XRT59L921 Datasheet, PDF (19/32 Pages) Exar Corporation – TWENTY-ONE CHANNEL E1 LINE INTERFACE UNIT

REV. 1.2.1
XRT59L921
TWENTY-ONE CHANNEL E1 LINE INTERFACE UNIT
FIGURE 5. ILLUSTRATION ON HOW THE TERMINAL EQUIPMENT SHOULD APPLY DATA TO THE TRANSMIT SECTION OF A
GIVEN CHANNEL (WITHIN THE XRT59L921), WHEN OPERATING IN THE CLOCKLESS MODE
DATA
Bit
Period
1
RZ Pulse is to be
applied in the first
half of the bit-period
1
0
1
No Pulse is to be
applied in the 2nd
half of the bit-period
1
1
0
TxPOS_n
TxNEG_n
TClk_n
No Activity in TxClk Line, TxClk_n="High"
Figure 5, indicates that when the user is operating a channel in the Clockless Mode, then the corresponding
Terminal Equipment must do the following:
• Not apply a signal on the TxClk_n line and connect TxClk to "High"
• When applying a pulse (to either the TxPOS_n or TxNEG_n input pin), apply an RZ pulse to the appropriate
input pin. This RZ pulse should only have a width of one-half the bit-period.
1.3 The Pulse Shaping Circuit
The purpose of the Transmit Pulse Shaping circuit is to generate Transmit Output pulses that comply with the
ITU-T G.703 Pulse Template Requirements for E1 Applications.
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