Figure - Agilent Technologies 54845B Manual

Chapter 3: Testing Performance
To test voltage measurement accuracy

Figure 3-7

Set the scale from the
table
Set the offset from the
table
Vertical Scaling and Offset for Voltage Accuracy Measurement
To Set Vertical Scale and Position
You can also use the knobs to set the vertical scale and position, but it is usually easier to use the dialog
box, particularly for the fine position setting.
With the supply disconnected from the channel input, note the V
11
____________ V
It may take a moment for this value to settle because of averaging.
Set the power supply voltage from the first line of the table. Use the voltmeter to adjust
12
the power supply for the most accurate output.
Connect the power supply to the channel input and note the V
13
Press Clear Display and wait a moment to read the value (so that averaging is complete).
Subtract the value in step 11 from the value in step 13. Record the difference in the
14
Performance Test Record.
On the same channel, repeat steps 10 through 14 for the rest of the rows in the table.
15
With the channel keys, set the active channel OFF and the next ON.
16
A channel is ON if its key is illuminated and OFF if it is not illuminated.
Move the BNC tee to the next channel and repeat steps 8 through 15 for that channel.
17
Repeat steps 8 through 17 for the rest of the channels.
18
Repeat steps 3 through 18 for the 50Ω input.
19
If the test fails
Voltage measurement errors can be caused by the need for self-calibration. Before troubleshooting the
instrument, perform self-calibration. See "To run the self-calibration" in chapter 4, "Calibrating and
Adjusting." If self-calibration fails to correct the problem, the cause may be the attenuator or main
assembly.
3–10
mean reading.
avg
reading. _________ V
avg