XRT59L91 Datasheet, PDF (10/28 Pages) Exar Corporation – Single-Chip E1 Line Interface Unit

XRT59L91
Preliminary
Figure 3, indicates that when the user is operating the
XRT59L91 device in the “Clockless” Mode, then the
Terminal Equipment must do the following.
l Not apply a signal on the “TxClk” line.
l When applying a pulse (to either the TxPOS or
TxNEG 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. Addition,
the RZ pulse should occupy only the first half of
the bit-period. The TxPOS and TxNEG input pins
must be at 0V, during the second half of every 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.
An illustration of the “ITU-T G.703 Pulse Template
Requirements” is presented below in Figure 4.
V = 100%
50%
269ns
(244 + 25)
194ns
Nominal Pulse
10%
0%
10%
244ns
219ns
(244 - 25)
20%
Figure 4. Illustration of the ITU-T G.703 Pulse Template for E1 Application
Rev. P2.00
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