GNU Radio 3.7.1-34 C++ API
dc_blocker_ff.h
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/* -*- c++ -*- */
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/*
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* Copyright 2011,2012 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_FILTER_DC_BLOCKER_FF_H
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#define INCLUDED_FILTER_DC_BLOCKER_FF_H
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#include <
gnuradio/filter/api.h
>
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#include <
gnuradio/sync_block.h
>
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namespace
gr {
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namespace
filter {
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/*!
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* \brief a computationally efficient controllable DC blocker
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* \ingroup filter_blk
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*
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* \details
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* This block implements a computationally efficient DC blocker
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* that produces a tighter notch filter around DC for a smaller
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* group delay than an equivalent FIR filter or using a single
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* pole IIR filter (though the IIR filter is computationally
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* cheaper).
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*
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* The block defaults to using a delay line of length 32 and the
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* long form of the filter. Optionally, the delay line length can
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* be changed to alter the width of the DC notch (longer lines
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* will decrease the width).
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*
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* The long form of the filter produces a nearly flat response
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* outside of the notch but at the cost of a group delay of 2D-2.
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*
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* The short form of the filter does not have as flat a response
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* in the passband but has a group delay of only D-1 and is
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* cheaper to compute.
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*
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* The theory behind this block can be found in the paper:
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*
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* <B><EM>R. Yates, "DC Blocker Algorithms," IEEE Signal Processing Magazine,
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* Mar. 2008, pp 132-134.</EM></B>
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*/
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class
FILTER_API
dc_blocker_ff
:
virtual
public
sync_block
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{
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public
:
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// gr::filter::dc_blocker_ff::sptr
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typedef
boost::shared_ptr<dc_blocker_ff>
sptr
;
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/*!
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* Make a DC blocker block.
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*
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* \param D (int) the length of the delay line
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* \param long_form (bool) whether to use long (true, default) or short form
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*/
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static
sptr
make(
int
D,
bool
long_form=
true
);
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virtual
int
group_delay() = 0;
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};
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}
/* namespace filter */
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}
/* namespace gr */
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#endif
/* INCLUDED_FILTER_DC_BLOCKER_FF_H */
gnuradio
gr-filter
include
gnuradio
filter
dc_blocker_ff.h
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