[Commit-gnuradio] r4156 - gnuradio/branches/developers/n4hy/ofdm/gnuradio-core/src/lib/general

[trondeau]

Author: trondeau
Date: 2006-12-20 00:36:24 -0700 (Wed, 20 Dec 2006)
New Revision: 4156

Modified:
   
gnuradio/branches/developers/n4hy/ofdm/gnuradio-core/src/lib/general/gr_fft_vcc.cc
   
gnuradio/branches/developers/n4hy/ofdm/gnuradio-core/src/lib/general/gr_fft_vcc.h
   
gnuradio/branches/developers/n4hy/ofdm/gnuradio-core/src/lib/general/gr_fft_vcc.i
Log:
added ifftshift (working) and fftshift (needs checking)

Modified: 
gnuradio/branches/developers/n4hy/ofdm/gnuradio-core/src/lib/general/gr_fft_vcc.cc
===================================================================
--- 
gnuradio/branches/developers/n4hy/ofdm/gnuradio-core/src/lib/general/gr_fft_vcc.cc
  2006-12-20 01:35:26 UTC (rev 4155)
+++ 
gnuradio/branches/developers/n4hy/ofdm/gnuradio-core/src/lib/general/gr_fft_vcc.cc
  2006-12-20 07:36:24 UTC (rev 4156)
@@ -30,16 +30,16 @@
 #include <math.h>
 
 gr_fft_vcc_sptr
-gr_make_fft_vcc (int fft_size, bool forward,const std::vector<float> window)
+gr_make_fft_vcc (int fft_size, bool forward,const std::vector<float> window, 
bool shift)
 {
-  return gr_fft_vcc_sptr (new gr_fft_vcc (fft_size, forward, window));
+  return gr_fft_vcc_sptr (new gr_fft_vcc (fft_size, forward, window, shift));
 }
 
-gr_fft_vcc::gr_fft_vcc (int fft_size, bool forward, const std::vector<float> 
window)
+gr_fft_vcc::gr_fft_vcc (int fft_size, bool forward, const std::vector<float> 
window, bool shift)
   : gr_sync_block ("fft_vcc",
                   gr_make_io_signature (1, 1, fft_size * sizeof (gr_complex)),
                   gr_make_io_signature (1, 1, fft_size * sizeof (gr_complex))),
-    d_fft_size(fft_size)
+    d_fft_size(fft_size), d_forward(forward), d_shift(shift)
 {
   d_fft = new gri_fft_complex (d_fft_size, forward);
 
@@ -66,27 +66,48 @@
   int count = 0;
 
   while (count++ < noutput_items){
-
+    
     // copy input into optimally aligned buffer
-
+    
     if (d_window.size()){
       gr_complex *dst = d_fft->get_inbuf();
       for (unsigned int i = 0; i < d_fft_size; i++)            // apply window
        dst[i] = in[i] * d_window[i];
     }
-    else
-      memcpy (d_fft->get_inbuf(), in, input_data_size);
-
+    else {
+      if(!d_forward && d_shift) {  // apply an ifft shift on the data
+       gr_complex *dst = d_fft->get_inbuf();
+       unsigned int len = (unsigned int)(floor(d_fft_size/2.0));
+       unsigned int i=0,j=0;
+       for(i=0; i < d_fft_size-len; i++) {
+         dst[i] = in[len+i];
+       }
+       for(; i < d_fft_size; i++) {
+         dst[i] = in[j++];
+       }
+      }
+      else {
+       memcpy (d_fft->get_inbuf(), in, input_data_size);
+      }
+    }
+    
     // compute the fft
     d_fft->execute ();
-
-    // cpoy result to our output
-    memcpy (out, d_fft->get_outbuf (), output_data_size);
-
+    
+    // copy result to our output
+    if(d_forward && d_shift) {  // apply a fft shift on the data
+      unsigned int len = (unsigned int)(ceil(d_fft_size/2.0));
+      memcpy(&out[0], &d_fft->get_outbuf()[len], d_fft_size - len);
+      memcpy(&out[d_fft_size - len], &d_fft->get_outbuf()[0], len);
+    }
+    else {
+      memcpy (out, d_fft->get_outbuf (), output_data_size);
+    }
+    
     in  += d_fft_size;
     out += d_fft_size;
   }
-
+  
   return noutput_items;
 }
 
@@ -100,3 +121,18 @@
   else 
     return false;
 }
+
+/*
+fftshift
+
+  for(i=0; i < ceil(d_occupied_carriers/2.0); i++) {
+    unsigned int k=ceil(d_occupied_carriers/2.0);
+    out[i] = gr_complex(-1+2*in[i+k],0);
+  }
+  for(; i < d_vlen - ceil(d_occupied_carriers/2.0); i++) {
+    out[i]=gr_complex(0,0);
+  }
+  for(unsigned int j=0;i<d_vlen;i++,j++) {
+    out[i]= gr_complex((-1+2*in[j]),0);
+  }
+*/

Modified: 
gnuradio/branches/developers/n4hy/ofdm/gnuradio-core/src/lib/general/gr_fft_vcc.h
===================================================================
--- 
gnuradio/branches/developers/n4hy/ofdm/gnuradio-core/src/lib/general/gr_fft_vcc.h
   2006-12-20 01:35:26 UTC (rev 4155)
+++ 
gnuradio/branches/developers/n4hy/ofdm/gnuradio-core/src/lib/general/gr_fft_vcc.h
   2006-12-20 07:36:24 UTC (rev 4156)
@@ -31,7 +31,7 @@
 typedef boost::shared_ptr<gr_fft_vcc> gr_fft_vcc_sptr;
 
 gr_fft_vcc_sptr
-gr_make_fft_vcc (int fft_size, bool forward, const std::vector<float> window);
+gr_make_fft_vcc (int fft_size, bool forward, const std::vector<float> window, 
bool shift=false);
 
 /*!
  * \brief Compute forward or reverse FFT.  complex vector in / complex vector 
out.
@@ -41,13 +41,15 @@
 class gr_fft_vcc : public gr_sync_block
 {
   friend gr_fft_vcc_sptr
-  gr_make_fft_vcc (int fft_size, bool forward, const std::vector<float> 
window);
+  gr_make_fft_vcc (int fft_size, bool forward, const std::vector<float> 
window, bool shift);
 
   unsigned int    d_fft_size;
   std::vector<float>   d_window;
   gri_fft_complex *d_fft;
+  bool d_forward;
+  bool d_shift;
 
-  gr_fft_vcc (int fft_size, bool forward, const std::vector<float> window);
+  gr_fft_vcc (int fft_size, bool forward, const std::vector<float> window, 
bool shift);
 
  public:
   ~gr_fft_vcc ();

Modified: 
gnuradio/branches/developers/n4hy/ofdm/gnuradio-core/src/lib/general/gr_fft_vcc.i
===================================================================
--- 
gnuradio/branches/developers/n4hy/ofdm/gnuradio-core/src/lib/general/gr_fft_vcc.i
   2006-12-20 01:35:26 UTC (rev 4155)
+++ 
gnuradio/branches/developers/n4hy/ofdm/gnuradio-core/src/lib/general/gr_fft_vcc.i
   2006-12-20 07:36:24 UTC (rev 4156)
@@ -23,12 +23,12 @@
 GR_SWIG_BLOCK_MAGIC(gr, fft_vcc)
 
 gr_fft_vcc_sptr 
-gr_make_fft_vcc (int fft_size, bool forward, const std::vector<float> window);
+gr_make_fft_vcc (int fft_size, bool forward, const std::vector<float> window, 
bool shift=false);
 
 class gr_fft_vcc : public gr_sync_block
 {
  protected:
-  gr_fft_vcc (int fft_size, bool forward, const std::vector<float> window);
+  gr_fft_vcc (int fft_size, bool forward, const std::vector<float> window, 
bool shift);
 
  public:
   bool set_window(const std::vector<float> window);