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PRELIMINARY
XRT79L71
344
REV. P2.0.0
1-CHANNEL DS3/E3 CLEAR-CHANNEL FRAMERLIU COMBO - CC/HDLC ARCHITECTURE
This section presents the Jitter Transfer Characteristics of the XRT79L71, if the Jitter Attenuator PLL has been
enabled. As we present the Jitter Transfer Characteristics of the XRT79L71, we will also present some of the
various Jitter Transfer Characteristic requirements that the XRT79L71 complies with.
5.2.5.3
The Transmit Control Block
The purpose of the "Transmit Control" Block is to accept any of the following signals from the on-chip
Registers, and route the state of these signals to either the Transmit Pulse Shaping Block and the Line Driver
block.
TAOS - Transmit All OneS Pattern
TxON - Transmit Driver ON/OFF
The role that "TxON" plays is address in Section 3.3.1.5.6.5. However, none of these sections address the
"TAOS" signal. As a consequence, TAOS will be addressed in this section.
TAOS - Transmit All OneS
The user can configure the Transmit DS3/E3 LIU Block transmit an un-framed "All Ones" pattern via the TTIP
and TRING output pins. This can be accomplished by setting Bit 2 (TAOS), within the "LIU Transmit Control"
Register, to "1" as depicted below.
If the TAOS bit-field is set to "1", then the Transmit DS3/E3 LIU Block will overwrite the contents of the
outbound DS3 or E3 data-stream that it receives from the Transmit DS3/E3 Framer block, with an unframed All
Ones pattern.
Conversely, if the TAOS bit-field is set to "0", then the Transmit DS3/E3 LIU Block will NOT overwrite the
contents of the outbound DS3 or E3 data-stream that it receives from the Transmit DS3/E3 Framer block, with
an unframed All Ones pattern, as it transmit this DS3 or E3 data out onto the line.
5.2.5.4
The Transmit Pulse Shaping Block
For E3 Applications, the purpose of the "Transmit Pulse Shaping" block is to permit the Transmit DS3/E3 LIU
Block to generate pulses (within the outbound E3 line signal) that comply with the ITU-T G.703 Pulse Template
requirements for E3 applications.
Figure 159 presents the results of some actual pulse template
measurements for E3 applications.
LIU Transmit Control Register (Address = 0x1304)
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
BIT 0
Unused
Internal
Transmit
Drive Monitor
Unused
TAOS
Unused
TxLEV
R/O
R/W
R/O
R/W
R/O
R/W
0
1
0