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Dear all,
I found some threads about this topic, but quite old.
So I would like to put some questions about the simulation of the ISL.
One post from 2005 says that ISF is obtained using transient functions.
How do I do it ? Are these steps wrong ?
1 - Generate a transient analysis (let's say...
Dear all,
I am designing a behavioral model for a PLL. As I am new to this language, I have decided to start with the oscillator. I have just to copied and paste a piece of code that I found on Cadence's documentation.
The problem is that I get an error which I cannot solve.
Some lines of...
Hi,
New day, and the problems persist :-| .
I took the generic control function,
\[ H(s)= \frac{\omega_n^2}{s^2 + 2\zeta \omega_n s + \omega_n^2}\]
and derived for s=jw/wn so I obtained,
\[ H \left(j \frac{\omega}{\omega_n} \right)=\frac{\omega_n^2}{-\left(\frac{\omega}{\omega_n}\right)^2+...
Hi,
Understand your point. Please try to answer these questions point by point:
1 - If you have H=tf(num,den), where num=[4] and den=[2 3 4], the outcome will be (MatLab) 4/(2*s^2 + 3s + 4), the denominator is equivalent to:
\[\frac{2 \zeta \omega_n s +...
Thanks for having answered to one more question.
I think that the curves look ok, but I have used a concept that uses the time constant of the filter as being tau2, thus w3db=1/tau2 (let´s say the BW of the loop). And I am not sure that this is correct.
I agree with you that to obtain the...
Hi,
I am not quite there yet, but I did some improvements, however the curves for different zeta values (damping), don't converge to the same point. There is no intersection.
I did what you wrote on the first post:
1 - I have chosen K (50e6)
2 - Found a value for tau2, such that zeta=0.707.
3...
Good afternoon,
I am sorry to post from the 3rd time. I did a small function in MatLab.
%% Plots magnitude of H(s)
K=5e7; %loop gain
zeta=[5 2 1 0.707 0.5 0.3 0.1]; %damping
for n=1:length(zeta)
tau2=((2*zeta(n)).^2)./K;
wn=sqrt(K./tau2)...
Hi,
I am not still seeing the way it is done, I am sorry I know I am being dumb.
For eg. Are you suggesting that I should create a vector with tau2 points, and then generate K ? But K is affected by other gains and tau2 and tau1,as well. Do I have to care about that, or should I see K as one...
Dear all,
I am doing some Matlab code to simulate PLLs. I am using the book "PhaseLock Techniques" by Gardner. I wanted to replicate some of the graphs to check my understanding. However I can't.
For eg. in the book Gardner plots 20 log|H(jw)| vs w/wn. Maybe this is a silly question, but all...
Dear all,
I am trying to simulate the phase noise on Matlab using only gaussian noise. What I expect is that, interms of the signal (eg. sinewave) it shifts in phase due to noise.
For that I don't need the awgn on top of the signal, but the signal itself with the noise built-in.
Best regards...
HI,
I am about to finish my 80 MHz Quartz Crystal VCO, but I am not confident on Jitter's results. Please try to answer these questions, as fast as you can, as I have the tape-out in August of the full PLL:
1 - For the VCO circuits (autonomous circuits), which jitter measurement type should I...
Hi,
Thanks for the link. It is very useful to understand the several types of Jitter. But I needed to know how to calculate jitter on Cadence having the phase noise already.
Best regards,
Pedro
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