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Oscilloscope Zoom Out Quirk
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Wuerstchenhund:

--- Quote from: EEVblog on May 08, 2020, 08:18:12 am ---
--- Quote from: Wuerstchenhund on May 08, 2020, 08:12:56 am ---Wouldn't this make a nice topic for one of your videos? Maybe coupled with a comparison of the nctnico method vs everyone else's method?  :-DD
--- End quote ---

What's his method again?, I must have missed that.
I just set the scopes max memory depth and a 1us timebase and STOP it. If it lets me zoom out to slower timebases and still show data then it passes.
Then repeat using a trigger signal just in case there is a difference between manual STOP mode and a trigger event capture.

--- End quote ---

Nico has used the example of an SPI frame where you are interested in a certain bit but also want to check the whole frame.

Nico's method (if I understand it correctly!) is this:
 
- Set the trigger to the data point of interest
- Set memory to max
- Set the time base so the specific data point fills the screen (i.e. max detail)
- Perform a single acquisition, then STOP
- Check out the data point
- Then zoom out to check out the rest of SPI frame

The method I know would be:
- Set the trigger to the data point of interest
- Set memory to max Not necessary as scopes will usually maximize the memory to an sufficient extend automatically
- Check what the length of that SPI frame is and set the timebase to capture the whole frame (say 100us)
- Perform a single acquisition Actually, I might not want to but prefer to look at life data, so I leave the scope on normal mode
- Check out the frame
- Zoom in to the datapoint of interest and check that out

The result is the same, it's just the opposite way of doing it. Nico's method is also perfectly valid, however won't be possible unless the scope allows him to zoom out (which many don't, especially on very short time bases). While the method I have described works on every DSO.

The other difference is that, when it comes setting up your scope and avoiding excessive acquisition time (keeping in mind that time saving was one of the arguments for his method!), Nico needs to know how much memory he needs to use, so he not only needs to establish what the frame lenght is but also how in how many points this translates in terms of sample memory. While the second method just requires knowledge of the frame length.

Keep in mind this is *not* "zooming out"as having your scope in normal mode and just changing the timebase so you can see more of the signal, which again works on every scope. It's really about if a scope can record beyond its screen on very short timebases when the memory is set accordingly, which is only visible in a single acquisition.

The contentious point was actually not about the methods itself (I just never heard of anyone doing it this way before) but if a scope should be expected to accommodate Nico's method and what the relevance of this is in real life.
nctnico:

--- Quote from: Wuerstchenhund on May 08, 2020, 09:18:13 am ---
--- Quote from: EEVblog on May 08, 2020, 08:18:12 am ---
--- Quote from: Wuerstchenhund on May 08, 2020, 08:12:56 am ---Wouldn't this make a nice topic for one of your videos? Maybe coupled with a comparison of the nctnico method vs everyone else's method?  :-DD
--- End quote ---

What's his method again?, I must have missed that.
I just set the scopes max memory depth and a 1us timebase and STOP it. If it lets me zoom out to slower timebases and still show data then it passes.
Then repeat using a trigger signal just in case there is a difference between manual STOP mode and a trigger event capture.

--- End quote ---

Nico has used the example of an SPI frame where you are interested in a certain bit but also want to check the whole frame.

Nico's method (if I understand it correctly!) is this:
 
- Set the trigger to the data point of interest
- Set memory to max
- Set the time base so the specific data point fills the screen (i.e. max detail)
- Perform a single acquisition, then STOP
- Check out the data point
- Then zoom out to check out the rest of SPI frame

The method I know would be:
- Set the trigger to the data point of interest
- Set memory to max Not necessary as scopes will usually maximize the memory to an sufficient extend automatically
- Check what the length of that SPI frame is and set the timebase to capture the whole frame (say 100us)
- Perform a single acquisition Actually, I might not want to but prefer to look at life data, so I leave the scope on normal mode
- Check out the frame
- Zoom in to the datapoint of interest and check that out

The result is the same, it's just the opposite way of doing it. Nico's method is also perfectly valid, however won't be possible unless the scope allows him to zoom out (which many don't, especially on very short time bases). While the method I have described works on every DSO.

The other difference is that, when it comes setting up your scope and avoiding excessive acquisition time (keeping in mind that time saving was one of the arguments for his method!), Nico needs to know how much memory he needs to use, so he not only needs to establish what the frame lenght is but also how in how many points this translates in terms of sample memory. While the second method just requires knowledge of the frame length.

Keep in mind this is *not* "zooming out"as having your scope in normal mode and just changing the timebase so you can see more of the signal, which again works on every scope. It's really about if a scope can record beyond its screen on very short timebases when the memory is set accordingly, which is only visible in a single acquisition.

The contentious point was actually not about the methods itself (I just never heard of anyone doing it this way before) but if a scope should be expected to accommodate Nico's method and what the relevance of this is in real life.

--- End quote ---
You are missing a few fine details:
- I'm not using single acquisition in most cases. I stop the oscilloscope when I see something of interest and in some cases I leave it in run mode because I have control over generating the trigger events somewhere else.
- I don't care about the time base setting and I'm not going to calculate how much memory I need. If it turns out to be not enough then I have to fallback to presetting the time base. The deeper the memory, the less this is necessary.

The key point to my method is that you don't need to worry about setting up the time/div and horizontal position of the scope properly before doing a measurement. Sometimes I forget to put the horizontal position back to the trigger point. With the oscilloscope recording outside the screen I can just scroll back to the trigger point. The benefits of my method are:

- Scope time/div setup is not critical to catch all data in many cases
- Least twiddling with knobs & settings


 Keep in mind that this usage mostly happens during debugging interaction between software and hardware. In the end it saves time. I think I already mentioned this workflow in my review of the SDS2204 I did 5 or 6 years ago. I have not checked that yet.
EEVblog:

--- Quote from: Wuerstchenhund on May 08, 2020, 09:18:13 am ---
--- Quote from: EEVblog on May 08, 2020, 08:18:12 am ---
--- Quote from: Wuerstchenhund on May 08, 2020, 08:12:56 am ---Wouldn't this make a nice topic for one of your videos? Maybe coupled with a comparison of the nctnico method vs everyone else's method?  :-DD
--- End quote ---

What's his method again?, I must have missed that.
I just set the scopes max memory depth and a 1us timebase and STOP it. If it lets me zoom out to slower timebases and still show data then it passes.
Then repeat using a trigger signal just in case there is a difference between manual STOP mode and a trigger event capture.

--- End quote ---

Nico has used the example of an SPI frame where you are interested in a certain bit but also want to check the whole frame.

Nico's method (if I understand it correctly!) is this:
 
- Set the trigger to the data point of interest
- Set memory to max
- Set the time base so the specific data point fills the screen (i.e. max detail)
- Perform a single acquisition, then STOP
- Check out the data point
- Then zoom out to check out the rest of SPI frame

--- End quote ---

Exactly the same as what I'm doing, except I couldn't be arsed to use any data  ;D
You don't need the data, it's obvious when the samples run out as the trace stops at both ends.


--- Quote ---The contentious point was actually not about the methods itself (I just never heard of anyone doing it this way before) but if a scope should be expected to accommodate Nico's method and what the relevance of this is in real life.

--- End quote ---

I don't see it as contentious, it has obvious use. It lets your trigger thing or interest and then say "gee I wonder what happened before or after that". If you have a scope that captures outside the display then you don't have to retrigger again at longer time base. This could actually be vital on something you can only trigger off intermittently for example.
Gandalf_Sr:

--- Quote from: EEVblog on May 08, 2020, 09:36:44 am ---Exactly the same as what I'm doing, except I couldn't be arsed to use any data  ;D
You don't need the data, it's obvious when the samples run out as the trace stops at both ends.

--- End quote ---
It's the story of my life, the data I need are always just after the scope runs out of memory  :(
2N3055:

--- Quote from: nctnico on May 08, 2020, 09:31:29 am ---
--- Quote from: Wuerstchenhund on May 08, 2020, 09:18:13 am ---
--- Quote from: EEVblog on May 08, 2020, 08:18:12 am ---
--- Quote from: Wuerstchenhund on May 08, 2020, 08:12:56 am ---Wouldn't this make a nice topic for one of your videos? Maybe coupled with a comparison of the nctnico method vs everyone else's method?  :-DD
--- End quote ---

What's his method again?, I must have missed that.
I just set the scopes max memory depth and a 1us timebase and STOP it. If it lets me zoom out to slower timebases and still show data then it passes.
Then repeat using a trigger signal just in case there is a difference between manual STOP mode and a trigger event capture.

--- End quote ---

Nico has used the example of an SPI frame where you are interested in a certain bit but also want to check the whole frame.

Nico's method (if I understand it correctly!) is this:
 
- Set the trigger to the data point of interest
- Set memory to max
- Set the time base so the specific data point fills the screen (i.e. max detail)
- Perform a single acquisition, then STOP
- Check out the data point
- Then zoom out to check out the rest of SPI frame

The method I know would be:
- Set the trigger to the data point of interest
- Set memory to max Not necessary as scopes will usually maximize the memory to an sufficient extend automatically
- Check what the length of that SPI frame is and set the timebase to capture the whole frame (say 100us)
- Perform a single acquisition Actually, I might not want to but prefer to look at life data, so I leave the scope on normal mode
- Check out the frame
- Zoom in to the datapoint of interest and check that out

The result is the same, it's just the opposite way of doing it. Nico's method is also perfectly valid, however won't be possible unless the scope allows him to zoom out (which many don't, especially on very short time bases). While the method I have described works on every DSO.

The other difference is that, when it comes setting up your scope and avoiding excessive acquisition time (keeping in mind that time saving was one of the arguments for his method!), Nico needs to know how much memory he needs to use, so he not only needs to establish what the frame lenght is but also how in how many points this translates in terms of sample memory. While the second method just requires knowledge of the frame length.

Keep in mind this is *not* "zooming out"as having your scope in normal mode and just changing the timebase so you can see more of the signal, which again works on every scope. It's really about if a scope can record beyond its screen on very short timebases when the memory is set accordingly, which is only visible in a single acquisition.

The contentious point was actually not about the methods itself (I just never heard of anyone doing it this way before) but if a scope should be expected to accommodate Nico's method and what the relevance of this is in real life.

--- End quote ---
You are missing a few fine details:
- I'm not using single acquisition in most cases. I stop the oscilloscope when I see something of interest and in some cases I leave it in run mode because I have control over generating the trigger events somewhere else.
- I don't care about the time base setting and I'm not going to calculate how much memory I need. If it turns out to be not enough then I have to fallback to presetting the time base. The deeper the memory, the less this is necessary.

The key point to my method is that you don't need to worry about setting up the time/div and horizontal position of the scope properly before doing a measurement. Sometimes I forget to put the horizontal position back to the trigger point. With the oscilloscope recording outside the screen I can just scroll back to the trigger point. The benefits of my method are:

- Scope time/div setup is not critical to catch all data in many cases
- Least twiddling with knobs & settings


 Keep in mind that this usage mostly happens during debugging interaction between software and hardware. In the end it saves time. I think I already mentioned this workflow in my review of the SDS2204 I did 5 or 6 years ago. I have not checked that yet.

--- End quote ---

But you do have lots of twiddling of knobs while you are looking at the data....

Like I said, what you do is runaround way doing same thing as I do simpler.  I put Pico to 200 MS depth, set it to 200 ms, and let it rip..
Sometimes in run mode where I stop it and look around, or zoom in to a window ( On Picoscope zoom mode is still full screen, no loss of size) and keep looking at that time in run  mode. Or I have a burst of something that I get in single mode and look at it.
I literally bought Picoscope for that purpose.... And many protocols, deep mem, and huge PC screens (plural) is much better for that than any standalone scope.
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