# General transfer function for a bandpass filter

Is there a general form of transfer function (with peak frequency $\omega_m$ and quality factor $Q$) relevant for any type of bandpass filter ?

• a bandpass filter has two cutoff frequencies! – stevenvh May 14 '12 at 12:00
• well I meant the peak frequency, the frequency at which the gain is maximum – snickers May 14 '12 at 12:02
• Some bandpass filters have multiple peaks, like a Chebychev for example. – Olin Lathrop May 14 '12 at 12:04
• @snickers - even without the multiple peaks (Olin's comment) the center frequency isn't enough to know the bandwidth. – stevenvh May 14 '12 at 12:06
• @snickers - example of the frequency response of a Chebychev filter: cnx.org/content/m16895/latest/c92.png – stevenvh May 14 '12 at 12:09

$H(s) = \dfrac{\dfrac{\omega_m}{Q}s}{s^2+\dfrac{\omega_m}{Q}s+\omega_m^2}$