Clock Tree

FMADIO Systems enable high precision nanosecond timestamping, this enables all packets to hardware timestamped on data ingress with accuracy. Below is the different clocking and disciplining architectures based on the hardware SKU.

NTP Clocking

NTP is the default clocking due to its wide availability and easy setup.

Accuracy: 100msec

Clock tree is shown below

The FMADIO Server System clock gets disciplined by the NTP Server.

The FMADIO FPGA clock gets disciplined by the FMADIO Server System Clock

PTP Clocking

PTP offers improved clock accuracy, at the expense of using a dedicated SFP port on the management network card. This improved precision due to hardware timestamping on the management network card, allowing the Clock on the Management NIC to be tightly disciplined against the PTP Grand Master.

Accuracy: 100nsec

Clock tree is shown below

The FMADIO Management interface clock is disciplined by the PTPv2 Grand Master

The FMADIO Server System clock gets disciplined by the FMADIO Management Interface Clock.

The FMADIO FPGA clock gets disciplined by the FMADIO Server System Clock

PPS (Pulse Per Second)

PPS  with NTP offers the most accuracy in timestamping, this is due to a hardware disciplining of the FPGA clock via the PPS signal (instead of software disciplining the FPGA clock). As the PPS signal only indicates the start of a second, it requires NTP to discipling the epoch value (what the global world time in seconds is). This is a hybrid approach using both PPS and NTP.

Accuracy: 10nsec

Clock tree is shown below

SyncE / White Rabbit

Next generation FMADIO Capture Devices, contact support for further details.