Timestamps
known by slave
t
4
t
2
t
1,
t
2
t
3
t
1,
t
2,
t
3,
t
1,
t
2,
Delay_Resp (t4)
t
4
t
3
Master
time
Slave
time
Sync
Follow_Up
Delay_Req
t-ms
t-sm
t
1
t
2
Figure 14.3:
Master/Slave offset measurement
The message exchange process is as follows:
1
The master sends a
Sync
message to the slave and notes the time,
t
1
, at
which it was sent.
2
The slave receives the
Sync
message and notes the time of reception,
t
2
.
3
The master conveys the
timestamp
t
1
to the slave the by either
a
Embedding the
timestamp
t
1
in the
Sync
message (One
-
Step). This
requires some sort of hardware processing for highest accuracy and
precision
or
b
Embedding the
timestamp
t
1
in a
Follow_Up
message (Two
-
Step).
4
The slave sends a
Delay_Req
message to the master and notes the time,
t
3
, at which it was sent.
5
The master receives the
Delay_Req
message and notes the time of
reception,
t
4
.
6
The master conveys the
timestamp
t
4
to the slave the by embedding it in
a
Delay_Resp
message.
GEN3t
I3995-3.1 en HBM: public
365
