- Generated on Sun Jun 2 2013 20:37:24 for GNU Radio 3.6.5 C++ API by
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GNU Radio 3.6.5 C++ API
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00001 /* -*- c++ -*- */ 00002 /* 00003 * Copyright 2002,2008,2012 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 _FILTER_FIRDES_H_ 00024 #define _FILTER_FIRDES_H_ 00025 00026 #include <filter/api.h> 00027 #include <vector> 00028 #include <cmath> 00029 #include <gr_complex.h> 00030 00031 namespace gr { 00032 namespace filter { 00033 00034 /*! 00035 * \brief Finite Impulse Response (FIR) filter design functions. 00036 * \ingroup filter_design 00037 */ 00038 00039 class FILTER_API firdes { 00040 public: 00041 00042 enum win_type { 00043 WIN_HAMMING = 0, // max attenuation 53 dB 00044 WIN_HANN = 1, // max attenuation 44 dB 00045 WIN_BLACKMAN = 2, // max attenuation 74 dB 00046 WIN_RECTANGULAR = 3, 00047 WIN_KAISER = 4, // max attenuation a function of beta, google it 00048 WIN_BLACKMAN_hARRIS = 5, 00049 WIN_BLACKMAN_HARRIS = 5, // alias for capitalization consistency 00050 }; 00051 00052 00053 // ... class methods ... 00054 00055 /*! 00056 * \brief use "window method" to design a low-pass FIR filter 00057 * 00058 * \p gain: overall gain of filter (typically 1.0) 00059 * \p sampling_freq: sampling freq (Hz) 00060 * \p cutoff_freq: center of transition band (Hz) 00061 * \p transition_width: width of transition band (Hz). 00062 * The normalized width of the transition 00063 * band is what sets the number of taps 00064 * required. Narrow --> more taps 00065 * \p window_type: What kind of window to use. Determines 00066 * maximum attenuation and passband ripple. 00067 * \p beta: parameter for Kaiser window 00068 */ 00069 static std::vector<float> 00070 low_pass(double gain, 00071 double sampling_freq, 00072 double cutoff_freq, // Hz center of transition band 00073 double transition_width, // Hz width of transition band 00074 win_type window = WIN_HAMMING, 00075 double beta = 6.76); // used only with Kaiser 00076 00077 /*! 00078 * \brief use "window method" to design a low-pass FIR filter 00079 * 00080 * \p gain: overall gain of filter (typically 1.0) 00081 * \p sampling_freq: sampling freq (Hz) 00082 * \p cutoff_freq: center of transition band (Hz) 00083 * \p transition_width: width of transition band (Hz). 00084 * \p attenuation_dB required stopband attenuation 00085 * The normalized width of the transition 00086 * band and the required stop band 00087 * attenuation is what sets the number of taps 00088 * required. Narrow --> more taps 00089 * More attenuatin --> more taps 00090 * \p window_type: What kind of window to use. Determines 00091 * maximum attenuation and passband ripple. 00092 * \p beta: parameter for Kaiser window 00093 */ 00094 00095 static std::vector<float> 00096 low_pass_2(double gain, 00097 double sampling_freq, 00098 double cutoff_freq, // Hz beginning transition band 00099 double transition_width, // Hz width of transition band 00100 double attenuation_dB, // out of band attenuation dB 00101 win_type window = WIN_HAMMING, 00102 double beta = 6.76); // used only with Kaiser 00103 00104 /*! 00105 * \brief use "window method" to design a high-pass FIR filter 00106 * 00107 * \p gain: overall gain of filter (typically 1.0) 00108 * \p sampling_freq: sampling freq (Hz) 00109 * \p cutoff_freq: center of transition band (Hz) 00110 * \p transition_width: width of transition band (Hz). 00111 * The normalized width of the transition 00112 * band is what sets the number of taps 00113 * required. Narrow --> more taps 00114 * \p window_type: What kind of window to use. Determines 00115 * maximum attenuation and passband ripple. 00116 * \p beta: parameter for Kaiser window 00117 */ 00118 00119 static std::vector<float> 00120 high_pass(double gain, 00121 double sampling_freq, 00122 double cutoff_freq, // Hz center of transition band 00123 double transition_width, // Hz width of transition band 00124 win_type window = WIN_HAMMING, 00125 double beta = 6.76); // used only with Kaiser 00126 00127 /*! 00128 * \brief use "window method" to design a high-pass FIR filter 00129 * 00130 * \p gain: overall gain of filter (typically 1.0) 00131 * \p sampling_freq: sampling freq (Hz) 00132 * \p cutoff_freq: center of transition band (Hz) 00133 * \p transition_width: width of transition band (Hz). 00134 * \p attenuation_dB out of band attenuation 00135 * The normalized width of the transition 00136 * band and the required stop band 00137 * attenuation is what sets the number of taps 00138 * required. Narrow --> more taps 00139 * More attenuation --> more taps 00140 * \p window_type: What kind of window to use. Determines 00141 * maximum attenuation and passband ripple. 00142 * \p beta: parameter for Kaiser window 00143 */ 00144 00145 static std::vector<float> 00146 high_pass_2(double gain, 00147 double sampling_freq, 00148 double cutoff_freq, // Hz center of transition band 00149 double transition_width, // Hz width of transition band 00150 double attenuation_dB, // out of band attenuation dB 00151 win_type window = WIN_HAMMING, 00152 double beta = 6.76); // used only with Kaiser 00153 00154 /*! 00155 * \brief use "window method" to design a band-pass FIR filter 00156 * 00157 * \p gain: overall gain of filter (typically 1.0) 00158 * \p sampling_freq: sampling freq (Hz) 00159 * \p low_cutoff_freq: center of transition band (Hz) 00160 * \p high_cutoff_freq: center of transition band (Hz) 00161 * \p transition_width: width of transition band (Hz). 00162 * The normalized width of the transition 00163 * band is what sets the number of taps 00164 * required. Narrow --> more taps 00165 * \p window_type: What kind of window to use. Determines 00166 * maximum attenuation and passband ripple. 00167 * \p beta: parameter for Kaiser window 00168 */ 00169 static std::vector<float> 00170 band_pass(double gain, 00171 double sampling_freq, 00172 double low_cutoff_freq, // Hz center of transition band 00173 double high_cutoff_freq, // Hz center of transition band 00174 double transition_width, // Hz width of transition band 00175 win_type window = WIN_HAMMING, 00176 double beta = 6.76); // used only with Kaiser 00177 00178 /*! 00179 * \brief use "window method" to design a band-pass FIR filter 00180 * 00181 * \p gain: overall gain of filter (typically 1.0) 00182 * \p sampling_freq: sampling freq (Hz) 00183 * \p low_cutoff_freq: center of transition band (Hz) 00184 * \p high_cutoff_freq: center of transition band (Hz) 00185 * \p transition_width: width of transition band (Hz). 00186 * \p attenuation_dB out of band attenuation 00187 * The normalized width of the transition 00188 * band and the required stop band 00189 * attenuation is what sets the number of taps 00190 * required. Narrow --> more taps 00191 * More attenuation --> more taps 00192 * \p window_type: What kind of window to use. Determines 00193 * maximum attenuation and passband ripple. 00194 * \p beta: parameter for Kaiser window 00195 */ 00196 00197 static std::vector<float> 00198 band_pass_2(double gain, 00199 double sampling_freq, 00200 double low_cutoff_freq, // Hz beginning transition band 00201 double high_cutoff_freq, // Hz beginning transition band 00202 double transition_width, // Hz width of transition band 00203 double attenuation_dB, // out of band attenuation dB 00204 win_type window = WIN_HAMMING, 00205 double beta = 6.76); // used only with Kaiser 00206 00207 /*! 00208 * \brief use "window method" to design a complex band-pass FIR filter 00209 * 00210 * \p gain: overall gain of filter (typically 1.0) 00211 * \p sampling_freq: sampling freq (Hz) 00212 * \p low_cutoff_freq: center of transition band (Hz) 00213 * \p high_cutoff_freq: center of transition band (Hz) 00214 * \p transition_width: width of transition band (Hz). 00215 * The normalized width of the transition 00216 * band is what sets the number of taps 00217 * required. Narrow --> more taps 00218 * \p window_type: What kind of window to use. Determines 00219 * maximum attenuation and passband ripple. 00220 * \p beta: parameter for Kaiser window 00221 */ 00222 static std::vector<gr_complex> 00223 complex_band_pass(double gain, 00224 double sampling_freq, 00225 double low_cutoff_freq, // Hz center of transition band 00226 double high_cutoff_freq, // Hz center of transition band 00227 double transition_width, // Hz width of transition band 00228 win_type window = WIN_HAMMING, 00229 double beta = 6.76); // used only with Kaiser 00230 00231 /*! 00232 * \brief use "window method" to design a complex band-pass FIR filter 00233 * 00234 * \p gain: overall gain of filter (typically 1.0) 00235 * \p sampling_freq: sampling freq (Hz) 00236 * \p low_cutoff_freq: center of transition band (Hz) 00237 * \p high_cutoff_freq: center of transition band (Hz) 00238 * \p transition_width: width of transition band (Hz). 00239 * \p attenuation_dB out of band attenuation 00240 * The normalized width of the transition 00241 * band and the required stop band 00242 * attenuation is what sets the number of taps 00243 * required. Narrow --> more taps 00244 * More attenuation --> more taps 00245 * \p window_type: What kind of window to use. Determines 00246 * maximum attenuation and passband ripple. 00247 * \p beta: parameter for Kaiser window 00248 */ 00249 00250 static std::vector<gr_complex> 00251 complex_band_pass_2(double gain, 00252 double sampling_freq, 00253 double low_cutoff_freq, // Hz beginning transition band 00254 double high_cutoff_freq, // Hz beginning transition band 00255 double transition_width, // Hz width of transition band 00256 double attenuation_dB, // out of band attenuation dB 00257 win_type window = WIN_HAMMING, 00258 double beta = 6.76); // used only with Kaiser 00259 00260 /*! 00261 * \brief use "window method" to design a band-reject FIR filter 00262 * 00263 * \p gain: overall gain of filter (typically 1.0) 00264 * \p sampling_freq: sampling freq (Hz) 00265 * \p low_cutoff_freq: center of transition band (Hz) 00266 * \p high_cutoff_freq: center of transition band (Hz) 00267 * \p transition_width: width of transition band (Hz). 00268 * The normalized width of the transition 00269 * band is what sets the number of taps 00270 * required. Narrow --> more taps 00271 * \p window_type: What kind of window to use. Determines 00272 * maximum attenuation and passband ripple. 00273 * \p beta: parameter for Kaiser window 00274 */ 00275 00276 static std::vector<float> 00277 band_reject(double gain, 00278 double sampling_freq, 00279 double low_cutoff_freq, // Hz center of transition band 00280 double high_cutoff_freq, // Hz center of transition band 00281 double transition_width, // Hz width of transition band 00282 win_type window = WIN_HAMMING, 00283 double beta = 6.76); // used only with Kaiser 00284 00285 /*! 00286 * \brief use "window method" to design a band-reject FIR filter 00287 * 00288 * \p gain: overall gain of filter (typically 1.0) 00289 * \p sampling_freq: sampling freq (Hz) 00290 * \p low_cutoff_freq: center of transition band (Hz) 00291 * \p high_cutoff_freq: center of transition band (Hz) 00292 * \p transition_width: width of transition band (Hz). 00293 * \p attenuation_dB out of band attenuation 00294 * The normalized width of the transition 00295 * band and the required stop band 00296 * attenuation is what sets the number of taps 00297 * required. Narrow --> more taps 00298 * More attenuation --> more taps 00299 * \p window_type: What kind of window to use. Determines 00300 * maximum attenuation and passband ripple. 00301 * \p beta: parameter for Kaiser window 00302 */ 00303 00304 static std::vector<float> 00305 band_reject_2(double gain, 00306 double sampling_freq, 00307 double low_cutoff_freq, // Hz beginning transition band 00308 double high_cutoff_freq, // Hz beginning transition band 00309 double transition_width, // Hz width of transition band 00310 double attenuation_dB, // out of band attenuation dB 00311 win_type window = WIN_HAMMING, 00312 double beta = 6.76); // used only with Kaiser 00313 00314 /*!\brief design a Hilbert Transform Filter 00315 * 00316 * \p ntaps: Number of taps, must be odd 00317 * \p window_type: What kind of window to use 00318 * \p beta: Only used for Kaiser 00319 */ 00320 static std::vector<float> 00321 hilbert(unsigned int ntaps = 19, 00322 win_type windowtype = WIN_RECTANGULAR, 00323 double beta = 6.76); 00324 00325 /*! 00326 * \brief design a Root Cosine FIR Filter (do we need a window?) 00327 * 00328 * \p gain: overall gain of filter (typically 1.0) 00329 * \p sampling_freq: sampling freq (Hz) 00330 * \p symbol rate: symbol rate, must be a factor of sample rate 00331 * \p alpha: excess bandwidth factor 00332 * \p ntaps: number of taps 00333 */ 00334 static std::vector<float> 00335 root_raised_cosine(double gain, 00336 double sampling_freq, 00337 double symbol_rate, // Symbol rate, NOT bitrate (unless BPSK) 00338 double alpha, // Excess Bandwidth Factor 00339 int ntaps); 00340 00341 /*! 00342 * \brief design a Gaussian filter 00343 * 00344 * \p gain: overall gain of filter (typically 1.0) 00345 * \p symbols per bit: symbol rate, must be a factor of sample rate 00346 * \p ntaps: number of taps 00347 */ 00348 static std::vector<float> 00349 gaussian(double gain, 00350 double spb, 00351 double bt, // Bandwidth to bitrate ratio 00352 int ntaps); 00353 00354 // window functions ... 00355 static std::vector<float> window (win_type type, int ntaps, double beta); 00356 00357 private: 00358 static double bessi0(double x); 00359 static void sanity_check_1f(double sampling_freq, double f1, 00360 double transition_width); 00361 static void sanity_check_2f(double sampling_freq, double f1, double f2, 00362 double transition_width); 00363 static void sanity_check_2f_c(double sampling_freq, double f1, double f2, 00364 double transition_width); 00365 00366 static int compute_ntaps(double sampling_freq, 00367 double transition_width, 00368 win_type window_type, double beta); 00369 00370 static int compute_ntaps_windes(double sampling_freq, 00371 double transition_width, 00372 double attenuation_dB); 00373 }; 00374 00375 } /* namespace filter */ 00376 } /* namespace gr */ 00377 00378 #endif /* _FILTER_FIRDES_H_ */
1.7.3