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# Pnoise analysis

Last post Wed, Apr 10 2013 5:24 AM by Andrew Beckett. 6 replies.
 Started by Jithin 03 Apr 2013 04:27 AM. Topic has 6 replies and 892 views
• #### Wed, Apr 3 2013 4:27 AM

• Jithin
• Joined on Thu, Mar 8 2012
• Posts 25
• Points 365
Pnoise analysis
 Hi,I have been doing a pnoise analysis for a PLL . Looking into the Pnoise simulation profile I have found a tab regarding thevalue for " Reference sideband" .What is the value that I should put while my "Maximum number of sidebands =7".With Regards,Jithin K
• Post Points: 20
• #### Wed, Apr 3 2013 4:59 AM

Re: Pnoise analysis
 Jithin,The reference sideband is needed to compute either input referred noise or noise figure. If you only require the output noise, you can set the input source on the form to "none", and then you won't have to fill this in.If you do want either of these quantities, then this is to allow you to define the relationship between the desired signal path from the input to the output so that you can get the right gain used to divide the output noise, or compute the amount of noise caused by the input port at the output. The number specified is to define the frequency translation, so for a given output frequency Fout, the input frequency would be |k*PSSfund+Fout| - or you can use the select from list to pick the right frequency.  So for example you are simulating a switch cap filter where the input and output frequencies are the same, it would be 0. For a down converting mixer it might be -1 and so on. Regards,Andrew
• Post Points: 20
• #### Thu, Apr 4 2013 12:59 AM

• Jithin
• Joined on Thu, Mar 8 2012
• Posts 25
• Points 365
Re: Pnoise analysis
 Thank you for your kind reply. After doing simulation I will come up with results. With regards, Jithin
• Post Points: 5
• #### Sun, Apr 7 2013 9:18 PM

• Jithin
• Joined on Thu, Mar 8 2012
• Posts 25
• Points 365
Re: Pnoise analysis
 Hi,I have been done the Pnoise analysis setting noise type as "sorces". Unfortunately I was unable to plot the phase noise response.My design was  "Pnoise analysis" and the setup was described below.My apparatus was a PLL with a fixed divider ratio of 20 and output frequency of 500MzIn PSS analysis I have set the beat frequency as reference frequency ie 20 MHz. In Pnoise tab I have put output node as VCO output ie 500MHz node and Input source kept as none.Even though the PSS analysis had been converged and done the Pnoise analysis, I haven't got any Phase noise Plot.Please guide me to overcome this problem.Thanking you .With regards,Jithin
• Post Points: 20
• #### Wed, Apr 10 2013 3:40 AM

Re: Pnoise analysis
 To avoid this question being answered twice, it has been logged again as http://www.cadence.com/Community/forums/p/25899/1322529.aspx#1322529
• Post Points: 20
• #### Wed, Apr 10 2013 5:21 AM

• Jithin
• Joined on Thu, Mar 8 2012
• Posts 25
• Points 365
Re: Pnoise analysis
 I am sorry for asking the same question again .The thing is that I am stuck with this problem . If in Pnoise analysis setup, I consider the Output node as "Divider out" then I am getting all the required that is Phase noise plot. But if I'm considering the output node as PLL output node (ie VCO output node ) then I am not getting the result that is phase noise plot. With Regards, jithin
• Post Points: 20
• #### Wed, Apr 10 2013 5:24 AM

Re: Pnoise analysis
 I'm busy doing my day job, and will take a look at this later today if I have time (or rather your other post).Andrew.
• Post Points: 5
###### Sort Posts: Oldest to newest Newest to oldest
 Started by Jithin at 03 Apr 2013 04:27 AM. Topic has 6 replies.
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