Fluke PM3082, Service Manual

Page: 457 / 496

PERFORMANCE TEST
6- 31
6.3.37 DTB triggering PM3092/3094; trigger sensitivity via CH1, CH2, CH3 and CH4
The trigger sensitivity depends on the amplitude and frequency of the trigger signal. In this test the
main timebase trigger sensitivity via the CH1, CH2, CH3 and CH4 inputs is checked.
test equipment:
Fluke 5500A mode: levsine (Alternative: constant amplitude sine wave generators (SG 503 +
SG 504)
test set-up:
5500A OSCILLOSCOPE UNDER TEST
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OUTPUT
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settings/procedure and requirements:
1 - Apply a 100 MHz sine-wave signal of 1 V(pp into 500) from the calibrator to input CH1.
2 - Press the AUTOSET key and set CH1 to 0.5 V/div.
3 - Use a 500 termination. For instruments with switchable 500 input impedance it is
recommended to make use of this feature.
4 - Set the input coupling of CH1 to DC and Position the signal in the vertical center of screen.
5 - Select ’trig’ in the menu under menukey TB MODE.
6 - Press menukey TRIGGER MTB and select in the TRIGGER MAIN TB menu level-pp ’off’ and
’dc’ trigger coupling.
7 - Adjust LEVEL MTB for a correctly triggered display.
8 - Press menukey DTB and select DEL’D TB ’on’ and MAIN TB ’on’ in the belonging menu.
9 - Set MTB to 0.2 us/div and DTB to 20 ns/div.
10 - Adjust the DELAY control to a delay time of 1.000 (is.
11 - Select ’trig’d’ and ’dc’ coupling in the DELAYED TIME BASE menu and press the front panel
key TRIG1. Or TRIG2 (CH2 on), TRIG3 (CH3 on), TRIG4 (CH4 on).
12 - Adjust the LEVEL DTB control for a well-triggered signal (intensified part must be visible).
13 - Operate the TRACE SEPARATION keys (or TRACK control) to separate MTB and DTB for well
visible displays.
14 - Decrease the amplitude of the input signal.
15 - Verify that the DTB is well triggered at signal amplitudes of 0.5 divisions and more.
16 - Decrease the input frequency to 50 kHz. Set MTB to 50 (is/div and DTB to 20 |is/div.
17 - Verify that the DTB stays well triggered at signal amplitudes of 0.5 divisions and more.
18 - Increase the input frequency to 200 MHz.
19 - Increase the input voltage to 1 division.
20 - Operate the LEVEL DTB control.
21 - Verify that the DTB is well triggered at all amplitudes of 1 division or more.
22 - Apply a 300 MHz sine-wave signal of 2 V(pp into 50 ohm) from the calibrator to input CH1.
23 - Adjust the input voltage to 2 divisions.
24 - Verify that the DTB is well-triggered at signal amplitudes of 2 divisions and more: adjust the
LEVEL DTB control if necessary.
Repeat the procedure for CH2, CH3 and CH4 for the frequencies 50 kHz (0.5 div input signal) and
300 MHz (2 div input signal)