Transmitter C/N versus Spectrum regrowth
Although the spectrum regrowth is a reflection of what is occurring within the band of data, there is a 1 to 2dB higher level of “N” within the data area. Hence the regrowth level should be allowed to be 2dB higher than the required Transmitted C/N.
Aim for a Transmitted C/N of 43 dB.
A Transmission C/N of 22 dB is likely to ensure failure of all decoders !
These requirements are for 64QAM @ FEC of 2/3.