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D S L / P H O N E F I LT E R S
THE INTERNETS
TALKIN’ ON THE TELEPHONE…
Image credit: http://www.accesscomms.com.au/Reference/ADSL_wiring.htm
Voice band: 0.3 - 3.4 kHzDSL band: 30 – 1104 kHz
DSL PHONE FILTER
Commercial filter What’s in the Box
L1 = 6.8 mH L2 = 10 mH C1 = 22 nF C2 = 15 pF C3 = 15 nF.
INTRODUCING INDUCTORS
In the lab On paper/In The Ether
NODAL IS POWERFUL
“Someone say Nadal is
powerful? Heck, ya, he is!”
“Settle down, Rafa.”
LOADING THE MATRIX
• Where, for convenience:
FREQUENCY SPECTRUM
-1 0 1 2 3 4 5 6 7 8 9-250
-200
-150
-100
-50
0
50
100
Frequency (Hz)
G(f
) dB
DSL phone filter
~ -80 dB/dec rolloffSteep slope!
ANOTHER DESIGN USING DIFFERENT L’S AND C’S
-1 0 1 2 3 4 5 6 7 8 9-200
-150
-100
-50
0
50
100
Frequency (Hz)
G(f
) dB
DSL phone filter: model 2
L1 = 15 mH L2 = 60 mH C1 = 10 nF C2 = 5.6 nF C3 = 2.2 nF
~ -40 dB/dec rolloff