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 681XXC as follows:
a. Reset the instrument by pressing
SYSTEM , then RESET . Upon reset,
the CW Menu (below) 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 (Table5-2A is
the test record for standard models;
Table5-2B for models with Option 11).
Step 2 Verifythat the Frequency Counter read-
ing meets specifications (±100 Hz of the
value shown on the test record for stan-
dard models; ±10 Hz for instruments with
Option 11).
Step 3 Record the Frequency Counter reading on
the test record (Table5-2A or Table 5-2B).
NOTE
The Frequency Counter reading is
typicallywithin ±1 Hz. Differences
of a few Hertz can be caused by
noiseor counter limitations. Differ-
ences of ³±100 Hz (³±10 Hz for in-
strumentswith 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.
5-6 681XXC OMOPERATION CW FREQUENCY
VERIFICATION ACCURACY TEST