I have discovered a fairly serious bug with recently released firmware version 2.13.00.07 when used with my DHO1204. This issue probably applies to all in the series and in addition to the DHO4000 series as well. It is possible that this error existed with earlier firmware but the latest firmware is the only version I have.
Maybe someone can confirm this. It would be interesting to see if the DHO800/900 series have this problem as well,
To repeat the bug:
1. Connect and trigger on a 10MHz signal to Channel 1 or probably any channel.
2. Set the acquisition depth to 10Mpts.
3. Set the main timebase to 50uS/division.Note that the sample rate is 500MHz 2ns per sample point.
4. Activate Zoom.
5. Set the Zoom timebase to 100nS/division.
6. Note that the cursor knobs can move AX and BX anywhere within the window.
The bug:
7. Now set the Zoom timebase to 50nS/division or faster.
8. Note that it is difficult, if not impossible, to place the cursors within the zoomed area and if you are able to do so the cursors will not stay in the zoomed area.
Note that the cursors should be able to be positioned anywhere within the zoomed area and be able to be positioned at any one of the sample points in the window.
9. If the Zoom timbase is reduced to 100nS or below the cursors work normally.
Sam
W3OHM