xrt83l30 Exar Corporation, xrt83l30 Datasheet - Page 21

• Manufacturer Part Number: xrt83l30
• Description: Xrt83l30 -single-channel T1/e1/j1 Long-haul, Short-haul Line Interface Unit
• Manufacturer: Exar Corporation

REV. 1.0.1
In Host mode the programming is achieved through the corresponding interface control bits, the state of the
CLKSEL[2:0] control bits and the state of the MCLKRATE interface control bit.
RECEIVER
RECEIVER INPUT
At the receiver input, a cable attenuated AMI signal can be coupled to the receiver through a capacitor or a 1:1
transformer. The input signal is first applied to a selective equalizer for signal conditioning. The maximum
equalizer gain is up to 36dB for T1 and 43dB for E1 modes. The equalized signal is subsequently applied to a
peak detector which in turn controls the equalizer settings and the data slicer. The slicer threshold for both E1
and T1 is typically set at 50% of the peak amplitude at the equalizer output. After the slicers, the digital
representation of the AMI signals are applied to the clock and data recovery circuit. The recovered data
subsequently goes through the jitter attenuator and decoder (if selected) for HDB3 or B8ZS decoding before
being applied to the RPOS/RDATA and RNEG/LCV pins. Clock recovery is accomplished by a digital phase-
locked loop (DPLL) which does not require any external components and can tolerate high levels of input jitter
that meets or exceeds the ITU-G.823 and TR-TSY000499 standards.
In Hardware mode only, this receive channel is turned on upon power-up and is always on. In Host mode, the
receiver can be turned on or off with the RXON bit.
DESCRIPTION” ON PAGE 48.
MCLKE1
2048
2048
2048
1544
1544
2048
K
128
128
256
256
16
16
56
56
64
64
H
8
8
Z
SINGLE-CHANNEL T1/E1/J1 LH/SH TRANSCEIVER WITH CLOCK RECOVERY AND JITTER ATTENUATOR
MCLKT1
2048
2048
1544
1544
1544
1544
K
H
x
x
x
x
x
x
x
x
x
x
x
x
Z
CLKSEL2
T
ABLE
0
0
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
1: M
ASTER
CLKSEL1
18
C
0
0
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
LOCK
SEE”MICROPROCESSOR REGISTER #2 BIT
G
ENERATOR
CLKSEL0
0
0
0
1
1
1
0
0
1
1
0
0
1
1
0
0
1
1
MCLKRATE
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
XRT83L30
M
ASTER
2048
1544
2048
1544
2048
1544
2048
1544
2048
1544
2048
1544
2048
1544
2048
1544
2048
1544
K
H
C
Z
LOCK