Users manual
NR3700-O/G
Revision #:
A
Date:
9-13-16
Page #:
9 of 19
is used to discipline the timing device. Timing accuracy to a few ppb is readily
achievable.
The GNSS is used to provide timing for a DDS (direct digital waveform synthesizer).
While the DDS has outstanding long-term accuracy, the short-term stability is very poor
due to the nature of the timing source. A GNSS timing source has considerable short-
term instability due to the numerous radio effects-multi-path, signal weakness etc. In
order to develop a stable reference, the GNSS timing waveform is used to discipline a
low noise source with a Kalman filter. A good example of the improved jitter
performance of a Kalman filter is shown below:
Kalman Filter Performance
.
