DMT-Based ADSL Disturbers Near-End Crosstalk Calculation |
DMT downstream disturber model from T1E1.4/95-007R2, Annex B (p144)
;f is in KHz
PSD (dBm/Hz)
of a DMT Downstream Disturber vs f (KHz)
;f is in KHz
;n = number of DMT NEXT disturbers (1, ... , 49)
PSD (dBm/Hz) of DMT Downstream Disturber NEXT vs f (KHz)
Low-frequency integrated DMT ADSL downstream NEXT power (spot power for df =
1) (dBm), f must be < 20 KHz for this model:
High-frequency integrated DMT ADSL downstream NEXT power (spot power for df
= 1) (dBm), f must be > 20 KHz for this model:
Total power (dBm) is:
;n = number of DMT FEXT disturbers = 10 for the FEXT model given
;coupling constant for 10, 1% worst-case disturbers
FEXT crosstalk binder coupling gain model for 10, 1% worst-case disturbers
from T1E1.4/95-007R2 Annex B (page 144). Channel amplitude transfer function
uses the sqrt(f) relationship:
Note large diameter wire maximizes FEXT (also maximizes RX power), but 19
AWG is used only in 2.7 % of the pair miles per 1983 loop survey, Figure
9-28.
;f is in KHz
;l is in Kft
;dB loss/Kft at freq f1, 24-PIC-70C
;dB loss/Kft at freq f1, 26-PIC-70C
;f is in KHz
;f is in KHz
;dB loss/Kft at freq f2, 24-PIC-70C
;dB loss/Kft at freq f2, 26-PIC-70C
;f is in KHz
;f is in KHz
;dB loss/Kft at freq f3, 24-PIC-70C
;dB loss/Kft at freq f3, 26-PIC-70C
;f is in KHz
;f is in KHz
;this equation uses complete channel approximation for 26 AWG
;this equation uses the sqrt(f) approximation for 26 AWG
PSD (dBm/Hz) of DMT Downstream Disturber FEXT vs f (KHz)
Integrated DMT ADSL downstream FEXT power (spot power for df = 1) (dBm),
using the complete channel response:
;matches the FEXT Power for 10 DMT ADSL disturbers in T1E1.4/95-007R2 Table
B.4
Integrated DMT ADSL downstream FEXT power (spot power for df = 1) (dBm),
using the incomplete channel response:
DMT upstream disturber model from T1E1.4/95-007R2, Annex B (p144)
;f is in KHz
PSD (dBm/Hz) of a DMT Upstream Disturber vs f (KHz)
;f is in KHz
;n = number of disturbers (1, ... , 49)
PSD (dBm/Hz) of DMT Upstream Disturber NEXT vs f (KHz)
High-frequency integrated DMT ADSL upstream NEXT power (spot power for df =
1) (dBm),
28000 < f < 138000 for this model:
High-frequency integrated DMT ADSL upstream NEXT power (spot power for df =
1) (dBm), f > 138000 for this model:
Total power (dBm) is:
;n = number of DMT FEXT disturbers = 10 for the FEXT model given
;coupling constant for 10, 1% worst-case disturbers
FEXT crosstalk binder coupling gain model for 10, 1% worst-case disturbers
from T1E1.4/95-007R2 Annex B (page 144). Channel amplitude transfer function
uses the sqrt(f) relationship:
Note large diameter wire maximizes FEXT (also maximizes RX power), but 19
AWG is used only in 2.7 % of the pair miles per 1983 loop survey, Figure
9-28.
;l is in Kft
;this equation uses complete channel approximation for 26 AWG
;this equation uses the sqrt(f) approximation for 26 AWG
PSD (dBm/Hz) of DMT Upstream Disturber FEXT vs f (KHz)
Integrated DMT ADSL upstream FEXT power (spot power for df = 1) (dBm), using
the complete channel response, f > 28000 for this model as DMT upstream is
defined for f > 28000:
Integrated DMT ADSL downstream FEXT power (spot power for df = 1) (dBm),
using the incomplete channel response:
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