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23 #ifndef INCLUDED_GR_SINGLE_POLE_IIR_FILTER_CC_H
24 #define INCLUDED_GR_SINGLE_POLE_IIR_FILTER_CC_H
26 #include <gr_sync_block.h>
27 #include <gr_single_pole_iir.h>
28 #include <gr_complex.h>
31 class gr_single_pole_iir_filter_cc;
32 typedef boost::shared_ptr<gr_single_pole_iir_filter_cc> gr_single_pole_iir_filter_cc_sptr;
34 gr_single_pole_iir_filter_cc_sptr
35 gr_make_single_pole_iir_filter_cc (double alpha, unsigned int vlen=1);
38 * \brief single pole IIR filter with complex input, complex output
41 * The input and output satisfy a difference equation of the form
44 y[n] - (1-alpha) y[n-1] = alpha x[n]
47 * with the corresponding rational system function
50 H(z) = \frac{alpha}{1 - (1-alpha) z^{-1}}
53 * Note that some texts define the system function with a + in the denominator.
54 * If you're using that convention, you'll need to negate the feedback tap.
56 class gr_single_pole_iir_filter_cc : public gr_sync_block
59 friend gr_single_pole_iir_filter_cc_sptr
60 gr_make_single_pole_iir_filter_cc (double alpha, unsigned int vlen);
63 std::vector<gr_single_pole_iir<gr_complex,gr_complex,double> > d_iir;
65 gr_single_pole_iir_filter_cc (double alpha, unsigned int vlen);
68 ~gr_single_pole_iir_filter_cc ();
70 void set_taps (double alpha);
72 int work (int noutput_items,
73 gr_vector_const_void_star &input_items,
74 gr_vector_void_star &output_items);