The Designer's Guide Community Forum

The Designer's Guide Community Forum
https://designers-guide.org/forum/YaBB.pl
Simulators >> RF Simulators >> pnoise simulation
https://designers-guide.org/forum/YaBB.pl?num=1439374126

Message started by sdtpeo on Aug 12^th, 2015, 3:08am

Title: pnoise simulation
Post by sdtpeo on Aug 12^th, 2015, 3:08am

Hi all,

I'm simulating a very simple circuit compose of an ideal vsin source in series with a noisy resistor (see attached picture) whose value is 1K ohm.

If I run pnoise, type=sources and I plot the output noise power I get 1.67e-17 V**2/Hz that is exactelly 4KTR (simulation temperature is 27 C)

If I run pnoise, type=modulated and I plot the output noise AM/PM power I get:
AM output power: 1.67e-17 V**2/Hz
PM output power: 1.67e-17 V**2/Hz

Now what I don't understand is that I was expecting the AM and PM noise to be 1/2 of 4KTR.

Is that because the AM and PM output noise power is calculated as DSB noise instead of SSB noise?

Thanks!

Title: Re: pnoise simulation
Post by Frank Wiedmann on Aug 12^th, 2015, 5:38am

The formulas used for calculating AM and PM noise assume bandlimited noise (see http://www.designers-guide.org/Forum/YaBB.pl?num=1309258199/28#28).