Technical data

48 4000 X-Series Oscilloscopes Service Guide
2 Testing Performance
d Set the time base to 500 ns/div.
e Set the Volts/Div for channel 1 to 200 mV/div.
f Press the [Acquire] key, then press the Averaging softkey.
g Turn the Entry knob to set # Avgs to 8 averages.
4 Set the signal generator for 1 MHz and six divisions of
amplitude.
The signal on the oscilloscope screen should be about five
cycles at six divisions amplitude.
5 Set up the Amplitude measurement
a Press the [Meas] key.
b Press the Clear Meas softkey and then the Clear All
softkey.
c Press the Ty pe: softkey and use the Entry knob to select
AC RMS - Full Screen (Std Deviation) within the select menu.
d Press the Add Measurement softkey.
6 Note the oscilloscope AC RMS - FS(1) reading at the
bottom of the screen. (This is the RMS value with any dc
offset removed.)
7 Set the power meter Cal Factor % to the 1 MHz value on
the calibration chart on the power sensor.
8 Note the reading on the power meter and covert to Vrms
using the expression:
For example, if the power meter reading is 892 uW, then
Vin
1MHz
= (892*10
-6
* 50Ω)
1/2
= 211.2 mV
rms
.
Vin
1MHz
Pmeas
1MHz
50Ω×=