Time Cursor Accuracy (Continuation Of 6.3.25) - Fluke Autoranging CombiScope PM3370B Service Manual
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Also See for Autoranging CombiScope PM3370B:
- User manual (297 pages) ,
- User manual (298 pages) ,
- Reference manual (133 pages)
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PERFORMANCE TEST
Test set-up:
Settings/procedure:
1 -
Apply a 5 us time marker signal to input CH1.
2 -
Press the AUTOSET key.
3 -
Use a 50Ω termination. For instruments with switchable 50Ω input impedance it is
recommended to make use of this feature.
4 -
Press the TRIGGER menu key.
5 -
Select level-pp 'off' and trigger coupling 'dc' from the TRIGGER MAIN TB menu.
6 -
Adjust the TRIGGER LEVEL control for a correctly triggered display.
7 -
Set the MAIN TB TIME/DIV to 5.00 us.
8 -
Select the MTB VARiable mode by pressing both MAIN TB TIME/DIV keys at a time: the
message; 'VARIABLE TIMEBASE' is displayed briefly.
9 -
Press the 'ns' key and adjust the readout to 2.50 us.
Requirements:
-
Verify that the horizontal distance between the time markers equals 2 divisions.
-
Use the X POS control to align the marker pulses with the graticule.
Now check (across the central 8 divisions) if the timebase accuracy is ±2.8%: make use of the
-
deflection error facility of the time marker generator to check this.
6.3.26 Time cursor accuracy (continuation of 6.3.25)
This test verifies the accuracy of the time cursors.
Settings/procedure:
1 -
Switch the MAIN TB VARiable mode off by pressing both MAIN TB TIME/DIV keys at a time.
The message '1-2-5 STEPS'.
Select 5.00 µs/division for the MAIN TB.
2 -
3 -
Switch off the deflection error facility of the time marker generator.
4 -
Press the CURSORS menu key.
5 -
Select 'on' and time cursors (//) from the CURSORS menu.
Select ∆ T in the READOUT menu.
6 -
Requirements:
-
Position one cursor line exactly on the 2nd time marker on the screen and the other cursor on the
10th time marker. The distance between both cursors is now 8 time marker intervals. Check for a
cursor readout between 39.5 and 40.5 µs.
Press the ANALOG key ('DIGITAL MODE' is displayed briefly) and repeat the check in this section
for the digital mode. Press the TEXT OFF key to have the full screen width available to display the
time markers.
Press the ANALOG key ('ANALOG MODE' is displayed briefly) to return to analog mode.
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