Keysight Technologies Infiniium 90000A Series, Service Manual

Page: 37 / 136

Testing Performance
3
90000 A-Series Service Guide 37
For example, if (Vout @ Max Frequency) = 13.825 mV, (Vin @ Max Frequency) =
13.461 mV and Gain @ 50MHz = 1.0023, then:
Record this value in the Calculated Gain @Max Freq column in the Analog
Bandwidth—Maximum Frequency Check section of the Performance Test
Record. To pass this test, this value must be greater than -3.0 dB.
16
Change the oscilloscope setup as follows:
a
Change the channel vertical scale to 10 mV/div.
b
Reset the horizontal scale to 16 ns/div (to display 8 cycles of a 50 MHz
waveform).
17
Change the generator output as follows:
a
Reset the generator frequency to 50 MHz.
b
Change the amplitude to the value suggested for this scale setting in the
Nominal Generator Amplitude Settings table.
18
Repeat steps 8, 9, and 10 to measure the reference gain at 50 MHz for this
scale setting.
19
Repeat steps 11 through 14 to measure the gain at maximum frequency for this
scale setting.
20
Repeat steps 15 through 19 to complete measuring gains for the remaining
scale settings for channel 1 in the Analog Bandwidth—Maximum Frequency
Check section of the Performance Test Record.
21
Move the splitter to channel 2 and change the oscilloscope configuration as
follows:
a
Press [Default Setup] .
b
Ensure Channel 2 is displayed and all other channels are turned off.
c
Set the vertical scale of channel 2 to 5 mV/div.
d
Set the horizontal scale to 16 ns/div (to display 8 cycles of a 50 MHz
waveform).
e
Click Trigger > Setup Trigger... and change the source to channel 2.
f
Click Measure > Add Measurement... . Select the RMS voltage measurement,
Channel 2 as the source, Entire Display as the Measurement Area, and AC
for the RMS Type.
22
Repeat steps 7 to 20 to complete measuring gains for channel 2.
Gain
Max Freq
20 log
10
13.825 mV 13.461 mV
⁄
1.0023
------------------------------------------------------------- 0.212
dB = =