Testing external clock detection and auto-switch

Simplified audio spectrum computation and transfer
ACARS RX in debug mode
Disabled ABI warnings
Updated binary

firmware/baseband/symbol_coding.hpp

@@ -39,6 +39,17 @@ private:
 	uint_fast8_t last { 0 };
 };
 
+class ACARSDecoder {
+public:
+	uint_fast8_t operator()(const uint_fast8_t symbol) {
+		last ^= (~symbol & 1);
+		return last;
+	}
+
+private:
+	uint_fast8_t last { 0 };
+};
+
 } /* namespace symbol_coding */
 
 #endif/*__SYMBOL_CODING_H__*/