How to plot multiple filter response on the same filter visualizer?

I have two filter responses and I would like to plot them on the same figure on the filter visulizer but I could not find any way to do it. I was trying to retrieve xData and yData but I could not find them in the figure handler of the filter visualizer.

Answer 1

[Honglei Chen]

To get XData and YData of phase noise visualization, you can do the following

pn = comm.PhaseNoise;
h = visualize(pn);
x = h.CurrentAxes.Children.XData;
y = h.CurrentAxes.Children.YData;

HTH

[mostafa]

I did the following instead of the code you sent and it works:

pn = comm.PhaseNoise ;

visualize(pn );

h = get(gcf);

x = h.CurrentAxes.Children.XData ;

y = h.CurrentAxes.Children.YData ;

Thank you,

Mostafa

Answer 2

[Honglei Chen]

How do you describe your filter? The following example plots two filter responses in one figure and you should be able to do similar with your filters.

    b1 = firpm(20,[0 0.4 0.5 1],[1 1 0 0]); 
    b2 = firpm(40,[0 0.4 0.5 1],[1 1 0 0]); 
    fvtool(b1,1,b2,1);

HTH

Answer 3

[mostafa]

One problem with Matlab is that there is no integrity among different tools and definitions. For example, the DSP toolbox has its own way of defining filters, which is differetn from the way that communications toolbox does. I am using comm.PhaseNoise object. It has a "visualize" method which plots the response but if I could not find a way to plot another phase noise response on the same figure. I would like to plot two comm.PhaseNoise responses on the same figure.

Best,

Mostafa