diff --git a/radio/DeSymbolizer.cpp b/radio/DeSymbolizer.cpp
index b4db051..ca8e3e7 100644
--- a/radio/DeSymbolizer.cpp
+++ b/radio/DeSymbolizer.cpp
@@ -145,7 +145,7 @@ void DeSymbolizer::process()
 	}
 }
 
-uint32_t DeSymbolizer::differentialDecode(uint32_t symbol)
+symbol_t DeSymbolizer::differentialDecode(symbol_t symbol)
 {
 	uint32_t res;
 
diff --git a/radio/Symbolizer.cpp b/radio/Symbolizer.cpp
index c20ecb4..d26a5a3 100644
--- a/radio/Symbolizer.cpp
+++ b/radio/Symbolizer.cpp
@@ -78,10 +78,10 @@ void Symbolizer::process()
 	}
 }
 
-uint32_t Symbolizer::differentialEncode(uint32_t symbol)
+symbol_t Symbolizer::differentialEncode(symbol_t symbol)
 {
 	// Differential encode
-	m_lastSymbol = (uint32_t)(m_symbolMask & (symbol + m_lastSymbol));
+	m_lastSymbol = (symbol_t)(m_symbolMask & (symbol + m_lastSymbol));
 
 	return m_lastSymbol;
 }
diff --git a/radio/Symbolizer.hpp b/radio/Symbolizer.hpp
index a934b7f..be06cdd 100644
--- a/radio/Symbolizer.hpp
+++ b/radio/Symbolizer.hpp
@@ -17,6 +17,7 @@ public:
 	// Processor::Block
 	void prepare() override;
 	void process();
+	symbol_t differentialEncode(symbol_t symbol);
 
 private:
 	uint32_t m_nBitsPerSym;
@@ -25,7 +26,6 @@ private:
 	symbol_t m_symbolMask;
 	Processor::Buffer<uint8_t> *m_buf_in;
 	Processor::Buffer<symbol_t> *m_buf_out;
-	symbol_t differentialEncode(symbol_t symbol);
 	void commit(symbol_t src);
 	void assemble_and_commit(uint8_t src);
 };