Parameters

Class

Choose the class of filter to create.  There are five from which to choose:

Bessel:

Has the slowest rolloff and requires the highest order to meet an attenuation specification.

Butterworth:

Maximally flat in the passband and stopband, but has a transition region that is less steep than the other filters.

Chebyshev:

Achieves a steeper transition region by allowing ripple in the passband. The stopband is maximally flat.

Elliptic:

Minimizes the transition width by allowing ripple in the both the passband and the stopband. This class generally meets filter requirements with the lowest order.

Inverse Chebyshev:

Achieves a steeper transition region by allowing ripple in the stopband. The passband is maximally flat.

Order

Specify the desired order for the filter.  Higher order filters require more computation but generate responses that are closer to ideal.

Passband Ripple

Specify the maximum amount of ripple in the passband in decibels (dB).  This parameter is only used for Chebyshev and Elliptic filter classes.

Attenuation

Specify the minimum attenuation for the stopband in decibels (dB).  In other words, specify the number of decibels below the passband that the stopband must be.  This is parameter is only used for Inverse Chebyshev and Elliptic filter classes.

Response

Choose the type of filter response.

Lowpass:

Attenuates frequency components above a specified corner frequency.

Highpass:

Attenuates frequency components below a specified corner frequency.

Bandpass:

Attenuates frequency components outside of a range specified by two corner frequencies.

Stopband:

Attenuates frequency components inside of a range specified by two corner frequencies.

Corner Frequency 1

Specify the first corner frequency in Hertz (Hz).

Corner Frequency 2

Specify the second corner frequency in Hertz (Hz). This is only necessary for bandpass and stopband filters. Corner Frequency 2 must be greater than Corner Frequency 1.