Question

我目前正在实施具有残余载波的相位调制方案。该调制方案主要用于深空通信。我已经推导出I-Q组件如下

I（t）= Power_total * sin（h）* d（t）

Q（t）= -1 * Power_total * cos（h）

其中h是调制方案，d（t）是输入数据（比特流）。注意，当h = 90度时，我们具有抑制载波a.k.a BPSK的相位调制方案。调制指数确定如何在残余载波和数据载波之间共享功率。这简化了同步，因为接收器可以跟踪残留的未调制载波。

以下是我在GNU Radio中的代码。不幸的是，每当我将输入数据分配给[i]到oi和oq（数据和残余载波分量的同相和正交因子）时，这个代码就会崩溃。任何可以帮助我消除问题的建议，参考或链接将受到高度赞赏。提前致谢。

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <gnuradio/io_signature.h>
#include "phase_mod_impl.h"
#include <gnuradio/sincos.h>
#include <math.h>
namespace gr {
  namespace GS {

phase_mod::sptr
phase_mod::make(float mod_index)
{
  return gnuradio::get_initial_sptr
    (new phase_mod_impl(mod_index));
}

/*
 * The private constructor
 */
phase_mod_impl::phase_mod_impl(float mod_index)
  : gr::sync_block("phase_mod",
          gr::io_signature::make(1, 1, sizeof(float)),
           gr::io_signature::make(1, 1, sizeof(gr_complex))),
h(mod_index)
{}

/*
 * Our virtual destructor.
 */
phase_mod_impl::~phase_mod_impl()
{
}

int
phase_mod_impl::work(int noutput_items,
    gr_vector_const_void_star &input_items,
    gr_vector_void_star &output_items)
{
  const float *in = (const float *) input_items[0];
  gr_complex *out = (gr_complex *) output_items[0];
  // Do <+signal processing+>
  for(int i = 0; i < noutput_items; i++) {
     float oq, oi;
     gr::sincosf(h,&oi, &oq);
     oi *= in[i];
     oq *= -1;
     out[i] = gr_complex(oi,oq);
  }
  // Tell runtime system how many output items we produced.
     return noutput_items;
}
/*


   } /* namespace GS */
} /* namespace gr */code here

Answer 1

I found out the problem was with the gnuradio flowgraph I was using to test the code. Basically one of the blocks was generating numbers in the order of 10^34. That is what caused the crashes. Otherwise, the phase modulation block is working as expected –

具有残余载波的相位调制

1 个答案: