Jagged plot - skipping resonant peak

Posted by admin 08/11/2015 0 Comment(s) FAQs,

I am running a circuit and trying to find the resonant frequency. The AC analysis plot shows a small peak where the resonant frequency should be, but it is not nearly the correct magnitude. Also, the plot seems jagged when it should appear smooth.

 

Most likely, you are not taking enough data points. The data points on the screen are correct, but the simulator interpolates between data points. Therefore, it may skip over a narrow peak (narrow in relation to the frequency range). You will have to increase the number of data points taken. In the AC analysis limits, change the Frequency Range step type from Auto to Linear or Log. Linear is better for smaller scale ranges, and Log is better when the frequency range encompasses multiple decades. Increase the value in the Number of Points text field to the amount of data points that you would like to have taken and run the analysis again. With more data points, the resonant peak will be plotted more completely. The Number of Points text field will have no effect on the plot when the Frequency Range step type is set to Auto.

Tags: AC Analysis