I actually need to know how to evaluate EVM
say by spectreRF simulation
with simplifed simulation rather than injecting
OFDM waveform with pseudo-random data.
That's not very practical way to design transmitter circuit blocks
like PA, modulator,...
I am not sure, but I think EVM calculations should be done by extracting the main non-idealities from circuit simulations and then performing a behavioral/system level simulations