[Commit-gnuradio] r3482 - in gnuradio/branches/developers/jcorgan/pager/gr-pager/src: lib python

[jcorgan]

Author: jcorgan
Date: 2006-09-04 02:43:39 -0600 (Mon, 04 Sep 2006)
New Revision: 3482

Modified:
   gnuradio/branches/developers/jcorgan/pager/gr-pager/src/lib/pager.i
   
gnuradio/branches/developers/jcorgan/pager/gr-pager/src/lib/pager_slicer_ff.cc
   gnuradio/branches/developers/jcorgan/pager/gr-pager/src/lib/pager_slicer_ff.h
   gnuradio/branches/developers/jcorgan/pager/gr-pager/src/python/flex_demod.py
Log:
Implemented 4-level slicer.

Modified: gnuradio/branches/developers/jcorgan/pager/gr-pager/src/lib/pager.i
===================================================================
--- gnuradio/branches/developers/jcorgan/pager/gr-pager/src/lib/pager.i 
2006-09-04 06:31:12 UTC (rev 3481)
+++ gnuradio/branches/developers/jcorgan/pager/gr-pager/src/lib/pager.i 
2006-09-04 08:43:39 UTC (rev 3482)
@@ -33,12 +33,12 @@
 
 GR_SWIG_BLOCK_MAGIC(pager,slicer_ff);
 
-pager_slicer_ff_sptr pager_make_slicer_ff();
+pager_slicer_ff_sptr pager_make_slicer_ff(float alpha);
 
-class pager_slicer_ff
+class pager_slicer_ff : public gr_sync_block
 {
 private:
-    pager_slicer_ff();
+    pager_slicer_ff(float alpha);
 
 public:
 };

Modified: 
gnuradio/branches/developers/jcorgan/pager/gr-pager/src/lib/pager_slicer_ff.cc
===================================================================
--- 
gnuradio/branches/developers/jcorgan/pager/gr-pager/src/lib/pager_slicer_ff.cc  
    2006-09-04 06:31:12 UTC (rev 3481)
+++ 
gnuradio/branches/developers/jcorgan/pager/gr-pager/src/lib/pager_slicer_ff.cc  
    2006-09-04 08:43:39 UTC (rev 3482)
@@ -26,26 +26,53 @@
 #include <pager_slicer_ff.h>
 #include <gr_io_signature.h>
 
-pager_slicer_ff_sptr pager_make_slicer_ff()
+pager_slicer_ff_sptr pager_make_slicer_ff(float alpha)
 {
-  return pager_slicer_ff_sptr(new pager_slicer_ff());
+  return pager_slicer_ff_sptr(new pager_slicer_ff(alpha));
 }
 
-pager_slicer_ff::pager_slicer_ff() :
+pager_slicer_ff::pager_slicer_ff(float alpha) :
     gr_sync_block ("slicer_ff",
                       gr_make_io_signature (1, 1, sizeof(float)),
                       gr_make_io_signature (1, 1, sizeof(float)))
 {
+    d_alpha = alpha;
+    d_max = 1.0;
+    d_avg = 0.0;
+    d_min = -1.0;
 }
 
+float pager_slicer_ff::slice(float sample)
+{
+    float result = 0.0;
+    d_avg = d_avg*(1-d_alpha)+sample*d_alpha;
+
+    if (sample > (d_max-d_avg)*2.0/3.0) {        // In max region
+        result = 1.0;
+        d_max = d_max*(1-d_alpha)+sample*d_alpha;
+    } else if (sample > d_avg) {
+        result = 1.0/3.0;
+    } else if (sample < (d_min-d_avg)*2.0/3.0) { // In min region
+        result = -1.0;
+        d_min = d_min*(1-d_alpha)+sample*d_alpha;
+    } else {
+        return -1.0/3.0;
+    }
+
+    return result;
+}
+
 int pager_slicer_ff::work(int noutput_items,
                            gr_vector_const_void_star &input_items,
                                   gr_vector_void_star &output_items)
 {
-  float *iptr = (float *) input_items[0];
-  float *optr = (float *) output_items[0];
+    float *iptr = (float *) input_items[0];
+    float *optr = (float *) output_items[0];
 
-  int size = noutput_items;
+    int size = noutput_items;
 
-  return noutput_items;
+    for (int i = 0; i < size; i++)
+        *optr++ = slice(*iptr++);
+
+    return noutput_items;
 }

Modified: 
gnuradio/branches/developers/jcorgan/pager/gr-pager/src/lib/pager_slicer_ff.h
===================================================================
--- 
gnuradio/branches/developers/jcorgan/pager/gr-pager/src/lib/pager_slicer_ff.h   
    2006-09-04 06:31:12 UTC (rev 3481)
+++ 
gnuradio/branches/developers/jcorgan/pager/gr-pager/src/lib/pager_slicer_ff.h   
    2006-09-04 08:43:39 UTC (rev 3482)
@@ -27,7 +27,7 @@
 class pager_slicer_ff;
 typedef boost::shared_ptr<pager_slicer_ff> pager_slicer_ff_sptr;
 
-pager_slicer_ff_sptr pager_make_slicer_ff();
+pager_slicer_ff_sptr pager_make_slicer_ff(float alpha);
 
 /*!
  * \brief slicer description
@@ -36,9 +36,16 @@
 class pager_slicer_ff : public gr_sync_block
 {
 private:
-    friend pager_slicer_ff_sptr pager_make_slicer_ff();
-    pager_slicer_ff();
+    friend pager_slicer_ff_sptr pager_make_slicer_ff(float alpha);
+    pager_slicer_ff(float alpha);
 
+    float slice(float sample);
+
+    float d_alpha;      // Exponential constant
+    float d_max;        // Maximum value for symbol comparison
+    float d_avg;        // Average value for DC offset subtraction
+    float d_min;        // Minimum value for symbol comparison
+
 public:
   int work (int noutput_items,
             gr_vector_const_void_star &input_items, 

Modified: 
gnuradio/branches/developers/jcorgan/pager/gr-pager/src/python/flex_demod.py
===================================================================
--- 
gnuradio/branches/developers/jcorgan/pager/gr-pager/src/python/flex_demod.py    
    2006-09-04 06:31:12 UTC (rev 3481)
+++ 
gnuradio/branches/developers/jcorgan/pager/gr-pager/src/python/flex_demod.py    
    2006-09-04 08:43:39 UTC (rev 3482)
@@ -19,7 +19,7 @@
 # Boston, MA 02111-1307, USA.
 # 
 
-from gnuradio import gr
+from gnuradio import gr, optfir, pager
 from math import pi
 
 class flex_demod(gr.hier_block):
@@ -31,8 +31,9 @@
 
     Flow graph (so far):
 
-    QUAD - Quadrature demodulator converts FSK to baseband amplitudes  
-
+    QUAD   - Quadrature demodulator converts FSK to baseband amplitudes  
+    LPF    - Low pass filter to remove noise prior to slicer
+    SLICER - Limits values to four values (-1.0, -0.333, 0.333, 1.0)
     ---
 
     @param fg: flowgraph
@@ -44,4 +45,10 @@
         k = channel_rate/(2*pi*4800)        # 4800 Hz max deviation
         QUAD = gr.quadrature_demod_cf(k)
 
-        gr.hier_block.__init__(self, fg, QUAD, QUAD)
+        taps = optfir.low_pass(1.0, channel_rate, 3200, 6400, 0.1, 60)
+        LPF = gr.fir_filter_fff(1, taps)
+       SLICER = pager.slicer_ff(.00005)
+       
+        fg.connect(QUAD, LPF, SLICER)
+
+        gr.hier_block.__init__(self, fg, QUAD, SLICER)