IDT82P2284 Integrated Device Technology, Inc., IDT82P2284 Datasheet - Page 43

• Manufacturer Part Number: IDT82P2284
• Description: 4 Channel T1/J1/E1 Transceiver
• Manufacturer: Integrated Device Technology, Inc.

IDT82P2284
3.8.2.1
3.8.2.1.1
pattern (as shown in Figure 10) meets the ITU-T Recommendation
G.706 4.1.2 and 4.2.
FAS sequence. If STEP 2 is not met, a new searching will start after the
following frame is skipped. If STEP 3 is not met, a new searching will
start immediately in the next frame. Once the Basic Frame alignment
pattern is detected in the received PCM data stream, the Basic Frame
synchronization is found and the OOFV bit will be set to ‘0’ for indication.
Functional Description
one frame,
The algorithm used to search for the E1 Basic Frame alignment
Generally, it is performed by detecting a successive FAS/NFAS/
No (skip
N=N+3)
Figure 10. Basic Frame Searching Process
2nd bit of TS0 of the (N+1) frame to ensure
Synchronization Searching
Basic Frame
that this is a non-frame alignment
the correct 7-bit FAS (X0011011)
Sequence (FAS) (X0011011)
STEP 2: Find logic 1 in the
for 7-bit Frame Alignment
Synchronization Found
in the TS0 in the (N+2)
Yes
STEP 3: Search for
sequence (NFAS)
STEP1: Search
in the N frame
Basic Frame
Yes
Yes
frame
th
th
th
No (N=N+1)
(N=N+3)
No
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QUAD T1/E1/J1 LONG HAUL / SHORT HAUL TRANSCEIVER
March 22, 2004