[time-nuts] Thermal noise contribution to phase noise

[Bruce Griffiths]

The thermal contribution to SSB phase noise power is -177dBm/Hz.
For a carrier level of 0dBm the corresponding SSB phase noise is -177dBc/Hz.

Its even possible to measure the residual phase noise of components 
where the component phase noise is below the phase noise due to thermal 
noise.

PN is only significant in an FM receiver when there is no significant AM 
to PM conversion in any limiters that may be employed.

Bruce

Joe Leikhim wrote:
> From a practical standpoint, which is it -177 or -174 dBm?
> This is confusing topic.
>
> If for example an FM receiver, does the AM component become irrelevant?
>
>
> _(snip)__
>
> As Bob stated thermal noise is equally divided between AM and PM
> components when a carrier is present.
>
> Both  the AM and PM noise components are -177dBm/Hz their sum is
> -174dBm/Hz.
>
> Bruce_
>