Information about phase noise

[Sadegh.j]

Could some one please give me something on phase noise?

Thanks

 

[paladinzlp]

Phase noise

PLL phase noise?

 

[prajit]

Re: Phase noise

Phase is a measure of the relative position of a signal with respect to a reference point.
Therefore if a signal is defined as sine wave..then
x=sin(ωt+0)..It's reference is zero....i.e signal is originating from zero....
y=sin(ωt+θ)..it is displaced from it's orgin by θ.. it means there is gap of θ between x and y signal.....

Now consider due to some condition we are not able to define this "θ" properly..i.e we are not able to tell the exact origin of signal "y"..
It means there is a error in defining θ...let's say that error as Δ ..so our

New Phase(due to error)=θ+Δ
Z (New Signal)=sin(ωt+θ+Δ)
though signal 'y' and Z are same...but "Z" contains some noise..This noise is coming because we are not able to tell the exact origin of signal "Z"

Therefore there will be always some error in describing the position of signal 'Z" from the origin i.e reference point...... This error is the Phase noise.....

Now what does it mean....

In Frequency domain if we analyse signal x,y, and Z...we will get a single frequency component for x and y (i.e a straight line in Frequency spectrum) ..but for Z it will not be a single line in the frequency spectrum......It will have some unwanted frequency components....This unwanted frequency components comes because we don't know the exact origin of the signal ..As a result of it the frequency is not determined correctly...The frequency component with maximum energy in the frequency spectrum will be defined as the main frequency component or carrier frequency....

Now how it is measured...........

It is measured and specified as noise power, relative to carrier power, in a one Hz bandwidth at a given frequency offset.

 

[pankajdudulwar]

Re: Phase noise

I have attached one paper please go through the equations in it and some papers referred in the reference sections written by Hajimiri and LEE.If u don't have acces please free to contact me I will provide you. And refer to Thomas Lee book titled RFIC design one whole chapter is on Phase noise or Behzad Razavi Book tilted RF Microelectronics.

Best of luck,

 

[haley_8]

Re: Phase noise

Razavi's book explains phase noise well. Leeson's equation is another resource to look into for LTI phase noise model. Hajimir's LTV phase noise model is another good model to look into.

 

[paladinzlp]

Phase noise

about PLL phase noise
(1)VCO noise-> PLL phase noise(high-pass)
(2)LPF noise-> PLL phase noise(band-pass)
(3)Charge-pump noise-> PLL phase noise (low-pass)

 

[crossbow_123]

Re: Phase noise

Could some one please give me something on phase noise?

Thanks

PLease see this attachment