The Designer's Guide Community Forum

The Designer's Guide Community Forum
https://designers-guide.org/forum/YaBB.pl
Design >> Analog Design >> how to make a noise source?
https://designers-guide.org/forum/YaBB.pl?num=1164750917

Message started by Aigneryu on Nov 28^th, 2006, 1:55pm

Title: how to make a noise source?
Post by Aigneryu on Nov 28^th, 2006, 1:55pm

Hi,

I tried to make an ideal noise source with a predefined noise spectrum in order to find out how
different injecting nodes give different transfer properties.
Is it possible to make a noise source, say, current source with zero DC current and open impedence?

Title: Re: how to make a noise source?
Post by Ken Kundert on Nov 28^th, 2006, 3:01pm

If you are using Spectre none of this is necessary. Just use xf analysis with 'stimuli' set to nodes_and_terminals.

-Ken

Title: Re: how to make a noise source?
Post by Yutao Liu on Nov 17^th, 2012, 10:45pm

Ken Kundert wrote on Nov 28^th, 2006, 3:01pm:

If you are using Spectre none of this is necessary. Just use xf analysis with 'stimuli' set to nodes_and_terminals.

-Ken

Hello Ken,

For XF simulation in ADE, only the output terminal can be set. And after the simulation, only the "port" and "vdc" can be available to plot the transfer function. What if the voltage-controlled voltage source. Can I use the method you mentioned above?

And where I can find information about 'stimuli' setting?

Thanks,
Yutao Liu

Title: Re: how to make a noise source?
Post by rfidea on Nov 18^th, 2012, 6:07am

You can set noise/frequency points in the idc source from analogLib.

Title: Re: how to make a noise source?
Post by Yutao Liu on Nov 19^th, 2012, 4:59am

rfidea wrote on Nov 18^th, 2012, 6:07am:

You can set noise/frequency points in the idc source from analogLib.

Thanks for your reply.
Could you tell me some detail?

Actually, I made a phase domain behavioral model of pll with component in analogLib. I used vccs to model the charge pump, vcvs to model an amplifier. I want to simulate the noise shaping effect for a given noise source, like resistor in the loop filter or charge pump.

Is XF simulation able to get what I want? How to do that?

Thanks,
Yutao Liu

Title: Re: how to make a noise source?
Post by Ken Kundert on Nov 19^th, 2012, 12:16pm

Quote:

And where I can find information about 'stimuli' setting?

It is in the XF options form.

-Ken

Title: Re: how to make a noise source?
Post by rfidea on Nov 19^th, 2012, 12:25pm

I do not have the Virtuoso environment in front of me but there is parameters in the components options list called noise/frequency pairs. Just fill in what you want.

About resistors, yes, spectre will calculate thermal noise from them. That is the idea with a simulator.