diff --git a/radio/src/debug.cpp b/radio/src/debug.cpp
index 30ced2354..101359994 100644
--- a/radio/src/debug.cpp
+++ b/radio/src/debug.cpp
@@ -223,6 +223,8 @@ const char * debugTimerNames[DEBUG_TIMERS_COUNT] = {
   ,"ADC read   "   // debugTimerAdcRead,
   ,"ADC loop   "   // debugTimerAdcLoop,
   ,"ADC wait   "   // debugTimerAdcWait,
+  ,"mix-pulses "   // debugTimerMixerCalcToUsage
+  ,"mix-int.   "   // debugTimerMixerIterval
 };
 
 #endif
diff --git a/radio/src/debug.h b/radio/src/debug.h
index 089943cd8..6edabc6f0 100644
--- a/radio/src/debug.h
+++ b/radio/src/debug.h
@@ -324,6 +324,9 @@ enum DebugTimers {
   debugTimerAdcLoop,
   debugTimerAdcWait,
 
+  debugTimerMixerCalcToUsage,
+  debugTimerMixerIterval,
+
   DEBUG_TIMERS_COUNT
 };
 
diff --git a/radio/src/opentx.h b/radio/src/opentx.h
index 0d90d15fa..5e17361ac 100644
--- a/radio/src/opentx.h
+++ b/radio/src/opentx.h
@@ -717,6 +717,7 @@ extern uint8_t flightModeTransitionLast;
 void evalFlightModeMixes(uint8_t mode, uint8_t tick10ms);
 void evalMixes(uint8_t tick10ms);
 void doMixerCalculations();
+void scheduleNextMixerCalculation(uint8_t module, uint16_t delay);
 
 #if defined(CPUARM)
   void checkTrims();
diff --git a/radio/src/pulses/pulses_arm.cpp b/radio/src/pulses/pulses_arm.cpp
index 0354e180d..7bfd01775 100644
--- a/radio/src/pulses/pulses_arm.cpp
+++ b/radio/src/pulses/pulses_arm.cpp
@@ -179,12 +179,14 @@ void setupPulses(unsigned int port)
   switch (required_protocol) {
     case PROTO_PXX:
       setupPulsesPXX(port);
+      scheduleNextMixerCalculation(port, 9);
       break;
 #if defined(DSM2)
     case PROTO_DSM2_LP45:
     case PROTO_DSM2_DSM2:
     case PROTO_DSM2_DSMX:
       setupPulsesDSM2(port);
+      scheduleNextMixerCalculation(port, 11);
       break;
 #endif
 #if defined(CROSSFIRE)
@@ -194,6 +196,7 @@ void setupPulses(unsigned int port)
         uint8_t * crossfire = modulePulsesData[port].crossfire.pulses;
         createCrossfireFrame(crossfire, &channelOutputs[g_model.moduleData[port].channelsStart]);
         sportSendBuffer(crossfire, CROSSFIRE_FRAME_LEN);
+        // TODO scheduleNextMixerCalculation()
       }
       break;
     }
@@ -205,6 +208,7 @@ void setupPulses(unsigned int port)
 #endif
     case PROTO_PPM:
       setupPulsesPPM(port);
+      scheduleNextMixerCalculation(port, (45+g_model.moduleData[port].ppm.frameLength)/2);
       break ;
     default:
       break;
diff --git a/radio/src/tasks_arm.cpp b/radio/src/tasks_arm.cpp
index 1bea7d9d6..88f6e9324 100644
--- a/radio/src/tasks_arm.cpp
+++ b/radio/src/tasks_arm.cpp
@@ -91,8 +91,11 @@ uint16_t stackAvailable()
 }
 #endif
 
+uint32_t nextMixerTime[NUM_MODULES];
+
 void mixerTask(void * pdata)
 {
+  static uint32_t lastRunTime;
   s_pulses_paused = true;
 
   while(1) {
@@ -102,12 +105,35 @@ void mixerTask(void * pdata)
       return;
 #endif
 
+    CoTickDelay(1);
+
+    uint32_t now = CoGetOSTime();
+    bool run = false;
+    if ((now - lastRunTime) > 10) {     // run at least every 20ms
+      run = true;
+    }
+    else if (now == nextMixerTime[0]) {
+      run = true;
+    }
+#if NUM_MODULES >= 2
+    else if (now == nextMixerTime[1]) {
+      run = true;
+    }
+#endif
+    if (!run) {
+      continue;  // go back to sleep
+    }
+
+    lastRunTime = now;
+
     if (!s_pulses_paused) {
       uint16_t t0 = getTmr2MHz();
 
       DEBUG_TIMER_START(debugTimerMixer);
       CoEnterMutexSection(mixerMutex);
       doMixerCalculations();
+      DEBUG_TIMER_START(debugTimerMixerCalcToUsage);
+      DEBUG_TIMER_SAMPLE(debugTimerMixerIterval);
       CoLeaveMutexSection(mixerMutex);
       DEBUG_TIMER_STOP(debugTimerMixer);
 
@@ -125,12 +151,18 @@ void mixerTask(void * pdata)
       t0 = getTmr2MHz() - t0;
       if (t0 > maxMixerDuration) maxMixerDuration = t0 ;
     }
-
-    CoTickDelay(1);  // 2ms for now
   }
 }
 
-#define MENU_TASK_PERIOD_TICKS      10    // 20ms
+void scheduleNextMixerCalculation(uint8_t module, uint16_t delay)
+{
+  // Schedule next mixer calculation time, 
+  // for now assume mixer calculation takes 2 ms.
+  nextMixerTime[module] = (uint32_t)CoGetOSTime() + (delay)/2 - 1/*2ms*/;
+  DEBUG_TIMER_STOP(debugTimerMixerCalcToUsage);
+}
+
+#define MENU_TASK_PERIOD_TICKS      25    // 50ms
 
 void menusTask(void * pdata)
 {