Agilent Technologies 54830 Series, Service Manual

Page: 74 / 170

Chapter 3: Testing Performance
To test trigger sensitivity
3–25
Procedure—Auxiliary Trigger Test (4-channel models only)
This test is necessary only on the Agilent 54831B/D and Agilent 54832B/D.
The auxiliary trigger input is on the front panel of the oscilloscope near the vertical inputs. The
dc input resistance of the aux trigger is 2.58k
Ω , so to avoid reflections, the trigger source is
back-terminated with 50 Ω .
1
With an N-to-BNC adapter and BNC cable, connect the signal generator to the input of
the power splitter. Connect one output of the power splitter to the Aux Trig input
through a 50
Ω
feedthrough termination. Connect the other output of the power splitter
to channel 1.
2
Set the signal generator for 500 MHz, approximately 0 dBm.
3
Set the channel 1 input to 50-
Ω
input impedance and press Autoscale.
4
Set the channel 1 scaling to 50 mV/div. Then set the signal generator for 6 divisions of
signal (300 mV
pp
).
5
Press the Source key (Trigger section of front panel) to highlight Aux.
6
Set the trigger level to 0.000 V.
7
Slowly adjust the Trigger Level knob slightly around the 0 V setting to obtain a stable
trigger. Otherwise, the test fails. Record the result in the Performance Test Record.
If a test fails
Failure of the internal trigger or external trigger sensitivity tests can be caused by a defective main
assembly or attenuator. Failure of the auxiliary trigger sensitivity is caused by a problem on the main
assembly or a bad input cable. If you need further troubleshooting information, go to chapter 5,
“Troubleshooting.”