Main Page | Modules | Namespace List | Class Hierarchy | Compound List | File List | Compound Members | File Members

gr_nco.h

Go to the documentation of this file.
00001 /* -*- c++ -*- */
00002 /*
00003  * Copyright 2002 Free Software Foundation, Inc.
00004  * 
00005  * This file is part of GNU Radio
00006  * 
00007  * GNU Radio is free software; you can redistribute it and/or modify
00008  * it under the terms of the GNU General Public License as published by
00009  * the Free Software Foundation; either version 2, or (at your option)
00010  * any later version.
00011  * 
00012  * GNU Radio is distributed in the hope that it will be useful,
00013  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00014  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00015  * GNU General Public License for more details.
00016  * 
00017  * You should have received a copy of the GNU General Public License
00018  * along with GNU Radio; see the file COPYING.  If not, write to
00019  * the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
00020  * Boston, MA 02111-1307, USA.
00021  */
00022 #ifndef _GR_NCO_H_
00023 #define _GR_NCO_H_
00024 
00025 
00026 #include <vector>
00027 // #include <gr_sincos.h>
00028 #include <cmath>
00029 
00030 using std::vector;
00031 
00037 //FIXME  Eventually generalize this to fixed point
00038 
00039 template<class o_type, class i_type> 
00040 class gr_nco {
00041 public:
00042   gr_nco () : phase (0), phase_inc(0) {}
00043 
00044   virtual ~gr_nco () {}
00045 
00046   // radians
00047   void set_phase (float angle) {
00048     phase = angle;
00049   }
00050 
00051   void adjust_phase (float delta_phase) {
00052     phase += delta_phase;
00053   }
00054 
00055 
00056   // angle_rate is in radians / step
00057   void set_freq (float angle_rate){
00058     phase_inc = angle_rate;
00059   }
00060 
00061   // angle_rate is a delta in radians / step
00062   void adjust_freq (float delta_angle_rate)
00063   {
00064     phase_inc += delta_angle_rate;
00065   }
00066 
00067   // increment current phase angle
00068 
00069   void step () 
00070   { 
00071     phase += phase_inc; 
00072     if (fabs (phase) > M_PI){
00073       
00074       while (phase > M_PI)
00075         phase -= 2*M_PI;
00076 
00077       while (phase < -M_PI)
00078         phase += 2*M_PI;
00079     }
00080   }
00081 
00082   void step (int n) { phase += phase_inc * n; }
00083 
00084   // units are radians / step
00085   float get_phase () const { return phase; }
00086   float get_freq () const { return phase_inc; }
00087 
00088   // compute cos and sin for current phase angle
00089   void cossin (float &i, float &q) const;
00090 
00091   // compute cos or sin for current phase angle
00092   float cos () const { return std::cos (phase); }
00093   float sin () const { return std::sin (phase); }
00094 
00095 protected:
00096   float phase;
00097   float phase_inc;
00098 };
00099 
00100 /*
00101  * FIXME: since this is a template, we can't include <config.h>.
00102  * This appears to preclude conditionalizing the availability of 
00103  * __sincosf.  If you know better, please fix this code.
00104  * Actually, I guess we could create out own function and have
00105  * it do the include (later...)
00106  */
00107 
00108 template<class o_type, class i_type> 
00109 void
00110 gr_nco<o_type,i_type>::cossin (float &i, float &q) const
00111 {
00112 #if 0
00113   __sincosf (phase, &q, &i);
00114 #else
00115   i = std::cos (phase);
00116   q = std::sin (phase);
00117 #endif
00118 }
00119 
00120 #endif /* _NCO_H_ */

Generated on Mon Jul 12 15:00:43 2004 for GNU Radio 2.x by doxygen 1.3.3