xrt75r12 Exar Corporation, xrt75r12 Datasheet - Page 30

• Manufacturer Part Number: xrt75r12
• Description: Twelve Channel E3/ds3/sts-1 Line Interface Unit With Jitter
• Manufacturer: Exar Corporation

XRT75R12
TWELVE CHANNEL E3/DS3/STS-1 LINE INTERFACE UNIT WITH JITTER ATTENUATOR
The transmitter is designed so that the LIU can accept serial data from a local device, encode the data
properly, and then output an analog pulse according to the pulse shape chosen in the appropriate registers.
This section describes the detailed operation of various blocks within the transmit path. A simplified block
diagram of the transmit path is shown in
The method for applying data to the transmit inputs of the LIU is a serial interface consisting of TxClk, TxPOS,
and TxNEG. For single rail mode, only TxClk and TxPOS are necessary for providing the local data from a
Framer device or ASIC. Data can be sampled on either edge of the input clock signal by programming the
appropriate register. A typical interface is shown in
F
F
4.0 THE TRANSMITTER SECTION
4.1
IGURE
IGURE
TRing_n
MRing_n
TTIP_n
MTIP_n
13. T
DMO_n
14. T
Transmit Digital Input Interface
YPICAL INTERFACE BETWEEN TERMINAL EQUIPMENT AND THE
RANSMIT
P
Monitor
Device
ATH
(E3/DS3 or STS-1
Driver
Line
Equipment
B
Terminal
Framer)
LOCK
Shaping
D
Control
Pulse
Tx
IAGRAM
Tx
Figure
TxPOS
TxNEG
TxLineClk
Control
Timing
13.
Figure
27
TPData
TNData
TxClk
Exar E3/DS3/STS-1 LIU
Attenuator
14.
Jitter
Transmit
Logic
Block
MUX
XRT75R12 (
Channel n
Encoder
HDB3/
B3ZS
DUAL
-
RAIL DATA
TxClk_n
TxPOS_n
TxNEG_n
TxON
)
REV. 1.0.4