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/*
* Copyright 2011 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.
*/
/*
* GNU Radio C++ example creating dial tone
* ("the simplest thing that could possibly work")
*
* Send a tone each to the left and right channels of stereo audio
* output and let the user's brain sum them.
*
* GNU Radio makes extensive use of Boost shared pointers. Signal processing
* blocks are typically created by calling a "make" factory function, which
* returns an instance of the block as a typedef'd shared pointer that can
* be used in any way a regular pointer can. Shared pointers created this way
* keep track of their memory and free it at the right time, so the user
* doesn't need to worry about it (really).
*
*/
// Include header files for each block used in flowgraph
#include <gr_top_block.h>
#include <gr_sig_source_f.h>
#include <gr_audio_sink.h>
int main(int argc, char **argv)
{
int rate = 48000; // Audio card sample rate
float ampl = 0.1; // Don't exceed 0.5 or clipping will occur
// Construct a top block that will contain flowgraph blocks. Alternatively,
// one may create a derived class from gr_top_block and hold instantiated blocks
// as member data for later manipulation.
gr_top_block_sptr tb = gr_make_top_block("dial_tone");
// Construct a real-valued signal source for each tone, at given sample rate
gr_sig_source_f_sptr src0 = gr_make_sig_source_f(rate, GR_SIN_WAVE, 350, ampl);
gr_sig_source_f_sptr src1 = gr_make_sig_source_f(rate, GR_SIN_WAVE, 440, ampl);
// Construct an audio sink to accept audio tones
audio_sink::sptr sink = audio_make_sink(rate);
// Connect output #0 of src0 to input #0 of sink (left channel)
tb->connect(src0, 0, sink, 0);
// Connect output #0 of src1 to input #1 of sink (right channel)
tb->connect(src1, 0, sink, 1);
// Tell GNU Radio runtime to start flowgraph threads; the foreground thread
// will block until either flowgraph exits (this example doesn't) or the
// application receives SIGINT (e.g., user hits CTRL-C).
//
// Real applications may use tb->start() which returns, allowing the foreground
// thread to proceed, then later use tb->stop(), followed by tb->wait(), to cleanup
// GNU Radio before exiting.
tb->run();
// Exit normally.
return 0;
}
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