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Filter property
Butterworth
Chebyshev
Inverse Chebyshev
Bessel  also called Thomson
Advantages:
Maximally flat magnitude response in the passband.
Good allaround performance.
Pulse response better than Chebyshev.
Rate of attenuation better than Bessel.
Diavantages:
Some overshoot and ringing in step response.
Advantages:
Better rate of attenuation beyond the passband than Butterworth.Diavantages:
Ripple in passband.
Considerably more ringing in step response than Butterworth.
This filter response has the steeper initial rate of attenuation beyond the cutoff frequency than Butterworth.This advantage comes at the penalty of amplitude variation(ripple) in the passband. Unlike Butterworth and Bessel response, which have 3dB attenuation at the cutoff frequency,Cebyshev cutoff frequency is defined as the frequency at which the response falls below the ripple band. For evenorder filters, all riple is above the dcnormalized passband gain response, so cutoff is at 0dB. For oddorder filters, all riple is below the dcnormalized passband gain response, so cutoff is at (ripple) dB. For a given number of poles, a steeper cutoff can be achieved by allowing more passband ripple. The Chebyshev has more ringing in its pulse response than the Butterworth  especially for highripple designs. Back
Advantages:
Flat magnitude response in passband with steep rate of attenuation in transitionband.
Diavantages:
Ripple in stopband.
Some overshoot and ringing in step response.
As its name implies, this filter type is cousin to the
Chebyshev. The difference is that the ripple of the Inverse Chebyshev filter
is confined to the stopband. This filter type has a steep rate of rollof and
a flat magnitude response in passband. Cutoff of the Inverse Chebyshev is defined
as the frequency where the response first enters the specified stopband. Step
response of the Inverse Chebyshev is similar to the Butterworth. Back
Advantages:
Best step responsevery little overshoot or ringing.
Diavantages:
Slower initial rate of attenuation beyond the passband than Butterworth.
Due to its linear phase response, this filter has excellent
pulse response (minimal overshoot and ringing). For a given number of poles,
its magnitude response is not as flat, nor is its initial rate of attenation
beyond the 3dB cutoff frequency as steep as the Butterworth.It takes a higherorder
Bessel filter to give a magnitude response similar to a given Butterworth filter,
but the pulse response fidelity of the Bessel filter may make the added complexity
worthwile. Back
You are  th visitors since 5 december 2000. 
Last update:
February 19, 2002
