kopia lustrzana https://github.com/xaelsouth/rtl-wmbus
Simultaneous Frecuency shifting optimization
New center frecuency at 868,625. Uses one function to apply two complex rotations reusing calculations, should speed up in systems with limited resources. Help needed to profile the program and see if it really improves. Never done that. Requires new frequency step at 25Khz to get to the exact frequencies displacing 325khz up and down. Also made decimation float to test lower sample rates hoping it will require less computational power. Tested down to 1.15 decimation and 960000 (1.15*800khz)samples/s on S1 and C1 mode. Test 2.7 decimation and 2160000 sample rate (2.7*800khz) best rssi levels Test 3 decimation 2400000 sample rate, rssi decreasespull/20/head
alalons
GitHub
rodzic
686356d201
commit
e777c0f20d
70
rtl_wmbus.c
70
rtl_wmbus.c
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@ -574,7 +574,7 @@ static void time2_algorithm_s1(unsigned bit, unsigned rssi, struct time2_algorit
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static int opts_run_length_algorithm_enabled = 1;
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static int opts_time2_algorithm_enabled = 1;
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static unsigned opts_decimation_rate = 2u;
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static float opts_decimation_rate = 2;
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static int opts_s1_t1_c1_simultaneously = 0;
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int opts_show_used_algorithm = 0;
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static const unsigned opts_CLOCK_LOCK_THRESHOLD_T1_C1 = 2;
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@ -588,7 +588,7 @@ static void print_usage(const char *program_name)
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fprintf(stdout, "\t-t 0 to disable time2 algorithm\n");
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fprintf(stdout, "\t-d 2 set decimation rate to 2 (defaults to 2 if omitted)\n");
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fprintf(stdout, "\t-v show used algorithm in the output\n");
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fprintf(stdout, "\t-s receive S1 and T1/C1 datagrams simultaneously. rtl_sdr _MUST_ be set to 868.7MHz (-f 868.7M)\n");
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fprintf(stdout, "\t-s receive S1 and T1/C1 datagrams simultaneously. rtl_sdt _MUST_ be set to 868.7MHz\n");
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}
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@ -623,7 +623,7 @@ static void process_options(int argc, char *argv[])
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}
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break;
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case 'd':
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opts_decimation_rate = strtoul(optarg, NULL, 10);
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opts_decimation_rate = strtof(optarg, NULL);
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break;
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case 's':
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opts_s1_t1_c1_simultaneously = 1;
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@ -640,7 +640,7 @@ static void process_options(int argc, char *argv[])
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static float complex *LUT_FREQUENCY_TRANSLATION_PLUS = NULL;
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static float complex *LUT_FREQUENCY_TRANSLATION_MINUS = NULL;
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#define FREQ_STEP_KHZ (50)
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#define FREQ_STEP_KHZ (25) //to acomodate symetric filter we need more resolution or maybe use floats
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/* fs_kHz is the sample rate in kHz. */
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void setup_lookup_tables_for_frequency_translation(int fs_kHz)
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@ -677,11 +677,13 @@ static void shift_freq_250(float *i, float *q, int fs_kHz)
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n++;
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#else
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const float complex freq_shift = LUT_FREQUENCY_TRANSLATION_PLUS[n];
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n += ft/FREQ_STEP_KHZ;
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#endif
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//fprintf(stdout, "%ld, %ld: %f, %f\n", n, n_max, crealf(freq_shift), cimagf(freq_shift));
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if (n >= n_max) n -= n_max;
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float complex s = (*i) + (*q) * _Complex_I;
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s = s * freq_shift;
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@ -699,7 +701,9 @@ static void shift_freq_minus400(float *i, float *q, int fs_kHz)
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const float complex freq_shift = cosf(2.*M_PI*(ft*n)/fs_kHz) + sin(2.*M_PI*(ft*n)/fs_kHz) * _Complex_I;
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n++;
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#else
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const float complex freq_shift = LUT_FREQUENCY_TRANSLATION_MINUS[n];
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n += ft/FREQ_STEP_KHZ;
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#endif
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//fprintf(stdout, "%ld, %ld: %f, %f\n", n, n_max, crealf(freq_shift), cimagf(freq_shift));
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@ -712,15 +716,52 @@ static void shift_freq_minus400(float *i, float *q, int fs_kHz)
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*q = cimagf(s);
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}
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static void shift_freq_plus_minus325(float *iplus, float *qplus,float *iminus, float *qminus, int fs_kHz)
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{
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const int ft = 325;
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static size_t n = 0;
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const size_t n_max = fs_kHz/FREQ_STEP_KHZ;
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#if 0
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const float complex freq_shift = cosf(2.*M_PI*(ft*n)/fs_kHz) + sin(2.*M_PI*(ft*n)/fs_kHz) * _Complex_I;
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n++;
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#else
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const float x=crealf(LUT_FREQUENCY_TRANSLATION_PLUS[n]);
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const float z=cimagf(LUT_FREQUENCY_TRANSLATION_PLUS[n]);
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n += ft/FREQ_STEP_KHZ;
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#endif
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//fprintf(stdout, "%ld, %ld: %f, %f\n", n, n_max, crealf(freq_shift), cimagf(freq_shift));
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if (n >= n_max) n -= n_max;
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float ix,iz,qx,qz;
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//(i+Jq)*(x+Jz) =ix-qz+ J(qx+iz) positive rotation
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//(i+Jq)*(x-Jz) =ix+qz+ J(qx-iz) negative rotation
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ix=*iplus * x;
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qx=*qplus * x;
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iz=*iplus * z;
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qz=*qplus * z;
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//simetric negative shift
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*iminus=ix+qz;
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*qminus=qx-iz;
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//simetric positive shift
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*iplus=ix-qz;
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*qplus=qx+iz;
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}
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int main(int argc, char *argv[])
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{
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process_options(argc, argv);
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__attribute__((__aligned__(16))) uint8_t samples[4096];
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const int fs_kHz = opts_decimation_rate*800; // Sample rate [kHz] as a multiple of 800 kHz.
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const float fs_kHz = opts_decimation_rate*800; // Sample rate [kHz] as a multiple of 800 kHz.
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float i_t1_c1 = 0, q_t1_c1 = 0;
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float i_s1 = 0, q_s1 = 0;
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unsigned decimation_rate_index = 0;
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float decimation_rate_index = 0;
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int16_t old_clock_t1_c1 = INT16_MIN, old_clock_s1 = INT16_MIN;
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unsigned clock_lock_t1_c1 = 0, clock_lock_s1 = 0;
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@ -766,12 +807,10 @@ int main(int argc, char *argv[])
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for (size_t k = 0; k < sizeof(samples)/sizeof(samples[0]); k += 2) // +2 : i and q interleaved
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{
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const float i_unfilt = ((float)samples[k] - 127.5f);
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const float q_unfilt = ((float)samples[k + 1] - 127.5f);
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// rtl_sdr -f 868.35M -s 2400000 - 2>/dev/null | build/rtl_wmbus -d 3
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//shift_freq(&i_unfilt, &q_unfilt, 600, 2400);
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const float i_unfilt = ((float)samples[k] - 127.5);
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const float q_unfilt = ((float)samples[k + 1] - 127.5);
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float i_t1_c1_unfilt = i_unfilt;
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float q_t1_c1_unfilt = q_unfilt;
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@ -780,9 +819,7 @@ int main(int argc, char *argv[])
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if (opts_s1_t1_c1_simultaneously)
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{
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shift_freq_250(&i_t1_c1_unfilt, &q_t1_c1_unfilt, fs_kHz);
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shift_freq_minus400(&i_s1_unfilt, &q_s1_unfilt, fs_kHz);
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shift_freq_plus_minus325(&i_t1_c1_unfilt, &q_t1_c1_unfilt,&i_s1_unfilt, &q_s1_unfilt, fs_kHz);
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}
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// Low-Pass-Filtering before decimation is necessary, to ensure
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@ -823,7 +860,7 @@ int main(int argc, char *argv[])
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++decimation_rate_index;
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if (decimation_rate_index < opts_decimation_rate) continue;
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decimation_rate_index = 0;
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decimation_rate_index -= opts_decimation_rate;
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// Demodulate.
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const float _delta_phi_t1_c1 = polar_discriminator_t1_c1(i_t1_c1, q_t1_c1);
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@ -937,4 +974,3 @@ int main(int argc, char *argv[])
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free(LUT_FREQUENCY_TRANSLATION_MINUS);
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return EXIT_SUCCESS;
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}
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