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mayhem-firmware/firmware/common/dsp_fir_taps.hpp
Brumi-2021 dfadd38e32
Adding 2 WFM filters more to current Audio App ( bw 180Khz and 40 khz to support rx for weather NOAA APT) (#961) 
* First part new filter 40k for NOAA in Audio App

* Adding a third WFM filter 180Khz general pursose
2023-05-07 16:08:45 +02:00

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/*
* Copyright (C) 2015 Jared Boone, ShareBrained Technology, Inc.
* Copyright (C) 2017 Furrtek
*
* This file is part of PortaPack.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2, or (at your option)
* any later version.
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; see the file COPYING. If not, write to
* the Free Software Foundation, Inc., 51 Franklin Street,
* Boston, MA 02110-1301, USA.
*/
#ifndef __DSP_FIR_TAPS_H__
#define __DSP_FIR_TAPS_H__
#include <cstdint>
#include <array>
#include "complex.hpp"
template<size_t N>
struct fir_taps_real {
float low_frequency_normalized;
float high_frequency_normalized;
float transition_normalized;
std::array<int16_t, N> taps;
};
template<size_t N>
struct fir_taps_complex {
float low_frequency_normalized;
float high_frequency_normalized;
float transition_normalized;
std::array<complex16_t, N> taps;
};
// NBFM 16K0F3E emission type /////////////////////////////////////////////
// IFIR image-reject filter: fs=3072000, pass=8000, stop=344000, decim=8, fout=384000
constexpr fir_taps_real<24> taps_16k0_decim_0 {
.low_frequency_normalized = -8000.0f / 3072000.0f,
.high_frequency_normalized = 8000.0f / 3072000.0f,
.transition_normalized = 336000.0f / 3072000.0f,
.taps = { {
1, 67, 165, 340, 599, 944, 1361, 1820,
2278, 2684, 2988, 3152, 3152, 2988, 2684, 2278,
1820, 1361, 944, 599, 340, 165, 67, 1,
} },
};
// IFIR prototype filter: fs=384000, pass=8000, stop=40000, decim=8, fout=48000
constexpr fir_taps_real<32> taps_16k0_decim_1 {
.low_frequency_normalized = -8000.0f / 384000.0f,
.high_frequency_normalized = 8000.0f / 384000.0f,
.transition_normalized = 32000.0f / 384000.0f,
.taps = { {
-26, -125, -180, -275, -342, -359, -286, -90,
250, 733, 1337, 2011, 2688, 3289, 3740, 3982,
3982, 3740, 3289, 2688, 2011, 1337, 733, 250,
-90, -286, -359, -342, -275, -180, -125, -26,
} },
};
// Channel filter: fs=48000, pass=8000, stop=12400, decim=1, fout=48000
constexpr fir_taps_real<32> taps_16k0_channel {
.low_frequency_normalized = -8000.0f / 48000.0f,
.high_frequency_normalized = 8000.0f / 48000.0f,
.transition_normalized = 4400.0f / 48000.0f,
.taps = { {
-73, -285, -376, -8, 609, 538, -584, -1387,
-148, 2173, 1959, -2146, -5267, -297, 12915, 24737,
24737, 12915, -297, -5267, -2146, 1959, 2173, -148,
-1387, -584, 538, 609, -8, -376, -285, -73,
} },
};
// NBFM 11K0F3E emission type /////////////////////////////////////////////
// IFIR image-reject filter: fs=3072000, pass=5500, stop=341500, decim=8, fout=384000
constexpr fir_taps_real<24> taps_11k0_decim_0 {
.low_frequency_normalized = -5500.0f / 3072000.0f,
.high_frequency_normalized = 5500.0f / 3072000.0f,
.transition_normalized = 336000.0f / 3072000.0f,
.taps = { {
38, 102, 220, 406, 668, 1004, 1397, 1822,
2238, 2603, 2875, 3020, 3020, 2875, 2603, 2238,
1822, 1397, 1004, 668, 406, 220, 102, 38,
} },
};
// IFIR prototype filter: fs=384000, pass=5500, stop=42500, decim=8, fout=48000
constexpr fir_taps_real<32> taps_11k0_decim_1 {
.low_frequency_normalized = -5500.0f / 384000.0f,
.high_frequency_normalized = 5500.0f / 384000.0f,
.transition_normalized = 37000.0f / 384000.0f,
.taps = { {
-42, -87, -157, -234, -298, -318, -255, -75,
246, 713, 1306, 1976, 2656, 3265, 3724, 3971,
3971, 3724, 3265, 2656, 1976, 1306, 713, 246,
-75, -255, -318, -298, -234, -157, -87, -42,
} },
};
// Channel filter: fs=48000, pass=5500, stop=8900, decim=1, fout=48000
constexpr fir_taps_real<32> taps_11k0_channel {
.low_frequency_normalized = -5500.0f / 48000.0f,
.high_frequency_normalized = 5500.0f / 48000.0f,
.transition_normalized = 3400.0f / 48000.0f,
.taps = { {
-68, -345, -675, -867, -582, 247, 1222, 1562,
634, -1379, -3219, -3068, 310, 6510, 13331, 17795,
17795, 13331, 6510, 310, -3068, -3219, -1379, 634,
1562, 1222, 247, -582, -867, -675, -345, -68,
} },
};
// NBFM 8K50F3E emission type /////////////////////////////////////////////
// IFIR image-reject filter: fs=3072000, pass=4250, stop=340250, decim=8, fout=384000
constexpr fir_taps_real<24> taps_4k25_decim_0 {
.low_frequency_normalized = -4250.0f / 3072000.0f,
.high_frequency_normalized = 4250.0f / 3072000.0f,
.transition_normalized = 33600.0f / 3072000.0f,
.taps = { {
38, 103, 222, 409, 671, 1006, 1399, 1821,
2236, 2599, 2868, 3012, 3012, 2868, 2599, 2236,
1821, 1399, 1006, 671, 409, 222, 103, 38,
} },
};
// IFIR prototype filter: fs=384000, pass=4250, stop=43750, decim=8, fout=48000
constexpr fir_taps_real<32> taps_4k25_decim_1 {
.low_frequency_normalized = -4250.0f / 384000.0f,
.high_frequency_normalized = 4250.0f / 384000.0f,
.transition_normalized = 39500.0f / 384000.0f,
.taps = { {
-33, -74, -139, -214, -280, -306, -254, -87,
222, 682, 1274, 1951, 2644, 3268, 3741, 3996,
3996, 3741, 3268, 2644, 1951, 1274, 682, 222,
-87, -254, -306, -280, -214, -139, -74, -33,
} },
};
// Channel filter: fs=48000, pass=4250, stop=7900, decim=1, fout=48000
constexpr fir_taps_real<32> taps_4k25_channel {
.low_frequency_normalized = -4250.0f / 48000.0f,
.high_frequency_normalized = 4250.0f / 48000.0f,
.transition_normalized = 3650.0f / 48000.0f,
.taps = { {
-58, -14, 153, 484, 871, 1063, 770, -141,
-1440, -2488, -2435, -614, 3035, 7771, 12226, 14927,
14927, 12226, 7771, 3035, -614, -2435, -2488, -1440,
-141, 770, 1063, 871, 484, 153, -14, -58,
} },
};
/* CTCSS audio filter */
/* 12kHz int16_t input
* -> FIR filter, <300Hz pass, >300Hz stop, gain of 1
* -> 6kHz int16_t output, gain of 1.0 (I think).
* Padded to multiple of four taps for unrolled FIR code.
* sum(abs(taps)): 125270
*/
/*constexpr fir_taps_real<64> taps_64_lp_025_025 {
.taps = { {
0, 0, -3, -7, -13, -20, -27, -32,
-34, -33, -25, -10, 13, 47, 94, 152,
223, 307, 402, 508, 622, 742, 866, 991,
1113, 1229, 1336, 1430, 1510, 1571, 1614, 1635,
1635, 1614, 1571, 1510, 1430, 1336, 1229, 1113,
991, 866, 742, 622, 508, 402, 307, 223,
152, 94, 47, 13, -10, -25, -33, -34,
-32, -27, -20, -13, -7, -3, 0, 0
} },
};*/
/* CTCSS audio filter */
/* 24kHz int16_t input
* -> FIR filter, <300Hz pass, >300Hz stop, gain of 1
* -> 12kHz int16_t output, gain of 1.0 (I think).
* Padded to multiple of four taps for unrolled FIR code.
* sum(abs(taps)): 125270
*/
constexpr fir_taps_real<64> taps_64_lp_025_025 {
.low_frequency_normalized = 0,
.high_frequency_normalized = 0,
.transition_normalized = 0,
.taps = { {
0, 0, 2, 6, 12, 20, 32, 46,
64, 85, 110, 138, 169, 204, 241, 281,
323, 367, 412, 457, 502, 547, 590, 631,
669, 704, 735, 762, 784, 801, 812, 818,
818, 812, 801, 784, 762, 735, 704, 669,
631, 590, 547, 502, 457, 412, 367, 323,
281, 241, 204, 169, 138, 110, 85, 64,
46, 32, 20, 12, 6, 2, 0, 0
} },
};
// DSB AM 6K00A3E emission type ///////////////////////////////////////////
// IFIR image-reject filter: fs=3072000, pass=3000, stop=339000, decim=8, fout=384000
constexpr fir_taps_real<24> taps_6k0_decim_0 {
.low_frequency_normalized = -3000.0f / 3072000.0f,
.high_frequency_normalized = 3000.0f / 3072000.0f,
.transition_normalized = 336000.0f / 3072000.0f,
.taps = { {
39, 104, 224, 412, 674, 1008, 1400, 1821,
2234, 2594, 2863, 3006, 3006, 2863, 2594, 2234,
1821, 1400, 1008, 674, 412, 224, 104, 39,
} },
};
// IFIR prototype filter: fs=384000, pass=3000, stop=45000, decim=8, fout=48000
constexpr fir_taps_real<32> taps_6k0_decim_1 {
.low_frequency_normalized = -3000.0f / 384000.0f,
.high_frequency_normalized = 3000.0f / 384000.0f,
.transition_normalized = 43000.0f / 384000.0f,
.taps = { {
-26, -63, -123, -195, -263, -295, -253, -99,
199, 651, 1242, 1927, 2633, 3273, 3760, 4023,
4023, 3760, 3273, 2633, 1927, 1242, 651, 199,
-99, -253, -295, -263, -195, -123, -63, -26,
} },
};
// IFIR prototype filter: fs=48000, pass=3000, stop=6700, decim=4, fout=12000
constexpr fir_taps_real<32> taps_6k0_decim_2 {
.low_frequency_normalized = -3000.0f / 48000.0f,
.high_frequency_normalized = 3000.0f / 48000.0f,
.transition_normalized = 3700.0f / 48000.0f,
.taps = { {
95, 178, 247, 208, -21, -474, -1080, -1640,
-1857, -1411, -83, 2134, 4978, 7946, 10413, 11815,
11815, 10413, 7946, 4978, 2134, -83, -1411, -1857,
-1640, -1080, -474, -21, 208, 247, 178, 95,
} },
};
// IFIR prototype filter fs=48000 ; pass=4500 (cutt off -3dBs) , stop=8000 (<-60dBs), decim=4, fout=12000
// For Europe AM commercial broadcasting stations in LF/MF/HF, Emissions Designator 9K00A3E Bandwidth: 9.00 kHz (derivated from taps_6k0_decim_2 )
// Pre-decimate LPF FIR filter design Created with SciPy Python with the "window method", num_taps = 32, cut_off = 5150. sample_rate = 48000 # Hz,
// Created with h = signal.firwin(num_taps, cut_off, nyq=sample_rate/2, window=('chebwin',50)) , achieving good STOP band plot < -60 dB's with some ripple.
// post-scaled h taps to avoid decimals , targeting <= similar int values as previous taps_6k0_dsb_channel peak < 32.767 (2 exp 15) and similar H(f)gain
constexpr fir_taps_real<32> taps_9k0_decim_2 {
.low_frequency_normalized = -4500.0f / 48000.0f, // Negative -cutt off freq -3dB (real achieved data ,in the plot and measurements)
.high_frequency_normalized = 4500.0f / 48000.0f, // Positive +cutt off freq -3dB (idem)
.transition_normalized = 3500.0f / 48000.0f, // 3500 Hz = (8000 Hz - 4500 Hz) (both from plot H(f) curve plot)
.taps = { {
-53, -30, 47, 198, 355, 372, 89, -535,
-1307, -1771, -1353, 370, 3384, 7109, 10535, 12591,
12591, 10535, 7109, 3384, 370, -1353, -1771, -1307,
-535, 89, 372, 355, 198, 47, -30, -53
} },
};
// Channel filter: fs=12000, pass=3000, stop=3300, decim=1, fout=12000
/* NOTE: Slightly less than 1.0 gain (normalized to 65536) due to max(taps) being
* slightly larger than 32767 (33312).
*/
constexpr fir_taps_complex<64> taps_6k0_dsb_channel {
.low_frequency_normalized = -3000.0f / 12000.0f,
.high_frequency_normalized = 3000.0f / 12000.0f,
.transition_normalized = 300.0f / 12000.0f,
.taps = { {
{ -69, 0 }, { -140, 0 }, { 119, 0 }, { 89, 0 },
{ -132, 0 }, { -134, 0 }, { 197, 0 }, { 167, 0 },
{ -273, 0 }, { -206, 0 }, { 372, 0 }, { 247, 0 },
{ -497, 0 }, { -289, 0 }, { 654, 0 }, { 331, 0 },
{ -854, 0 }, { -372, 0 }, { 1112, 0 }, { 411, 0 },
{ -1455, 0 }, { -446, 0 }, { 1933, 0 }, { 476, 0 },
{ -2654, 0 }, { -501, 0 }, { 3902, 0 }, { 520, 0 },
{ -6717, 0 }, { -531, 0 }, { 20478, 0 }, { 32767, 0 },
{ 20478, 0 }, { -531, 0 }, { -6717, 0 }, { 520, 0 },
{ 3902, 0 }, { -501, 0 }, { -2654, 0 }, { 476, 0 },
{ 1933, 0 }, { -446, 0 }, { -1455, 0 }, { 411, 0 },
{ 1112, 0 }, { -372, 0 }, { -854, 0 }, { 331, 0 },
{ 654, 0 }, { -289, 0 }, { -497, 0 }, { 247, 0 },
{ 372, 0 }, { -206, 0 }, { -273, 0 }, { 167, 0 },
{ 197, 0 }, { -134, 0 }, { -132, 0 }, { 89, 0 },
{ 119, 0 }, { -140, 0 }, { -69, 0 }, { 0, 0 },
} },
};
// Channel filter: fs=12000, pass=4500 (cutt off -3dBs), stop=4940 (<-60dBs), decim=1, fout=12000 (*1) real frec pass / stop , based on plotted H(f) curve)
// For Europe AM commercial broadcasting stations in LF/MF/HF, Emissions Designator 9K00A3E Bandwidth: 9.00 kHz (derivative from taps_6k0_dsb_channel)
// FIR filter design created with SciPy Python using "window method"; selected design parameters: num_taps = 64, cut_off = 4575. sample_rate = 12000 # Hz,
// Created with : h = signal.firwin(num_taps, cut_off, nyq=sample_rate/2, window=('chebwin',50)) , achieving real plot curve (*1) with peak stop band ripple -60dBs.
// post-scaled h taps to avoid decimals , targeting <= similar int values as previous taps_6k0_dsb_channel peak < 32.767 (2 exp 15), (29625) and similar H(f)gain
constexpr fir_taps_complex<64> taps_9k0_dsb_channel {
.low_frequency_normalized = -4500.0f / 12000.0f, // Negative -cutt off freq -3dB (in the H(f) curve plot)
.high_frequency_normalized = 4500.0f / 12000.0f, // Positive +cutt off freq -3dB (in the H(f) curve plot)
.transition_normalized = 440.0f / 12000.0f, // 440Hz = (4940 Hz -4500 Hz) cut-3dB's (both data comes from H(f) curve plot and confirmed by measurements )
.taps = { {
{ 2, 0 }, { -18, 0 }, { 34, 0 }, { -33, 0 },
{ 6, 0 }, { 44, 0 }, { -91, 0 }, { 96, 0 },
{ -35, 0 }, { -80, 0 }, { 193, 0 }, { -223, 0 },
{ 116, 0 }, { 112, 0 }, { -353, 0 }, { 452, 0 },
{ -293, 0 }, { -111, 0 }, { 584, 0 }, { -844, 0 },
{ 653, 0 }, { 22, 0 }, { -921, 0 }, { 1554, 0 },
{ -1422, 0 }, { 301, 0 }, { 1533, 0 }, { -3282, 0 },
{ 3804, 0 }, { -1819, 0 }, { -4605, 0 }, { 29625, 0 },
{ 29625, 0 }, { -4605, 0 }, { -1819, 0 }, { 3804, 0 },
{ -3282, 0 }, { 1533, 0 }, { 301, 0 }, { -1422, 0 },
{ 1554, 0 }, { -921, 0 }, { 22, 0 }, { 653, 0 },
{ -844, 0 }, { 584, 0 }, { -111, 0 }, { -293, 0 },
{ 452, 0 }, { -353, 0 }, { 112, 0 }, { 116, 0 },
{ -223, 0 }, { 193, 0 }, { -80, 0 }, { -35, 0 },
{ 96, 0 }, { -91, 0 }, { 44, 0 }, { 6, 0 },
{ -33, 0 }, { 34, 0 }, { -18, 0 }, { 2, 0 },
} },
};
// USB AM 2K80J3E emission type ///////////////////////////////////////////
// IFIR prototype filter: fs=12000, pass=3000, stop=3300, decim=1, fout=12000
constexpr fir_taps_complex<64> taps_2k8_usb_channel {
.low_frequency_normalized = 0,
.high_frequency_normalized = 3000.0f / 12000.0f,
.transition_normalized = 300.0f / 12000.0f,
.taps = { {
{ -146, 0 }, { -41, -45 }, { -1, 10 }, { -95, 69 },
{ -194, -41 }, { -91, -158 }, { 14, -43 }, { -150, 67 },
{ -299, -133 }, { -100, -307 }, { 50, -86 }, { -254, 54 },
{ -453, -329 }, { -62, -587 }, { 170, -189 }, { -334, 0 },
{ -580, -645 }, { 104, -986 }, { 418, -304 }, { -412, -88 },
{ -680, -1178 }, { 527, -1623 }, { 970, -432 }, { -441, -196 },
{ -698, -2149 }, { 1617, -2800 }, { 2384, -507 }, { -429, -311 },
{ -545, -5181 }, { 6925, -7691 }, { 14340, 0 }, { 10601, 11773 },
{ -1499, 14261 }, { -8373, 6083 }, { -5095, -1083 }, { -265, -459 },
{ -753, 2318 }, { -2954, 1315 }, { -2064, -919 }, { -149, -459 },
{ -531, 920 }, { -1669, 355 }, { -1100, -800 }, { -44, -419 },
{ -346, 384 }, { -992, 0 }, { -580, -645 }, { 35, -332 },
{ -205, 149 }, { -577, -123 }, { -280, -485 }, { 80, -247 },
{ -91, 40 }, { -294, -131 }, { -101, -312 }, { 82, -142 },
{ -44, 9 }, { -147, -107 }, { -21, -197 }, { 79, -88 },
{ 10, 0 }, { -41, -45 }, { 15, -145 }, { 0, 0 },
} },
};
// LSB AM 2K80J3E emission type ///////////////////////////////////////////
// IFIR prototype filter: fs=12000, pass=3000, stop=3300, decim=1, fout=12000
constexpr fir_taps_complex<64> taps_2k8_lsb_channel {
.low_frequency_normalized = -3000.0f / 12000.0f,
.high_frequency_normalized = 0,
.transition_normalized = 300.0f / 12000.0f,
.taps = { {
{ -146, 0 }, { -41, 45 }, { -1, -10 }, { -95, -69 },
{ -194, 41 }, { -91, 158 }, { 14, 43 }, { -150, -67 },
{ -299, 133 }, { -100, 307 }, { 50, 86 }, { -254, -54 },
{ -453, 329 }, { -62, 587 }, { 170, 189 }, { -334, 0 },
{ -580, 645 }, { 104, 986 }, { 418, 304 }, { -412, 88 },
{ -680, 1178 }, { 527, 1623 }, { 970, 432 }, { -441, 196 },
{ -698, 2149 }, { 1617, 2800 }, { 2384, 507 }, { -429, 311 },
{ -545, 5181 }, { 6925, 7691 }, { 14340, 0 }, { 10601, -11773 },
{ -1499, -14261 }, { -8373, -6083 }, { -5095, 1083 }, { -265, 459 },
{ -753, -2318 }, { -2954, -1315 }, { -2064, 919 }, { -149, 459 },
{ -531, -920 }, { -1669, -355 }, { -1100, 800 }, { -44, 419 },
{ -346, -384 }, { -992, 0 }, { -580, 645 }, { 35, 332 },
{ -205, -149 }, { -577, 123 }, { -280, 485 }, { 80, 247 },
{ -91, -40 }, { -294, 131 }, { -101, 312 }, { 82, 142 },
{ -44, -9 }, { -147, 107 }, { -21, 197 }, { 79, 88 },
{ 10, 0 }, { -41, 45 }, { 15, 145 }, { 0, 0 },
} },
};
// USB AM 700Hz filter: fs=12000, start=600, end=800, width=200, stop=40db, decim=1, fout=12000
constexpr fir_taps_complex<64> taps_0k7_usb_channel {
.low_frequency_normalized = 600.0f / 12000.0f,
.high_frequency_normalized = 800.0f / 12000.0f,
.transition_normalized = 200.0f / 12000.0f,
.taps = { {
{ 531, 0 }, { 192, 73 }, { 181, 163 }, { 129, 254 },
{ 34, 328 }, { -97, 364 }, { -251, 345 }, { -403, 261 },
{ -524, 111 }, { -585, -92 }, { -564, -326 }, { -448, -554 },
{ -239, -737 }, { 43, -836 }, { 366, -822 }, { 681, -681 },
{ 936, -417 }, { 1085, -56 }, { 1090, 354 }, { 935, 757 },
{ 629, 1090 }, { 205, 1296 }, { -283, 1331 }, { -766, 1180 },
{ -1172, 851 }, { -1435, 384 }, { -1510, -158 }, { -1377, -702 },
{ -1049, -1165 }, { -568, -1480 }, { 0, -1596 }, { 574, -1496 },
{ 1072, -1191 }, { 1422, -724 }, { 1576, -165 }, { 1515, 406 },
{ 1251, 908 }, { 827, 1273 }, { 309, 1453 }, { -226, 1431 },
{ -703, 1218 }, { -1058, 856 }, { -1248, 405 }, { -1257, -65 },
{ -1100, -489 }, { -810, -810 }, { -441, -992 }, { -53, -1024 },
{ 297, -916 }, { 566, -699 }, { 725, -418 }, { 765, -121 },
{ 697, 148 }, { 546, 355 }, { 348, 479 }, { 138, 517 },
{ -50, 477 }, { -194, 381 }, { -280, 252 }, { -308, 118 },
{ -285, 0 }, { -228, -87 }, { -153, -138 }, { -241, -473 },
} },
};
// WFM 200KF8E emission type //////////////////////////////////////////////
// IFIR image-reject filter: fs=3072000, pass=100000, stop=484000, decim=4, fout=768000
constexpr fir_taps_real<24> taps_200k_wfm_decim_0 = {
.low_frequency_normalized = -100000.0f / 3072000.0f,
.high_frequency_normalized = 100000.0f / 3072000.0f,
.transition_normalized = 384000.0f / 3072000.0f,
.taps = { {
48, -18, -151, -364, -557, -548, -139, 789,
2187, 3800, 5230, 6071, 6071, 5230, 3800, 2187,
789, -139, -548, -557, -364, -151, -18, 48,
} },
};
// IFIR prototype filter: fs=768000, pass=100000, stop=284000, decim=2, fout=384000
constexpr fir_taps_real<16> taps_200k_wfm_decim_1 = {
.low_frequency_normalized = -100000.0f / 768000.0f,
.high_frequency_normalized = 100000.0f / 768000.0f,
.transition_normalized = 184000.0f / 768000.0f,
.taps = { {
-67, -123, 388, 622, -1342, -2185, 4599, 14486,
14486, 4599, -2185, -1342, 622, 388, -123, -67,
} },
};
/* Wideband audio filter */
/* 96kHz int16_t input
* -> FIR filter, <15kHz (0.156fs) pass, >19kHz (0.198fs) stop
* -> 48kHz int16_t output, gain of 1.0 (I think).
* Padded to multiple of four taps for unrolled FIR code.
* sum(abs(taps)): 125270
*/
constexpr fir_taps_real<64> taps_64_lp_156_198 {
.low_frequency_normalized = -0.156f,
.high_frequency_normalized = 0.156f,
.transition_normalized = 0.04f,
.taps = { {
-27, 166, 104, -36, -174, -129, 109, 287,
148, -232, -430, -130, 427, 597, 49, -716,
-778, 137, 1131, 957, -493, -1740, -1121, 1167,
2733, 1252, -2633, -4899, -1336, 8210, 18660, 23254,
18660, 8210, -1336, -4899, -2633, 1252, 2733, 1167,
-1121, -1740, -493, 957, 1131, 137, -778, -716,
49, 597, 427, -130, -430, -232, 148, 287,
109, -129, -174, -36, 104, 166, -27, 0,
} },
};
// WFM 180kHZ General purpose filter with sharp transition , it improves Commercial WFM S/N in weak signals //////////////////////////////////////////////
// IFIR image-reject filter: fs=3072000, pass=90000, stop=250000, decim=4, fout=768000
constexpr fir_taps_real<24> taps_180k_wfm_decim_0 = {
.low_frequency_normalized = -90000.0f / 3072000.0f,
.high_frequency_normalized = 90000.0f / 3072000.0f,
.transition_normalized = 160000.0f / 3072000.0f,
.taps = { {
55, 122, 244, 424, 666, 965, 1308, 1669,
2019, 2321, 2544, 2663, 2663, 2544, 2321, 2019,
1669, 1308, 965, 666, 424, 244, 122, 55,
} },
};
// IFIR prototype filter: fs=768000, pass=90000, stop=110000, decim=2, fout=384000
constexpr fir_taps_real<16> taps_180k_wfm_decim_1 = {
.low_frequency_normalized = -90000.0f / 768000.0f,
.high_frequency_normalized = 90000.0f / 768000.0f,
.transition_normalized = 20000.0f / 768000.0f,
.taps = { {
55, 19, -356, -916, -529, 2139, 6695, 10392,
10392, 6695, 2139, -529, -916, -356, 19, 55,
} },
};
// WFM 40kHZ filter for NOAA APT reception in 137Mhz band with sharp transition //////////////////////////////////////////////
// IFIR image-reject filter: fs=3072000, pass=20000, stop=97000, decim=4, fout=768000
constexpr fir_taps_real<24> taps_40k_wfm_decim_0 = {
.low_frequency_normalized = -20000.0f / 3072000.0f,
.high_frequency_normalized = 20000.0f / 3072000.0f,
.transition_normalized = 67000.0f / 3072000.0f,
.taps = { {
46, 112, 230, 408, 650, 953, 1301, 1671,
2029, 2340, 2570, 2692, 2692, 2570, 2340, 2029,
1671, 1301, 953, 650, 408, 230, 112, 46,
} },
};
// IFIR prototype filter: fs=768000, pass=20000, stop=55000, decim=2, fout=384000
constexpr fir_taps_real<16> taps_40k_wfm_decim_1 = {
.low_frequency_normalized = -20000.0f / 768000.0f,
.high_frequency_normalized = 20000.0f / 768000.0f,
.transition_normalized = 35000.0f / 768000.0f,
.taps = { {
83, 299, 743, 1456, 2396, 3418, 4297, 4808,
4808, 4297, 3418, 2396, 1456, 743, 299, 83,
} },
};
// TPMS decimation filters ////////////////////////////////////////////////
// IFIR image-reject filter: fs=2457600, pass=100000, stop=407200, decim=4, fout=614400
static constexpr fir_taps_real<24> taps_200k_decim_0 = {
.low_frequency_normalized = -100000.0f / 2457600.0f,
.high_frequency_normalized = 100000.0f / 2457600.0f,
.transition_normalized = 307200.0f / 2457600.0f,
.taps = { {
90, 94, 4, -240, -570, -776, -563, 309,
1861, 3808, 5618, 6710, 6710, 5618, 3808, 1861,
309, -563, -776, -570, -240, 4, 94, 90,
} },
};
// IFIR prototype filter: fs=614400, pass=100000, stop=207200, decim=2, fout=307200
static constexpr fir_taps_real<16> taps_200k_decim_1 = {
.low_frequency_normalized = -100000.0f / 614400.0f,
.high_frequency_normalized = 100000.0f / 614400.0f,
.transition_normalized = 107200.0f / 614400.0f,
.taps = { {
-132, -256, 545, 834, -1507, -2401, 4666, 14583,
14583, 4666, -2401, -1507, 834, 545, -256, -132,
} },
};
#endif/*__DSP_FIR_TAPS_H__*/
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