The Signal Analyzer app currently does not support changing the scale of the plot directly. However, a workaround here is to use the "Generate Script" functionality in the app and follow the comments in the generated code to plot your graph. Once the figure is plotted, click the "Open Property Inspector" button and in the Property inspector window, under "Rulers" section. you can find the "XScale", "YScale" and "ZScale" options which enable you to change the scale to logarithmic and vice - versa. I hope this helps!