1/* 2** Copyright (C) 2002-2015 Erik de Castro Lopo <erikd@mega-nerd.com> 3** 4** This program is free software; you can redistribute it and/or modify 5** it under the terms of the GNU General Public License as published by 6** the Free Software Foundation; either version 2 of the License, or 7** (at your option) any later version. 8** 9** This program is distributed in the hope that it will be useful, 10** but WITHOUT ANY WARRANTY; without even the implied warranty of 11** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 12** GNU General Public License for more details. 13** 14** You should have received a copy of the GNU General Public License 15** along with this program; if not, write to the Free Software 16** Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. 17*/ 18 19#include "sfconfig.h" 20 21#include <stdio.h> 22#include <stdlib.h> 23#include <math.h> 24 25#include "dft_cmp.h" 26#include "utils.h" 27 28#ifndef M_PI 29#define M_PI 3.14159265358979323846264338 30#endif 31 32#define DFT_SPEC_LENGTH (DFT_DATA_LENGTH / 2) 33 34static void dft_magnitude (const double *data, double *spectrum) ; 35static double calc_max_spectral_difference (const double *spec1, const double *spec2) ; 36 37/*-------------------------------------------------------------------------------- 38** Public functions. 39*/ 40 41double 42dft_cmp_float (int linenum, const float *in_data, const float *test_data, int len, double target_snr, int allow_exit) 43{ static double orig [DFT_DATA_LENGTH] ; 44 static double test [DFT_DATA_LENGTH] ; 45 unsigned k ; 46 47 if (len != DFT_DATA_LENGTH) 48 { printf ("Error (line %d) : dft_cmp_float : Bad input array length.\n", linenum) ; 49 return 1 ; 50 } ; 51 52 for (k = 0 ; k < ARRAY_LEN (orig) ; k++) 53 { test [k] = test_data [k] ; 54 orig [k] = in_data [k] ; 55 } ; 56 57 return dft_cmp_double (linenum, orig, test, len, target_snr, allow_exit) ; 58} /* dft_cmp_float */ 59 60double 61dft_cmp_double (int linenum, const double *orig, const double *test, int len, double target_snr, int allow_exit) 62{ static double orig_spec [DFT_SPEC_LENGTH] ; 63 static double test_spec [DFT_SPEC_LENGTH] ; 64 double snr ; 65 66 if (! orig || ! test) 67 { printf ("Error (line %d) : dft_cmp_double : Bad input arrays.\n", linenum) ; 68 return 1 ; 69 } ; 70 71 if (len != DFT_DATA_LENGTH) 72 { printf ("Error (line %d) : dft_cmp_double : Bad input array length.\n", linenum) ; 73 return 1 ; 74 } ; 75 76 dft_magnitude (orig, orig_spec) ; 77 dft_magnitude (test, test_spec) ; 78 79 snr = calc_max_spectral_difference (orig_spec, test_spec) ; 80 81 if (snr > target_snr) 82 { printf ("\n\nLine %d: Actual SNR (% 4.1f) > target SNR (% 4.1f).\n\n", linenum, snr, target_snr) ; 83 oct_save_double (orig, test, len) ; 84 if (allow_exit) 85 exit (1) ; 86 } ; 87 88 if (snr < -500.0) 89 snr = -500.0 ; 90 91 return snr ; 92} /* dft_cmp_double */ 93 94/*-------------------------------------------------------------------------------- 95** Quick dirty calculation of magnitude spectrum for real valued data using 96** Discrete Fourier Transform. Since the data is real, the DFT is only 97** calculated for positive frequencies. 98*/ 99 100static void 101dft_magnitude (const double *data, double *spectrum) 102{ static double cos_angle [DFT_DATA_LENGTH] = { 0.0 } ; 103 static double sin_angle [DFT_DATA_LENGTH] ; 104 105 double real_part, imag_part ; 106 int k, n ; 107 108 /* If sine and cosine tables haven't been initialised, do so. */ 109 if (cos_angle [0] == 0.0) 110 for (n = 0 ; n < DFT_DATA_LENGTH ; n++) 111 { cos_angle [n] = cos (2.0 * M_PI * n / DFT_DATA_LENGTH) ; 112 sin_angle [n] = -1.0 * sin (2.0 * M_PI * n / DFT_DATA_LENGTH) ; 113 } ; 114 115 /* DFT proper. Since the data is real, only generate a half spectrum. */ 116 for (k = 1 ; k < DFT_SPEC_LENGTH ; k++) 117 { real_part = 0.0 ; 118 imag_part = 0.0 ; 119 120 for (n = 0 ; n < DFT_DATA_LENGTH ; n++) 121 { real_part += data [n] * cos_angle [(k * n) % DFT_DATA_LENGTH] ; 122 imag_part += data [n] * sin_angle [(k * n) % DFT_DATA_LENGTH] ; 123 } ; 124 125 spectrum [k] = sqrt (real_part * real_part + imag_part * imag_part) ; 126 } ; 127 128 spectrum [DFT_SPEC_LENGTH - 1] = 0.0 ; 129 130 spectrum [0] = spectrum [1] = spectrum [2] = 0.0 ; 131 132 return ; 133} /* dft_magnitude */ 134 135static double 136calc_max_spectral_difference (const double *orig, const double *test) 137{ double orig_max = 0.0, max_diff = 0.0 ; 138 int k ; 139 140 for (k = 0 ; k < DFT_SPEC_LENGTH ; k++) 141 { if (orig_max < orig [k]) 142 orig_max = orig [k] ; 143 if (max_diff < fabs (orig [k] - test [k])) 144 max_diff = fabs (orig [k] - test [k]) ; 145 } ; 146 147 if (max_diff < 1e-25) 148 return -500.0 ; 149 150 return 20.0 * log10 (max_diff / orig_max) ; 151} /* calc_max_spectral_difference */ 152