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Oct 13th, 2019, 9:29pm
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How to build up a simulink model for simulating PSD of a Sigma Delta Modulator (Read 4185 times)
Esther
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How to build up a simulink model for simulating PSD of a Sigma Delta Modulator
Sep 01st, 2009, 12:27am
 
Hi, All,

I am designing a fractional N PLL. Currently I am trying to simulate noise of each block in the PLL.

For SD modulator, simulation of it is my problem.  I build a structure in simulink. It is a  Mash1-1-1. then I do transient simulation. The output of it is -3,-2,-1,0,1,2,3( i don't know why 4 has never happened??).. Then I put a FFT spectrum block at it's output. BUt i can see nothing. the Spectrum gave me nothing.. what's wrong? Or is my method is not correct?

Thank you in advance!
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ywguo
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Re: How to build up a simulink model for simulating PSD of a Sigma Delta Modulator
Reply #1 - Sep 2nd, 2009, 8:14pm
 
Generally, I don't know what's wrong with your simulink model. But why do you expect the output stream contains code 4? I have a MASH 1-1-1 model, too. It works fine.

Can you put your model in the post?


Yawei
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