Technical data

2Performance Tests
30 N1911A/1912A P-Series Power Meters Service Guide
Zero Set (Average Path)
Description
Zero set is defined as the amount of residual offset error that is present
following a zero operation. This offset error is caused by contamination
from several sources, including circuit noise. This test measures the effec-
tiveness of zero set by performing 15 back- to- back zero operations of the
average path (with no sensor attached), after which the standard deviation
of the results is calculated and returned as the measured value.
Equipment
• No test equipment required
Test Method
1 Execute the internal zero set measurement procedure for channel A.
2 Read back the result of the measurement from the DUT.
3 If the DUT model number is N1912A, then repeat this procedure for
channel B.
4 The test will take a few minutes to complete.
5 The measurement result should be less than 0.0000175. The smaller the
measurement result, the smaller the amount of residual offset error.
NOTE
• This test can be performed manually via the commands:
SERV:BIST:PEAK[1|2]:ZSET
SERV:BIST:CW[1|2]:ZSET:NUM?
(Refer to the programming guide for further details on the use of these commands)
• No adjustment is available for this test if it fails (see Chapter 5, “Troubleshooting
Guide”).