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Standardised Way To Test Oscilloscope Screen Update Rate
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thm_w:

--- Quote from: radiolistener on April 30, 2024, 07:57:26 pm ---it will be easy if lcd/led matrix is rated for much higher refresh rate than actually used (very much higher). But usually it is close to actual refresh rate or even worse. In such case you cannot see pixel on/off event immediately, it will be very smooth and it will be hard to determine exact frame when pixel appears or disappears.

If video camera uses lossy compression format, it will be even more hard because compression will remove very small change of pixel brightness between frames.

--- End quote ---

If on screen trace refresh is keeping up with the LCD refresh, which on any modern scope should be 60-75Hz, then that would be great, perfect A rating, whatever you want to call it. What we are looking at with the siglent was probably sub 20 or 15 fps.
Could have two categories then to make it harder:
1) Single channel, no measurements on, no processing on.
2) All four channels on, 10 measurements on, something like that.

Though I would expect any good modern scope to not slow down noticeable with measurements or multiple traces?
David Hess:

--- Quote from: bdunham7 on April 30, 2024, 01:42:45 pm ---
--- Quote from: joeqsmith on April 30, 2024, 12:47:43 pm ---Your video requires some codec I don't have.
--- End quote ---

That's Windows pissing in your ear and telling you that it is raining.  HEVC (h265) has been around for quite a while now, but MS still wants a fee to let you use it.  Download VideoLan if you want a decent video viewer.

https://www.videolan.org/vlc/download-windows.html
--- End quote ---

When I first ran into that problem, I stupidly followed Microsoft's advice and bought the codec though the Microsoft store, which of course never worked.  My prefered solution now is the K-Lite Codec Pack:

https://www.codecguide.com/about_kl.htm
joeqsmith:

--- Quote from: joeqsmith on April 30, 2024, 04:59:50 pm --- I'll try it with mine.
--- End quote ---

On my scope, using your setup, they appear to display the latest data with the previous data (two lines).  Next it erases the previous, left with current (one line).  Then turn on the latest data (two lines) and continues to cycle.   So the screen updates at 60Hz but they only update the latest data at 30Hz.   The LCD appears to require a long time to clear so you get a very gradual fade out.   

So with persistence turned off, my scope will also not fully disable it.   

One thing I did try was increasing the trigger to 120Hz to see if they would stack more traces on.  There was no difference.   

No thanks to LeCroy (still not privileged enough to have an account with them), I am running the latest firmware available for this this scope. 

joeqsmith:
8-level staircase, 10Gsps, dot mode, 1000fps capture.  Showing 1 second of data.
EEVblog:

--- Quote from: bdunham7 on April 30, 2024, 02:21:46 am ---What is bit  confusing about the video I posted is that the waveform update is set at 60/s (using line trigger) and the 60fps video shows a display update (pixel change) on each and every frame yet there are multiple traces showing.  This is why I was saying that 'screen rate' or 'screen update' may not be simple, clear-cut concepts.
--- End quote ---

They are not. I'm sure there are scopes that manipulate the data to provide a more "analog like" display.
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