Dear All,
I simulated a simple LC oscillator noise ( PSS+PNOISE) at the oscillator output ( IC5141, .sub-version 12.1.0.402.isr5).
I have also saw the topic "Explain the differences between the 4 noisetype settings for pnoise". But it could not answer what I want.
I used Shooting Method for PSS. I actually wanted to find the AM Noise & PM noise component separately. For total output noise I used PSS+PNOISE analysis. The noise power in db10 looks ok as it is matching the analysis. And it is a Single Sided PSD.
I have attached the waveform of it as Total-Noise.png
However, when I tried to plot AM noise component and PM Noise component separately I faced a really horrible experience. It is really confusing !!
Could anybody please clarify the following. It will be really helpful not only for me but also for many other designers.
1:-
First of all the plot form format in pnoise -source-modulated is very different form.
a) Power is being plotted in absolute value? why not in db10 like Pnoise ( is it because of IC5141 )
b) dBV option is there unlike PNOISE form. Why ?
c) USB, LSB, AM & PM
What is USB:-
is it total noise (AM+PM) in Fcenter + Fif ? ( is it Single sided or double sided PSD )
What is LSB :-
is it total noise in Fcenter - Fif ? ( is it Single sided or double sided PSD )
What is AM:-
Is it only AM noise component ?
is it ( Single-Sided or Double Sided PSD ) As there is dbV I suspect it is all Single Sided PSD ) ?
is it possible to plot AM Noise in Fcenter + Fif band & Fcenter - Fif band ?
What is PM:-
Is it only PM noise component ?
Is it ( Single-Sided or Double Sided PSD ) ?
Is it possible to plot AM Noise in Fcenter + Fif band & Fcenter - Fif band ?
2:-
When I plotted the AM noise ( I have captured it in the figure as AM-Noise_dBV.png ), It didn't match the analysis in the lower frequncy range. I plotted in dBV as when I Plotted it gives me -ve value also below 1MHz ( attached as AM-Noise-Power.png).
Beyond 10MHz it was matching with analysis. Also I am finding a NOTCH in the AM-PSD why is this ?
3:-
When I plotted the PM noise ( I have captured it in the figure as PM-Noise_dBV.png ), itis exactly folllowing the total -power as drawn in pnoise analysis but with around 3-dB less
Kind Regards,