27-01-2012, 11:49 AM
A Frequency Domain Approach To Crosstalk identificaion in xDSL Systems
[attachment=16687]
Introduction to DSL
DSL :
High bit rate digital information over telephone subscriber lines
Basic types of DSL
> Basic Rate ISDN (up to 160 kbps)
> HDSL ( up to 1.544 or 2.048 Mbps)
> ADSL (up to 1Mbps(u.s) ,9Mbps(d.s))
> VDSL (up to 52 d.s and 6.4Mbps u.s)
Why Noise Estimation?
Tele phone cables gives rise to a series of impairments at broad band range
Noise occurs because of imperfect balance
Balance is function of frequency ,reduces with higher frequencies
There are 3 types of noises in DSL
>> Crosstalk
>> Impulse noise
>> Radio noise
Crosstalk
Definition :
“ Leakage into one channel of signal power from another channel.”
No two binder groups are adjacent for long runs, to minimize the crosstalk.
There are 2 types of crosstalk
>> Near End Crosstalk(NEXT):
It is the coupling between transmitters and receivers at the same end of a cable
[attachment=16687]
Introduction to DSL
DSL :
High bit rate digital information over telephone subscriber lines
Basic types of DSL
> Basic Rate ISDN (up to 160 kbps)
> HDSL ( up to 1.544 or 2.048 Mbps)
> ADSL (up to 1Mbps(u.s) ,9Mbps(d.s))
> VDSL (up to 52 d.s and 6.4Mbps u.s)
Why Noise Estimation?
Tele phone cables gives rise to a series of impairments at broad band range
Noise occurs because of imperfect balance
Balance is function of frequency ,reduces with higher frequencies
There are 3 types of noises in DSL
>> Crosstalk
>> Impulse noise
>> Radio noise
Crosstalk
Definition :
“ Leakage into one channel of signal power from another channel.”
No two binder groups are adjacent for long runs, to minimize the crosstalk.
There are 2 types of crosstalk
>> Near End Crosstalk(NEXT):
It is the coupling between transmitters and receivers at the same end of a cable