Products > Test Equipment
Oscilloscope Zoom Out Quirk
nctnico:
--- Quote from: nfmax on May 10, 2020, 10:41:46 am ---Because the latter option also reduces the headline waveform update rate (because each waveform is longer), it tended to lose out. Maybe this is why @nctnico so disparages waveform update rate as a parameter - because it goes against his way of using the scope?
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No. In some case having lots of waveforms/s is useful; setting the memory length shorter either manually or automatically gets you the highest waveform update. You can have the best of everything no matter what.
My beef with waveforms/s is that it is a number used purely for marketing wankery because the maximum number is only achieved in very specific use cases which don't represent actual use cases. The number of waveforms/s is highest with the least number of points, where the trigger dead-time versus acquisition time is at an optimum and (usually) in dot mode only. This means that you'll be looking at a screen with a whole bunch of dots instead of a signal in some cases.
EEVblog:
--- Quote from: nfmax on May 10, 2020, 11:02:29 am ---
--- Quote from: EEVblog on May 10, 2020, 10:56:35 am ---
--- Quote from: nctnico on May 10, 2020, 09:40:59 am ---And I don't get how fast waveform updates suddenly become relevant in this thread; capturing beyond the screen has no downsides.
--- End quote ---
It's only relevant if designing in this feature was done at the sacrifice of update rate in the design.
Obviously with Keysight having the fastest update rate and having this feature, that's obviously not a trade off that needs to be made in basic scope design.
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But that only works because when you press Stop, the Keysight scopes make one last acquisition using the maximum available memory (providing a trigger arrives in time). It's a neat trick, and it does work.
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Ah, you just came to the same conclusion I did in my post above!
That's exactly what Keysight have elected to do, and I think it's smart.
2N3055:
--- Quote from: nctnico on May 10, 2020, 10:07:07 am ---
--- Quote from: tautech on May 10, 2020, 10:00:31 am ---
--- Quote from: nctnico on May 10, 2020, 09:49:25 am ---
--- Quote from: tautech on May 10, 2020, 09:45:08 am ---Or we could just start the car in gear because pressing of the clutch is just another further unnecessary operation ! :horse:
--- End quote ---
That is another advantage of an automatic gearbox; you don't have to press the clutch pedal. Good point!
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::)
Another thing you haven't properly thought through.
You can't start an auto in gear and once started you need to select D after pressing the foot brake and the guy that started the manual in gear is already way off down the road !
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But you don't need your left foot at all. But let's stop discussing car gears.
The point is that it makes no sense trying to argue that less is somehow more. In the real world less is just less. Use your time to point Siglent to this thread and add this feature. Likely it is 3 lines of extra code. Maybe they can beat Dave to making a video showing how it doesn't work on Siglent scopes but it does work on Rigol's 8)
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Exactly. In real world less is less.
You keep forgetting to warn people that what you do makes scope retrigger at a very, very slow rate (few times per second). So you are looking at some edge at nanosecond scale, but your screen refreshes few times per second or slower. What you are proposing is good for events that are sparse, and where things happen so slow, you actually have time to literally see something weird on screen, mentally have time to recognize it as weird and make a decisions to stop, and then have time for you to move hand and manually stop acquisitions.
Segmented acquisitions are literally invented for those kinds of events... So to work on that kind problems, you use segmented mode. On LeCroy, Siglent, Pic and some R&S scopes (I know of those if there are more please let me know)you have history mode, that is sort of always running segmented mode, with no penalties to normal running.
For that kind of events, I put Pico to slow timescale with deep memory so I keep high acquisition rate, and capture 100 ms at a time, and keep getting those captures to memory, 100s of them if needed.
Then I use built in search to scour trough captures..I also use DeepMeasure to search for analog anomalies across all of those (edges, P-P, pulse widths). I export DeepMeasure to Excel, and make statistics and histograms of all those prameters, to catch outliers and get a feeling of distribution... Or I put my 3000T or Pico to segmented mode and just capture those bursts of data, ignoring "eons" of pause in between. Pico 3406D has retrigger time in segmented mode even faster that 3000T (Trigger rearm time < 0.7 µs at 1 GS/s sampling rate, )
When looking at normal scope stuff, I like that my 3000T uses auto memory management, so it can reach up to 1.2 MHz retrigger rate. It makes it feel like "real scope".
nfmax:
--- Quote from: Someone on May 10, 2020, 11:12:19 am ---
--- Quote from: EEVblog on May 10, 2020, 10:56:35 am ---
--- Quote from: nctnico on May 10, 2020, 09:40:59 am ---And I don't get how fast waveform updates suddenly become relevant in this thread; capturing beyond the screen has no downsides.
--- End quote ---
It's only relevant if designing in this feature was done at the sacrifice of update rate in the design.
Obviously with Keysight having the fastest update rate and having this feature, that's obviously not a trade off that needs to be made in basic scope design.
--- End quote ---
Except they are mutually exclusive, the bonus full length capture of the megazoom scopes only occurs when there is another trigger after pressing stop. If you're trying to capture long record lengths of short bursts between infrequent events, pressing stop won't help.
--- End quote ---
You should use Single mode in that case
tautech:
--- Quote from: Martin72 on May 10, 2020, 12:08:08 am ---Apart from this I wonder, what siglent will do with it´s waste amount of memory ( 200MP/250MP SDS 2K+/SDS5K) when only could used in lower timebases.
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:-//
It's YOUR memory to know how to use wisely......again yours !
Lower timebases, bah humbug. :P
Study the dot mode screenshot below.....left at that timebase setting for understanding but 1 dot/div (1 memory point) is available at 200ps/div.
Total of 500 MPts with 2 channels on alternative ADC's.
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