ref: d8c8e7b910b05f6e13d4ffb5baa634b13d06afaa
dir: /src/cvsdfilt.h/
/* * CVSD (Continuously Variable Slope Delta modulation) * conversion routines * * The CVSD format is described in the MIL Std 188 113, which is * available from http://bbs.itsi.disa.mil:5580/T3564 * * Copyright (C) 1996 * Thomas Sailer (sailer@ife.ee.ethz.ch) (HB9JNX/AE4WA) * Swiss Federal Institute of Technology, Electronics Lab * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2 of the License, or (at your option) any later version. * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this library; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA * */ /* ---------------------------------------------------------------------- */ #define ENC_FILTERLEN 16 /* PCM sampling rate */ #define DEC_FILTERLEN 48 /* CVSD sampling rate */ /* ---------------------------------------------------------------------- */ static float dec_filter_16[48] = { 0.001102, 0.001159, 0.000187, -0.000175, 0.002097, 0.006543, 0.009384, 0.008004, 0.006562, 0.013569, 0.030745, 0.047053, 0.050491, 0.047388, 0.062171, 0.109115, 0.167120, 0.197144, 0.195471, 0.222098, 0.354745, 0.599184, 0.849632, 0.956536, 0.849632, 0.599184, 0.354745, 0.222098, 0.195471, 0.197144, 0.167120, 0.109115, 0.062171, 0.047388, 0.050491, 0.047053, 0.030745, 0.013569, 0.006562, 0.008004, 0.009384, 0.006543, 0.002097, -0.000175, 0.000187, 0.001159, 0.001102, 0.000000 }; /* ---------------------------------------------------------------------- */ static float dec_filter_32[48] = { 0.001950, 0.004180, 0.006331, 0.007907, 0.008510, 0.008342, 0.008678, 0.011827, 0.020282, 0.035231, 0.055200, 0.075849, 0.091585, 0.098745, 0.099031, 0.101287, 0.120058, 0.170672, 0.262333, 0.392047, 0.542347, 0.684488, 0.786557, 0.823702, 0.786557, 0.684488, 0.542347, 0.392047, 0.262333, 0.170672, 0.120058, 0.101287, 0.099031, 0.098745, 0.091585, 0.075849, 0.055200, 0.035231, 0.020282, 0.011827, 0.008678, 0.008342, 0.008510, 0.007907, 0.006331, 0.004180, 0.001950, -0.000000 }; /* ---------------------------------------------------------------------- */ static float enc_filter_16_0[16] = { -0.000362, 0.004648, 0.001381, 0.008312, 0.041490, -0.001410, 0.124061, 0.247446, -0.106761, -0.236326, -0.023798, -0.023506, -0.030097, 0.001493, -0.005363, -0.001672 }; static float enc_filter_16_1[16] = { 0.001672, 0.005363, -0.001493, 0.030097, 0.023506, 0.023798, 0.236326, 0.106761, -0.247446, -0.124061, 0.001410, -0.041490, -0.008312, -0.001381, -0.004648, 0.000362 }; static float *enc_filter_16[2] = { enc_filter_16_0, enc_filter_16_1 }; /* ---------------------------------------------------------------------- */ static float enc_filter_32_0[16] = { -0.000289, 0.002112, 0.001421, 0.002235, 0.021003, 0.001237, 0.047132, 0.129636, -0.027328, -0.126462, -0.021456, -0.008069, -0.017959, 0.000301, -0.002538, -0.001278 }; static float enc_filter_32_1[16] = { -0.000010, 0.002787, 0.000055, 0.006813, 0.020249, -0.000995, 0.077912, 0.112870, -0.076980, -0.106971, -0.005096, -0.015449, -0.012591, 0.000813, -0.003003, -0.000527 }; static float enc_filter_32_2[16] = { 0.000527, 0.003003, -0.000813, 0.012591, 0.015449, 0.005096, 0.106971, 0.076980, -0.112870, -0.077912, 0.000995, -0.020249, -0.006813, -0.000055, -0.002787, 0.000010 }; static float enc_filter_32_3[16] = { 0.001278, 0.002538, -0.000301, 0.017959, 0.008069, 0.021456, 0.126462, 0.027328, -0.129636, -0.047132, -0.001237, -0.021003, -0.002235, -0.001421, -0.002112, 0.000289 }; static float *enc_filter_32[4] = { enc_filter_32_0, enc_filter_32_1, enc_filter_32_2, enc_filter_32_3 }; /* ---------------------------------------------------------------------- */