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Chapter 3: Testing Performance
To test bandwidth
7 Change the signal generator to 500 MHz and set the power meter Cal Factor to
500 MHz % value from the chart.
8 Adjust the signal generator eee
for a power reading as close as possible to
0.0 dB(REL). Reading =
9 Set the time/div to 2 ns/div.
10 After the measurement settles (averaging complete), note the V amptd (1) reading:
Vs500MHz=__
mV,
11 Calculate the response using the formula:
response(dB) = 20 logio Seoodis =20 logic
=
dB
12 Correct the result from step 11 with any difference in the power meter from step 8.
Observe signs. For example:
Result from step 11 = -2.3 dB
. Power meter reading = -0.2 dB(REL)
then true response = (-2.3)-(-0.2) = -2.1 dB
¢
-¢
)=
dB
13 The result from step 12 should be between +3.0 dB and -3.0 dB. Record the result in
the Test Record.
14 Switch the power splitter from channel 1 to channel 2 input.
15 On the oscilloscope, set the following parameters.
Menu (hardkey)
Function/Parameter
Setting
Vertical (channel keys)
1
off
2
on
Horizontal
(time/div)
200 ns/div
TRIG
source
2
16 Press
(blue)
,thenpress
clr . Repeat steps 3 through 16 for untested
channels, setting 'the parameters of the channel being tested where appropriate.
Real Time Test
In the real time mode, the bandwidth is limited by the software; the hardware is unchanged.
Therefore, testing real-time bandwidth is optional.
17 Press Horizontal Setup
and set the mode to realtime.
18 Repeat steps 2 through 16, testing all vertical channels using as an upper frequency
test limit the following:
HP 54522A and 545424; 500 MHz
HP 545404; 250 MHz (1 or 2 channels on), 125 MHz (8 or 4 channels on)
HP 54520A; 125 MHz
If the test fails
Failure of the bandwidth test can be caused by faulty attenuator or main assembly, or the need for
high-frequency pulse response adjustment.
3-10
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