Improved RSID with new si filter profile, leave some time for si startup

firmware/inc/rf_tests.h

@@ -31,6 +31,7 @@ enum rf_tests {
   RF_TEST_APRS_HIGH_FM_TONE,
   RF_TEST_APRS_TONE,
   RF_TEST_TELEMETRY_TONE,
+  RF_TEST_RSID,
 };
 
 #define RF_TEST	RF_TEST_NONE

firmware/inc/si_trx.h

@@ -27,12 +27,18 @@
 
 #include "samd20.h"
 
+enum si_filter_model {
+  SI_FILTER_DEFAULT,
+  SI_FILTER_APRS,
+  SI_FILTER_RSID
+};
+
 float si_trx_get_temperature(void);
 
 void si_trx_modem_set_deviation(uint32_t deviation);
 
 void si_trx_on(uint8_t modulation_type, uint32_t frequency,
-               uint16_t deviation, uint8_t power);
+                 uint16_t deviation, uint8_t power, enum si_filter_model filter);
 void si_trx_off(void);
 
 void si_trx_modem_set_offset(int16_t channel);

firmware/src/rf_tests.c

@@ -39,12 +39,12 @@
 void telemetry_tone(void)
 {
   while (1) {
-    si_trx_on(SI_MODEM_MOD_TYPE_CW, TELEMETRY_FREQUENCY, 0, 36);
+    si_trx_on(SI_MODEM_MOD_TYPE_CW, TELEMETRY_FREQUENCY, 0, 36, SI_FILTER_DEFAULT);
     for (int i = 0; i < 200*1000; i++) {
       idle(IDLE_TELEMETRY_ACTIVE);
     }
     si_trx_off();
-    si_trx_on(SI_MODEM_MOD_TYPE_CW, TELEMETRY_FREQUENCY, 0, 0x7f);
+    si_trx_on(SI_MODEM_MOD_TYPE_CW, TELEMETRY_FREQUENCY, 0, 0x7f, SI_FILTER_DEFAULT);
     for (int i = 0; i < 200*1000; i++) {
       idle(IDLE_TELEMETRY_ACTIVE);
     }
@@ -54,12 +54,12 @@ void telemetry_tone(void)
 void aprs_tone(void)
 {
   while (1) {
-    si_trx_on(SI_MODEM_MOD_TYPE_CW, APRS_TEST_FREQUENCY, 0, 36);
+    si_trx_on(SI_MODEM_MOD_TYPE_CW, APRS_TEST_FREQUENCY, 0, 36, SI_FILTER_DEFAULT);
     for (int i = 0; i < 200*1000; i++) {
       idle(IDLE_TELEMETRY_ACTIVE);
     }
     si_trx_off();
-    si_trx_on(SI_MODEM_MOD_TYPE_CW, APRS_TEST_FREQUENCY, 0, 0x7f);
+    si_trx_on(SI_MODEM_MOD_TYPE_CW, APRS_TEST_FREQUENCY, 0, 0x7f, SI_FILTER_DEFAULT);
     for (int i = 0; i < 200*1000; i++) {
       idle(IDLE_TELEMETRY_ACTIVE);
     }
@@ -83,7 +83,7 @@ void aprs_high_fm_tone(void)
                              false);		/* Output Pin Enable	*/
 
   si_trx_on(SI_MODEM_MOD_TYPE_2GFSK, APRS_TEST_FREQUENCY,
-            AX25_DEVIATION, APRS_POWER);
+            AX25_DEVIATION, APRS_POWER, SI_FILTER_APRS);
   while (1) {
     idle(IDLE_TELEMETRY_ACTIVE);
   }
@@ -109,6 +109,23 @@ void aprs_test(void)
   }
 }
 
+/**
+ * RSID function for use during testing. Not for flight
+ */
+void rsid_test(void)
+{
+  while (1) {
+
+   telemetry_start_rsid(RSID_CONTESTIA_32_1000);
+
+//    Sleep wait for RSID
+   while (telemetry_active()) {
+     idle(IDLE_TELEMETRY_ACTIVE);
+   }
+
+    for (int i = 3*200*1000; i; i--);
+  }
+}
 
 void rf_tests(void)
 {
@@ -125,6 +142,9 @@ void rf_tests(void)
     case RF_TEST_TELEMETRY_TONE:
       telemetry_tone();
       break;
+    case RF_TEST_RSID:
+      rsid_test();
+      break;
     default:
       break;
   }

firmware/src/rsid.c

@@ -100,6 +100,7 @@ void rsid_encode(rsid_code_t rsid_code, int8_t* rsid)
  */
 
 uint8_t rsid_index = 0xFE;
+uint8_t rsid_subtick;
 int8_t rsid[RSID_NSYMBOLS];
 
 #define MODEM_TONE_SPACING 7.805
@@ -118,6 +119,7 @@ void rsid_start(rsid_code_t rsid_code)
 {
   /* Start transmission */
   rsid_index = 0;
+  rsid_subtick = 0;
   rsid_encode(rsid_code, rsid);
 }
 
@@ -147,24 +149,35 @@ void rsid_tone(uint8_t tone)
   deviation = tone_offset - (float)channel;
 #endif
 
-  float duty_cycle = 0.5 + (deviation / 2); // FSK only provides a marginal improvement in performance!
+  float duty_cycle = 0.5 + deviation;
 
-  si_trx_switch_channel(channel);
+  si_trx_switch_channel(channel-2); /* -2 offset to line up with contestia signal */
   telemetry_gpio1_pwm_duty(duty_cycle);
 }
 
 /**
  * Called at the rsid baud rate
+ *
+ * We mantain the first tone longer than the others to give the radio
+ * time to start up. Oh so hacky but hey
  */
 uint8_t rsid_tick(void)
 {
+  if (rsid_index < RSID_NSYMBOLS || rsid_subtick) {
 
-  if (rsid_index < RSID_NSYMBOLS) {
+    /* Actual tick */
+    if (rsid_subtick == 0) {
+      /* Transmit this tone */
+      rsid_tone(rsid[rsid_index]);
+      rsid_index++;
+    }
 
-    /* Transmit this tone */
+    rsid_subtick++;
-    rsid_tone(rsid[rsid_index]);
+    if ((rsid_index-1 == 0 && rsid_subtick == 3) || /* First tone */
+        (rsid_index-1 != 0 && rsid_subtick == 2)) { /* Other tones */
+      rsid_subtick = 0;
+    }
 
-    rsid_index++;
     return 1;
   }
 

firmware/src/si_trx.c

@@ -427,7 +427,7 @@ static float si_trx_set_frequency(uint32_t frequency, uint16_t deviation)
  * Resets the transceiver
  */
 void si_trx_reset(uint8_t modulation_type, uint32_t frequency,
-                  uint16_t deviation, uint8_t power)
+                  uint16_t deviation, uint8_t power, enum si_filter_model filter)
 {
   _si_trx_sdn_enable();  /* active high shutdown = reset */
 
@@ -459,22 +459,40 @@ void si_trx_reset(uint8_t modulation_type, uint32_t frequency,
   si_trx_set_frequency(frequency, deviation);
   si_trx_set_tx_power(power);
 
-  /**
+  /* Modem tx filter coefficients */
-   * Modem tx filter coefficients for APRS
+  uint8_t rsid_si_coeff[] = {0x1, 0x4, 0x9, 0x11, 0x19, 0x22, 0x2a, 0x30, 0x31};
-   * 0dB @ 2.2kHz
-   * -6dB @ 1.2kHz (for pre-emphasis)
-   * < -30dB from 3.6KHz
-   */
   uint8_t p_si_coeff[] = {0x6, 0x8, 0x1, 0xf2, 0xe4, 0xe7, 0xff, 0x1d, 0x2b};
-  si_trx_modem_set_tx_datarate(1600); /* Filter sampling rate 1600*10 = 16kHz */
+
-  si_trx_modem_tx_filter_coefficients(p_si_coeff);
+  switch (filter) {
+    case SI_FILTER_APRS:
+      /**
+       * Modem tx filter coefficients for APRS
+       * 0dB @ 2.2kHz
+       * -6dB @ 1.2kHz (for pre-emphasis)
+       * < -30dB from 3.6KHz
+       */
+      si_trx_modem_set_tx_datarate(1600); /* Filter sampling rate 1600*10 = 16kHz */
+      si_trx_modem_tx_filter_coefficients(p_si_coeff);
+      break;
+    case SI_FILTER_RSID:
+      /**
+       * Modem tx filter coefficients for RSID
+       * -6dB @ dc (for ±0.5 deviation max)
+       * < -50dB from 1.8KHz
+       */
+      si_trx_modem_set_tx_datarate(1600); /* Filter sampling rate 1600*10 = 16kHz */
+      si_trx_modem_tx_filter_coefficients(rsid_si_coeff);
+      break;
+    default:                      /* Just leave the defaults from startup in place */
+      break;
+  }
 
 
   /* RTTY from GPIO1 */
   si_trx_modem_set_modulation(SI_MODEM_MOD_DIRECT_MODE_SYNC, // ASYNC
-			      SI_MODEM_MOD_GPIO_1,
+                              SI_MODEM_MOD_GPIO_1,
-			      SI_MODEM_MOD_SOURCE_DIRECT,
+                              SI_MODEM_MOD_SOURCE_DIRECT,
-			      modulation_type);
+                              modulation_type);
 
   si_trx_state_tx_tune();
 }
@@ -483,9 +501,9 @@ void si_trx_reset(uint8_t modulation_type, uint32_t frequency,
  * Enables the radio and starts transmitting
  */
 void si_trx_on(uint8_t modulation_type, uint32_t frequency,
-               uint16_t deviation, uint8_t power)
+    uint16_t deviation, uint8_t power, enum si_filter_model filter)
 {
-  si_trx_reset(modulation_type, frequency, deviation, power);
+  si_trx_reset(modulation_type, frequency, deviation, power, filter);
   si_trx_start_tx(0);
 }
 /**

firmware/src/telemetry.c

@@ -238,7 +238,8 @@ void telemetry_tick(void) {
 
       if (!radio_on) {
         /* Contestia: We use the modem offset to modulate */
-        si_trx_on(SI_MODEM_MOD_TYPE_CW, TELEMETRY_FREQUENCY, 1, TELEMETRY_POWER);
+        si_trx_on(SI_MODEM_MOD_TYPE_CW, TELEMETRY_FREQUENCY, 1, TELEMETRY_POWER,
+                  SI_FILTER_DEFAULT);
         radio_on = 1;
         contestia_preamble();
       }
@@ -259,7 +260,8 @@ void telemetry_tick(void) {
 
       if (!radio_on) {
         /* RTTY: We use the modem offset to modulate */
-        si_trx_on(SI_MODEM_MOD_TYPE_CW, TELEMETRY_FREQUENCY, 1, TELEMETRY_POWER);
+        si_trx_on(SI_MODEM_MOD_TYPE_CW, TELEMETRY_FREQUENCY, 1, TELEMETRY_POWER,
+                  SI_FILTER_DEFAULT);
         radio_on = 1;
         rtty_preamble();
       }
@@ -290,10 +292,9 @@ void telemetry_tick(void) {
         /* RSID: We PWM frequencies with the external pin */
         telemetry_gpio1_pwm_init();
 
-        si_trx_on(SI_MODEM_MOD_TYPE_2GFSK, TELEMETRY_FREQUENCY, 1, TELEMETRY_POWER);
+        si_trx_on(SI_MODEM_MOD_TYPE_2GFSK, TELEMETRY_FREQUENCY, 1, TELEMETRY_POWER,
+                  SI_FILTER_RSID);
         radio_on = 1;
-
-        return;
       }
 
       /* Do Tx */
@@ -304,6 +305,7 @@ void telemetry_tick(void) {
         telemetry_gpio1_pwm_deinit();
         return;
       }
+
       break;
 
     case TELEMETRY_APRS: /* ---- ---- APRS */
@@ -313,8 +315,8 @@ void telemetry_tick(void) {
         if (aprs_start() && _aprs_frequency) {
 
           /* Radio on */
-          si_trx_on(SI_MODEM_MOD_TYPE_2GFSK, _aprs_frequency,
+          si_trx_on(SI_MODEM_MOD_TYPE_2GFSK, _aprs_frequency, AX25_DEVIATION,
-                    AX25_DEVIATION, APRS_POWER);
+                    APRS_POWER, SI_FILTER_APRS);
           radio_on = 1;
         } else {
           /* Stop immediately */
@@ -333,7 +335,8 @@ void telemetry_tick(void) {
 
       if (!radio_on) { /* Turn on */
         /* Pips: Cw */
-        si_trx_on(SI_MODEM_MOD_TYPE_CW, TELEMETRY_FREQUENCY, 1, TELEMETRY_POWER);
+        si_trx_on(SI_MODEM_MOD_TYPE_CW, TELEMETRY_FREQUENCY, 1, TELEMETRY_POWER,
+                  SI_FILTER_DEFAULT);
         radio_on = 1;
 
       } else { /* Turn off */
@@ -430,7 +433,7 @@ void telemetry_init(void)
   rtty_timer_count	= timer0_get_count_value(RTTY_BITRATE);
   pips_timer_count	= timer0_get_count_value(PIPS_FREQUENCY);
   ax25_timer_count      = timer0_get_count_value(AX25_TICK_RATE);
-  rsid_timer_count	= timer0_get_count_value(RSID_SYMBOL_RATE);
+  rsid_timer_count	= timer0_get_count_value(RSID_SYMBOL_RATE*2); /* 2x Subtick */
 }