XRT75L03D Datasheet, PDF (46/134 Pages) Exar Corporation – THREE CHANNEL E3/DS3/STS-1 LINE INTERFACE UNIT WITH SONET DESYNCHRONIZER

XRT75L03D
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REV. 1.0.0 THREE CHANNEL E3/DS3/STS-1 LINE INTERFACE UNIT WITH SONET DESYNCHRONIZER
FUNCTIONAL DESCRIPTION:
Figure 1 shows the functional block diagram of the device. Each channel can be independently configured
either by Hardware Mode or by Host Mode to support E3, DS3 or STS-1 modes. A detailed operation of each
section is described below.
Each channel consists of the following functional blocks:
4.0 THE TRANSMITTER SECTION:
The Transmitter Section, within each Channel, accepts TTL/CMOS level signals from the Terminal Equipment
in selectable data formats.
• Convert the CMOS level B3ZS or HDB3 encoded data into pulses with shapes that are compliant with the
various industry standard pulse template requirements. Figures 7, 8 and 9 illustrate the pulse template
requirements.
• Encode the un-encoded NRZ data into either B3ZS format for (DS3 or STS-1) or HDB3 format (for E3) and
convert to pulses with shapes and width that are compliant with industry standard pulse template
requirements. Figures 7, 8 and 9 illustrate the pulse template requirements.
• In Single-Rail or un-encoded Non-Return-to-Zero (NRZ) mode, data is input via TPData_n pins while
TNData_n pins must be grounded. The NRZ or Single-Rail mode is selected when the SR/DR input pin is
“High” (in Hardware Mode) or bit 0 of channel control register is “1” (in Host Mode). Figure 12 illustrates the
Single-Rail or NRZ format.
FIGURE 12. SINGLE-RAIL OR NRZ DATA FORMAT (ENCODER AND DECODER ARE ENABLED)
Data
TPData
TxClk
1
1
0
• In Dual-Rail mode, data is input via TPData_n and TNData_n pins. TPData_n contains positive data and
TNData_n contains negative data. The SR/DR input pin = “Low” (in Hardware Mode) or bit 0 of channel
register = “0” (in Host Mode) enables the Dual-Rail mode. Figure 13 illustrates the Dual-Rail data format.
FIGURE 13. DUAL-RAIL DATA FORMAT (ENCODER AND DECODER ARE DISABLED)
Data
TPData
TNData
TxClk
1
1
0
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