APPLICATION NOTE
5
Band pass Filter Behavioral Models
The three bandpass filter models are:
Butt_BP (Butterworth filter)
Ch2p5_BP (0.25dB ripple Chebyshev filter)
Bessel_BP (Bessel filter)
One approach to obtain bandpass filters is to cascade lowpass and highpass circuits. The cutoff frequency of the
lowpass circuit defines the lower -3 dB point of the bandpass filter bandwidth, while the cutoff frequency of the
highpass filter defines the upper -3 dB point of the filter bandwidth. On the basis of this approach and by using the
lowpass and highpass filter models discussed earlier, a behavioral bandpass filter model can be defined and that
is shown in Figure 7.
Figure 7: Butterworth bandpass filter model
Figure 6: Frequency response of the Butterworth highpass filter model for various orders
