I was reading whitepaper on time varying noise (cyclostationary) and something odd struck me :
Quoted from page 5 , step 8 from white paper
To calculate time-varying noise power, bring up the Direct Plot PSS results form. Click on tdnoise and then select Integrated noise power. Enter 0 as the start frequency and the PSS fundamental frequency as the stop period, for example, 1G, if the PSS period is 1ns. A periodic waveform should appear that represents the expected noise power at each point in the fundamental period
The problem back here is that integrated noise power is calculated for bandwidth from 0 Hz to 1 GHz. However spectrum of a clock signal usually starts with fundamental frequency (1GHz in this case) followed by amplitude of odd harmonics.So why is the integrated noise power calculated for 0 Hz to 1 GHz instead of 1 GHz to some finite frequency ?
Do we consider noise bandwidth of signal in a non-linear system like mixer which is exhibited as example in original whitepaper ?
Thanks.