Products > Test Equipment
Oscilloscope Zoom Out Quirk
rf-loop:
--- Quote from: nctnico on June 15, 2020, 12:38:38 pm ---........... IOW: With auto memory depth you can't have both deep memory and see two parts of the same signal at the same time.
--- End quote ---
In this previous extremely simple "single toggle button" solution this is not possible of course if need two separate zoomed in parts displayed. But also in your explanation this full deep memory is available only after stop. Edit: clarified: Runtime you can see only these two zoomed in parts with more or less limited positioning. (I use also "zoomed in" thinking for this full window zoom mode what is just how many (most) scopes work. You may have 10M sample memory and 1Gsa/s and your fastest 2ns/div "timebase" zoomed in (full screen zoom in) 10 div wide window is just example 20ns slice from this example 10000000ns long acquistion length. And what happen when turn "timebase" only zoom in factor change.
Now if your time base is 20ns you can select zoom 20ns and move it to other position in this long memory.
But how if you then have moved it but you suddenly want zoom it out. many scopes do not accept it. You need first change this "main timebase" aka zoom factor aka horizontal scale.
Full memory lenght to display + dual independent zoom in to details like in some ancient good analog scope is this.
Digital scope can do it and also in runtime whole memory length display is possible to see or shut off and these two separate "zoomed in" traces can draw overlaid with free time position related to each others and or each others based fixed difference where all are user adjustable including also freedom for set fixed trigger time position in acquisition memory. Three timebase with dual independent delayed timebases (timebase is bit fun word with digital scopes but Im from analog scopes golden era). Of course all can do, even Rolls Royce. But there is markets and how much some features really add sales and more importantly profit to maker.... all is nice to have but money talks.
But I want scope what can display full current memory length always when/if I want on the screen and many scopes can not. Even if length is 1G I want see whole trace without hiding parts out from display except cases when I do not care this. If I want cdetails today it is best there is user settable windows available with different scales overlaid on screen and full freedom for user to position and adjust these scales and time relations to each others and trigger-.
rf-loop:
--- Quote from: nctnico on June 15, 2020, 02:35:45 pm ---You choose an example in which you can still see both signals on an oscilloscope with very little memory. Set the bitrate to 1Mbit/s (100 times higher) with a much higher packet rate as well and try to do the same with the top zoom window set to 5ms/. You'll see a contigous colored band. If you set the zoom window to 50us/ in order to see the packets a Siglent scope will shorten the memory depth and there is nothing you can do about it. You have a choice between either having long memory but not being able to see the packets in the zoom window OR seeing the packets but not have deep memory.
--- End quote ---
What is real reason for these lies?
This is handled many many times including document images etc. Only what Sig do not have is hardware decode with pros and cons. Yes it is slower to decode and also some limits with decode result length but also it can decode without real time live signal just afterwards..
nctnico:
--- Quote from: 2N3055 on June 15, 2020, 03:29:01 pm ---
--- Quote from: nctnico on June 15, 2020, 02:35:45 pm ---You choose an example in which you can still see both signals on an oscilloscope with very little memory. Set the bitrate to 1Mbit/s (100 times higher) with a much higher packet rate as well and try to do the same with the top zoom window set to 5ms/. You'll see a contigous colored band. If you set the zoom window to 50us/ in order to see the packets a Siglent scope will shorten the memory depth and there is nothing you can do about it. You have a choice between either having long memory but not being able to see the packets in the zoom window OR seeing the packets but not have deep memory.
--- End quote ---
No it won't. I showed you example from my Pico where I sampled 100 MPoints in 200ms and shown it zoomed in to 20ns /div, zoom factor of 1M X. Yes, one million times.
Tautech posted one image above, where he got 50 MPoints at 20 ms/div (200 ms total) and is showing details at 20 us/div.
This is how it works but you don't seem to understand. On main timebase you grab big chunk of data, and zoom shows a subset of that, in such a detail that is only defined by sampling rate. Which will be limited by memory size.
But zooming in won't change anything from how timebase and sampling is set, only what are you looking at.
So you enable 100 MPoints, set timebase to use all 100 MPoints, and you can zoom in to every single point...
And zoom will not shorten or change anything.
What are you saying is SIMPLY NOT TRUTH. Just look at the overwhelming evidence shown here..
--- End quote ---
Sorry, but again you are not understanding the problem; you should try the steps I wrote on a Siglent or Lecroy oscilloscope and you'll see the limitations for yourself. You think you achieve the same but you don't. It is true there are many routes to Rome. You keep insisting the taking the long route to Rome is that same as taking the short route to Rome. That simply isn't true. It is no my fault you can't see the short route to Rome.
jemangedeslolos:
--- Quote from: nctnico on June 15, 2020, 04:19:08 pm ---
--- Quote from: 2N3055 on June 15, 2020, 03:29:01 pm ---
--- Quote from: nctnico on June 15, 2020, 02:35:45 pm ---You choose an example in which you can still see both signals on an oscilloscope with very little memory. Set the bitrate to 1Mbit/s (100 times higher) with a much higher packet rate as well and try to do the same with the top zoom window set to 5ms/. You'll see a contigous colored band. If you set the zoom window to 50us/ in order to see the packets a Siglent scope will shorten the memory depth and there is nothing you can do about it. You have a choice between either having long memory but not being able to see the packets in the zoom window OR seeing the packets but not have deep memory.
--- End quote ---
No it won't. I showed you example from my Pico where I sampled 100 MPoints in 200ms and shown it zoomed in to 20ns /div, zoom factor of 1M X. Yes, one million times.
Tautech posted one image above, where he got 50 MPoints at 20 ms/div (200 ms total) and is showing details at 20 us/div.
This is how it works but you don't seem to understand. On main timebase you grab big chunk of data, and zoom shows a subset of that, in such a detail that is only defined by sampling rate. Which will be limited by memory size.
But zooming in won't change anything from how timebase and sampling is set, only what are you looking at.
So you enable 100 MPoints, set timebase to use all 100 MPoints, and you can zoom in to every single point...
And zoom will not shorten or change anything.
What are you saying is SIMPLY NOT TRUTH. Just look at the overwhelming evidence shown here..
--- End quote ---
Sorry, but again you are not understanding the problem; you should try the steps I wrote on a Siglent or Lecroy oscilloscope and you'll see the limitations for yourself. You think you achieve the same but you don't. It is true there are many routes to Rome. You keep insisting the taking the long route to Rome is that same as taking the short route to Rome. That simply isn't true. It is no my fault you can't see the short route to Rome.
--- End quote ---
I think there are people full of good will who try to understand with the support of screenshots.
So I believe the best thing to make yourself understood is that you make a capture with your manual memory depth capable R&S or GW Instek and you do the same with your Lecroy in a scenario where clearly demonstrates the difference between the two memory management implementation.
So that everyone understands without ambiguity.
I know it takes time, but it could reduce the 100-year war and save millions of lives.
tv84:
Dave's video already shows the "problem" explicitly (at least for my knowledge level).
The rest of the rumblings are different ways of explaining the thing (with more or less expert details) but, in the end, after all the juice has been squeezed, all come down to the same.
Those that disagree with this analysis, have misunderstood the simplicity of the bad/wrong (strike the one that makes you itchy) implementation that Dave's has showed in the video.
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