XRT73L03 Datasheet, PDF (30/62 Pages) Exar Corporation – 3 CHANNEL E3/DS3/STS-1 LINE INTERFCE UNIT

XRT73L03 3 CHANNEL E3/DS3/STS-1 LINE INTERFACE UNIT
REV. P1.0.13
áç
PRELIMINARY
FIGURE 9. THE TYPICAL INTERFACE FOR DATA TRANSMISSION IN DUAL-RAIL FORMAT FROM
THE TRANSMITTING TERMINAL EQUIPMENT TO THE TRANSMIT SECTION OF A CHANNEL OF THE
XRT73L03
TxPOS
TPData
Terminal
Equipment
(E3/DS3 or STS-1
Framer)
TxNEG
TxLineClk
TNData
TxClk
Transmit
Logic
Block
Exar E3/DS3/STS-1 LIU
The manner that the LIU handles Dual-Rail data is
described below and illustrated in Figure 10. The
Transmit Section of a Channel typically samples the
data on the TPData and TNData input pins on the fall-
ing edge of TxClk(n).
FIGURE 10. HOW THE XRT73L03 SAMPLES THE DATA ON THE TPDATA AND TNDATA INPUT PINS
Data
TPData
TNData
TxClk
1
1
0
TxClk(n) is the clock signal that is of the selected data
rate frequency for E3 = 34.368 MHz, DS3 = 44.736
MHz and STS-1 = 51.84 MHz. If the Transmit Section
samples a “1" on the TPData input pin, the Transmit
Section of the XRT73L03 generates a positive polari-
ty pulse via the TTIP(n) and TRing(n) output pins
across a 1:1 transformer. If the Transmit Section
samples a "1" on the TNData input pin, then the
Transmit Section ultimately generates a negative po-
larity pulse via the TTIP(n) and TRing(n) output pins
across a 1:1 transformer.
2.1.2 Configure Channel(n) to accept Single-
Rail Data from the Terminal Equipment
To transmit data in a Single-Rail data from the Termi-
nal Equipment, configure the XRT73L03 in the HOST
Mode.
Write a "1" into the TxBin(n) (TRANSMIT BINary) bit-
field of Command Register CR1-(n) shown below.
NOTE: Please refer to Table 2 for the Address of the individ-
ual Channel(n).
COMMAND REGISTER CR1-(N)
D4
D3
D2
D1
D0
TxOFF(n) TAOS(n) TxClkINV(n) TxLEV(n) TxBin(n)
x
x
x
x
1
The Transmit Section of each channel samples this
input pin on the falling edge of the TxClk(n) clock sig-
nal and encodes this data into the appropriate bipolar
line signal across the TTIP(n) and TRing(n) output
pins.
NOTES:
27