Testing Performance 3
S-Series Oscilloscopes Service Guide 33
7 Change the DC Supply voltage to -15 mV.
8 Press [Clear Display] on the oscilloscope, wait for the number of averages to
return to 256, and then record the DMM voltage reading (V
DMM-
column) and
the scope V avg reading (Vscope- column) in the DC Gain Accuracy Test (50 Ω)
section of the Performance Test Record.
9 Repeat step 8 for the remaining vertical scale settings for channel 1 shown in
the DC Gain Accuracy Test (50 Ω) section of the Performance Test Record.
10 Click Control > Factory Default, turn off channel 1 and turn the channel 2 display
on.
11 Set the DC Supply voltage (External Supply Setting) to +15 mV.
12 Configure the oscilloscope to measure the average voltage on channel 2:
a Click Setup > Acquisition.... In the Acquisition dialog box, enable averaging
and set # of Averages to 256.
b Change the vertical scale of channel 2 to 5 mV/div.
c Drag and drop the Average voltage measurement icon onto the channel 2
waveform.
13 Press [Clear Display] on the oscilloscope, wait for the number of averages to
return to 256, and then record the DMM voltage reading (V
DMM+
) and the
scope V avg reading (V
Scope+
) in the DC Gain Accuracy Test (50 Ω) section of
the Performance Test Record.
14 Repeat step 13 for the remaining vertical scale settings for channel 2 in the DC
Gain Accuracy Test (50 Ω) section of the Performance Test Record.
15 Repeat step 10 through step 14 for channels 3 and 4.
16 Repeat steps 2 through 15 using 1 MΩ for the scope input impedance rather
than 50 Ω. The steps should be followed exactly except in step 4, you should
select the 1 MΩ button from the Impedance section of the Channel dialog box
rather than 50 Ω and all values should be entered in the DC Gain Accuracy Test
(1 MΩ) section rather than the DC Gain Accuracy Test (50 Ω) section.
17 Calculate the offset gains for the 50 Ω test and the 1 MΩ test using the
following expression and record this value in the DC Gain Accuracy Test section
of the Performance Test Record.
DCGainError =
ΔV
out
ΔV
in
---------------
V
scope+
– V
scope-
V
DMM+
– V
DMM-
--------------------------------------------1–
75=
To Next Page
Loading...
