usrp b210如何用pps设置同步，c代码

以下是使用C代码设置USRP B210同步的步骤：

1.包含必要的头文件：

#include <uhd/usrp/multi_usrp.hpp>
#include <uhd/utils/thread.hpp>
#include <uhd/utils/safe_main.hpp>
#include <boost/program_options.hpp>
#include <boost/format.hpp>
#include <iostream>
#include <csignal>
#include <cmath>

2.定义全局变量：

uhd::usrp::multi_usrp::sptr usrp;
uhd::time_spec_t start_time;

3.定义设置同步的函数：

void setup_sync()
{
    std::cout << boost::format("Setting up synchronization with PPS...\n");

    // Lock mboard clocks
    usrp->set_clock_source("external");
    usrp->set_time_source("external");

    // Set time to zero (actually the time of the next PPS edge)
    usrp->set_time_now(uhd::time_spec_t(0.0));

    // Wait for PPS edge
    while (true) {
        if (usrp->get_time_last_pps().get_real_secs() > 0.0) {
            break;
        }
        uhd::this_thread::sleep_for(uhd::time_spec_t(0.1));
    }

    // Get time of PPS edge
    start_time = usrp->get_time_last_pps();

    std::cout << boost::format("Synchronization successful!\n");
}

4.定义主函数：

int UHD_SAFE_MAIN(int argc, char* argv[])
{
    // Set up program options
    namespace po = boost::program_options;
    po::options_description desc("Allowed options");
    desc.add_options()
        ("help", "produce help message")
        ("freq", po::value<double>()->default_value(100e6), "set center frequency in Hz")
        ("gain", po::value<double>()->default_value(0), "set gain in dB")
        ("ppstime", "set up synchronization with PPS")
    ;

    // Parse program options
    po::variables_map vm;
    po::store(po::parse_command_line(argc, argv, desc), vm);
    po::notify(vm);

    if (vm.count("help")) {
        std::cout << desc << std::endl;
        return 0;
    }

    double freq = vm["freq"].as<double>();
    double gain = vm["gain"].as<double>();
    bool use_pps = vm.count("ppstime") > 0;

    // Create USRP object
    usrp = uhd::usrp::multi_usrp::make("");
    usrp->set_rx_subdev_spec("A:A", 0);
    usrp->set_rx_rate(1e6);
    usrp->set_rx_freq(freq);
    usrp->set_rx_gain(gain);

    // Set up synchronization with PPS
    if (use_pps) {
        setup_sync();
    }

    // Start receiving samples
    uhd::stream_args_t stream_args("fc32");
    uhd::rx_streamer::sptr rx_stream = usrp->get_rx_stream(stream_args);
    uhd::rx_metadata_t rx_md;
    std::vector<std::complex<float>> buff(1000);
    int num_rx_samples = rx_stream->recv(&buff[0], buff.size(), rx_md);

    return 0;
}

在主函数中，首先解析命令行参数，然后创建USRP对象并设置接收参数。如果使用PPS同步，则调用setup_sync()函数进行同步设置。最后，启动接收并获取接收到的样本。