The Designer's Guide Community Forum

The Designer's Guide Community Forum
https://designers-guide.org/forum/YaBB.pl
Simulators >> RF Simulators >> How to measure NMF(Noise Modulating Function)
https://designers-guide.org/forum/YaBB.pl?num=1179862648

Message started by JC on May 22^nd, 2007, 12:37pm

Title: How to measure NMF(Noise Modulating Function)
Post by JC on May 22^nd, 2007, 12:37pm

Recently I am trying to simulate the ISF(Impulse Sensitity Function) for my VCO using Spectre. I have to measure the NMF for transistor's drain thermal noise. I have two methods as shown in the following figure.

The second method is approximately derived from the frist one, because I don't konw clearly how to measure the drain noise current correctly.

My questions: 1. How to measure drain noise current using Spectre?
2. Is there other methods to measure NMF?

Title: Re: How to measure NMF(Noise Modulating Function)
Post by sheldon on May 24^th, 2007, 5:22am

JC,

It may not help you directly, but there is another figures of Oscillator
merit the perturbation projection vector, PPV. For more information, see
Frank Wiedmann's comment in the following e-mail,
http://www.designers-guide.org/Forum/YaBB.pl?num=1179739160/1#1
or the following reference,
<<reference to chapter 2 of Hegazi, Rael, and Abidi (http://www.designers-guide.org/Books/dg-osc/index.html) was deleted by forum administrator>>

The good news is that SpectreRF will directly output the PPV for a VCO. To save
the PPV, in the PSS window:
select "Oscillator" then "options", in the options window select "save osc ppv".
You can use the Results Browser to access the PPV.

Best Regards,

Sheldon

Title: Re: How to measure NMF(Noise Modulating Function)
Post by JC on May 25^th, 2007, 6:41am

Sheldon,
Thanks for your help.
Unfortunately the Cadence version IC5104 doesn't contail this option in PSS simulation. So I cann't see anything about PPV. Is the PPV contained in this version (IC5104)?

Another quesion is: If I have to use the second method described above, How to get threshold voltage? Can I just treat threshold voltage as a constant value? Dose this impact the accuracy a lot?

JC