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authorLogan Fagg <logan.fagg@ni.com>2017-03-15 15:03:46 -0700
committerMartin Braun <martin.braun@ettus.com>2017-03-21 18:01:16 -0700
commit75495138932ba8536d7771409c26f4d3d98b7dff (patch)
tree153e17e3e6444d647bb9a7597c92f99369fedf3f
parenta59643f73c45d052d5150f7a2ee7a104cec11adc (diff)
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examples: Revised frequency hopping example for best practices
-rw-r--r--host/examples/twinrx_freq_hopping.cpp240
1 files changed, 114 insertions, 126 deletions
diff --git a/host/examples/twinrx_freq_hopping.cpp b/host/examples/twinrx_freq_hopping.cpp
index 1fc0249ed..6d7018912 100644
--- a/host/examples/twinrx_freq_hopping.cpp
+++ b/host/examples/twinrx_freq_hopping.cpp
@@ -15,29 +15,25 @@
// along with this program. If not, see <http://www.gnu.org/licenses/>.
//
+// FFT conversion
+#include "ascii_art_dft.hpp"
+
#include <uhd/utils/thread_priority.hpp>
#include <uhd/utils/safe_main.hpp>
#include <uhd/usrp/multi_usrp.hpp>
#include <boost/program_options.hpp>
-#include <boost/format.hpp>
#include <boost/thread.hpp>
#include <fstream>
-#include <iostream>
-#include <complex>
-#include <utility>
-
-// FFT conversion
-#include "ascii_art_dft.hpp"
/*
* This example shows how to implement fast frequency hopping using an X-Series
* motherboard and a TwinRX daughterboard.
*
- * The TwinRX daughterboard is different than previous daughterboards in that it
- * has two RX channels and two LOs. Either channel can be set to use either LO,
- * allowing for the two channels to share an LO source.
+ * The TwinRX daughterboard is different than previous daughterboards in that it has two
+ * RX channels, each with a set of Local Oscillators (LOs). Either channel can be configured
+ * to use either LO set, allowing for the two channels to share an LO source.
*
* The TwinRX can be used like any other daughterboard, as the multi_usrp::set_rx_freq()
* function will automatically calculate and set the two LO frequencies as needed.
@@ -48,7 +44,7 @@
*
* 1. Tune across the given frequency range, storing the calculated LO frequencies along
* the way.
- * 2. Use timed commands to tell the TwinRX to send samples to the host at given intervals.
+ * 2. Use timed commands to tell the TwinRX to receive bursts of samples at given intervals.
* 3. For each frequency, tune the LOs for the inactive channel for the next frequency and
* receive at the current frequency.
* 4. If applicable, send the next timed command for streaming.
@@ -57,12 +53,9 @@
namespace pt = boost::posix_time;
namespace po = boost::program_options;
-typedef std::pair<double, double> lo_freqs_t;
typedef std::vector<std::complex<float> > recv_buff_t;
typedef std::vector<recv_buff_t> recv_buffs_t;
-double pipeline_time;
-
// Global objects
static uhd::usrp::multi_usrp::sptr usrp;
static uhd::rx_streamer::sptr rx_stream;
@@ -70,55 +63,47 @@ static recv_buffs_t buffs;
static size_t recv_spb, spb;
static std::vector<double> rf_freqs;
-static std::vector<lo_freqs_t> lo_freqs;
static uhd::stream_cmd_t stream_cmd(uhd::stream_cmd_t::STREAM_MODE_NUM_SAMPS_AND_DONE);
-static uhd::time_spec_t pipeline_timespec;
-static size_t last_cmd_index;
-// Determine the active channel (hooked to antenna) and the slave channel
+double receive_interval;
+
+// Define the active channel (connected to antenna) and the unused channel
size_t ACTIVE_CHAN = 0;
size_t UNUSED_CHAN = 1;
-const std::string ALL_STAGES = "all";
-
const int X300_COMMAND_FIFO_DEPTH = 16;
-static void twinrx_recv(size_t index) {
+
+// This is a helper function for receiving samples from the USRP
+static void twinrx_recv(recv_buff_t &buffer) {
+
size_t num_acc_samps = 0;
uhd::rx_metadata_t md;
- while(num_acc_samps < spb) {
+ // Repeatedly retrieve samples until the entire acquisition is received
+ while (num_acc_samps < spb) {
size_t num_to_recv = std::min<size_t>(recv_spb, (spb - num_acc_samps));
- size_t num_recvd = rx_stream->recv(
- &buffs[index][num_acc_samps],
- num_to_recv, md, pipeline_time
- );
+ // recv call will block until samples are ready or the call times out
+ size_t num_recvd = rx_stream->recv(&buffer[num_acc_samps], num_to_recv, md, receive_interval);
if(md.error_code != uhd::rx_metadata_t::ERROR_CODE_NONE) {
- std::cout << index << " " << md.strerror() << std::endl;
+ std::cout << md.strerror() << std::endl;
break;
}
-
num_acc_samps += num_recvd;
}
-
- // Send the next stream_cmd
- if(last_cmd_index < buffs.size()) {
- stream_cmd.time_spec += pipeline_timespec;
- rx_stream->issue_stream_cmd(stream_cmd);
- ++last_cmd_index;
- }
}
+// Function to write the acquisition FFT to a binary file
static void write_fft_to_file(const std::string &fft_path) {
- std::cout << "Creating FFT (this may take a while)..." << std::flush;
+ std::cout << "Calculating FFTs (this may take a while)... " << std::flush;
std::ofstream ofile(fft_path.c_str(), std::ios::binary);
BOOST_FOREACH(const recv_buff_t &buff, buffs) {
- std::vector<float> fft = acsii_art_dft::log_pwr_dft(&buff.front(), buff.size());
- ofile.write((char*)&fft[0], (sizeof(float)*fft.size()));
- }
+ std::vector<float> fft = acsii_art_dft::log_pwr_dft(&buff.front(), buff.size());
+ ofile.write((char*)&fft[0], (sizeof(float)*fft.size()));
+ }
ofile.close();
std::cout << "done." << std::endl;
}
@@ -127,43 +112,43 @@ int UHD_SAFE_MAIN(int argc, char *argv[]){
uhd::set_thread_priority_safe();
// Program options
- std::string args, fft_path, subdev;
+ std::string args, fft_path, subdev, ant;
double rate, gain;
double start_freq, end_freq;
// Set up the program options
po::options_description desc("Allowed options");
desc.add_options()
- ("help", "Print this help message")
- ("args", po::value<std::string>(&args)->default_value(""), "UHD device args")
- ("subdev", po::value<std::string>(&subdev)->default_value("A:0 A:1"), "Subdevice specification")
- ("start-freq", po::value<double>(&start_freq), "Start frequency (defaults to lowest valid frequency)")
- ("end-freq", po::value<double>(&end_freq), "End frequency (defaults to highest valid frequency)")
- ("pipeline-time", po::value<double>(&pipeline_time)->default_value(5e-3), "Time spent tuning and receiving")
- ("rate", po::value<double>(&rate)->default_value(1e6), "Incoming sample rate")
- ("gain", po::value<double>(&gain)->default_value(60), "RX gain")
- ("spb", po::value<size_t>(&spb)->default_value(1024), "Samples per buffer")
- ("fft-path", po::value<std::string>(&fft_path), "Output an FFT to this file (optional)")
- ("repeat", "repeat loop until Ctrl-C is pressed")
- ;
+ ("help", "Print this help message")
+ ("args", po::value<std::string>(&args)->default_value(""), "UHD device args")
+ ("subdev", po::value<std::string>(&subdev)->default_value("A:0 A:1"), "Subdevice specification")
+ ("ant", po::value<std::string>(&ant)->default_value("RX1"), "RX Antenna")
+ ("start-freq", po::value<double>(&start_freq), "Start frequency (defaults to lowest valid frequency)")
+ ("end-freq", po::value<double>(&end_freq), "End frequency (defaults to highest valid frequency)")
+ ("receive-interval", po::value<double>(&receive_interval)->default_value(5e-3), "Interval between scheduled receives")
+ ("rate", po::value<double>(&rate)->default_value(1e6), "Incoming sample rate")
+ ("gain", po::value<double>(&gain)->default_value(60), "RX gain")
+ ("spb", po::value<size_t>(&spb)->default_value(1024), "Samples per buffer")
+ ("fft-path", po::value<std::string>(&fft_path), "Output an FFT to this file (optional)")
+ ("repeat", "repeat sweep until Ctrl-C is pressed")
+ ;
po::variables_map vm;
po::store(po::parse_command_line(argc, argv, desc), vm);
po::notify(vm);
if(vm.count("help")) {
- std::cout << "TwinRX Example - " << desc << std::endl;
+ std::cout << "TwinRX Frequency Hopping Example - " << desc << std::endl;
return EXIT_SUCCESS;
}
// Create a USRP device
- std::cout << std::endl;
- std::cout << boost::format("Creating the USRP device with args: \"%s\"...") % args << std::endl;
+ std::cout << boost::format("\nCreating the USRP device with args: \"%s\"...\n") % args;
usrp = uhd::usrp::multi_usrp::make(args);
- // Make sure this is an X3xx with a TwinRX
+ // Make sure the USRP is an X3xx with a TwinRX
uhd::dict<std::string, std::string> info = usrp->get_usrp_rx_info();
if(info.get("mboard_id").find("X3") == std::string::npos) {
- throw uhd::runtime_error("This example can only be used with an X-Series device.");
+ throw uhd::runtime_error("This example can only be used with an X-Series motherboard.");
}
if(info.get("rx_id").find("TwinRX") == std::string::npos) {
throw uhd::runtime_error("This example can only be used with a TwinRX daughterboard.");
@@ -171,122 +156,125 @@ int UHD_SAFE_MAIN(int argc, char *argv[]){
// Validate frequency range
uhd::freq_range_t rx_freq_range = usrp->get_rx_freq_range();
- if(!vm.count("start-freq")) {
+ if (!vm.count("start-freq")) {
start_freq = rx_freq_range.start();
}
- if(!vm.count("end-freq")) {
+ if (!vm.count("end-freq")) {
end_freq = rx_freq_range.stop();
}
- if(start_freq > end_freq) {
+ if (start_freq < rx_freq_range.start() or end_freq > rx_freq_range.stop()) {
+ throw uhd::runtime_error((boost::format("Start and stop frequencies must be between %d and %d MHz")
+ % ((rx_freq_range.start() / 1e6), (rx_freq_range.stop() / 1e6))).str());
+ }
+ if (start_freq > end_freq) {
throw uhd::runtime_error("Start frequency must be less than end frequency.");
}
- if((end_freq - start_freq) > 0 and (end_freq - start_freq) < rate) {
+ if ((end_freq - start_freq) > 0 and (end_freq - start_freq) < rate) {
throw uhd::runtime_error("The sample rate must be less than the range between the start and end frequencies.");
}
// Set TwinRX settings
- usrp->set_rx_subdev_spec(uhd::usrp::subdev_spec_t(subdev));
- usrp->set_rx_antenna("RX1", 0);
- usrp->set_rx_antenna("RX2", 1);
-
- // Disable the LO for the unused channel
- usrp->set_rx_lo_source("disabled", ALL_STAGES, UNUSED_CHAN);
+ usrp->set_rx_subdev_spec(subdev);
+
+ // Set the unused channel to not use any LOs. This allows the active channel to control them.
+ usrp->set_rx_lo_source("disabled", uhd::usrp::multi_usrp::ALL_LOS, UNUSED_CHAN);
// Set user settings
- std::cout << boost::format("\nSetting sample rate to: %d") % rate << std::endl;
+ std::cout << boost::format("Setting antenna to: %s\n") % ant;
+ usrp->set_rx_antenna(ant, ACTIVE_CHAN);
+ std::cout << boost::format("Actual antenna: %s\n") % usrp->get_rx_antenna(ACTIVE_CHAN);
+
+ std::cout << boost::format("Setting sample rate to: %d\n") % rate;
usrp->set_rx_rate(rate);
- std::cout << boost::format("Actual sample rate: %d") % usrp->get_rx_rate() << std::endl;
+ std::cout << boost::format("Actual sample rate: %d\n") % usrp->get_rx_rate();
- std::cout << boost::format("\nSetting gain to: %d") % gain << std::endl;
+ std::cout << boost::format("Setting gain to: %d\n") % gain;
usrp->set_rx_gain(gain);
- std::cout << boost::format("Actual gain: %d") % usrp->get_rx_gain() << std::endl;
+ std::cout << boost::format("Actual gain: %d\n") % usrp->get_rx_gain();
- // Get a stream from the device
+ // Get an rx_streamer from the device
uhd::stream_args_t stream_args("fc32", "sc16");
stream_args.channels.push_back(0);
rx_stream = usrp->get_rx_stream(stream_args);
recv_spb = rx_stream->get_max_num_samps();
// Calculate the frequency hops
- for(double rx_freq = start_freq; rx_freq <= end_freq; rx_freq += rate) {
+ for (double rx_freq = start_freq; rx_freq <= end_freq; rx_freq += rate) {
rf_freqs.push_back(rx_freq);
}
- std::cout << boost::format("\nTotal Hops: %d") % rf_freqs.size() << std::endl;
+ std::cout << boost::format("Total Hops: %d\n") % rf_freqs.size();
// Set up buffers
- buffs = recv_buffs_t(
- rf_freqs.size(), recv_buff_t(spb)
- );
-
- while(1){
- /*
- * Each receive+tune time gets a set amount of time before moving on to the next. However,
- * the software needs some lead time before the USRP starts to stream the next set of samples.
- */
- pipeline_timespec = uhd::time_spec_t(pipeline_time);
- pt::time_duration polltime_ptime = pt::milliseconds(pipeline_time*1000) - pt::microseconds(20);
- uhd::time_spec_t polltime_duration(double(polltime_ptime.total_microseconds()) / 1e9);
-
- /*
- * Send some initial timed commands to get started and send the rest as necessary
- * after receiving.
- */
- stream_cmd.num_samps = spb;
- stream_cmd.stream_now = false;
- stream_cmd.time_spec = uhd::time_spec_t(0.0);
- usrp->set_time_now(uhd::time_spec_t(0.0));
- size_t num_initial_cmds = std::min<size_t>(X300_COMMAND_FIFO_DEPTH, rf_freqs.size());
- for(last_cmd_index = 0; last_cmd_index < num_initial_cmds; ++last_cmd_index) {
- stream_cmd.time_spec += pipeline_timespec;
- rx_stream->issue_stream_cmd(stream_cmd);
- }
-
- std::cout << "\nScanning..." << std::flush;
- uhd::time_spec_t start_time = uhd::time_spec_t::get_system_time();
+ buffs = recv_buffs_t(rf_freqs.size(), recv_buff_t(spb));
- // The first pipeline segment is just tuning for the first receive
- uhd::time_spec_t polltime = usrp->get_time_now() + polltime_duration;
+ // Tune the active channel to the first frequency and reset the USRP's time
+ usrp->set_rx_freq(rf_freqs[0], ACTIVE_CHAN);
+ usrp->set_time_now(uhd::time_spec_t(0.0));
- // Initialize the first LO frequency
- usrp->set_rx_freq(rf_freqs[0], ACTIVE_CHAN);
+ // Configure the stream command which will be issued to acquire samples at each frequency
+ stream_cmd.num_samps = spb;
+ stream_cmd.stream_now = false;
+ stream_cmd.time_spec = uhd::time_spec_t(0.0);
- while(usrp->get_time_now() < polltime);
+ // Stream commands will be scheduled at regular intervals
+ uhd::time_spec_t receive_interval_ts = uhd::time_spec_t(receive_interval);
- for (size_t i = 0; i < rf_freqs.size() - 1; i++) {
- polltime = usrp->get_time_now() + polltime_duration;
-
- // Swap synthesizers by setting the LO source
- std::string lo_src = (i % 2) ? "companion" : "internal";
- usrp->set_rx_lo_source(lo_src, ALL_STAGES, ACTIVE_CHAN);
+ // Issue stream commands to fill the command queue on the FPGA
+ size_t num_initial_cmds = std::min<size_t>(X300_COMMAND_FIFO_DEPTH, rf_freqs.size());
+ size_t num_issued_commands;
- // Preconfigure the next frequency
- usrp->set_rx_freq(rf_freqs[i+1], UNUSED_CHAN);
+ for (num_issued_commands = 0; num_issued_commands < num_initial_cmds; num_issued_commands++) {
+ stream_cmd.time_spec += receive_interval_ts;
+ rx_stream->issue_stream_cmd(stream_cmd);
+ }
- // Program the current frequency
- // This frequency was already pre-programmed in the previous iteration
- // so this call will only configure front-end filter, etc
- usrp->set_rx_freq(rf_freqs[i], ACTIVE_CHAN);
+ // Hop frequencies and acquire bursts of samples at each until done sweeping
+ while(1) {
- twinrx_recv(i);
+ std::cout << "Scanning..." << std::endl;
+ uhd::time_spec_t start_time = uhd::time_spec_t::get_system_time();
- while(usrp->get_time_now() < polltime);
+ for (size_t i = 0; i < rf_freqs.size(); i++) {
+ // Swap the mapping of synthesizers by setting the LO source
+ // The unused channel will always
+ std::string lo_src = (i % 2) ? "companion" : "internal";
+ usrp->set_rx_lo_source(lo_src, uhd::usrp::multi_usrp::ALL_LOS, ACTIVE_CHAN);
+
+ // Preconfigure the next frequency
+ usrp->set_rx_freq(rf_freqs[(i+1) % rf_freqs.size()], UNUSED_CHAN);
+
+ // Program the current frequency
+ // This frequency was already pre-programmed in the previous iteration so the local oscillators
+ // are already tuned. This call will only configure front-end filter, amplifiers, etc
+ usrp->set_rx_freq(rf_freqs[i], ACTIVE_CHAN);
+
+ // Receive one burst of samples
+ twinrx_recv(buffs[i]);
+
+ // Schedule another acquisition if necessary
+ if (vm.count("repeat") or num_issued_commands < rf_freqs.size()) {
+ stream_cmd.time_spec += receive_interval_ts;
+ rx_stream->issue_stream_cmd(stream_cmd);
+ num_issued_commands++;
+ }
}
uhd::time_spec_t end_time = uhd::time_spec_t::get_system_time();
- std::cout << boost::format("done in %d seconds.\n") % (end_time - start_time).get_real_secs();
+ std::cout << boost::format("Sweep done in %d milliseconds.\n") % ((end_time - start_time).get_real_secs() * 1000);
// Optionally convert received samples to FFT and write to file
if(vm.count("fft-path")) {
write_fft_to_file(fft_path);
}
- std::cout << std::endl << "Done!" << std::endl << std::endl;
-
if (!vm.count("repeat")){
break;
}
-
}
+
+ std::cout << "Done!" << std::endl;
+
+ usrp.reset();
return EXIT_SUCCESS;
}