Microchip Technology GPS-2700, User Manual

Page: 27 / 77

Quick-Start Instructions
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2020 Microchip Technology Inc. DS50003016A-page 27
Figure 2-15 shows that the Allan Deviation of the free running unit (GPS holdover, no
GNSS antenna is attached) is quite good, approaching 5E-12 over 100,000 seconds in
this typical plot.
FIGURE 2-15: Allan Deviation of Free Running CSAC.
As shown in Figure 2-16 , the Phase Noise of the GPS-2700 unit with the Phase Noise
filter disabled shows a higher baseline noise with a floor of about –145 dBc/Hz, and
numerous spurs.
FIGURE 2-16: Phase Noise of the GPS-2700 with the Phase Noise Filter
Disabled.