Sign macro fix

Author: vedderb

utils.h

@@ -67,8 +67,8 @@ uint16_t utils_median_filter_uint16_run(uint16_t *buffer,
 		unsigned int *buffer_index, unsigned int filter_len, uint16_t sample);
 const char* utils_hw_type_to_string(HW_TYPE hw);
 
-// Return the sign of the argument. -1 if negative, 1 if zero or positive.
-#define SIGN(x)				((x < 0) ? -1 : 1)
+// Return the sign of the argument. -1.0 if negative, 1.0 if zero or positive.
+#define SIGN(x)				(((x) < 0.0) ? -1.0 : 1.0)
 
 // Squared
 #define SQ(x)				((x) * (x))