Bt8370/8375/8376
2.0 Circuit Description
Fully Integrated T1/E1 Framer and Line Interface
2.9 Transmit Line Interface Unit
2.9.2.2 Output Jitter
The maximum output jitter generated on XTIP/XRING dependents on the
transmit clock source selected. Refer to CLAD and JAT descriptions.
2.9.3 Line Build Out
In the Bt8370 long haul device, three LBO filter networks can be enabled in the
TLIU to attenuate XTIP/XRING outputs in 7.5 dB steps, per the signal transfer
function defined by FCC Part 68 Regulations. (See LBO[1:0] in TLIU_CR.) The
number of LBO filters selected is based on the attached cable length. For short
line lengths, larger LBO attenuation prevents far-end crosstalk. For longer line
lengths, the appropriate line build-out must be selected. The following equation
lists the transfer function for each of the 7.5 dB LBO filters:
2
V
n S + n S + n
out
2
1
0
----------
--------------------------------------------------------
d S + d S + d S + d
0
=
3
2
V
in
3
2
1
where:
n0 = 1.6049 × 106
n1 = 7.9861 × 10–1
n2 = 9.2404 × 10–8
d0 = 2.1612 × 10+6
d1 = 1.7223
d2 = 4.575 × 10–7
d3 = 3.8307 × 10–14
S = j2πf
f = frequency( Hz)
N8370DSE
Conexant
2-77
CONEXANT [ CONEXANT SYSTEMS, INC ]
