I'm manually drawing a straight-line Bode magnitude plot. Say, I have the following transfer function in standard form for a Bode plot:

$$ T(j\omega) = \frac{1+j\omega/10}{(1+j\omega/50)^2} $$

Should I treat the pole at \$\omega_C = 50\$ rad/s as I would treat the zero at \$\omega_C = 10\$ (except that it would have opposite slope change), or is there something special I have to do with repeated corner frequencies?


  1. The Analysis and Design of Linear Circuits, Thomas
  2. http://en.wikipedia.org/wiki/Bode_plot

The slope change is 20dB/decade multiplied by the order (squared, cubed, etc.) of the pole or zero. The pole at \$\omega_C = 50 rad/s\$ would change the slope by -40dB/decade. The same applies for the phase: the mentioned pole would shift it by -90deg/decade (\$2\times-45deg/dec\$), starting one decade earlier.


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