Here is an extract from the SNRM vs freqency data obtained from my modem. DSL tone numbers vs SNRM. See the peak at tone 125:
113 22.9375
114 22.8125
115 22.3750
116 21.8125
117 21.1250
118 21.1250
119 20.3750
120 19.8750
121 18.3750
122 17.7500
123 13.0625
124 10.5625
125 8.8125
126 11.3125
127 13.7500
128 15.1875
129 15.1250
130 16.2500
131 16.1875
132 15.8750
133 15.1875
134 15.3750
135 15.1875
What could that be? That would equate to what -539 kHz?
Thing is, I can’t see a corresponding thing in the QLN.
That doesn’t prove that it is noise as it could be reduced received signal level too - frequency-dependent increased attenuation, a loss of power or cancellation - is that even possible?
What am I looking at?