1 files changed, 91 insertions, 0 deletions
diff --git a/nyqstk/include/PoleZero.h b/nyqstk/include/PoleZero.h
new file mode 100644
index 0000000..5ee5d10
--- /dev/null
+++ b/nyqstk/include/PoleZero.h
@@ -0,0 +1,91 @@
+/***************************************************/
+/*! \class PoleZero
+    \brief STK one-pole, one-zero filter class.
+
+    This protected Filter subclass implements
+    a one-pole, one-zero digital filter.  A
+    method is provided for creating an allpass
+    filter with a given coefficient.  Another
+    method is provided to create a DC blocking filter.
+
+    by Perry R. Cook and Gary P. Scavone, 1995 - 2005.
+*/
+/***************************************************/
+
+#ifndef STK_POLEZERO_H
+#define STK_POLEZERO_H
+
+#include "Filter.h"
+
+namespace Nyq
+{
+
+class PoleZero : protected Filter
+{
+ public:
+
+  //! Default constructor creates a first-order pass-through filter.
+  PoleZero();
+
+  //! Class destructor.
+  ~PoleZero();
+
+  //! Clears the internal states of the filter.
+  void clear(void);
+
+  //! Set the b[0] coefficient value.
+  void setB0(StkFloat b0);
+
+  //! Set the b[1] coefficient value.
+  void setB1(StkFloat b1);
+
+  //! Set the a[1] coefficient value.
+  void setA1(StkFloat a1);
+
+  //! Set the filter for allpass behavior using \e coefficient.
+  /*!
+    This method uses \e coefficient to create an allpass filter,
+    which has unity gain at all frequencies.  Note that the \e
+    coefficient magnitude must be less than one to maintain stability.
+  */
+  void setAllpass(StkFloat coefficient);
+
+  //! Create a DC blocking filter with the given pole position in the z-plane.
+  /*!
+    This method sets the given pole position, together with a zero
+    at z=1, to create a DC blocking filter.  \e thePole should be
+    close to one to minimize low-frequency attenuation.
+
+  */
+  void setBlockZero(StkFloat thePole = 0.99);
+
+  //! Set the filter gain.
+  /*!
+    The gain is applied at the filter input and does not affect the
+    coefficient values.  The default gain value is 1.0.
+   */
+  void setGain( StkFloat gain );
+
+  //! Return the current filter gain.
+  StkFloat getGain( void ) const;
+
+  //! Return the last computed output value.
+  StkFloat lastOut( void ) const;
+
+  //! Input one sample to the filter and return one output.
+  StkFloat tick( StkFloat sample );
+
+  //! Take a channel of the StkFrames object as inputs to the filter and replace with corresponding outputs.
+  /*!
+    The \c channel argument should be zero or greater (the first
+    channel is specified by 0).  An StkError will be thrown if the \c
+    channel argument is equal to or greater than the number of
+    channels in the StkFrames object.
+  */
+  StkFrames& tick( StkFrames& frames, unsigned int channel = 0 );
+
+};
+
+} // namespace Nyq
+
+#endif