examples: Created TwinRX frequency hopping example

2 files changed, 296 insertions, 0 deletions

diff --git a/host/examples/CMakeLists.txt b/host/examples/CMakeLists.txt
index e61fd897f..e10c463f8 100644
--- a/host/examples/CMakeLists.txt
+++ b/host/examples/CMakeLists.txt
@@ -61,6 +61,10 @@ IF(CURSES_FOUND)
     ADD_EXECUTABLE(rx_ascii_art_dft rx_ascii_art_dft.cpp)
     TARGET_LINK_LIBRARIES(rx_ascii_art_dft uhd ${CURSES_LIBRARIES} ${Boost_LIBRARIES})
     UHD_INSTALL(TARGETS rx_ascii_art_dft RUNTIME DESTINATION ${PKG_LIB_DIR}/examples COMPONENT examples)
+
+    ADD_EXECUTABLE(twinrx_freq_hopping twinrx_freq_hopping.cpp)
+    TARGET_LINK_LIBRARIES(twinrx_freq_hopping uhd ${CURSES_LIBRARIES} ${Boost_LIBRARIES})
+    UHD_INSTALL(TARGETS twinrx_freq_hopping RUNTIME DESTINATION ${PKG_LIB_DIR}/examples COMPONENT examples)
 ENDIF(CURSES_FOUND)
 
 ########################################################################
diff --git a/host/examples/twinrx_freq_hopping.cpp b/host/examples/twinrx_freq_hopping.cpp
new file mode 100644
index 000000000..1fc0249ed
--- /dev/null
+++ b/host/examples/twinrx_freq_hopping.cpp
@@ -0,0 +1,292 @@
+//
+// Copyright 2016 Ettus Research LLC
+//
+// This program 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 of the License, or
+// (at your option) any later version.
+//
+// This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
+//
+
+#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 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.
+ * However, this adds to the overall tuning time. If the LO frequencies are manually set
+ * with the multi_usrp::set_rx_lo_freq() function, the TwinRX will will not perform the
+ * calculation itself, resulting in a faster tune time. This example shows how to take
+ * advantage of this as follows:
+ *
+ * 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.
+ * 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.
+ */
+
+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;
+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
+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) {
+    size_t num_acc_samps = 0;
+    uhd::rx_metadata_t md;
+
+    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
+        );
+
+        if(md.error_code != uhd::rx_metadata_t::ERROR_CODE_NONE) {
+            std::cout << index << " " << 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;
+    }
+}
+
+static void write_fft_to_file(const std::string &fft_path) {
+    std::cout << "Creating FFT (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()));
+    }
+    ofile.close();
+    std::cout << "done." << std::endl;
+}
+
+int UHD_SAFE_MAIN(int argc, char *argv[]){
+    uhd::set_thread_priority_safe();
+
+    // Program options
+    std::string args, fft_path, subdev;
+    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")
+    ;
+    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;
+        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;
+    usrp = uhd::usrp::multi_usrp::make(args);
+
+    // Make sure this 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.");
+    }
+    if(info.get("rx_id").find("TwinRX") == std::string::npos) {
+        throw uhd::runtime_error("This example can only be used with a TwinRX daughterboard.");
+    }
+
+    // Validate frequency range
+    uhd::freq_range_t rx_freq_range = usrp->get_rx_freq_range();
+    if(!vm.count("start-freq")) {
+        start_freq = rx_freq_range.start();
+    }
+    if(!vm.count("end-freq")) {
+        end_freq = rx_freq_range.stop();
+    }
+    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) {
+        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);
+
+    // Set user settings
+    std::cout << boost::format("\nSetting sample rate to: %d") % rate << std::endl;
+    usrp->set_rx_rate(rate);
+    std::cout << boost::format("Actual sample rate:     %d") % usrp->get_rx_rate() << std::endl;
+
+    std::cout << boost::format("\nSetting gain to: %d") % gain << std::endl;
+    usrp->set_rx_gain(gain);
+    std::cout << boost::format("Actual gain:     %d") % usrp->get_rx_gain() << std::endl;
+
+    // Get a stream 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) {
+        rf_freqs.push_back(rx_freq);
+    }
+    std::cout << boost::format("\nTotal Hops: %d") % rf_freqs.size() << std::endl;
+
+    // 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();
+
+        // The first pipeline segment is just tuning for the first receive
+        uhd::time_spec_t polltime = usrp->get_time_now() + polltime_duration;
+
+        // Initialize the first LO frequency
+        usrp->set_rx_freq(rf_freqs[0], ACTIVE_CHAN);
+
+        while(usrp->get_time_now() < polltime);
+
+        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);
+
+           // Preconfigure the next frequency
+           usrp->set_rx_freq(rf_freqs[i+1], UNUSED_CHAN);
+
+           // 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);
+
+           twinrx_recv(i);
+
+           while(usrp->get_time_now() < polltime);
+        }
+
+        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();
+
+        // 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;
+        }
+
+    }
+    return EXIT_SUCCESS;
+}
+