XRT75R03IVTR-F Exar Corporation, XRT75R03IVTR-F Datasheet - Page 44

• Manufacturer Part Number: XRT75R03IVTR-F
• Description: IC LIU E3/DS3/STS-1 3CH 128LQFP
• Manufacturer: Exar Corporation

Specifications of XRT75R03IVTR-F

• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

XRT75R03
REV. 1.0.8
The Transmit Clock applied via TxClk_n pins, for the selected data rate (for E3 = 34.368 MHz, DS3 = 44.736
MHz or STS-1 = 51.84 MHz), is duty cycle corrected by the internal PLL circuit to provide a 50% duty cycle
clock to the pulse shaping circuit. This allows a 30% to 70% duty cycle Transmit Clock to be supplied.
When the Single-Rail (NRZ) data format is selected, the Encoder Block encodes the data into either B3ZS
format (for either DS3 or STS-1) or HDB3 format (for E3).
An example of B3ZS encoding is shown in Figure 14. If the encoder detects an occurrence of three
consecutive zeros in the data stream, it is replaced with either B0V or 00V, where ‘B’ refers to Bipolar pulse
that is compliant with the Alternating polarity requirement of the AMI (Alternate Mark Inversion) line code and
‘V’ refers to a Bipolar Violation (e.g., a bipolar pulse that violates the AMI line code). The substitution of B0V or
00V is made so that an odd number of bipolar pulses exist between any two consecutive violation (V) pulses.
This avoids the introduction of a DC component into the line signal.
An example of the HDB3 encoding is shown in Figure 15. If the HDB3 encoder detects an occurrence of four
consecutive zeros in the data stream, then the four zeros are substituted with either 000V or B00V pattern. The
substitution code is made in such a way that an odd number of pulses exist between any consecutive V pulses.
This avoids the introduction of DC component into the analog signal.
F
F
5.1
5.2
5.2.1
5.2.2
IGURE
IGURE
15. B3ZS E
16. HDB3 E
T
B3ZS/HDB3 E
RANSMIT
B3ZS Encoding:
TPDATA
HDB3 Encoding:
TPDATA
Signal
Signal
TClk
TClk
Line
Line
THREE CHANNEL E3/DS3/STS-1 LINE INTERFACE UNIT WITH JITTER ATTENUATOR
C
LOCK
NCODING
NCODING
NCODER
1
1
1
1
:
0
0
0
0
F
F
:
ORMAT
ORMAT
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
V
0
0
0
V
41
0
0
0
1
1
1
1
0
0
0
0
0
0
0
0
V
0
0
0
B
V
0
0
B
0
0
0
0
V
0
0
B
0
0
0
V
0
0
xr
xr
xr
xr
V
0