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https://github.com/ttrftech/NanoVNA.git
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Add limited variable offset support, and constant sin_cos tables for various offset and ADC speed
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DiSlord
parent
018b9c7776
commit
c322d5e3cb
124
dsp.c
124
dsp.c
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@ -26,22 +26,7 @@ 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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#if 1
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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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#else
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#ifdef USE_VARIABLE_OFFSET
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int16_t sincos_tbl[AUDIO_SAMPLES_COUNT][2];
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void generate_DSP_Table(int offset){
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float audio_freq = AUDIO_ADC_FREQ;
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@ -56,15 +41,66 @@ void generate_DSP_Table(int offset){
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v+=step;
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}
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}
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#elif FREQUENCY_OFFSET==5000*(AUDIO_ADC_FREQ/AUDIO_SAMPLES_COUNT/1000)
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// static Table for 10kHz IF and 96kHz ADC (or 5kHz IF and 48kHz ADC) audio ADC
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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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#elif FREQUENCY_OFFSET==4000*(AUDIO_ADC_FREQ/AUDIO_SAMPLES_COUNT/1000)
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// static Table for 8kHz IF and 96kHz audio ADC (or 4kHz IF and 48kHz ADC) audio ADC
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const int16_t sincos_tbl[48][2] = {
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{ 4277, 32488}, { 19948, 25997}, { 30274, 12540}, { 32488, -4277},
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{ 25997,-19948}, { 12540,-30274}, { -4277,-32488}, {-19948,-25997},
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{-30274,-12540}, {-32488, 4277}, {-25997, 19948}, {-12540, 30274},
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{ 4277, 32488}, { 19948, 25997}, { 30274, 12540}, { 32488, -4277},
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{ 25997,-19948}, { 12540,-30274}, { -4277,-32488}, {-19948,-25997},
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{-30274,-12540}, {-32488, 4277}, {-25997, 19948}, {-12540, 30274},
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{ 4277, 32488}, { 19948, 25997}, { 30274, 12540}, { 32488, -4277},
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{ 25997,-19948}, { 12540,-30274}, { -4277,-32488}, {-19948,-25997},
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{-30274,-12540}, {-32488, 4277}, {-25997, 19948}, {-12540, 30274},
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{ 4277, 32488}, { 19948, 25997}, { 30274, 12540}, { 32488, -4277},
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{ 25997,-19948}, { 12540,-30274}, { -4277,-32488}, {-19948,-25997},
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{-30274,-12540}, {-32488, 4277}, {-25997, 19948}, {-12540, 30274}
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};
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#elif FREQUENCY_OFFSET==3000*(AUDIO_ADC_FREQ/AUDIO_SAMPLES_COUNT/1000)
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// static Table for 6kHz IF and 96kHz audio ADC (or 3kHz IF and 48kHz ADC) audio ADC
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const int16_t sincos_tbl[48][2] = {
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{ 3212, 32610}, { 15447, 28899}, { 25330, 20788}, { 31357, 9512},
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{ 32610, -3212}, { 28899,-15447}, { 20788,-25330}, { 9512,-31357},
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{ -3212,-32610}, {-15447,-28899}, {-25330,-20788}, {-31357, -9512},
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{-32610, 3212}, {-28899, 15447}, {-20788, 25330}, { -9512, 31357},
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{ 3212, 32610}, { 15447, 28899}, { 25330, 20788}, { 31357, 9512},
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{ 32610, -3212}, { 28899,-15447}, { 20788,-25330}, { 9512,-31357},
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{ -3212,-32610}, {-15447,-28899}, {-25330,-20788}, {-31357, -9512},
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{-32610, 3212}, {-28899, 15447}, {-20788, 25330}, { -9512, 31357},
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{ 3212, 32610}, { 15447, 28899}, { 25330, 20788}, { 31357, 9512},
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{ 32610, -3212}, { 28899,-15447}, { 20788,-25330}, { 9512,-31357},
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{ -3212,-32610}, {-15447,-28899}, {-25330,-20788}, {-31357, -9512},
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{-32610, 3212}, {-28899, 15447}, {-20788, 25330}, { -9512, 31357}
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};
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#else
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#error "Need check/rebuild sin cos table for DAC"
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#endif
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#if 1
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// Define DSP accumulator value type
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typedef float acc_t;
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typedef float measure_t;
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acc_t acc_samp_s;
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acc_t acc_samp_c;
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acc_t acc_ref_s;
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acc_t acc_ref_c;
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#if 1
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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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@ -95,16 +131,25 @@ dsp_process(int16_t *capture, size_t length)
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}
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#else
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// Define DSP accumulator value type
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typedef int64_t acc_t;
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typedef float measure_t;
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acc_t acc_samp_s;
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acc_t acc_samp_c;
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acc_t acc_ref_s;
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acc_t acc_ref_c;
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// Cortex M4 DSP instruction use
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#include "dsp.h"
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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 = 0;
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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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// 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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i=0;
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do{
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int32_t sc = ((int32_t *)sincos_tbl)[i];
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int32_t sr = ((int32_t *)capture)[i];
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@ -114,17 +159,18 @@ dsp_process(int16_t *capture, size_t length)
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// ref_s = __smlabb(sr, sc, ref_s); // ref_s+= ref * sin
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// ref_c = __smlabt(sr, sc, ref_c); // ref_s+= ref * cos
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// int64_t acc DSP functions
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samp_s= __smlaltb(samp_s, sr, sc ); // samp_s+= smp * sin
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samp_c= __smlaltt(samp_c, sr, sc ); // samp_c+= smp * cos
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ref_s = __smlalbb( ref_s, sr, sc ); // ref_s+= ref * sin
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ref_c = __smlalbt( ref_c, sr, sc ); // ref_s+= ref * cos
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acc_samp_s= __smlaltb(acc_samp_s, sr, sc ); // samp_s+= smp * sin
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acc_samp_c= __smlaltt(acc_samp_c, sr, sc ); // samp_c+= smp * cos
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acc_ref_s = __smlalbb( acc_ref_s, sr, sc ); // ref_s+= ref * sin
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acc_ref_c = __smlalbt( acc_ref_c, sr, sc ); // ref_s+= ref * cos
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i++;
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} while (i < length/2);
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// Accumulate result, for faster calc and prevent overflow reduce size to int32_t
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acc_samp_s+= (int32_t)(samp_s>>3);
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acc_samp_c+= (int32_t)(samp_c>>3);
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acc_ref_s += (int32_t)( ref_s>>3);
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acc_ref_c += (int32_t)( ref_c>>3);
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// acc_samp_s+= (int32_t)(samp_s>>4);
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// acc_samp_c+= (int32_t)(samp_c>>4);
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// acc_ref_s += (int32_t)( ref_s>>4);
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// acc_ref_c += (int32_t)( ref_c>>4);
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}
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#endif
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@ -134,19 +180,19 @@ calculate_gamma(float gamma[2])
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#if 1
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// calculate reflection coeff. by samp divide by ref
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#if 0
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float rs = acc_ref_s;
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float rc = acc_ref_c;
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float rr = rs * rs + rc * rc;
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measure_t rs = acc_ref_s;
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measure_t rc = acc_ref_c;
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measure_t rr = rs * rs + rc * rc;
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//rr = sqrtf(rr) * 1e8;
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float ss = acc_samp_s;
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float sc = acc_samp_c;
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measure_t ss = acc_samp_s;
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measure_t 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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#else
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float rs_rc = (float) acc_ref_s / acc_ref_c;
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float sc_rc = (float)acc_samp_c / acc_ref_c;
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float ss_rc = (float)acc_samp_s / acc_ref_c;
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float rr = rs_rc * rs_rc + 1.0;
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measure_t rs_rc = (measure_t) acc_ref_s / acc_ref_c;
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measure_t sc_rc = (measure_t)acc_samp_c / acc_ref_c;
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measure_t ss_rc = (measure_t)acc_samp_s / acc_ref_c;
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measure_t rr = rs_rc * rs_rc + 1.0;
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gamma[0] = (sc_rc + ss_rc*rs_rc) / rr;
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gamma[1] = (ss_rc - sc_rc*rs_rc) / rr;
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#endif
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