty (slow) edges per second, and because of the trigger speed (waveform update rate) of 38kHz, the ‘examination rate’ is 3.8%. That means, if the fault is intermittent, statistically the test needs to run long enough for about 26 abnormal frames to occur, in order to detect the anomaly once. Not a bad prospect at all.


Now for the really tough test :)

I set up a second signal that can be superimposed on the basic waveform – it’s a nasty little positive spike, 100mV in amplitude and only 10ns wide at a repetition time of 100ms. Transition times are supposed to be a tad over 2ns and the scope says 3 – so my test setup isn’t that bad after all, considering the scope itself is supposed to have a rise time of about 1.2ns. Please note that both the vertical gain as well as the timebase settings are very different to the previous screenshot (Glitch)



Both signals mixed together provide the sporadic signal anomaly that I wanted to use for this test. Because of the low frequency of just 10Hz only one in 100000 waveforms gets disturbed and the deviation from the original is rather tiny. Please ignore channel 2 which is just a sync signal that was required for triggering in order to get a nice screenshot, as the glitch is not synchronized to the base waveform, i.e. it appears randomly anywhere on the trace (Waveform_Mix)




I did another 60 second pass/fail test with the signal shown before (Pass_Fail_Glitch_60s)



Because of the glitch just occurring once in 100000 periods of the base signal, we would expect a pass/fail ratio of just that. In fact, the scope detected almost twice as much abnormal acquisitions, as the ratio was 2298858 / 42 = 54700. I guess that’s just the pitfalls of statistics – if the test would run for a longer time, I expect it to converge to the expected ratio of 100000.

On a side note, when playing with the pass/fail test, a similar bug as already reported for the history mode can be observed. In rare instances, the scope stops showing a trace and only responds to keystrokes with a considerable delay. As with the problem in history mode, hitting Run/Stop twice brings the scope back to live. The bug happens much less frequently here than it did in history mode. According to the tests done by rf-loop, it might well be that it has something to do with the trigger channel. I consider it a good thing that I use channel 4 for the majority of my tests, as most folks – particularly firmware developers/testers ;) – will probably just use channels 1 and 2 most of the time and expect 3 and 4 to behave the same – which isn’t always true, as we have learned by now ;)


Conclusion

Apart from the little bug described above, the pass/fail test works just great – in fact much better than on many other scopes we’ve seen so far in this class. Well done Siglent!  :-+

rf-loop:
Note1: This test is old. From December 2014. At this time SDS2000 FW was some old V1 version.
Note2: Mask used in Siglent made using PC.
Note3: Images resized so that on the PC screen can note difference between 8" and 7" display.

In these tests SDS2k maximum wfm/s average speed was barely around 110kwfm/s. (highest burst speed of course more - inside one display update period)  Today with V2 FW versions average max 140kwfm/s.



First Rigol DS1000Z series oscilloscope.
Scope looks nice, rich of features, display looks nice and well finished and so on. 

First this is example how bad it can be.



In this test Mask test fails continuously (every acquire fail)
Speed is 1 waveform per second. Really, it can capture one waveform in one second in pass fail test in case that test result is fail. 



Then we can look how its speed go with Siglent.



Here with Siglent. Every acquired waveform fails in test. It capture 110000 waveform in one second ans also output signal tell "fail" for every captured failed waveform. (small image, made with other oscilloscope connected to pass/fail output BNC)






Here  every acquired waveform pass in test. It capture 110000 waveform in one second. (small image, made with other oscilloscope connected to Trig/out BNC (output mode changed for measure speed using trig out signal. In this case pass/fail do not give signal out)

Simply, with speed of Siglent this function is very powerful and useful as real tool for find signal anomalies.
As noted previously, I have  made full set of tests and it do all Mask tests with sama speed what it can capture without this function.

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