Control System::Bode Plot

         To draw a bode plot , follow these simple steps:

Magnitude Plot:

1. Put the frequency response equation into bode equation form.
2. identify the DC gain value, and mark this as a horizontal line coming in from the far left (where the radial frequency conceptually is zero).
3. At every "zero" break point, increase the slope of the line upwards by 20db/decade.
4. At every "pole" break point, decrease the slope of the line downwards by 20db/decade.
5. at every breakpoint, note that the "actual value" is 3db off from the value graphed.

Phase Plot

1. If A is positive, start your graph (with zero slope) at 0 degrees. If A is negative, start your graph with zero slope at 180 degrees (or -180 degrees, they are the same thing).
2. For every zero, slope the line up at 45 degrees per decade when  (1 decade before the break frequency). Multiple zeros means the slope is steeper.
3. For every pole, slope the line down at 45 degrees per decade when  (1 decade before the break frequency). Multiple poles means the slope is steeper.
4. Flatten the slope again when the phase has changed by 90 degrees (for a zero) or -90 degrees (for a pole) (or larger values, for multiple poles or multiple zeros.