Trigger Sensitivity In Logic Mode Pm3384B - Fluke Autoranging CombiScope PM3370B Service Manual

6 - 36

6.3.40 Trigger sensitivity in logic mode PM3384B

The trigger sensitivity in the logic mode 'pattern' depends on the amplitude and frequency of the
trigger signal. In this test, the trigger sensitivity is tested with a sine wave via the CH1, CH2, CH3,
and CH4 inputs.
Test equipment:
Fluke 5500A mode: levsine: (Alternative: constant amplitude sine wave generator SG 503).
Test setup:
1 - Press the ANALOG key ('DIGITAL MODE' is displayed briefly) to activate the digital mode.
2 - Apply a 50 MHz sine-wave signal of 1 V(pp into 50 ohm) from the constant amplitude sine-
wave generator to input CH1.
3 - Press the AUTOSET key, and set CH1 to 0.5V/division.
4 - Use a 50 ohm termination.
5 - Set the input coupling to DC and POSition the signal in the vertical center of the screen.
6 - Select 5.00 ns/division for MAIN TB.
7 - Press the TRIGGER menu key and select 'logic', 'pattern', and 'enter' from the related menu.
8 - Operate the front panel keys TRIG1, TRIG2, TRIG3 and TRIG4 to obtain the trigger pattern
Hxxx (x = don't care) in the menu.
9 - Press the TB MODE menu key and select 'trig' from the related menu.
10 - Decrease the amplitude of the generator voltage to 1 division.
11 - Turn the TRIGGER LEVEL control and check that a well-triggered signal is obtained.
12 - Increase the input frequency to 200 MHz.
13 - Increase the input voltage to 2 division.
14 - Turn the TRIGGER LEVEL control, and check that a well-triggered signal is obtained.
15 - Press the ANALOG key ('ANALOG MODE' is displayed briefly) to return to analog mode.
Repeat the procedure for CH2 with trigger pattern xHxx
Repeat the procedure for CH3 with trigger pattern xxHx
Repeat the procedure for CH4 with trigger pattern xxxH
PERFORMANCE TEST