Rigol DS1102E period display?

Discussion in 'General Electronics Chat' started by spinnaker, Jan 21, 2014.

  1. spinnaker

    Thread Starter AAC Fanatic!

    Oct 29, 2009
    Exactly how does the period (outlined in red below) work in the DS1102E?

    The manual mentions how to turn it on but I did not see where it explained what I am looking at.

    What I do not understand is that if I change vertical sensitivity, I would expect the period to stay the same but it changes. What does the number actually represent? And how do you turn it on for channel #2?
    I would assume the (1) represents the channel number?

  2. crutschow


    Mar 14, 2008
    You are correct, the period of the waveform (time for one cycle period) should not change appreciably with a change in vertical sensitivity. How much does it change?

    There should be a way to select which channel is being measured when you select the measurement function.
  3. spinnaker

    Thread Starter AAC Fanatic!

    Oct 29, 2009
    For the waveform I am displaying, it can change almost 10us. What is really strange is if I change the H sensitivity to where less than a full waveform can be displayed then the value can't be displayed. It displays ******* (and that is not a bad word it is really asterisks :) ).

    It is almost like it is calculating the period from the actual display much like you would read it, rather than display the measured period. That could explain the discrepancy in readings, as the sensitivity of the display is changed so does the accuracy of the reading.
  4. GopherT

    AAC Fanatic!

    Nov 23, 2012
    I am guessing that the scope has to "see it" on the display. That way, you can zoom in to the section of the waveform you want (sine wave of low amplitude riding on a bigger square wave) and read the frequency you want.

    It looks like you have to put the zero cross at the (t) at top of the screen center. Then measure a full period from there to right. Again, just a guess.
  5. MrChips


    Oct 2, 2009
    Tektronix TDS1000 series scopes behave in a similar fashion. The signal must be displayed on the screen otherwise it gets its math wrong.
  6. THE_RB

    AAC Fanatic!

    Feb 11, 2008
    I thought most digital 'scopes do all the measurements based on the trigger? That's how my Hantek does it.

    If I have a waveform I can adjust the trigger voltage line up or down, and the measurements change to suit.

    For instance if there is a + noise spike every few mains cycles I can raise the trigger high enough so only the noise spike crosses the trigger line, then the measurements will show the period/freq and duty of the noise artifact.

    I don't even think it needs to be on-screen, just that the trigger thresholds can trigger on the data.