Hi.
Here is my task:
Find ratio R1/R2 so that zero and pole of transfer function are spaced for one octave.



Solution:



But what "spaced for one octave" means?

 

From MathWorks: An octave is the interval between two frequencies having a ratio of 2:1
Here is a bit more explanation: http://www.diku.dk/~jda/biosignal/lab10.pdf

Lets say you pick a frequency of 1 kHz. Now multiply it by 2, 2*1 kHz= 2 kHz. The range of frequencies from 1 kHz to 2 kHz is an octave.