12-03-2014 09:48 AM
Hello,
I'm new to the forums and VirtualBench, and was hoping someone might be able to help.
When I export data from the VirtualBench, I get 4 columns of data for the 2 channels. They are "1Min", "1Max", "2Min", "2Max".
Example:
Timestamps (ns) | 1 Min | 1 Max | 2 Min | 2 Max |
-3000600000 | -0.205761317 | 0.12345679 | -0.013168724 | -0.001646091 |
-2990598000 | -0.205761317 | 0.12345679 | -0.013168724 | -0.003292181 |
-2980596000 | -0.205761317 | 0.12345679 | -0.013168724 | -0.003292181 |
-2970594000 | -0.205761317 | 0.12345679 | -0.013168724 | -0.001646091 |
I don't understand what the min/max refers to. I do not have any averaging on. Does VirtualBench actually take multiple samples at each point?
Thanks.
Solved! Go to Solution.
12-03-2014 09:57 AM
At some settings, the VirtualBench application will automatically put the hardware in peak-detect mode.
In peak-detect mode, the scope oversamples, and returns the min and the max voltage during each sample period.
You can manually control the sample mode by going to the acquisition settings:
12-03-2014 10:04 AM
Thank you, William.
My settings are "PeakDetect".
Would an averaging of the Min and Max after exporting be the most accurate representation of the waveform?
12-03-2014 10:25 AM
That depends on your input signal. For example, if you had a single, large glitch during a sample period, an average may not be a very accuracte representation of the signal. However, if the signal was relatively stable over the sample period, an average might be a good representation of the signal.
In peak detect mode, the scope oversamples at 250MS/s and saves the min and the max of each sample period. So for example, if the scope is sampling at 10MS/s and is in peak detect mode, it saves the min and the max of every 25 points that are oversampled at 250MS/s, or in other words the input is sampled every 4 ns, and the scope saves the min and max of the input over each 100 ns period. This mode is useful if you would like to be able to acquire for a long time, but still have a good chance of seeing glitches in your signal.
In sample mode, the scope saves every sample it acquires. If it's configured to sample at 250MS/s, it saves the state of the input every 4 ns. If it's configured to acquire at 10MS/s, if saves the state of the input every 100 ns. To get the most accurate representation of the waveform, use sample mode and acquire as fast as possible (zoom in to the smallest time per division in the app possible for your signal).
12-03-2014 10:29 AM
Also, to be clear, in sample mode the data export will just have the value of the input at each sample interval, instead of the min and max. For example:
Timestamps (ns) | 1 |
-102 | 0.009465 |
-100 | 0.011934 |
-98 | 0.006584 |
...
12-03-2014 10:40 AM
Thank you very much, William.