10.5.1 Functionality in Master Systems
10/100MBit
LAN
10 Mhz from GPS
RJ45 with
magnetics
and LEDs
PHYceiver
MAC
controller
USB hub
FPGA
microcontroller
with integrated
progr. memory
10M/activity
100M/activity
Rx/Tx
MII interface
USB
USB 1.1
to computer
module
Time Stamp Unit PTP Master
FPGA
configuration
memory
PPS from GPS
control
adr/data
control
data
USB
After power up, the module accepts the absolute time information (PTP seconds) of a reference time source (e.g.
GNSS reference clock) only once, and the PTP nanoseconds are set to zero. If the oscillator frequency of the
reference time source has reached its nominal value, the nanoseconds are reset again. This procedure leads to
a maximum deviation of 20 nsec of the pulse per second (1PPS) of the PTP Master compared to the 1PPS of
the GNSS reference clock. The reference clock of the PTP board’s time stamp unit (50 MHz) is derived from
the GNSS disciplined oscillator of the reference time source using a PLL (Phase Locked Loop) of the FPGA.
This achieves a direct coupling of the time stamp unit to the GNSS system.
10.5.2 Functionality in Slave Systems
10/100MBit
LAN
10 MHz
PPS
programmable
outputs
modulated
time code
RJ45 with
magnetics
and LEDs
PHYceiver
status LEDs
driver
circuits
FPGA
filter and
driver circuit
oscillator
DAC
microcontroller
with integrated MAC
and
progr. memory
FPGA
configuration
memory
10M/activity
100M/activity
Rx/Tx
MII interface
control
control
voltage
PWM time code
clock
adr/data
control
clock
status
SyncBox N2X - PTP Slave
After decoding valid time information from a PTP Master, the system sets its own PTP seconds and nanoseconds
accordingly. The PTP offset calculated by the PTP driver software is used to adjust the master oscillator of the
PTP Slave. This allows the PTP Slave to generate very high accuracy output signals (10 MHz/1PPS/IRIG).
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Date: 22nd June 2020
microSync