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https://github.com/ttrftech/NanoVNA.git
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a2d90a5e91
Use int64_t acc for values Use double on calculation Not cache freq on si5351_set_frequency_with_offset (to fast change in rare cases on cw mode, and process wrong DSP block) as i write before need change DSP delay tactic
141 lines
3.9 KiB
C
141 lines
3.9 KiB
C
/*
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* Copyright (c) 2014-2015, TAKAHASHI Tomohiro (TTRFTECH) edy555@gmail.com
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* All rights reserved.
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*
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* This is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 3, or (at your option)
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* any later version.
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*
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* The software is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with GNU Radio; see the file COPYING. If not, write to
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* the Free Software Foundation, Inc., 51 Franklin Street,
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* Boston, MA 02110-1301, USA.
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*/
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#include <arm_math.h>
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#include "nanovna.h"
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#ifdef ENABLED_DUMP
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int16_t samp_buf[SAMPLE_LEN];
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int16_t ref_buf[SAMPLE_LEN];
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#endif
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const int16_t sincos_tbl[48][2] = {
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{ 10533, 31029 }, { 27246, 18205 }, { 32698, -2143 }, { 24636, -21605 },
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{ 6393, -32138 }, {-14493, -29389 }, {-29389, -14493 }, {-32138, 6393 },
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{-21605, 24636 }, { -2143, 32698 }, { 18205, 27246 }, { 31029, 10533 },
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{ 31029, -10533 }, { 18205, -27246 }, { -2143, -32698 }, {-21605, -24636 },
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{-32138, -6393 }, {-29389, 14493 }, {-14493, 29389 }, { 6393, 32138 },
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{ 24636, 21605 }, { 32698, 2143 }, { 27246, -18205 }, { 10533, -31029 },
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{-10533, -31029 }, {-27246, -18205 }, {-32698, 2143 }, {-24636, 21605 },
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{ -6393, 32138 }, { 14493, 29389 }, { 29389, 14493 }, { 32138, -6393 },
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{ 21605, -24636 }, { 2143, -32698 }, {-18205, -27246 }, {-31029, -10533 },
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{-31029, 10533 }, {-18205, 27246 }, { 2143, 32698 }, { 21605, 24636 },
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{ 32138, 6393 }, { 29389, -14493 }, { 14493, -29389 }, { -6393, -32138 },
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{-24636, -21605 }, {-32698, -2143 }, {-27246, 18205 }, {-10533, 31029 }
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};
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int64_t acc_samp_s;
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int64_t acc_samp_c;
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int64_t acc_ref_s;
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int64_t acc_ref_c;
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void
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dsp_process(int16_t *capture, size_t length)
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{
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uint32_t i;
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#if 1
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acc_samp_s = 0;
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acc_samp_c = 0;
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acc_ref_s = 0;
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acc_ref_c = 0;
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for (i = 0; i < length; i+=2) {
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int32_t ref = capture[i+0];
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int32_t smp = capture[i+1];
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#ifdef ENABLED_DUMP
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ref_buf[i] = ref;
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samp_buf[i] = smp;
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#endif
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int32_t s = ((int16_t *)sincos_tbl)[i+0];
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int32_t c = ((int16_t *)sincos_tbl)[i+1];
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acc_samp_s += (smp * s);
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acc_samp_c += (smp * c);
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acc_ref_s += (ref * s);
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acc_ref_c += (ref * c);
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}
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#else
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uint32_t len = length / 2;
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int64_t samp_s = 0;
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int64_t samp_c = 0;
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int64_t ref_s = 0;
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int64_t ref_c = 0;
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// HI LO
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int32_t *cos_sin = (int32_t *)sincos_tbl;
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int32_t *ref_smp = (int32_t *)capture;
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for (i = 0; i < len; i++) {
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//
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samp_s = __SMLALBB(*ref_smp, *cos_sin, samp_s); // samp_s+= smp * sin
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samp_c = __SMLALBT(*ref_smp, *cos_sin, samp_c); // samp_c+= smp * cos
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ref_s = __SMLALTB(*ref_smp, *cos_sin, ref_s); // ref_s += ref * sin
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ref_c = __SMLALTT(*ref_smp, *cos_sin, ref_c); // ref_s += ref * cos
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ref_smp++;
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cos_sin++;
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}
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acc_samp_s = samp_s;
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acc_samp_c = samp_c;
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acc_ref_s = ref_s;
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acc_ref_c = ref_c;
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#endif
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}
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void
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calculate_gamma(float gamma[2])
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{
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#if 1
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// calculate reflection coeff. by samp divide by ref
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double rs = acc_ref_s;
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double rc = acc_ref_c;
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double rr = rs * rs + rc * rc;
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//rr = sqrtf(rr) * 1e8;
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double ss = acc_samp_s;
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double sc = acc_samp_c;
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gamma[0] = (sc * rc + ss * rs) / rr;
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gamma[1] = (ss * rc - sc * rs) / rr;
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#elif 0
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gamma[0] = acc_samp_s;
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gamma[1] = acc_samp_c;
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#else
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gamma[0] = acc_ref_s;
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gamma[1] = acc_ref_c;
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#endif
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}
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void
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fetch_amplitude(float gamma[2])
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{
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gamma[0] = acc_samp_s * 1e-9;
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gamma[1] = acc_samp_c * 1e-9;
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}
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void
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fetch_amplitude_ref(float gamma[2])
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{
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gamma[0] = acc_ref_s * 1e-9;
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gamma[1] = acc_ref_c * 1e-9;
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}
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void
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reset_dsp_accumerator(void)
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{
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acc_ref_s = 0;
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acc_ref_c = 0;
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acc_samp_s = 0;
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acc_samp_c = 0;
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}
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