diff options
Diffstat (limited to 'host/examples')
| -rw-r--r-- | host/examples/tx_waveforms.cpp | 123 |
1 files changed, 64 insertions, 59 deletions
diff --git a/host/examples/tx_waveforms.cpp b/host/examples/tx_waveforms.cpp index f150f520a..b78cc7d0a 100644 --- a/host/examples/tx_waveforms.cpp +++ b/host/examples/tx_waveforms.cpp @@ -23,7 +23,6 @@ #include <boost/math/special_functions/round.hpp> #include <boost/foreach.hpp> #include <boost/format.hpp> -#include <boost/function.hpp> #include <iostream> #include <complex> #include <csignal> @@ -31,36 +30,61 @@ namespace po = boost::program_options; +/*********************************************************************** + * Signal handlers + **********************************************************************/ static bool stop_signal_called = false; void sig_int_handler(int){stop_signal_called = true;} /*********************************************************************** * Waveform generators **********************************************************************/ -float gen_const(float){ - return 1; -} - -float gen_square(float x){ - return float((std::fmod(x, 1) < float(0.5))? 0 : 1); -} +static const size_t wave_table_len = 8192; + +class wave_table_class{ +public: + wave_table_class(const std::string &wave_type, const float ampl): + _wave_table(wave_table_len) + { + //compute real wave table with 1.0 amplitude + std::vector<double> real_wave_table(wave_table_len); + if (wave_type == "CONST"){ + for (size_t i = 0; i < wave_table_len; i++) + real_wave_table[i] = 1.0; + } + else if (wave_type == "SQUARE"){ + for (size_t i = 0; i < wave_table_len; i++) + real_wave_table[i] = (i < wave_table_len/2)? 0.0 : 1.0; + } + else if (wave_type == "RAMP"){ + for (size_t i = 0; i < wave_table_len; i++) + real_wave_table[i] = 2.0*i/(wave_table_len-1) - 1.0; + } + else if (wave_type == "SINE"){ + static const double tau = 2*std::acos(-1.0); + for (size_t i = 0; i < wave_table_len; i++) + real_wave_table[i] = std::sin((tau*i)/wave_table_len); + } + else throw std::runtime_error("unknown waveform type: " + wave_type); -float gen_ramp(float x){ - return std::fmod(x, 1)*2 - 1; -} + //compute i and q pairs with 90% offset and scale to amplitude + for (size_t i = 0; i < wave_table_len; i++){ + const size_t q = (i+(3*wave_table_len)/4)%wave_table_len; + _wave_table[i] = std::complex<float>(ampl*real_wave_table[i], ampl*real_wave_table[q]); + } + } -#define sine_table_len 2048 -static float sine_table[sine_table_len]; -UHD_STATIC_BLOCK(gen_sine_table){ - static const double tau = 2*std::acos(-1.0); - for (size_t i = 0; i < sine_table_len; i++) - sine_table[i] = float(std::sin((tau*i)/sine_table_len)); -} + inline std::complex<float> operator()(const double theta) const{ + return _wave_table[unsigned(boost::math::iround(theta*wave_table_len))%wave_table_len]; + } -float gen_sine(float x){ - return sine_table[size_t(x*sine_table_len)%sine_table_len]; -} +private: + std::vector<std::complex<float> > _wave_table; +}; +/*********************************************************************** + * Main function + **********************************************************************/ int UHD_SAFE_MAIN(int argc, char *argv[]){ uhd::set_thread_priority_safe(); @@ -144,9 +168,6 @@ int UHD_SAFE_MAIN(int argc, char *argv[]){ if (vm.count("ant")) usrp->set_tx_antenna(ant, chan); } - std::cout << boost::format("Setting device timestamp to 0...") << std::endl; - usrp->set_time_now(uhd::time_spec_t(0.0)); - //for the const wave, set the wave freq for small samples per period if (wave_freq == 0 and wave_type == "CONST"){ wave_freq = usrp->get_tx_rate()/2; @@ -156,49 +177,37 @@ int UHD_SAFE_MAIN(int argc, char *argv[]){ if (std::abs(wave_freq) > usrp->get_tx_rate()/2){ throw std::runtime_error("wave freq out of Nyquist zone"); } - if (usrp->get_tx_rate()/std::abs(wave_freq) > sine_table_len/2 and wave_type == "SINE"){ - throw std::runtime_error("sine freq too small for table"); + if (usrp->get_tx_rate()/std::abs(wave_freq) > wave_table_len/2){ + throw std::runtime_error("wave freq too small for table"); } - //store the generator function for the selected waveform - boost::function<float(float)> wave_gen; - if (wave_type == "CONST") wave_gen = &gen_const; - else if (wave_type == "SQUARE") wave_gen = &gen_square; - else if (wave_type == "RAMP") wave_gen = &gen_ramp; - else if (wave_type == "SINE") wave_gen = &gen_sine; - else throw std::runtime_error("unknown waveform type: " + wave_type); + //pre-compute the waveform values + const wave_table_class wave_table(wave_type, ampl); + const double cps = wave_freq/usrp->get_tx_rate(); + double theta = 0; - //allocate the buffer and precalculate values - const float cps = float(wave_freq/usrp->get_tx_rate()); - const float i_off = (wave_freq > 0)? float(0.25) : 0; - const float q_off = (wave_freq < 0)? float(0.25) : 0; - float theta = 0; - - std::vector<std::complex<float> *> buffs; - for(size_t i=0; i < usrp->get_num_mboards(); i++) - buffs.push_back(new std::complex<float>[spb]); + //allocate a buffer which we re-use for each channel + std::vector<std::complex<float> > buff(spb); + std::vector<std::complex<float> *> buffs(usrp->get_tx_num_channels(), &buff.front()); //setup the metadata flags uhd::tx_metadata_t md; - md.start_of_burst = false; //no for continuous streaming + md.start_of_burst = true; md.end_of_burst = false; - md.has_time_spec = true; + md.has_time_spec = true; md.time_spec = uhd::time_spec_t(0.1); + std::cout << boost::format("Setting device timestamp to 0...") << std::endl; + usrp->set_time_now(uhd::time_spec_t(0.0)); + std::signal(SIGINT, &sig_int_handler); std::cout << "Press Ctrl + C to stop streaming..." << std::endl; //send data until the signal handler gets called while(not stop_signal_called){ //fill the buffer with the waveform - for (size_t n = 0; n < spb; n++){ - BOOST_FOREACH(std::complex<float> *buff, buffs) { - buff[n] = std::complex<float>( - ampl*wave_gen(i_off + theta), - ampl*wave_gen(q_off + theta) - ); - } - theta += cps; + for (size_t n = 0; n < buff.size(); n++){ + buff[n] = wave_table(theta += cps); } //bring the theta back into range [0, 1) @@ -206,16 +215,17 @@ int UHD_SAFE_MAIN(int argc, char *argv[]){ //send the entire contents of the buffer usrp->get_device()->send( - buffs, spb, md, + buffs, buff.size(), md, uhd::io_type_t::COMPLEX_FLOAT32, uhd::device::SEND_MODE_FULL_BUFF ); + md.start_of_burst = false; md.has_time_spec = false; } //send a mini EOB packet - md.end_of_burst = true; + md.end_of_burst = true; usrp->get_device()->send("", 0, md, uhd::io_type_t::COMPLEX_FLOAT32, uhd::device::SEND_MODE_FULL_BUFF @@ -223,10 +233,5 @@ int UHD_SAFE_MAIN(int argc, char *argv[]){ //finished std::cout << std::endl << "Done!" << std::endl << std::endl; - - BOOST_FOREACH(std::complex<float> *buff, buffs){ - delete buff; - } - return 0; } |