26 S-Series Oscilloscopes Service Guide
3 Testing Performance
 
4 Configure the oscilloscope to measure the average voltage (V avg) on channel 
1 as follows:
a Change the vertical scale of channel 1 to 5 mV/div.
b Click the Vertical Meas tab on the left side of the screen, then drag and drop 
the Average measurement icon onto the channel 1 waveform. 
5 Press [Clear Display] on the oscilloscope and wait for the number of averages 
display (top right area of screen) to return to 256. Record the oscilloscope's 
mean V avg reading in the V
zero-error
 column of the Offset Accuracy Test (50 Ω) 
table. Use the Channel dialog box to select 1 MΩ impedance and then repeat 
steps 3 to 5. Record the reading in the Offset Accuracy Test (1 MΩ) table for 
channel 1.
• For all oscilloscope readings in this procedure, use the mean value in the Measurement 
Results pane at the bottom of the screen.
• If a question mark appears in front of any values in the Results pane, press [Clear Display] 
on the oscilloscope, wait for the number of averages to return to 256, and then record the 
oscilloscope reading. The question mark indicates that the oscilloscope could not make a 
reliable measurement.