Test
Procedure
The following procedure tests both the coarse and
fine loops to verify the accuracy of the CW frequency
output.
1. Set up the 681XXA as follows:
a. Reset the instrument by pressing
SYSTEM
,
then
RESET
. Upon reset, the CW Menu is dis-
played.
b. Press
Edit F1
to open the current frequency
parameter for editing.
c. Set F1 to the first test frequency for the model
being tested (Table 5-2A is the test record for
standard models; Table 5-2B is for models with
Option 11).
2. Verify that the Frequency Counter reading meets
specifications (
±
100 Hz of the value shown on the
test record for standard models;
±
10 Hz for instru-
ments with Option 11).
3. Record the Frequency Counter reading on the test
record (Table 5-2A or Table 5-2B).
NOTE
The Frequency Counter reading is typically
within
±
1 Hz because the instruments use
a common time base. Differences of a few
Hertz can be caused by noise or counter
limitations. Differences of
≥±
100 Hz
(
≥±
10 Hz for instruments with Option 11)
indicate a frequency synthesis problem.
4. Set F1 to the next test frequency on the test re-
cord and record the Frequency Counter reading.
5. Repeat step 4 until all frequencies listed on the
test record have been recorded.
OPERATION
CW FREQUENCY
VERIFICATION
ACCURACY TEST
5-6
681XXA OM
