GNU Radio 3.7.0-50 C++ API
pfb_interpolator_ccf.h
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/* -*- c++ -*- */
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/*
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* Copyright 2009,2012 Free Software Foundation, Inc.
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*
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* This file is part of GNU Radio
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*
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* GNU Radio is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 3, or (at your option)
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* any later version.
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*
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* GNU Radio is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with GNU Radio; see the file COPYING. If not, write to
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* the Free Software Foundation, Inc., 51 Franklin Street,
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* Boston, MA 02110-1301, USA.
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*/
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#ifndef INCLUDED_PFB_INTERPOLATOR_CCF_H
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#define INCLUDED_PFB_INTERPOLATOR_CCF_H
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#include <
gnuradio/filter/api.h
>
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#include <
gnuradio/sync_interpolator.h
>
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namespace
gr {
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namespace
filter {
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/*!
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* \brief Polyphase filterbank interpolator with gr_complex input,
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* gr_complex output and float taps
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* \ingroup channelizers_blk
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*
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* \details
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* This block takes in a signal stream and performs interger up-
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* sampling (interpolation) with a polyphase filterbank. The first
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* input is the integer specifying how much to interpolate by. The
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* second input is a vector (Python list) of floating-point taps
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* of the prototype filter.
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*
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* The filter's taps should be based on the interpolation rate
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* specified. That is, the bandwidth specified is relative to the
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* bandwidth after interpolation.
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*
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* For example, using the GNU Radio's firdes utility to building
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* filters, we build a low-pass filter with a sampling rate of
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* <EM>fs</EM>, a 3-dB bandwidth of <EM>BW</EM> and a transition
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* bandwidth of <EM>TB</EM>. We can also specify the out-of-band
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* attenuation to use, ATT, and the filter window function (a
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* Blackman-harris window in this case). The first input is the
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* gain, which is also specified as the interpolation rate so that
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* the output levels are the same as the input (this creates an
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* overall increase in power).
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*
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* <B><EM>self._taps = filter.firdes.low_pass_2(interp, interp*fs, BW, TB,
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* attenuation_dB=ATT, window=filter.firdes.WIN_BLACKMAN_hARRIS)</EM></B>
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*
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* The PFB interpolator code takes the taps generated above and
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* builds a set of filters. The set contains <EM>interp</EM>
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* number of filters and each filter contains
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* ceil(taps.size()/interp) number of taps. Each tap from the
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* filter prototype is sequentially inserted into the next
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* filter. When all of the input taps are used, the remaining
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* filters in the filterbank are filled out with 0's to make sure
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* each filter has the same number of taps.
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*
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* The theory behind this block can be found in Chapter 7.1 of the
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* following book.
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*
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* <B><EM>f. harris, "Multirate Signal Processing for Communication
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* Systems</EM>," Upper Saddle River, NJ: Prentice Hall,
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* Inc. 2004.</EM></B>
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*/
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class
FILTER_API
pfb_interpolator_ccf
:
virtual
public
sync_interpolator
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{
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public
:
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// gr::filter::pfb_interpolator_ccf::sptr
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typedef
boost::shared_ptr<pfb_interpolator_ccf>
sptr
;
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/*!
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* Build the polyphase filterbank interpolator.
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* \param interp (unsigned integer) Specifies the interpolation rate to use
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* \param taps (vector/list of floats) The prototype filter to populate the filterbank. The taps
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* should be generated at the interpolated sampling rate.
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*/
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static
sptr
make(
unsigned
int
interp,
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const
std::vector<float> &
taps
);
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/*!
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* Resets the filterbank's filter taps with the new prototype filter
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* \param taps (vector/list of floats) The prototype filter to populate the filterbank.
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* The taps should be generated at the interpolated sampling rate.
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*/
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virtual
void
set_taps(
const
std::vector<float> &
taps
) = 0;
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/*!
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* Return a vector<vector<>> of the filterbank taps
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*/
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virtual
std::vector<std::vector<float> >
taps
()
const
= 0;
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/*!
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* Print all of the filterbank taps to screen.
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*/
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virtual
void
print_taps() = 0;
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};
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}
/* namespace filter */
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}
/* namespace gr */
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#endif
/* INCLUDED_FILTER_PFB_INTERPOLATOR_CCF_H */
gnuradio
gr-filter
include
gnuradio
filter
pfb_interpolator_ccf.h
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