PEB 2091
PEF 2091
Application Hints
7.1.2
U-Interface
Note 70: The requirements for the power spectral density of the transmitted
2B1Q signal on the U-interface has been changed by ETSI. This change
aims to reduce interference between basic rate 2B1Q signals on the one
hand and ADSL and VDSL signals on the other. All of these signals will
be transmitted on the same kind of lines in the future. For more
information, refer to the ETSI document “Technical Specification
101080" (1999).
To meet the new specification some modifications of the hybrid
recommended in previous IEC-Q versions are required. Figure 93 below
illustrates the hybrid circuit needed to meet these new ETSI
requirements.
Note 71: This change will be in force from January, 2000 onward. After this date
systems with the old hybrid will not comply to ETSI standards at this
point.
22 nF
24
Ω
1:1.6
$287
619
Ω
681
Ω
10 k
Ω
Ω
10 k
Ω
Ω
%,1
$,1
3.01 k
Ω
22 nF
≥ 1µF U
Ck
6.8 nF
10 k
10 k
619
Ω
24
Ω
%287
22 nF
Figure 93
U-Interface Hybrid Circuit
Semiconductor Group
250
Data Sheet 01.99
INFINEON [ Infineon ]
