Users manual
N4430-O-G
Revision #:
B
Date:
8-23-18
Page
10
of
74
3.2 PPS 1 / PPS 2 (MMCX)
MMCX - one pulse per second - 3.3 VDC CMOS - PPS can also be made available
on pin 1 of the power/serial connector.
There are two PPS signals available- Radio PPS and Synthesized PPS. The radio
PPS comes directly from the GNSS receiver. It is accurate to 1 sigma at 15 ns. It
has a jitter level that is on the order of 6 ns pulse to pulse. The Synthesized PPS is
derived from the crystal and has a pulse to pulse jitter level of below 1 ns after 30
mins at stable temperature.
The control loop modulates the OCXO to keep the Synthesized PPS to within 50 ns
of the Radio PPS. There are commands sent thru the serial port that allow the user
to configure the PPS output. The default output is synthesized PPS, disciplined to
the GNSS PPS. Selecting between GNSS PPS or Synthesized PPS will affect both
PPS outputs.
PPS from radio
