Agilent Technologies Infiniium 90000 A, Service Manual

Page: 28 / 148

Chapter 3: Testing Performance
Offset Accuracy Test
28
18
Change the channel 1 offset value to -400.0 mV.
19
Set the Aux Out voltage to -400.0 mV.
20
Press the Clear Display key on the scope, wait for the #Avgs value (top left corner of
screen) to return to 256 and then record the DMM voltage reading as V
DMM-
and the
scope Vavg reading as V
Scope-
in the Offset Gain Test section of the Performance Test
Record.
21
Change the channel 1 offset value to 0 mV.
22
Set the Aux Out voltage to 0 mV.
23
Press the Clear Display key on the scope, wait for the #Avgs value (top left corner of
screen) to return to 256 and then record the DMM voltage reading as V
DMM0
and the
scope Vavg reading as V
Scope0
in the Offset Gain Test section of the Performance Test
Record.
24
Calculate the offset gain error using the following expressions and record the value in
the Offset Gain Test section of the Performance Test Record. The offset gain error is
the greater (maximum magnitude) of either:
or
25
Repeat steps 15 to 24 for the remaining channel 1 vertical sensitivities in the Offset
Gain Test section of the Performance Test Record. For each measurement, set both
the Aux Out voltage (V
Aux Out
) and the Channel offset voltage to the positive V
Aux Out
value and then to the negative V
Aux Out
value in the "V
Aux Out
Setting" column of the
Offset Gain Test table in the Performance Test Record for each of the vertical
sensitivities.
26
Move the Tee connector to the next channel input and repeat steps 15 to 22 for the
channels 2 to 4.
V
scope +
– V
scope 0
V
DMM +
– V
DMM 0
------------------------------------------
1
–
 
 
100
V
scope -
– V
scope 0
V
DMM -
– V
DMM 0
-----------------------------------------
1
–
 
 
100