Mauricio Pardo
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Posts: 4
Atlanta, GA
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Hi everyone...
All the situation appeared when I disconnected the feedback loop in the PLL (from the VCO to the PFD). What I was trying to do was trying to plot the phase noise of the VCO only to keep the plot in the Waveform Window and then plot the response of the PLL (restoring the feedback connection). Thus, when I try to run the AC and Noise analysis for the first situation, I obtained the message about the zero en the matrix, and the message was indicating the instance of the VCO and also reported the idt0.
Therefore, I conclude that the integration of the VCO was the responsible for the error... To have my plot as reference, what I dit was to "comment" that statement in the Verilog model.
However, trying with different PLL configurations, once I while the error appears again limiting some of my ideas about alternative PLL configurations. Hence, my question is more directed in the "resulting noise transfer function plot" that an alternative configuration can configurate... I think that the "comment" strategy does not work here because without the idt statement the loop is broken...
Is there any possible way to remove this situation? Is the error a notice that the PLL configuration that I am trying is weird or impossible to construct?
Thanks to everyone!
Mauricio.
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