Anritsu MT1000A - Page 377

Measurement Result ExampleMeasurement Result Example
nn 1 2 3 4 5 6
δδ
nn
0.1 0 0.05 0 0.2 0
DeviationDeviation 0.1 0 0.05 0 0.2 0
Phase errorPhase error 0.1 0.1 0.15 0.15 0.35 0.35
The difference between two BNC cable lengths makes time difference of 1PPS
signals. Therefore it affects the phase error measurement result. You can set the
correction of the time difference caused from the cable length difference at
1PPS cable correction1PPS cable correction in the Control screen.
Filtered TE displays the phase error passed through the 0.1 Hz bandwidth low
pass filter. The phase error is displayed with suppressed noise.
OWD MeasurementOWD Measurement
This part explains how to measure the OWD. To perform the OWD
Measurement, select both of Enable IEEE1588v2Enable IEEE1588v2 and Slave modeSlave mode on the IEEE
1588v2 screen.
1. DUT (Device Under Test) sends Sync message to Network Master. T
1
is the
timestamp of DUT at the time Sync message has been sent. When not using
Follow_Up message, T
1
is notified to Network Master by Sync message.
2. τ
2
is the timestampe of Network Master at the time Sync message has
arrived.
3. If using Follow_Up message, T
1
is notified to Network Master by Follow_Up
message.
4. Network Master sends Delay_Request message to DUT. τ
3
is the timestamp
of Network Master at the time Delay_Request message has been sent.
5. T
4
is the timestampe of DUT at the time Delay_Request message has arrived.
6. Master clock sends Delay_Response message and notifies T
4
to Network
Master.
The OWD calculation formula are
below.
Sync OWD = τ
2
- T
1
Delay_Request OWD
= T
4
- τ
3
OWD contains the delay of the optical fiber cable between DUT and Network
Master. TEs (Time error) that the cable delay is subtracted from OWD are
defined as:
TE1= −1 × (Sync OWD) + Δms
Sync TestSync Test
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