From eec4cd82ff0948652fb073d81b426fa9ce1ab7c5 Mon Sep 17 00:00:00 2001 From: Josh Blum Date: Thu, 19 Aug 2010 19:44:01 -0700 Subject: uhd: work on tx waveforms to make it more accurate --- host/examples/tx_waveforms.cpp | 62 +++++++++++++++++++++++++++++------------- 1 file changed, 43 insertions(+), 19 deletions(-) (limited to 'host/examples') diff --git a/host/examples/tx_waveforms.cpp b/host/examples/tx_waveforms.cpp index e9cf210bb..22975da96 100644 --- a/host/examples/tx_waveforms.cpp +++ b/host/examples/tx_waveforms.cpp @@ -20,6 +20,7 @@ #include #include #include //system time +#include #include #include #include @@ -32,7 +33,7 @@ int UHD_SAFE_MAIN(int argc, char *argv[]){ //variables to be set by po std::string args, wave_type; - size_t total_duration, amspb; + size_t total_duration, mspb; double rate, freq, wave_freq; float ampl, gain; @@ -42,7 +43,7 @@ int UHD_SAFE_MAIN(int argc, char *argv[]){ ("help", "help message") ("args", po::value(&args)->default_value(""), "simple uhd device address args") ("duration", po::value(&total_duration)->default_value(3), "number of seconds to transmit") - ("amspb", po::value(&amspb)->default_value(10000), "approximate mimimum samples per buffer") + ("mspb", po::value(&mspb)->default_value(10000), "mimimum samples per buffer") ("rate", po::value(&rate)->default_value(100e6/16), "rate of outgoing samples") ("freq", po::value(&freq)->default_value(0), "rf center frequency in Hz") ("ampl", po::value(&l)->default_value(float(0.3)), "amplitude of the waveform") @@ -88,33 +89,56 @@ int UHD_SAFE_MAIN(int argc, char *argv[]){ } //error when the waveform is not possible to generate - if (std::abs(wave_freq)/sdev->get_tx_rate() < 0.5/amspb){ + if (std::abs(wave_freq)/sdev->get_tx_rate() < 0.5/mspb){ throw std::runtime_error("wave freq/tx rate too small"); } if (std::abs(wave_freq) > sdev->get_tx_rate()/2){ throw std::runtime_error("wave freq out of Nyquist zone"); } - //fill a buffer with one period worth of samples - std::vector period(size_t(sdev->get_tx_rate()/std::abs(wave_freq))); - std::cout << boost::format("Samples per waveform period: %d") % period.size() << std::endl; - for (size_t n = 0; n < period.size(); n++){ - if (wave_type == "CONST") period[n] = ampl; - else if (wave_type == "SQUARE") period[n] = (n > period.size()/2)? ampl : 0; - else if (wave_type == "RAMP") period[n] = float((n/double(period.size()-1)) * 2*ampl - ampl); - else if (wave_type == "SINE") period[n] = ampl*float(std::sin(2*M_PI*n/double(period.size()))); - else throw std::runtime_error("unknown waveform type: " + wave_type); + //how many periods should we have per buffer to mimimize error + double samps_per_period = sdev->get_tx_rate()/std::abs(wave_freq); + std::cout << boost::format("Samples per waveform period: %d") % samps_per_period << std::endl; + size_t periods_per_buff = std::max(1, mspb/samps_per_period); + while (true){ + double num_samps_per_buff = periods_per_buff*samps_per_period; + double sample_error = num_samps_per_buff - boost::math::round(num_samps_per_buff); + if (std::abs(sample_error/num_samps_per_buff) < 1e-5) break; + periods_per_buff++; } //allocate data to send (fill with several periods worth of IQ samples) - const size_t periods_per_buff = std::max(1, amspb/period.size()); - std::vector > buff(period.size()*periods_per_buff); + std::vector > buff(samps_per_period*periods_per_buff); + const double i_ahead = (wave_freq > 0)? samps_per_period/4 : 0; + const double q_ahead = (wave_freq < 0)? samps_per_period/4 : 0; std::cout << boost::format("Samples per send buffer: %d") % buff.size() << std::endl; - const size_t i_ahead = (wave_freq > 0)? period.size()/4 : 0; - const size_t q_ahead = (wave_freq < 0)? period.size()/4 : 0; - for (size_t n = 0; n < buff.size(); n++) buff[n] = std::complex( - period[(n+i_ahead)%period.size()], period[(n+q_ahead)%period.size()] //I,Q - ); + if (wave_type == "CONST"){ + for (size_t n = 0; n < buff.size(); n++){ + buff[n] = std::complex(ampl, ampl); + } + } + else if (wave_type == "SQUARE"){ + for (size_t n = 0; n < buff.size(); n++){ + float I = (std::fmod(n+i_ahead, samps_per_period) > samps_per_period/2)? ampl : 0; + float Q = (std::fmod(n+q_ahead, samps_per_period) > samps_per_period/2)? ampl : 0; + buff[n] = std::complex(I, Q); + } + } + else if (wave_type == "RAMP"){ + for (size_t n = 0; n < buff.size(); n++){ + float I = float(std::fmod(n+i_ahead, samps_per_period)/samps_per_period * 2*ampl - ampl); + float Q = float(std::fmod(n+q_ahead, samps_per_period)/samps_per_period * 2*ampl - ampl); + buff[n] = std::complex(I, Q); + } + } + else if (wave_type == "SINE"){ + for (size_t n = 0; n < buff.size(); n++){ + float I = float(ampl*std::sin(2*M_PI*(n+i_ahead)/samps_per_period)); + float Q = float(ampl*std::sin(2*M_PI*(n+q_ahead)/samps_per_period)); + buff[n] = std::complex(I, Q); + } + } + else throw std::runtime_error("unknown waveform type: " + wave_type); //setup the metadata flags uhd::tx_metadata_t md; -- cgit v1.2.3 From 605483a2cf38eecdd39222622b9eab93f8061186 Mon Sep 17 00:00:00 2001 From: Josh Blum Date: Fri, 20 Aug 2010 10:04:02 -0700 Subject: uhd: tx waveform change how error is measured --- host/examples/tx_waveforms.cpp | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'host/examples') diff --git a/host/examples/tx_waveforms.cpp b/host/examples/tx_waveforms.cpp index 22975da96..b9b24f516 100644 --- a/host/examples/tx_waveforms.cpp +++ b/host/examples/tx_waveforms.cpp @@ -34,7 +34,7 @@ int UHD_SAFE_MAIN(int argc, char *argv[]){ //variables to be set by po std::string args, wave_type; size_t total_duration, mspb; - double rate, freq, wave_freq; + double rate, freq, wave_freq, aepb; float ampl, gain; //setup the program options @@ -44,6 +44,7 @@ int UHD_SAFE_MAIN(int argc, char *argv[]){ ("args", po::value(&args)->default_value(""), "simple uhd device address args") ("duration", po::value(&total_duration)->default_value(3), "number of seconds to transmit") ("mspb", po::value(&mspb)->default_value(10000), "mimimum samples per buffer") + ("aepb", po::value(&aepb)->default_value(1e-5), "allowed error per buffer") ("rate", po::value(&rate)->default_value(100e6/16), "rate of outgoing samples") ("freq", po::value(&freq)->default_value(0), "rf center frequency in Hz") ("ampl", po::value(&l)->default_value(float(0.3)), "amplitude of the waveform") @@ -103,7 +104,7 @@ int UHD_SAFE_MAIN(int argc, char *argv[]){ while (true){ double num_samps_per_buff = periods_per_buff*samps_per_period; double sample_error = num_samps_per_buff - boost::math::round(num_samps_per_buff); - if (std::abs(sample_error/num_samps_per_buff) < 1e-5) break; + if (std::abs(sample_error) <= aepb) break; periods_per_buff++; } -- cgit v1.2.3 From 6798b4f8d7936cc77a979e8e6d22c24eb5c92678 Mon Sep 17 00:00:00 2001 From: Josh Blum Date: Fri, 20 Aug 2010 15:35:25 -0700 Subject: uhd: tx waveform generates on the fly now --- host/examples/tx_waveforms.cpp | 111 +++++++++++++++++++++-------------------- 1 file changed, 57 insertions(+), 54 deletions(-) (limited to 'host/examples') diff --git a/host/examples/tx_waveforms.cpp b/host/examples/tx_waveforms.cpp index b9b24f516..f9c42b1c9 100644 --- a/host/examples/tx_waveforms.cpp +++ b/host/examples/tx_waveforms.cpp @@ -22,19 +22,39 @@ #include //system time #include #include +#include #include #include #include namespace po = boost::program_options; +/*********************************************************************** + * Waveform generators + **********************************************************************/ +float gen_const(float){ + return 1; +} + +float gen_square(float x){ + return (std::fmod(x, 1) < float(0.5))? 0 : 1; +} + +float gen_ramp(float x){ + return std::fmod(x, 1)*2 - 1; +} + +float gen_sine(float x){ + return std::sin(x*2*M_PI); +} + int UHD_SAFE_MAIN(int argc, char *argv[]){ uhd::set_thread_priority_safe(); //variables to be set by po std::string args, wave_type; - size_t total_duration, mspb; - double rate, freq, wave_freq, aepb; + size_t total_duration, spb; + double rate, freq, wave_freq; float ampl, gain; //setup the program options @@ -43,8 +63,7 @@ int UHD_SAFE_MAIN(int argc, char *argv[]){ ("help", "help message") ("args", po::value(&args)->default_value(""), "simple uhd device address args") ("duration", po::value(&total_duration)->default_value(3), "number of seconds to transmit") - ("mspb", po::value(&mspb)->default_value(10000), "mimimum samples per buffer") - ("aepb", po::value(&aepb)->default_value(1e-5), "allowed error per buffer") + ("spb", po::value(&spb)->default_value(10000), "samples per buffer") ("rate", po::value(&rate)->default_value(100e6/16), "rate of outgoing samples") ("freq", po::value(&freq)->default_value(0), "rf center frequency in Hz") ("ampl", po::value(&l)->default_value(float(0.3)), "amplitude of the waveform") @@ -90,57 +109,25 @@ int UHD_SAFE_MAIN(int argc, char *argv[]){ } //error when the waveform is not possible to generate - if (std::abs(wave_freq)/sdev->get_tx_rate() < 0.5/mspb){ - throw std::runtime_error("wave freq/tx rate too small"); - } if (std::abs(wave_freq) > sdev->get_tx_rate()/2){ throw std::runtime_error("wave freq out of Nyquist zone"); } - //how many periods should we have per buffer to mimimize error - double samps_per_period = sdev->get_tx_rate()/std::abs(wave_freq); - std::cout << boost::format("Samples per waveform period: %d") % samps_per_period << std::endl; - size_t periods_per_buff = std::max(1, mspb/samps_per_period); - while (true){ - double num_samps_per_buff = periods_per_buff*samps_per_period; - double sample_error = num_samps_per_buff - boost::math::round(num_samps_per_buff); - if (std::abs(sample_error) <= aepb) break; - periods_per_buff++; - } - - //allocate data to send (fill with several periods worth of IQ samples) - std::vector > buff(samps_per_period*periods_per_buff); - const double i_ahead = (wave_freq > 0)? samps_per_period/4 : 0; - const double q_ahead = (wave_freq < 0)? samps_per_period/4 : 0; - std::cout << boost::format("Samples per send buffer: %d") % buff.size() << std::endl; - if (wave_type == "CONST"){ - for (size_t n = 0; n < buff.size(); n++){ - buff[n] = std::complex(ampl, ampl); - } - } - else if (wave_type == "SQUARE"){ - for (size_t n = 0; n < buff.size(); n++){ - float I = (std::fmod(n+i_ahead, samps_per_period) > samps_per_period/2)? ampl : 0; - float Q = (std::fmod(n+q_ahead, samps_per_period) > samps_per_period/2)? ampl : 0; - buff[n] = std::complex(I, Q); - } - } - else if (wave_type == "RAMP"){ - for (size_t n = 0; n < buff.size(); n++){ - float I = float(std::fmod(n+i_ahead, samps_per_period)/samps_per_period * 2*ampl - ampl); - float Q = float(std::fmod(n+q_ahead, samps_per_period)/samps_per_period * 2*ampl - ampl); - buff[n] = std::complex(I, Q); - } - } - else if (wave_type == "SINE"){ - for (size_t n = 0; n < buff.size(); n++){ - float I = float(ampl*std::sin(2*M_PI*(n+i_ahead)/samps_per_period)); - float Q = float(ampl*std::sin(2*M_PI*(n+q_ahead)/samps_per_period)); - buff[n] = std::complex(I, Q); - } - } + //store the generator function for the selected waveform + boost::function 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); + //allocate the buffer and precalculate values + std::vector > buff(spb); + const float cps = wave_freq/sdev->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; + //setup the metadata flags uhd::tx_metadata_t md; md.start_of_burst = true; //always SOB (good for continuous streaming) @@ -148,11 +135,27 @@ int UHD_SAFE_MAIN(int argc, char *argv[]){ //send the data in multiple packets boost::system_time end_time(boost::get_system_time() + boost::posix_time::seconds(total_duration)); - while(end_time > boost::get_system_time()) dev->send( - &buff.front(), buff.size(), md, - uhd::io_type_t::COMPLEX_FLOAT32, - uhd::device::SEND_MODE_FULL_BUFF - ); + while(end_time > boost::get_system_time()){ + + //fill the buffer with the waveform + for (size_t n = 0; n < buff.size(); n++){ + buff[n] = std::complex( + ampl*wave_gen(i_off + theta), + ampl*wave_gen(q_off + theta) + ); + theta += cps; + } + + //bring the theta back into range [0, 1) + theta = std::fmod(theta, 1); + + //send the entire contents of the buffer + dev->send( + &buff.front(), buff.size(), md, + uhd::io_type_t::COMPLEX_FLOAT32, + uhd::device::SEND_MODE_FULL_BUFF + ); + } //send a mini EOB packet md.start_of_burst = false; -- cgit v1.2.3 From 8673ee7235bb31f2f51ed2200952f605b0de1955 Mon Sep 17 00:00:00 2001 From: Josh Blum Date: Fri, 20 Aug 2010 16:19:41 -0700 Subject: uhd: removed msvc warnings and errors (no M_PI) --- host/examples/tx_waveforms.cpp | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) (limited to 'host/examples') diff --git a/host/examples/tx_waveforms.cpp b/host/examples/tx_waveforms.cpp index f9c42b1c9..9886000b1 100644 --- a/host/examples/tx_waveforms.cpp +++ b/host/examples/tx_waveforms.cpp @@ -37,7 +37,7 @@ float gen_const(float){ } float gen_square(float x){ - return (std::fmod(x, 1) < float(0.5))? 0 : 1; + return float((std::fmod(x, 1) < float(0.5))? 0 : 1); } float gen_ramp(float x){ @@ -45,7 +45,8 @@ float gen_ramp(float x){ } float gen_sine(float x){ - return std::sin(x*2*M_PI); + static const float two_pi = 2*std::acos(float(-1)); + return std::sin(x*two_pi); } int UHD_SAFE_MAIN(int argc, char *argv[]){ @@ -123,7 +124,7 @@ int UHD_SAFE_MAIN(int argc, char *argv[]){ //allocate the buffer and precalculate values std::vector > buff(spb); - const float cps = wave_freq/sdev->get_tx_rate(); + const float cps = float(wave_freq/sdev->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; -- cgit v1.2.3