EEVblog Electronics Community Forum
Products => Test Equipment => Topic started by: SharpEars on October 24, 2014, 09:27:49 pm
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Let's say I record 1 ms of signal while set to a horizontal scale of 100 us. I can pan through the entire recorded signal, but if I try to zoom out horizontally to say 200 us, all the scope does is to make the horizontal trace half it's width. It doesn't actually display the additional data to the left and to the right of the original trace which has been captured. I can pan through this data still, but I cannot use the full horizontal real-estate to view it at horizontal scales longer than the scale used during capture.
Is what I am describing a bug, a limitation of the hardware or some sort of misconfiguration on my part?
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Oh my. What becomes when you zoom out a picture on the computer? You are supposed to zoom in, not zoom out. If you want to capture a lot of data, choose larger horizontal scale, choose bigger capture memory setting if you want to zoom in very fine detail. Then zoom in after waveform captured.
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It doesn't actually display the additional data to the left and to the right of the original trace which has been captured.
why do you believe that additional data has been captured?
The scope only captures what you set with the timebase and what fits on one screen. If you want more, you need to increase the timebase before capturing, then you can later zoom in on that.
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Let's say I record 1 ms of signal while set to a horizontal scale of 100 us. I can pan through the entire recorded signal, but if I try to zoom out horizontally to say 200 us, all the scope does is to make the horizontal trace half it's width. It doesn't actually display the additional data to the left and to the right of the original trace which has been captured. I can pan through this data still, but I cannot use the full horizontal real-estate to view it at horizontal scales longer than the scale used during capture.
Is what I am describing a bug, a limitation of the hardware or some sort of misconfiguration on my part?
Hi, I'm not sure if I'm addressing the question(s) here but below are some screen captures showing decoding on a Rigol DS2072 (not the A version but I'm pretty sure the A version and the MSO version of the 2000 series will operate similarly). At 100ms per div I captured a waveform with decoding on; in the Stop mode I then adjusted the time setting to slower settings (50ms per div, 20ms per div, etc.). With this method if you want to see detailed decoding of individual Bytes (and bits) and you want a lot of Bytes (and bits) you can simply crank up the speed, capture the waveform, and then in the Stop mode zoom by slowing down the time per div (horizontal scale) and scrolling left/right until you have the detail you want. At any level of detail you can change the decoder between ASCII, HEX, Decimal, and Binary. EF
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It doesn't actually display the additional data to the left and to the right of the original trace which has been captured.
why do you believe that additional data has been captured?
The scope only captures what you set with the timebase and what fits on one screen. If you want more, you need to increase the timebase before capturing, then you can later zoom in on that.
I thought it captures as much as can fit into memory and stops when the memory is full. This is how I understood what pressing the record button does.
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I thought it captures as much as can fit into memory and stops when the memory is full. This is how I understood what pressing the record button does.
Actually it do, if you are using low horizontal scale and high memory setting it will capture additional data outside the screen. The requirement is that the scope cannot sample signal fast enough ( 1 or 2 Gsa/s depending on active channel number) that screen content can occupy all sample memory. This is if you just press start/stop or made a single capture. In that case you can zoom out.
As of record button, it is completely different beast. It is for segmented memory when you can replay many waveform captures made in series.
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I thought it captures as much as can fit into memory and stops when the memory is full. This is how I understood what pressing the record button does.
Actually it do, if you are using low horizontal scale and high memory setting it will capture additional data outside the screen. The requirement is that the scope cannot sample signal fast enough ( 1 or 2 Gsa/s depending on active channel number) that screen content can occupy all sample memory. This is if you just press start/stop or made a single capture. In that case you can zoom out.
As of record button, it is completely different beast. It is for segmented memory when you can replay many waveform captures made in series.
I guess I will have to play with it more to understand its limitations.