
PEB 2255
FALC-LH V1.3
Functional Description T1/J1
Data Sheet
13
8
2000-07
and FRS0.LMFA SSP
=
1:FT
→
FRS0.LFA
FS
→
FRS0.LMFA
ESF:ESF framing bits
→
FRS0.LFA
The resynchronization procedure may be controlled by either one of the following
procedure:
Automatically (FMR
4
.A
U
TO
=
1). Additionally, it may be triggered by the user by
setting/resetting one of the bits FMR0.FRS (Force Resynchronization) or FMR0.E
X
LS
(External Loss of Frame).
U
ser controlled,
exclusively, via
above
(FMR
4
.A
U
TO
=
0).
FT and FS bit conditions, i.e. pulse frame alignment and multiframe alignment can be
handled separately if programmed via bit FMR2.SSP. Thus, a multiframe re-
synchronization can be automatically initiated after detecting 2 errors out of
4
/5/6
consecutive multiframing bits without influencing the state of the terminal framing.
In the synchronous state, the setting of FMR0.FRS or FMR0.E
X
LS resets the
synchronizer and initiates a new frame search. The synchronous state is reached if there
is only one definite framing candidate. In the case of repeated apparent simulated
candidates, the synchronizer remains in the asynchronous state.
In asynchronous state, the function of FMR0.E
X
LS is the same as above. Setting bit
FMR0.FRS induces the synchronizer to lock onto the next available framing candidate if
there is one. Otherwise, a new frame search is started. This is useful in case the framing
pattern that defines the pulseframe position is imitated periodically by a pattern in one of
the speech/data channels.
The control bit FMR0.E
X
LS should be used first because it starts the synchronizer to
search for a definite framing candidate.
To observe actions of the synchronizer, the Frame Search Restart Flag FRS0.FSRF is
implemented. It toggles at the start of a new frame search if no candidate has been found
at previous attempt.
When resynchronization is initiated, the following values apply for the time required to
achieve the synchronous state in case there is one definite framing candidate within the
data stream:
control
bits
in
the
non-auto-mode
Table 32
Resynchronization Timing (T1/J1)
Frame Mode
F
4
F12
ESF
F72
Average
1.0
3.5
3.
4
13.0
Maximum
1.5
4
.5
6.125
17.75
Units
ms
ms
ms
ms