Keysight DSOX1204A - Page 27

Testing Performance 2
DSOX1204A/G Oscilloscopes Service Guide 27
11 Set the oscilloscope sweep speed according to the following:
• 200 MHz Models: 2 ns/div
• 100 MHz Models: 5 ns/div
• 70 MHz Models: 5 ns/div
12 Note the oscilloscope AC RMS - Cyc(1) reading at the bottom of the screen.
13 Note the reading on the power meter and covert to Vrms using the expression:
14 Calculate the response using the expression:
Example If:
Pmeas
1_MHz
= 892 uW
Std Dev(n)
1MHz
= 210.4 mV
Pmeas
max_freq
= 687 uW
Std Dev(n)
max freq
= 161.6 mV
Then after converting the values from the power meter to Vrms:
15 The result from step 14 should be between +3.0 dB and -3.0 dB. Record the
result in the Performance Test Record (see page 34).
16 Move the power splitter from the channel 1 to the channel 2 input.
17 Turn off the current channel and turn on channel 2 using the channel keys.
18 Set the trigger source to channel 2.
19 Repeat steps 3 through 15 for the remaining channels, setting the parameters
of the channel being tested where appropriate.
Vin
maxfreq
Pmeas
maxfreq
50Ω×=
response(dB) = 20 log
10






MHz 1 MHz 1
freqmax freqma x
Vin / Vout
Vin / Vout
response(dB) = 20 log
10






mV211.2mV/ 210.4
mV 185.3 / mV 161.6
= -1.16 dB