[time-nuts] Thermal noise contribution to phase noise

Bob Camp lists at rtty.us
Sat Jan 19 18:07:21 UTC 2013


Hi

If:

1)  You have a carrier. Let's say it is an ideal signal with absolutely no noise on it.
2) That carrier is in a real 50 ohm system

….there will be thermal noise at -174 dbm per Hz.

The model for a carrier includes both AM noise and PM noise. Correct?

The practical difference for small angle PM vs AM is the phasing of the sidebands. Correct?

Either:

a) All of the noise is AM noise. 
b) All of the noise is PM noise.
c) Half of the noise power is AM and half of the power is PM.

Pick one, a,b, or c.

If you pick a or b, *why* and equally importantly *how* does all the random thermal noise go only to one process? Since it's (by definition) random (amplitude and phase), it's going to be tough to get it all in just one bucket or the other. 

If the noise splits equally, then -177 is what you are going to get.

Bob

On Jan 18, 2013, at 11:52 PM, Joe Leikhim <jleikhim at leikhim.com> wrote:

> I have just sent off an e-mail to David Howe of NIST Metrology requesting clarification about this assertion that KTB is revised -3dB.
> 
> -- 
> Joe Leikhim
> 
> 
> Leikhim and Associates
> 
> Communications Consultants
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> Oviedo, Florida
> 
> JLeikhim at Leikhim.com
> 
> 407-982-0446
> 
> WWW.LEIKHIM.COM
> 
> 
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