Bonjour Rich,
In june 2001, that is yesterday, you wrote that, about 100Base-TX:
"The scrambling prevents IDLEs (and any other repetitive data pattern) from concentrating all of the transmitted energy into a narrow frequency band, and hence violating EMI requirements. (Without scrambling, the MLT-3 encoded IDLE would appear as a continuous, 31.25 MHz continuous-wave signal.)"
I agree with that statement.
In the same conditions, with the scrambling, we have now 125 MHz /
2047 = 61 kHz instead of 31.25 MHz continuous-wave signal.The value 2047 come from the (2^11 - 1) period with the 11 registers PRBS.
Perhaps the crosstalk can be acceptable, and the energy in this frequency (NEXT or FEXT) would be low.
Thanks if you have a comment. Best regards, Michelot