The zplane~ object provides a way to graph filter poles and zeros in the Z-plane for display. Use the zplane~ object in conjunction with the filtergraph~ object, or provide it with a list of biquad~ coefficients.
Like the filtergraph~ object, it does not process audio signals by itself, but it does react internally to the current MSP sampling rate. The zplane~ object is designed to help in digital filter design and visualization for MSP, and to provide a basic pedagogical tool which may be used to help explain digital filter theory.
You can change the filter parameters by clicking and dragging on the zplane~ object’s display. Clicking and dragging on any of the poles (shown as an x in the display) or zeros (shown as an o in the display) will modify the filter coefficients and output the new filter coefficient values.
bgcolor [4 floats]
Sets the background color of the zplane~ object in RGBA format.
gridlinecolor [4 floats]
Sets the colors for the grids and lines in RGBA format. The style color.attribute is mapped to the
order [int] (default: 2)
The word, followed by an even number between 2 and 24, sets the number of poles and zeros.
pconstrain [int] (default: 0)
When set to 1, poles will be constrained inside the unit circle, and thus yield a stable filter. An argument of zero will turn this feature off (the default).
polezerocolor [4 floats]
Sets the pole zero color in RGBA format. The style color.attribute is mapped to the
style [symbol] (default: )7.0.0
Common Box Attributes
If more than five values are sent, they are interpreted as sets of cascaded biquad coefficients. The zplane~ object will display a composite pole-zero graph which shows the multiplication of a group of biquad filters in cascade. Up to 24 groups of five float values may be cascaded.
Out left outlet: a list of 5 floating-point filter coefficients for the biquad~ object. Coefficients output in response to mouse clicks and changes in the coefficient inlets.
Out second outlet: a list of "zero" location values expressed as complex numbers (real, imaginary). These correspond to the "a" coefficients of the filter. A 2nd order (biquad) filter will have 2 zeros, a 4th order filter will have four, etc...
Out third outlet: a list of "pole" location values expressed as complex numbers (real, imaginary). These correspond to the "b" coefficients of the filter. A 2nd order (biquad) filter will have 2 zeros, a 4th order filter will have four, etc...
Out fourth outlet: a list of floating-point values representing the overall gain of each cascaded filter.
|Audio Filtering||Audio Filtering|