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Appendix D Performance Tests
Complete Performance Tests
Operating and Programming Guide D-19
Test 1: 10 MHz Frequency Accuracy and 1 PPS Jitter
(Locked to GPS)
This test measures the relative change in the 1 PPS pulses between
the unit under test and a known accurate source. A time interval is
measured and the data is stored to be compared with a second
measurement, 24 hours later. The 1 PPS source is derived from the
internal 10 MHz, and the relative accuracy of 1 PPS is directly related
to the accuracy of the 10 MHz.
Specifications Tested
Frequency Accuracy (locked): Better than 1 x 10
-12
for a one day
average, 0 degrees to 50 degrees C.
1 PPS Jitter of leading edge: <750 ps with at least one satellite in
view, Selective Availability on.
Procedure
1 Connect the terminal or computer to the Receiver using the cable
recommended in the Getting Started Guide and ensure that they are
both communicating.
2 Ensure that the Receiver is in “GPS Lock” mode as indicated by the
illuminated GPS Lock indicator, and that FFOM = 0. The current
value of FFOM and many other characteristics of the unit can be
determined by typing :SYSTEM:STATUS? on the terminal.
3 Connect the 10 MHz reference output from the reference 1 PPS source
(HP 5071A or another stable, traceable house standard) to the
rear-panel Ref In of the Universal Counter, as shown in Figure D-6, to
provide an external timebase for the Counter.
Figure D-6. 10 MHz Frequency Accuracy and 1 PPS Jitter Test Setup
(58503B GPS Receiver shown)
!
!
ANT
!
58503B or
59551A
GPS Receiver
Ref. In (rear panel)
50Ω Feedthrough (HP 10100C)
1PPS
Output
(Rear Panel)
5071A
PRIMARY FREQUENCY STANDARD
Continuous
Operation
HP 5071A
Primary Frequency Standard or
House Standard
HP 53132A
Universal
Counter
or equivalent
Channel 2Channel 1
Port1
10 MHz External
Reference Out
(rear panel)
GPS
Antenna
1PPS
(rear panel)