Plot the magnitude response of a Butterworth filter with linear magnitude

Hi,

I'm using a Butterworth filter to attenuate one of two frequency components in a signal, like so:

http://i.imgur.com/DEpRpAA.png

In the second subplot, I'd like to overlay the envelope of the filter. What's the easiest way to do this, keeping in mind that I need both axes to stay in linear form?

Thanks! Stefan

Answer 1

[Walter Roberson]

Plot with the linear plot first, and then

hold on

and plot the second plot. If it would normally switch to log form it will not do so because linear is already in effect.

[Stefan]

Got it, thanks!

http://i.imgur.com/tbnjvPr.png