Testing The Optional Auxiliary Outputs - Fluke Autoranging CombiScope PM3370B Service Manual

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6.3.44 Testing the optional auxiliary outputs

MTB-GATE and DTB-GATE outputs.
Test equipment: measuring oscilloscope.
Test set up:
Settings/procedure:
Oscilloscope under test:
- Take care that no input signal is applied to the oscilloscope inputs.
- Press the STATUS and TEXT OFF keys simultaneously. This assures that the oscilloscope
occupies its default position.
- Press the DTB menu key to display the DELAYED TIME BASE menu. Select the 'on' position of
the DEL'D TB softkey. The result is that MTB is in 1.00 ms/div and that DTB is in 100 µs/div and
that both time bases are on.
- Apply a 50Ω coaxial cable to rear panel output 'MTB-GATE'.
- Apply another 50Ω coaxial cable to rear panel output 'DTB-GATE'.
Measuring oscilloscope:
- Apply the coaxial cable from signal 'MTB GATE' of the oscilloscope under test to input CH1 of
the measuring oscilloscope.
- Apply the coaxial cable from signal 'DTB GATE' of the oscilloscope under test to input CH2 of
the measuring oscilloscope.
- Press the green AUTOSET key.
- Adjust CH1 and CH2 to DC input coupling; if the ocilloscope is in 50Ω ('LZ') position, select an
input impedance of 1MΩ.
- Adjust CH1 and CH2 to 2 V/div.
- Select 2 ms/div for MTB.
Requirements:
- Verify that two square-wave signals are displayed via CH1 and CH2 of the measuring
oscilloscope.
- Verify that the 'low' level of both square-waves is between 0 .. 0.4 V.
- Verify that the 'high' level of both square-waves is between 2.4 .. 5 V.
- Verify that the 'MTB GATE' signal (is displayed via CH1) is high during 10 ms or more.
- Verify that the 'DTB GATE' signal (is displayed via CH2) is high during 1 ms or more.
PERFORMANCE TEST