What is the difference between the plots of the following commands.

[h,w]=freqz(kw,1,256) ; % frequency response of the window 
mag=20*log10(abs(h)); 
plot(w/pi,mag,'k')

and

freqz(kw,1,256)

Answer 1

[Star Strider]

The second one draws the complete Bode plot (magnitude spectrum and phase spectrum) and plots it as a function of the angular frequency .

The first one draws only the magnitude spectrum, and normalises the frequency axis to [0 1] by dividing by π.