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Phase Unwrap (Read 2385 times)
WishToRemainAnonymous
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Phase Unwrap
Oct 14th, 2016, 10:07am
 
Hello All. I have a Veriloga code for phase unwrap block used in phase to voltage converter block that has been suggested in

http://delivery.acm.org/10.1145/1330000/1326256/p887-kim.pdf?ip=17.236.17.12&id=...

The code is given below.

Code:
`include "constants.vams"
`include "disciplines.vams"

module phase_unwrap(c,s,out);

input c,s;
output out;

voltage c,s,out;

parameter k=1e7;

real te,co,so;

analog begin

@(initial_step)
begin
te=0;
co=1;
so=0;
end

co=cos(V(out));
so=sin(V(out));

te=atan2(V(s)*co-V(c)*so,V(s)*so+V(c)*co);

V(out) <+ `M_PI*2*k*idt(te,`M_PI/4);

end
endmodule
 



There is an IQ demodulator block whose I and Q components are fed to the "c" and "s" inputs of the phase unwrap block. The phase unwrap block has an integrator block in it and an atan2 function which extracts the angle from the c and s inputs. Details of this block are given in the paper whose link I have pointed to above.

This block has a convergence issue. Unless I use "sigramp" option, this never converges. There are times when this cell works fine without "sigramp" option but then the output blows up.

I need your advice to somehow make this block more friendly towards convergence. I would greatly appreciate your help with this problem of mine.
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Ken Kundert
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Re: Phase Unwrap
Reply #1 - Oct 14th, 2016, 11:38am
 
Your link is broken.
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« Last Edit: Oct 14th, 2016, 7:46pm by Ken Kundert »  
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WishToRemainAnonymous
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Re: Phase Unwrap
Reply #2 - Oct 14th, 2016, 11:43am
 
Sorry about that. Wonder why the url would not work.

I am pasting the url below.

http://delivery.acm.org/10.1145/1330000/1326256/p887-kim.pdf?ip=17.236.17.12&id=...

It is a paper on Variable Domain Transformations and the ACM website for that is

http://dl.acm.org/citation.cfm?id=1326256

You can click on the pdf link to download the pdf from there.
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