PM4341AT1XC
DATA SHEET
PMC-900602
ISSUE 7
T1 FRAMER/TRANSCEIVER
Example 2 shows a DSX 1/0 Cross-Connect utilizing four T1XC chips and a Mitel
MT8980 Digital Time/Space Switch to implement a simple 1/0 cross-connect. An
alternate architecture could use two MT8980s, one as a voice switch and the
other as a signalling switch, and 8 T1XCs to cross-connect eight T1s. (Note: a
true implementation would require redundancy in the switch core.)
In this example, the T1XC chips are programmed to receive and generate the
same framing format, using the 2.048 MHz backplane data rate.The "system
frame pulse" signal is stretched through the two D-FF into a pulse of 488ns
duration, which is used to frame align the data out of each transceiver through
the elastic store and to provide frame alignment indication to the transmitters.
The raw system frame pulse signal is used to indicate frame alignment
synchronization to the MT8980. Another D-FF is configured as a toggle to
generate a 2.048MHz clock from the system 4.096MHz clock source,
synchronized to the system frame pulse.
Figure 3
- Example 3. Multi-featured, jitter attenuating CSU
TAP
TAP
BTPCM
BTSIG
BTFP
BTPCM
BTSIG
BTFP
DSX-1
DSX-1
N
e
t
w
o
r
C
u
s
t
o
m
e
r
Transm it
Transm it
TAN
TC
TAN
TC
BTCLK
BTCLK
AVD
AVD
BRFPI
BRFPI
BRCLK
BRCLK
BRPCM
BRSIG
BRFPO
BRPCM
BRSIG
BRFPO
RAS
RAS
k
DSX-1
DSX-1
Receive
RCLKO
Receive
RCLKO
REF
RRC
REF
RRC
#1
#2
XCLK
XCLK
AVS
AVS
37.056MHz
AVS
AVS
Example 3 is an application utilizing 2 T1XC chips to implement a multi-featured
Channel Service Unit with jitter attenuation. The T1XCs are programmed to
receive and generate the same framing format, using the 1.544 MHz backplane
data rate with the Elastic Stores bypassed.
T1XC #1's Timing Options Register is programmed to enable jitter attenuation of
the outgoing transmit data to the network, using the backplane transmit clock
(BTCLK= recovered clock from customer interface) as the jitter reference.
Similarly, T1XC #2 is programmed to attenuate the outgoing transmit data jitter to
the customer equipment using its backplane transmit clock (BTCLK= recovered
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8
PMC [ PMC-SIERRA, INC ]
