Agilent Technologies 54853A, Service Manual, Page: 81 / 194

Chapter 3: Testing Performance
Internal Channel Trigger Sensitivity Test
3–37
Low Sensitivity Measurements @ 2.5 GHz (54853A) or 4 GHz (54854A and 54855A)
1
Connect the microwave signal source to scope channel 1.
2
Set up the scope as follows:
a Press the Default Setup key.
b
Set channel 1 vertical sensitivity to 1.0 V/div.
c Set the horizontal scale to 2 ns/div.
d
Pull down the Setup menu, select trigger and then set up the trigger parameter as follows:
Mode = Edge
Source = Channel 1
Sweep = Auto
Click on Conditioning and select Low Sensitivity.
e Pull down the Setup menu, select Acquisition and then set up the acquisition parameters
as follows:
Memory Depth = Automatic
Sampling rate = Maximum 20 GSa/s
Sin(x)/x Interpolation filter enabled
Averaging enabled with # of Averages = 16
3
Set up the source generator as follows:
Frequency = 2.5 GHz (if testing 54853A) or 4.0 GHz (if testing 54854A or 54855A)
Amplitude = -1.5 dBm
4
Click the V p-p measurement icon on the left side of the display and then coarsely adjust
the signal amplitude until the mean amplitude is
≥1.0
Vp-p. Press the Clear Display key
after each amplitude adjustment.
5
Turn the V p-p measurement off.
6
Press the trigger Sweep key until Trig’d is illuminated and then carefully adjust the
trigger Level control until the Trig’d indicator by the Horizontal timebase knob turns
on solidly (not blinking) to indicate stable triggering.
7
Reduce the source generator signal amplitude in 0.2 dBm decrements until the Trig’d
indicator by the Horizontal timebase knob starts to blink on and off. When the Trig’d
indicator starts to blink, carefully re-adjust the trigger level to try to re-establish stable
triggering (Trig’d indicator not blinking.) If stable triggering is re-established, then
continue to reduce input signal amplitude until the Trig’d indicator starts to blink on
and off. Repeat this procedure until adjusting the trigger level cannot re-establish stable
triggering.
8
Measure the signal amplitude applied to channel 1 as follows:
a Increase the vertical sensitivity of channel 1 until the displayed waveform is at least 4
divisions in amplitude and is not clipped.
b Click the V p-p measurement icon on the left side of the screen.
c Record the V p-p mean value displayed at the bottom of the screen in the space provided
in the Internal Trigger Sensitivity Test section (Low Sensitivity @ 4 GHz or 2.5 GHz)
section of the Performance Test Record for channel 1.
d Convert this measurement into units of divisions at 1V/div using the expression:
e Record this peak-to-peak division value in the space provided in the Internal Trigger
Sensitivity Test section (Low Sensitivity @ 4 GHz or 2.5 GHz) section of the Performance
Test Record for channel 1.
Trig Sens
V
pp
1 V / div
------------------- ______ divisions = =