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resources:tools-software:sigmastudio:toolbox:filters:statevariable [15 Nov 2012 17:40] – Fixed filter examples link William Jahnresources:tools-software:sigmastudio:toolbox:filters:statevariable [23 Jun 2020 22:13] (current) – Added filter parameter definitions Joshua Berlin
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 {{ statepic1.png}} {{ statepic1.png}}
-The State-Variable block allows for simultaneous access to three different filter types: lowpass, highpass, and bandpass. See [[resources/tools-software/sigmastudio/toolbox/algorithminformation/statevariablefilters|State Variable Algorithms]] for information about the parameters and calculations for this algorithm.+The State-Variable block allows for simultaneous access to three different filter types: lowpass, highpass, and bandpass.
  
 Set the center frequency in the Freq (Hz) field or by dragging the arrows. For examples and details, see [[resources/tools-software/sigmastudio/tutorials/filterexamples|Filters Example]]. Set the center frequency in the Freq (Hz) field or by dragging the arrows. For examples and details, see [[resources/tools-software/sigmastudio/tutorials/filterexamples|Filters Example]].
  
-To have external control over Q from the block, refer to the State-Variable (Q input) Filter.+To have external control over Q from the block, refer to the [[resources:tools-software:sigmastudio:toolbox:filters:statevariableqinput|State-Variable (Q input) Filter]].
  
-The three output pins let you choose among LP, HP, BP filters. The nature of this algorithm is to compute the coefficients for all filter typesgiving you access to all of the filters simultaneously. If your application doesn't require use of all filter types, you can connect the output to a [[resources/tools-software/sigmastudio/toolbox/systemschematicdesign/schematicterminal|terminal block]]. +To have external control over Q and F from the blockrefer to the [[resources:tools-software:sigmastudio:toolbox:filters:statevariableqfinput|State-Variable (Q/F input) Filter]].
- +
  
 +The three output pins let you choose among LP, HP, BP filters. The nature of this algorithm is to compute the coefficients for all filter types, giving you access to all of the filters simultaneously.
  
 +===== Parameter Calculation =====
 +The following describes how the DSP uses input parameters to calculate the filter outputs.
 +
 +{{ :resources:tools-software:sigmastudio:toolbox:filters:statevariable_topology.png?direct&400 |}}
 +
 +<m> f = 2 sin (pi {F / Fs}) </m>
 +<m> q = {1/Q} </m>
 +
 +<m> D(z) = 1 + (f^2 + q f - 2) z^{-1} + (1 - q f) z^(-2) </m>
 +
 +<m> H_{BPF}(z) = {f - f z^{-1} } / {D(z)} </m>
 +<m> H_{HPF}(z) = {1 - 2z^{-1} + z^{-2}} / {D(z)} </m>
 +<m> H_{LPF}(z) = {f^2 z^{-1}} / {D(z)} </m>
resources/tools-software/sigmastudio/toolbox/filters/statevariable.txt · Last modified: 23 Jun 2020 22:13 by Joshua Berlin