I need to measure the average of a waveform over a specific period of time (like one line cycle), not the integer number of waveform periods which the DSO7104 does by default. It would be great to be able to set the X cursors to a fixed delta-T instead of having them automatically decide the period they want to average over. Is there any way to do this, short of dumping the trace data to a spreadsheet?
The scope automatically sets the averaging period to an integer number of waveform periods now. All I want is to be able to set the averaging period with the cursors too. That shouldn't require a change to the acquisition mode from whatever it is during averaging now.
Hard to believe averaging over delta-X is not available. I'm using MSO 7054B. User guide says: "The X cursors show what portion of the displayed waveform is being measured". But the X cursor is automatically set to Full screen when "measure" button is pressed. Any Avg read solution, besides recording the desired interval X2-X1 and calculating the avaerage?
I can't recall if this works on a 7000, but it sure works on the new 3000X series. Try this:
1. Turn on Zoom mode (a.k.a Delayed mode) in the Timebase/Horizontal menu. This is the split-screen mode. 2. Adjust the zoom window to be the delta-X that you desire (using the Timebase scale knob). So, the lower waveform should be showing what you really wanted to measure. 3. Perform the Average measurement.
I believe in 7000, the measurement will automatically choose between measuring the full-screen waveform vs. the zoomed waveform, whichever gives a better value. In the new 3000X series, we get to choose which one to measure on, which is awesome.
You might need to update your 7000 firmware.
Hope it works, I don't have a 7000 to try out anymore, but I'm 99% sure it works that way.
Thanks Bret. Looks like Avg measurement always chooses the full screen. Don't see any manual way to switch to zoomed part - didn't find in user guide either. Other measurements, like Top, Amplitude selects zoomed window automatically. My library version is 0.2.25 from April, 2011.
You are both correct. The 3000 X-Series oscilloscope allows you to choose whether your measurements are made on the Main screen OR the Zoom screen. The 7000 Series oscilloscope does not have this feature.
Here's what you CAN do on the 7000:
Set the Average measurement to Full Screen and zoom in on the signal using Fine Horizontal adjustments (you can make fine horizontal adjustments by pressing the Horizontal knob). If you don't have a repeating signal you can use the Single button to capture your whole waveform and then adjust the horizontal scaling and delay to "zoom in" on the part of the signal you want to average.
Thank you! It's taken a year and a half and I've long since moved on from that project, but finally here's something to work with. I also updated my scope software per a recommendation above, and dang it next time I need to do specific period averaging I'll be up to the task.