Always measure noise power, silently ignore --measure-noise if given.

convert.c

@@ -26,38 +26,7 @@ struct converter_state {
     float z1_Q;
 };
 
-static void convert_uc8_nodc_nopower(void *iq_data,
+static void convert_uc8_nodc(void *iq_data,
-                                     uint16_t *mag_data,
-                                     unsigned nsamples,
-                                     struct converter_state *state,
-                                     double *out_power)
-{
-    uint16_t *in = iq_data;
-    unsigned i;
-
-    MODES_NOTUSED(state);
-
-    // unroll this a bit
-    for (i = 0; i < (nsamples>>3); ++i) {
-        *mag_data++ = Modes.maglut[*in++];
-        *mag_data++ = Modes.maglut[*in++];
-        *mag_data++ = Modes.maglut[*in++];
-        *mag_data++ = Modes.maglut[*in++];
-        *mag_data++ = Modes.maglut[*in++];
-        *mag_data++ = Modes.maglut[*in++];
-        *mag_data++ = Modes.maglut[*in++];
-        *mag_data++ = Modes.maglut[*in++];
-    }
-
-    for (i = 0; i < (nsamples&7); ++i) {
-        *mag_data++ = Modes.maglut[*in++];
-    }
-
-    if (out_power)
-        *out_power = 0.0; // not measured
-}
-
-static void convert_uc8_nodc_power(void *iq_data,
                              uint16_t *mag_data,
                              unsigned nsamples,
                              struct converter_state *state,
@@ -251,23 +220,20 @@ static void convert_sc16q11_generic(void *iq_data,
 static struct {
     input_format_t format;
     int can_filter_dc;
-    int can_compute_power;
     iq_convert_fn fn;
     const char *description;
 } converters_table[] = {
     // In order of preference
-    { INPUT_UC8,     0, 0, convert_uc8_nodc_nopower, "UC8, integer/table path" },
+    { INPUT_UC8,     0, convert_uc8_nodc,         "UC8, integer/table path" },
-    { INPUT_UC8,     0, 1, convert_uc8_nodc_power,   "UC8, integer/table path, with power measurement" },
+    { INPUT_UC8,     1, convert_uc8_generic,      "UC8, float path" },
-    { INPUT_UC8,     1, 1, convert_uc8_generic,      "UC8, float path" },
+    { INPUT_SC16,    1, convert_sc16_generic,     "SC16, float path" },
-    { INPUT_SC16,    1, 1, convert_sc16_generic,     "SC16, float path" },
+    { INPUT_SC16Q11, 1, convert_sc16q11_generic,  "SC16Q11, float path" },
-    { INPUT_SC16Q11, 1, 1, convert_sc16q11_generic,  "SC16Q11, float path" },
+    { 0, 0, NULL, NULL }
-    { 0, 0, 0, NULL, NULL }
 };
 
 iq_convert_fn init_converter(input_format_t format,
                              double sample_rate,
                              int filter_dc,
-                             int compute_power,
                              struct converter_state **out_state)
 {
     int i;
@@ -277,14 +243,12 @@ iq_convert_fn init_converter(input_format_t format,
             continue;
         if (filter_dc && !converters_table[i].can_filter_dc)
             continue;
-        if (compute_power && !converters_table[i].can_compute_power)
-            continue;
         break;
     }
 
     if (!converters_table[i].fn) {
-        fprintf(stderr, "no suitable converter for format=%d power=%d dc=%d\n",
+        fprintf(stderr, "no suitable converter for format=%d dc=%d\n",
-                format, compute_power, filter_dc);
+                format, filter_dc);
         return NULL;
     }
 

convert.h

@@ -32,7 +32,6 @@ typedef void (*iq_convert_fn)(void *iq_data,
 iq_convert_fn init_converter(input_format_t format,
                              double sample_rate,
                              int filter_dc,
-                             int compute_power,
                              struct converter_state **out_state);
 
 void cleanup_converter(struct converter_state *state);

demod_2400.c

@@ -423,8 +423,8 @@ void demodulate2400(struct mag_buf *mag)
         useModesMessage(&mm);
     }
 
-    /* update noise power if measured */
+    /* update noise power */
-    if (Modes.measure_noise) {
+    {
         double sum_signal_power = sum_scaled_signal_power / 65535.0 / 65535.0;
         Modes.stats_current.noise_power_sum += (mag->total_power - sum_signal_power);
         Modes.stats_current.noise_power_count += mag->length;

dump1090.c

@@ -256,7 +256,6 @@ void modesInit(void) {
         Modes.converter_function = init_converter(Modes.input_format,
                                                   Modes.sample_rate,
                                                   Modes.dc_filter,
-                                                  Modes.measure_noise, /* total power is interesting if we want noise */
                                                   &Modes.converter_state);
         if (!Modes.converter_function) {
             fprintf(stderr, "Can't initialize sample converter, giving up.\n");
@@ -723,7 +722,6 @@ void showHelp(void) {
 "--json-location-accuracy <n>  Accuracy of receiver location in json metadata: 0=no location, 1=approximate, 2=exact\n"
 "--oversample             Use the 2.4MHz demodulator\n"
 "--dcfilter               Apply a 1Hz DC filter to input data (requires lots more CPU)\n"
-"--measure-noise          Measure noise power (requires slightly more CPU)\n"
 "--help                   Show this help\n"
 "\n"
 "Debug mode flags: d = Log frames decoded with errors\n"
@@ -955,7 +953,7 @@ int main(int argc, char **argv) {
         } else if (!strcmp(argv[j],"--dcfilter")) {
             Modes.dc_filter = 1;
         } else if (!strcmp(argv[j],"--measure-noise")) {
-            Modes.measure_noise = 1;
+            // Ignored
         } else if (!strcmp(argv[j],"--fix")) {
             Modes.nfix_crc = 1;
         } else if (!strcmp(argv[j],"--no-fix")) {

dump1090.h

@@ -253,7 +253,6 @@ struct {                             // Internal state
 
     // Sample conversion
     int            dc_filter;        // should we apply a DC filter?
-    int            measure_noise;    // should we measure noise power?
     iq_convert_fn  converter_function;
     struct converter_state *converter_state;