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gr_nco.h

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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 
00035 //FIXME  Eventually generalize this to fixed point
00036 
00037 template<class o_type, class i_type> 
00038 class gr_nco {
00039 public:
00040   gr_nco () : phase (0), phase_inc(0) {}
00041 
00042   virtual ~gr_nco () {}
00043 
00044   // radians
00045   void set_phase (float angle) {
00046     phase = angle;
00047   }
00048 
00049   void adjust_phase (float delta_phase) {
00050     phase += delta_phase;
00051   }
00052 
00053 
00054   // angle_rate is in radians / step
00055   void set_freq (float angle_rate){
00056     phase_inc = angle_rate;
00057   }
00058 
00059   // angle_rate is a delta in radians / step
00060   void adjust_freq (float delta_angle_rate)
00061   {
00062     phase_inc += delta_angle_rate;
00063   }
00064 
00065   // increment current phase angle
00066 
00067   void step () 
00068   { 
00069     phase += phase_inc; 
00070     if (fabs (phase) > M_PI){
00071       
00072       while (phase > M_PI)
00073         phase -= 2*M_PI;
00074 
00075       while (phase < -M_PI)
00076         phase += 2*M_PI;
00077     }
00078   }
00079 
00080   void step (int n) { phase += phase_inc * n; }
00081 
00082   // units are radians / step
00083   float get_phase () const { return phase; }
00084   float get_freq () const { return phase_inc; }
00085 
00086   // compute sin and cos for current phase angle
00087   void sincos (float *sinx, float *cosx) const;
00088 
00089   // compute cos or sin for current phase angle
00090   float cos () const { return std::cos (phase); }
00091   float sin () const { return std::sin (phase); }
00092 
00093 protected:
00094   float phase;
00095   float phase_inc;
00096 };
00097 
00098 template<class o_type, class i_type> 
00099 void
00100 gr_nco<o_type,i_type>::sincos (float *sinx, float *cosx) const
00101 {
00102   gr_sincosf (phase, sinx, cosx);
00103 }
00104 
00105 #endif /* _NCO_H_ */

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