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cnlohr
82 lines
2.2 KiB
C
82 lines
2.2 KiB
C
#include <stdio.h>
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#include <math.h>
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#include <stdint.h>
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uint32_t g_goertzel_omega_per_sample;
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uint32_t g_goertzel_coefficient;
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int32_t g_goertzel_coefficient_s;
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uint32_t g_goertzel_samples;
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uint32_t g_goertzel_outs;
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int32_t g_goertzelp, g_goertzelp2;
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int32_t g_goertzelp_store, g_goertzelp2_store;
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int main()
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{
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g_goertzel_omega_per_sample = 1.0/128 * 3.14159*2.0*65536;
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g_goertzel_coefficient = 2 * cos( g_goertzel_omega_per_sample / 65536.0 ) * 65536;
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g_goertzel_coefficient_s = 2 * sin( g_goertzel_omega_per_sample / 65536.0 ) * 65536;
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g_goertzelp = g_goertzel_omega_per_sample;
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int32_t goertzel_coefficient = g_goertzel_coefficient;
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int32_t goertzelp2 = g_goertzelp2;
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int32_t goertzelp = g_goertzelp;
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uint32_t goertzel_samples = g_goertzel_samples;
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uint32_t adc_tail;
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int js = 0;
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for( js = 0; js < 256/4; js++ )
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{
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int32_t t; // 1/2 of 4096, to try to keep our numbers reasonable.
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// Here is where the magic happens.
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int32_t goertzel;
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#define ITERATION(x) \
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t = sin( (x+js*4) ) * 65536; \
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goertzel = t + ( ( (int64_t)(goertzel_coefficient) * goertzelp ) >> 16 ) - goertzelp2; \
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goertzelp2 = goertzelp; \
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goertzelp = goertzel; \
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\
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/*printf( "%d,%d,%d,%d\n", ( ( (int64_t)(goertzel_coefficient) * (int64_t)goertzelp ) >> 32 ) , goertzel_coefficient, goertzelp, goertzelp2 ); */ \
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\
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{\
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float coeff_s = /* 2 * sin( g_goertzel_omega_per_sample/65536.0f ); */ 65536; \
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int32_t rr = ((g_goertzel_coefficient/2 * (int64_t)goertzelp)>>16) - g_goertzelp2; \
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int32_t ri = ((g_goertzel_coefficient_s/2 * (int64_t)goertzelp)>>16); \
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printf( "%3d %9d %9d %9d %9d / %9d %9d %9d\n", js, rr, ri, goertzelp, goertzelp2, goertzel_coefficient, g_goertzel_omega_per_sample, t ); \
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}
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ITERATION( 0 );
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ITERATION( 1 );
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ITERATION( 2 );
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ITERATION( 3 );
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adc_tail+=4;
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goertzel_samples+=4;
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// if( adc_tail == adc_buffer_top ) adc_tail = adc_buffer;
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if( goertzel_samples == 128 )
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{
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g_goertzelp_store = goertzelp;
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g_goertzelp2_store = goertzelp2;
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goertzelp = 0;
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goertzelp2 = 0;
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g_goertzel_outs++;
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goertzel_samples = 0;
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}
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}
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g_goertzelp2 = goertzelp2;
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g_goertzelp = goertzelp;
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g_goertzel_samples = goertzel_samples;
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}
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