[time-nuts] Re: Practical relation between Phase Noise and ADEV

[Richard (Rick) Karlquist]

I would say that Magnus's explanation is the best one
I have ever read.  And he did it without writing any
equations!  Yet another great time-nuts posting.

Rick N6RK

On 7/22/2022 3:26 PM, Magnus Danielson via time-nuts wrote:


> It is key to understand that ADEV does not determine phase-noise slopes.
> 
> Yes, there is a relationship, but the troublesome issue is that ADEV in 
> practice is unable to make white phase modulation and flicker phase 
> modulation phase noise slopes into different slopes in ADEV, they both 
> show up as 1/tau slopes despite having different phase-noise slopes. 
> This means that you with the ADEV slopes does not know if the 1/tau 
> slope is white or flicker phase modulation. This annoyed David Allan and 
> his colleagues and it took another 15 years to resolve it and that was 
> only achieved with the introduction of MDEV.
>