frequency [2 floats]
Filter cutoff frequencies specified in units defined by the units attribute. For lowpass and highpass filters a single frequency will be used to define the cutoff. For bandpass and bandstop filters two frequencies are required.
Name to which the output dictionary is bound
The order of the filter, which is to say the number of poles and zeroes. For reference, the biquad~ object is a second-order filter (2 poles and 2 zeroes).
Magnitude ripple in the passband for Chebyshev Type 1 filters in decibels. Higher amounts of ripple will provide a narrower transition band given a constant order for the filter.
Filter response shape
'lowpass' ( Low frequencies pass through, high frequencies are attenuated )
'highpass' ( High frequencies pass through, low frequencies are attenuated )
'bandpass' ( A band of frequencies pass through, low and high frequencies are attenuated )
'bandstop' ( A band of frequencies are attenuated, low and high frequencies pass through )
Samplerate used when unit attribute is set to hertz. If the samplerate is set to zero then MSP's samplerate will be used.
Minimum attenuation in Chebyshev Type 2 filter stopband in decibels. For given order of filter, greater attenuation results in a wider transition band and less attenuation in the stopband results in a narrower transition band.
Include single-section transfer function coefficients in the output dictionary. This representation works well for low-ordered filters but quickly becomes subject to floating-point precision roundoff as the order of the filter increases.
The organization of the zeroes and poles used to realize the filter.
'butterworth' ( Gentle transition, flat passband, monotonically decreasing stopband )
'chebyshev-1' ( Steepest transition, definable ripple in passband, monotonically decreasing stopband )
'chebyshev-2' ( Moderate transition, flat passband, definable ripple in the stopband )
Units of measurement for specifying frequencies
'hertz' ( Cycles per second, based on the samplerate attribute )
'normalized' ( Range from 0.0 to 1.0; 1.0 is the nyquist frequency )
'radians' ( Range from 0.0 to pi; pi is the nyquist frequency )
Include zeroes-poles-gain representation in the output dictionary. Zeroes-poles-gain (ZPK) provides a more accurate representation of the filter's response than the single-section transfer function (see tf_output attribute) for higher-order filters. If calculating coefficients for second-order-sections (see sos_output attribute) the ZPK representation is calculated as an intermediary stage.
Common Box Attributes
A filterdesign dictionary containing the specified filter characteristics.
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