diff --git a/src/modules/modem/Modem.h b/src/modules/modem/Modem.h
index e11e18d..035bbe4 100644
--- a/src/modules/modem/Modem.h
+++ b/src/modules/modem/Modem.h
@@ -3,6 +3,7 @@
 #include "liquid/liquid.h"
 #include "IOThread.h"
 #include "AudioThread.h"
+#include <cmath>
 
 class ModemKit {
 public:
@@ -48,4 +49,4 @@ public:
     virtual void demodulate(ModemKit *kit, ModemIQData *input, AudioThreadInput *audioOut) = 0;
 private:
     static ModemFactoryList modemFactories;
-};
\ No newline at end of file
+};