Model 3585A
Performance Tests
4·9. Frequency Accuracy
This test verifies the frequency accuracy of the 3585A by using an external counter to check
the internal frequency reference. It is important that the frequency counter used to do this
test has a reference which is more accurate than that of the 3585A.
Specification: Counter Accuracy, ± 0.3Hz ± lxlO·7/month
Equipment Required:
Frequency Counter . . . . . . . . . . . . . . . . . -hp- 5328A
Frequency Synthesizer . . . . . . . . . . . . . . . -hp- 3335A
Procedure:
a. Allow the instruments used in this test to warm up for 1 5 to 20 minutes before begin
ning this test.
b. Set the 3585A controls for:
INSTRUMENT PRESET
MANUAL ENTRY . . . . . . . . . . . . . . . . . . . . . 9 MHz
COUNTER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . on
c. Set the synthesizer controls for:
FREQUENCY . . . . . . . . . . . . . . . . . . . . . . . . . 9 MHz
AMPLITUDE . . . . . . . . . . . . . . . . . . . . . . . . . 0 dBM
d. Using a BNC "T" connector, connect 500 output of the synthesizer to the frequency
counter and the 50 ohm input of the 3585A.
NOTE
Be sure that the synthesizer and the 3585A are operating on their
own internal references. Disconnect any reference connection
common to both instruments.
e. Record the frequency difference between the frequency counter and the 3585A counter
reading. Difference frequency equals
__
Hz.
f. If the frequency accuracy derived from this test is not in accordance with your re
quirements, turn to Section 5 of this manual for the Reference Oscillator Adjustment pro
cedure.
g. This completes the Frequency Accuracy Test, reconnect the references as outlined in
Paragraph 4-8.
4-5