--- /dev/null
+/* -*- c++ -*- */
+/*
+ * Copyright 2009 Free Software Foundation, Inc.
+ *
+ * This file is part of GNU Radio
+ *
+ * GNU Radio is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3, or (at your option)
+ * any later version.
+ *
+ * GNU Radio is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with GNU Radio; see the file COPYING. If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street,
+ * Boston, MA 02110-1301, USA.
+ */
+
+
+#ifndef INCLUDED_GR_PFB_INTERPOLATOR_CCF_H
+#define INCLUDED_GR_PFB_INTERPOLATOR_CCF_H
+
+#include <gr_sync_interpolator.h>
+
+class gr_pfb_interpolator_ccf;
+typedef boost::shared_ptr<gr_pfb_interpolator_ccf> gr_pfb_interpolator_ccf_sptr;
+gr_pfb_interpolator_ccf_sptr gr_make_pfb_interpolator_ccf (unsigned int interp,
+ const std::vector<float> &taps);
+
+class gr_fir_ccf;
+
+/*!
+ * \class gr_pfb_interpolator_ccf
+ * \brief Polyphase filterbank interpolator with gr_complex input,
+ * gr_complex output and float taps
+ *
+ * \ingroup filter_blk
+ *
+ * This block takes in a signal stream and performs interger up-
+ * sampling (interpolation) with a polyphase filterbank. The first
+ * input is the integer specifying how much to interpolate by. The
+ * second input is a vector (Python list) of floating-point taps of
+ * the prototype filter.
+ *
+ * The filter's taps should be based on the interpolation rate
+ * specified. That is, the bandwidth specified is relative to the
+ * bandwidth after interpolation.
+ *
+ * For example, using the GNU Radio's firdes utility to building
+ * filters, we build a low-pass filter with a sampling rate of
+ * <EM>fs</EM>, a 3-dB bandwidth of <EM>BW</EM> and a transition
+ * bandwidth of <EM>TB</EM>. We can also specify the out-of-band
+ * attenuation to use, ATT, and the filter window function (a
+ * Blackman-harris window in this case). The first input is the gain,
+ * which is also specified as the interpolation rate so that the
+ * output levels are the same as the input (this creates an overall
+ * increase in power).
+ *
+ * <B><EM>self._taps = gr.firdes.low_pass_2(interp, interp*fs, BW, TB,
+ * attenuation_dB=ATT, window=gr.firdes.WIN_BLACKMAN_hARRIS)</EM></B>
+ *
+ * The PFB interpolator code takes the taps generated above and builds
+ * a set of filters. The set contains <EM>interp</EM> number of
+ * filters and each filter contains ceil(taps.size()/interp) number of
+ * taps. Each tap from the filter prototype is sequentially inserted
+ * into the next filter. When all of the input taps are used, the
+ * remaining filters in the filterbank are filled out with 0's to make
+ * sure each filter has the same number of taps.
+ *
+ * The theory behind this block can be found in Chapter 7.1 of the
+ * following book.
+ *
+ * <B><EM>f. harris, "Multirate Signal Processing for Communication
+ * Systems</EM>," Upper Saddle River, NJ: Prentice Hall,
+ * Inc. 2004.</EM></B>
+ */
+
+class gr_pfb_interpolator_ccf : public gr_sync_interpolator
+{
+ private:
+ /*!
+ * Build the polyphase filterbank interpolator.
+ * \param interp (unsigned integer) Specifies the interpolation rate to use
+ * \param taps (vector/list of floats) The prototype filter to populate the filterbank. The taps
+ * should be generated at the interpolated sampling rate.
+ */
+ friend gr_pfb_interpolator_ccf_sptr gr_make_pfb_interpolator_ccf (unsigned int interp,
+ const std::vector<float> &taps);
+
+ std::vector<gr_fir_ccf*> d_filters;
+ std::vector< std::vector<float> > d_taps;
+ unsigned int d_rate;
+ unsigned int d_taps_per_filter;
+ bool d_updated;
+
+ /*!
+ * Construct a Polyphase filterbank interpolator
+ * \param interp (unsigned integer) Specifies the interpolation rate to use
+ * \param taps (vector/list of floats) The prototype filter to populate the filterbank. The taps
+ * should be generated at the interpolated sampling rate.
+ */
+ gr_pfb_interpolator_ccf (unsigned int interp,
+ const std::vector<float> &taps);
+
+public:
+ ~gr_pfb_interpolator_ccf ();
+
+ /*!
+ * Resets the filterbank's filter taps with the new prototype filter
+ * \param taps (vector/list of floats) The prototype filter to populate the filterbank. The taps
+ * should be generated at the interpolated sampling rate.
+ */
+ void set_taps (const std::vector<float> &taps);
+
+ /*!
+ * Print all of the filterbank taps to screen.
+ */
+ void print_taps();
+
+ int work (int noutput_items,
+ gr_vector_const_void_star &input_items,
+ gr_vector_void_star &output_items);
+};
+
+#endif
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