Use ENBW in noise measurement

nanovna.h

@@ -1443,7 +1443,12 @@ extern void si_fm_offset(int16_t offset);
 extern bool ADF4351_frequency_changed;
 extern bool SI4463_frequency_changed;
 extern bool SI4463_offset_changed;
+extern int32_t SI4463_ENBW_Hz;
 extern int old_R;
 extern float Si446x_get_temp(void);
+#define ENBW_Hz    SI4463_ENBW_Hz
+#endif
+#ifdef TINYSA3
+#define ENBW_Hz    actual_rbw_x10*100;
 #endif
 /*EOF*/

plot.c

@@ -1430,8 +1430,8 @@ static void trace_print_value_string(     // Only used at one place
 //    *ptr2++  = 'N';
   *ptr2++ =  ' ';
   if (mtype & M_NOISE){
-//  v-= log10f(actual_rbw_x10*100.0) *  10.0;
+//  v-= log10f(ENBW_Hz) *  10.0;
-    v-=   logf(actual_rbw_x10*100.0) * (10.0/logf(10.0));
+    v-=   logf(ENBW_Hz) * (10.0/logf(10.0));
   }
   // Not possible ???
   if (v == -INFINITY){
@@ -1546,7 +1546,7 @@ static void cell_draw_marker_info(int x0, int y0)
         int ypos = 1 + (j/2)*(16) - y0;
         cell_printf(xpos, ypos, FONT_b"DEPTH: %3d%%", depth);
       } else if (setting.measurement == M_FM){
-        freq_t dev = markers[1].frequency + actual_rbw_x10 * 100;      // Temp value to prevent calculation of negative deviation
+        freq_t dev = markers[1].frequency + ENBW_Hz;      // Temp value to prevent calculation of negative deviation
         if ( markers[2].frequency < dev)
           break;
         dev = ( markers[2].frequency - dev ) >> 1;
@@ -1588,13 +1588,24 @@ static void cell_draw_marker_info(int x0, int y0)
         break;
       }
 #ifdef __NOISE_FIGURE__
-    } else if (i>=2 && setting.measurement == M_NF && markers[0].enabled && setting.external_gain != 0 ) {
+    } else if (i>=2 && setting.measurement == M_NF && markers[0].enabled) {
-      float mNF = marker_to_value(0) -  logf(actual_rbw_x10*100.0) * (10.0/logf(10.0)) + 174;   // measured noise figure at 18C
+      float aNP = 0;
+#if 1
+      for (int i =0; i < sweep_points; i++) {
+        aNP += actual_t[i];
+      }
+      aNP /= sweep_points;
+#else
+      aNP = marker_to_value(0);
+#endif
+      float mNF = aNP -  logf(ENBW_Hz) * (10.0/logf(10.0)) + 173.93;   // measured noise figure at 20C
+      if (setting.external_gain != 0) {
         float mnf = expf(mNF/10 * logf(10));     // measure noise factor
         float tnf = expf(config.noise_figure/10 * logf(10));     // tinySA noise factor
         float amp_gain = expf(setting.external_gain/10 * logf(10));
         float anf = mnf - (tnf - 1.0)/amp_gain;
-      float aNF = 10*logf(anf)/logf(10);
+        mNF = 10*logf(anf)/logf(10);
+      }
       // powf(10,x) =  expf(x * logf(10))
       // log10f(x)  =  logf(x)/logf(10)
 
@@ -1603,7 +1614,7 @@ static void cell_draw_marker_info(int x0, int y0)
 //        j = 1;
       int xpos = 1 + (j%2)*(WIDTH/2) + CELLOFFSETX - x0;
       int ypos = 1 + (j/2)*(16) - y0;
-      cell_printf(xpos, ypos, FONT_b"NF: %4.1f", aNF);
+      cell_printf(xpos, ypos, FONT_b"NF: %4.1f", mNF);
       break;
 #endif
     } else

sa_cmd.c

@@ -374,7 +374,7 @@ VNA_SHELL_FUNCTION(cmd_sweep_voltage)
 VNA_SHELL_FUNCTION(cmd_nf)
 {
   if (argc != 1) {
-    shell_printf("usage: nr {value}\r\n"\
+    shell_printf("usage: nf {value}\r\n"\
                  "%f\r\n", config.noise_figure);
     return;
   }

sa_core.c

@@ -4493,7 +4493,7 @@ static volatile int dummy;
 #endif
       }
 #ifdef __CHANNEL_POWER__
-      } else if (setting.measurement == M_CP || setting.measurement == M_SNR) {      // ----------------CHANNEL_POWER measurement
+      } else if (setting.measurement == M_CP || setting.measurement == M_SNR || setting.measurement == M_NF) {      // ----------------CHANNEL_POWER measurement
         freq_t bw = get_sweep_frequency(ST_SPAN)/3;
         int old_unit = setting.unit;
         setting.unit = U_WATT;

si4468.c

@@ -1517,25 +1517,27 @@ typedef struct {
   const uint8_t  *reg;                   // IF_BW(dwn3, ndec, filset)
   int16_t   RSSI_correction_x_10;  // Correction * 10
   int16_t RBWx10;                // RBW in kHz
+  int32_t ENBW_Hz;
 }RBW_t; // sizeof(RBW_t) = 8 bytes
 
 static const RBW_t RBW_choices[] =
 {
 // BW register    corr  freq
- {SI4463_RBW_02kHz, 15,3},
+ {SI4463_RBW_02kHz, 15,3,188},
- {SI4463_RBW_1kHz,  14,10},
+ {SI4463_RBW_1kHz,  14,10,1100},
- {SI4463_RBW_3kHz,  10,30},
+ {SI4463_RBW_3kHz,  10,30,3341},
- {SI4463_RBW_10kHz, 14,100},
+ {SI4463_RBW_10kHz, 14,100,10910},
- {SI4463_RBW_30kHz, 0,300},
+ {SI4463_RBW_30kHz, 0,300,32500},
- {SI4463_RBW_100kHz,0,1000},
+ {SI4463_RBW_100kHz,0,1000,106900},
- {SI4463_RBW_300kHz,1,3000},
+ {SI4463_RBW_300kHz,1,3000,342000},
- {SI4463_RBW_600kHz,11,6000},
+ {SI4463_RBW_600kHz,11,6000,640000},
- {SI4463_RBW_850kHz,11,8500},
+ {SI4463_RBW_850kHz,11,8500,877000},
 };
 
 const uint8_t SI4432_RBW_count = ((int)(sizeof(RBW_choices)/sizeof(RBW_t)));
 
 static pureRSSI_t SI4463_RSSI_correction = float_TO_PURE_RSSI(-120);
+int32_t SI4463_ENBW_Hz;
 static int prev_band = -1;
 
 pureRSSI_t getSI4463_RSSI_correction(void){
@@ -1561,6 +1563,7 @@ uint16_t force_rbw(int f)
   set_RSSI_comp();
 //  prev_band = -1;
   SI4463_RSSI_correction = float_TO_PURE_RSSI(RBW_choices[f].RSSI_correction_x_10 - 1200)/10;  // Set RSSI correction
+  SI4463_ENBW_Hz = RBW_choices[f].ENBW_Hz;
   return RBW_choices[f].RBWx10;                                                   // RBW achieved by SI4463 in kHz * 10
 }
 

ui_sa.c

@@ -1346,10 +1346,15 @@ static UI_FUNCTION_ADV_CALLBACK(menu_measure_acb)
     case M_NF:                             // noise figure
 //      reset_settings(setting.mode);
       markers[0].enabled = M_ENABLED;
-      markers[0].mtype = M_NOISE;
+      markers[0].mtype = M_NOISE;          // Not tracking
       set_extra_lna(true);
       kp_help_text = "Amplifier Gain ";
       ui_mode_keypad(KM_EXT_GAIN);
+      kp_help_text = "Noise frequency";
+      ui_mode_keypad(KM_CENTER);
+      set_marker_frequency(0, uistat.value);
+      kp_help_text = "Noise width";
+      ui_mode_keypad(KM_SPAN);
       set_average(AV_100);
       break;
 #endif