Test
Procedure
The following procedure tests both the coarse and
fine loops to verify the accuracy of the CW frequency
output.
Step 1
Set up the 681XXB as follows:
a. Reset the instrument by pressing
SYSTEM
, then
RESET
. Upon reset,
the CW Menu is displayed.
b. Press
Edit F1
to open the current fre-
quency 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; Ta-
ble 5-2B is for models with Option 11).
Step 2
Verify that the Frequency Counter read-
ing meets specifications (
±
100 Hz of the
value shown on the test record for stand-
ard models;
±
10 Hz for instruments with
Option 11).
Step 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. Differences
of a few Hertz can be caused by noise
or counter limitations. Differences
of
≥±
100 Hz (
≥±
10 Hz for instru-
ments with Option 11) indicate a
frequency synthesis problem.
Step 4
Set F1 to the next test frequency on the
test record and record the Frequency
Counter reading.
Step 5
Repeat step 4 until all frequencies listed
on the test record have been recorded.
OPERATION
CW FREQUENCY
VERIFICATION
ACCURACY TEST
5-6
681XXB OM
