- Generated on Sun Jun 2 2013 20:37:25 for GNU Radio 3.6.5 C++ API by
1.7.3
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GNU Radio 3.6.5 C++ API
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00001 /* -*- c++ -*- */ 00002 /* 00003 * Copyright 2002,2008 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 3, 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., 51 Franklin Street, 00020 * Boston, MA 02110-1301, USA. 00021 */ 00022 00023 #ifndef _GR_FIRDES_H_ 00024 #define _GR_FIRDES_H_ 00025 00026 #include <gr_core_api.h> 00027 #include <vector> 00028 #include <cmath> 00029 #include <gr_complex.h> 00030 00031 /*! 00032 * \brief Finite Impulse Response (FIR) filter design functions. 00033 * \ingroup filter_design 00034 */ 00035 00036 class GR_CORE_API gr_firdes { 00037 public: 00038 00039 enum win_type { 00040 WIN_HAMMING = 0, // max attenuation 53 dB 00041 WIN_HANN = 1, // max attenuation 44 dB 00042 WIN_BLACKMAN = 2, // max attenuation 74 dB 00043 WIN_RECTANGULAR = 3, 00044 WIN_KAISER = 4, // max attenuation a function of beta, google it 00045 WIN_BLACKMAN_hARRIS = 5, 00046 WIN_BLACKMAN_HARRIS = 5, // alias for capitalization consistency 00047 }; 00048 00049 00050 // ... class methods ... 00051 00052 /*! 00053 * \brief use "window method" to design a low-pass FIR filter 00054 * 00055 * \p gain: overall gain of filter (typically 1.0) 00056 * \p sampling_freq: sampling freq (Hz) 00057 * \p cutoff_freq: center of transition band (Hz) 00058 * \p transition_width: width of transition band (Hz). 00059 * The normalized width of the transition 00060 * band is what sets the number of taps 00061 * required. Narrow --> more taps 00062 * \p window_type: What kind of window to use. Determines 00063 * maximum attenuation and passband ripple. 00064 * \p beta: parameter for Kaiser window 00065 */ 00066 static std::vector<float> 00067 low_pass (double gain, 00068 double sampling_freq, 00069 double cutoff_freq, // Hz center of transition band 00070 double transition_width, // Hz width of transition band 00071 win_type window = WIN_HAMMING, 00072 double beta = 6.76); // used only with Kaiser 00073 00074 /*! 00075 * \brief use "window method" to design a low-pass FIR filter 00076 * 00077 * \p gain: overall gain of filter (typically 1.0) 00078 * \p sampling_freq: sampling freq (Hz) 00079 * \p cutoff_freq: center of transition band (Hz) 00080 * \p transition_width: width of transition band (Hz). 00081 * \p attenuation_dB required stopband attenuation 00082 * The normalized width of the transition 00083 * band and the required stop band 00084 * attenuation is what sets the number of taps 00085 * required. Narrow --> more taps 00086 * More attenuatin --> more taps 00087 * \p window_type: What kind of window to use. Determines 00088 * maximum attenuation and passband ripple. 00089 * \p beta: parameter for Kaiser window 00090 */ 00091 00092 static std::vector<float> 00093 low_pass_2 (double gain, 00094 double sampling_freq, 00095 double cutoff_freq, // Hz beginning transition band 00096 double transition_width, // Hz width of transition band 00097 double attenuation_dB, // out of band attenuation dB 00098 win_type window = WIN_HAMMING, 00099 double beta = 6.76); // used only with Kaiser 00100 00101 /*! 00102 * \brief use "window method" to design a high-pass FIR filter 00103 * 00104 * \p gain: overall gain of filter (typically 1.0) 00105 * \p sampling_freq: sampling freq (Hz) 00106 * \p cutoff_freq: center of transition band (Hz) 00107 * \p transition_width: width of transition band (Hz). 00108 * The normalized width of the transition 00109 * band is what sets the number of taps 00110 * required. Narrow --> more taps 00111 * \p window_type: What kind of window to use. Determines 00112 * maximum attenuation and passband ripple. 00113 * \p beta: parameter for Kaiser window 00114 */ 00115 00116 static std::vector<float> 00117 high_pass (double gain, 00118 double sampling_freq, 00119 double cutoff_freq, // Hz center of transition band 00120 double transition_width, // Hz width of transition band 00121 win_type window = WIN_HAMMING, 00122 double beta = 6.76); // used only with Kaiser 00123 00124 /*! 00125 * \brief use "window method" to design a high-pass FIR filter 00126 * 00127 * \p gain: overall gain of filter (typically 1.0) 00128 * \p sampling_freq: sampling freq (Hz) 00129 * \p cutoff_freq: center of transition band (Hz) 00130 * \p transition_width: width of transition band (Hz). 00131 * \p attenuation_dB out of band attenuation 00132 * The normalized width of the transition 00133 * band and the required stop band 00134 * attenuation is what sets the number of taps 00135 * required. Narrow --> more taps 00136 * More attenuation --> more taps 00137 * \p window_type: What kind of window to use. Determines 00138 * maximum attenuation and passband ripple. 00139 * \p beta: parameter for Kaiser window 00140 */ 00141 00142 static std::vector<float> 00143 high_pass_2 (double gain, 00144 double sampling_freq, 00145 double cutoff_freq, // Hz center of transition band 00146 double transition_width, // Hz width of transition band 00147 double attenuation_dB, // out of band attenuation dB 00148 win_type window = WIN_HAMMING, 00149 double beta = 6.76); // used only with Kaiser 00150 00151 /*! 00152 * \brief use "window method" to design a band-pass FIR filter 00153 * 00154 * \p gain: overall gain of filter (typically 1.0) 00155 * \p sampling_freq: sampling freq (Hz) 00156 * \p low_cutoff_freq: center of transition band (Hz) 00157 * \p high_cutoff_freq: center of transition band (Hz) 00158 * \p transition_width: width of transition band (Hz). 00159 * The normalized width of the transition 00160 * band is what sets the number of taps 00161 * required. Narrow --> more taps 00162 * \p window_type: What kind of window to use. Determines 00163 * maximum attenuation and passband ripple. 00164 * \p beta: parameter for Kaiser window 00165 */ 00166 static std::vector<float> 00167 band_pass (double gain, 00168 double sampling_freq, 00169 double low_cutoff_freq, // Hz center of transition band 00170 double high_cutoff_freq, // Hz center of transition band 00171 double transition_width, // Hz width of transition band 00172 win_type window = WIN_HAMMING, 00173 double beta = 6.76); // used only with Kaiser 00174 00175 /*! 00176 * \brief use "window method" to design a band-pass FIR filter 00177 * 00178 * \p gain: overall gain of filter (typically 1.0) 00179 * \p sampling_freq: sampling freq (Hz) 00180 * \p low_cutoff_freq: center of transition band (Hz) 00181 * \p high_cutoff_freq: center of transition band (Hz) 00182 * \p transition_width: width of transition band (Hz). 00183 * \p attenuation_dB out of band attenuation 00184 * The normalized width of the transition 00185 * band and the required stop band 00186 * attenuation is what sets the number of taps 00187 * required. Narrow --> more taps 00188 * More attenuation --> more taps 00189 * \p window_type: What kind of window to use. Determines 00190 * maximum attenuation and passband ripple. 00191 * \p beta: parameter for Kaiser window 00192 */ 00193 00194 static std::vector<float> 00195 band_pass_2 (double gain, 00196 double sampling_freq, 00197 double low_cutoff_freq, // Hz beginning transition band 00198 double high_cutoff_freq, // Hz beginning transition band 00199 double transition_width, // Hz width of transition band 00200 double attenuation_dB, // out of band attenuation dB 00201 win_type window = WIN_HAMMING, 00202 double beta = 6.76); // used only with Kaiser 00203 00204 /*! 00205 * \brief use "window method" to design a complex band-pass FIR filter 00206 * 00207 * \p gain: overall gain of filter (typically 1.0) 00208 * \p sampling_freq: sampling freq (Hz) 00209 * \p low_cutoff_freq: center of transition band (Hz) 00210 * \p high_cutoff_freq: center of transition band (Hz) 00211 * \p transition_width: width of transition band (Hz). 00212 * The normalized width of the transition 00213 * band is what sets the number of taps 00214 * required. Narrow --> more taps 00215 * \p window_type: What kind of window to use. Determines 00216 * maximum attenuation and passband ripple. 00217 * \p beta: parameter for Kaiser window 00218 */ 00219 00220 static std::vector<gr_complex> 00221 complex_band_pass (double gain, 00222 double sampling_freq, 00223 double low_cutoff_freq, // Hz center of transition band 00224 double high_cutoff_freq, // Hz center of transition band 00225 double transition_width, // Hz width of transition band 00226 win_type window = WIN_HAMMING, 00227 double beta = 6.76); // used only with Kaiser 00228 00229 /*! 00230 * \brief use "window method" to design a complex band-pass FIR filter 00231 * 00232 * \p gain: overall gain of filter (typically 1.0) 00233 * \p sampling_freq: sampling freq (Hz) 00234 * \p low_cutoff_freq: center of transition band (Hz) 00235 * \p high_cutoff_freq: center of transition band (Hz) 00236 * \p transition_width: width of transition band (Hz). 00237 * \p attenuation_dB out of band attenuation 00238 * The normalized width of the transition 00239 * band and the required stop band 00240 * attenuation is what sets the number of taps 00241 * required. Narrow --> more taps 00242 * More attenuation --> more taps 00243 * \p window_type: What kind of window to use. Determines 00244 * maximum attenuation and passband ripple. 00245 * \p beta: parameter for Kaiser window 00246 */ 00247 00248 static std::vector<gr_complex> 00249 complex_band_pass_2 (double gain, 00250 double sampling_freq, 00251 double low_cutoff_freq, // Hz beginning transition band 00252 double high_cutoff_freq, // Hz beginning transition band 00253 double transition_width, // Hz width of transition band 00254 double attenuation_dB, // out of band attenuation dB 00255 win_type window = WIN_HAMMING, 00256 double beta = 6.76); // used only with Kaiser 00257 00258 /*! 00259 * \brief use "window method" to design a band-reject FIR filter 00260 * 00261 * \p gain: overall gain of filter (typically 1.0) 00262 * \p sampling_freq: sampling freq (Hz) 00263 * \p low_cutoff_freq: center of transition band (Hz) 00264 * \p high_cutoff_freq: center of transition band (Hz) 00265 * \p transition_width: width of transition band (Hz). 00266 * The normalized width of the transition 00267 * band is what sets the number of taps 00268 * required. Narrow --> more taps 00269 * \p window_type: What kind of window to use. Determines 00270 * maximum attenuation and passband ripple. 00271 * \p beta: parameter for Kaiser window 00272 */ 00273 00274 static std::vector<float> 00275 band_reject (double gain, 00276 double sampling_freq, 00277 double low_cutoff_freq, // Hz center of transition band 00278 double high_cutoff_freq, // Hz center of transition band 00279 double transition_width, // Hz width of transition band 00280 win_type window = WIN_HAMMING, 00281 double beta = 6.76); // used only with Kaiser 00282 00283 /*! 00284 * \brief use "window method" to design a band-reject FIR filter 00285 * 00286 * \p gain: overall gain of filter (typically 1.0) 00287 * \p sampling_freq: sampling freq (Hz) 00288 * \p low_cutoff_freq: center of transition band (Hz) 00289 * \p high_cutoff_freq: center of transition band (Hz) 00290 * \p transition_width: width of transition band (Hz). 00291 * \p attenuation_dB out of band attenuation 00292 * The normalized width of the transition 00293 * band and the required stop band 00294 * attenuation is what sets the number of taps 00295 * required. Narrow --> more taps 00296 * More attenuation --> more taps 00297 * \p window_type: What kind of window to use. Determines 00298 * maximum attenuation and passband ripple. 00299 * \p beta: parameter for Kaiser window 00300 */ 00301 00302 static std::vector<float> 00303 band_reject_2 (double gain, 00304 double sampling_freq, 00305 double low_cutoff_freq, // Hz beginning transition band 00306 double high_cutoff_freq, // Hz beginning transition band 00307 double transition_width, // Hz width of transition band 00308 double attenuation_dB, // out of band attenuation dB 00309 win_type window = WIN_HAMMING, 00310 double beta = 6.76); // used only with Kaiser 00311 00312 /*!\brief design a Hilbert Transform Filter 00313 * 00314 * \p ntaps: Number of taps, must be odd 00315 * \p window_type: What kind of window to use 00316 * \p beta: Only used for Kaiser 00317 */ 00318 static std::vector<float> 00319 hilbert (unsigned int ntaps = 19, 00320 win_type windowtype = WIN_RECTANGULAR, 00321 double beta = 6.76); 00322 00323 /*! 00324 * \brief design a Root Cosine FIR Filter (do we need a window?) 00325 * 00326 * \p gain: overall gain of filter (typically 1.0) 00327 * \p sampling_freq: sampling freq (Hz) 00328 * \p symbol rate: symbol rate, must be a factor of sample rate 00329 * \p alpha: excess bandwidth factor 00330 * \p ntaps: number of taps 00331 */ 00332 static std::vector<float> 00333 root_raised_cosine (double gain, 00334 double sampling_freq, 00335 double symbol_rate, // Symbol rate, NOT bitrate (unless BPSK) 00336 double alpha, // Excess Bandwidth Factor 00337 int ntaps); 00338 00339 /*! 00340 * \brief design a Gaussian filter 00341 * 00342 * \p gain: overall gain of filter (typically 1.0) 00343 * \p symbols per bit: symbol rate, must be a factor of sample rate 00344 * \p ntaps: number of taps 00345 */ 00346 static std::vector<float> 00347 gaussian (double gain, 00348 double spb, 00349 double bt, // Bandwidth to bitrate ratio 00350 int ntaps); 00351 00352 // window functions ... 00353 static std::vector<float> window (win_type type, int ntaps, double beta); 00354 00355 private: 00356 static double bessi0(double x); 00357 static void sanity_check_1f (double sampling_freq, double f1, 00358 double transition_width); 00359 static void sanity_check_2f (double sampling_freq, double f1, double f2, 00360 double transition_width); 00361 static void sanity_check_2f_c (double sampling_freq, double f1, double f2, 00362 double transition_width); 00363 00364 static int compute_ntaps (double sampling_freq, 00365 double transition_width, 00366 win_type window_type, double beta); 00367 00368 static int compute_ntaps_windes (double sampling_freq, 00369 double transition_width, 00370 double attenuation_dB); 00371 }; 00372 00373 #endif
1.7.3