diff --git a/radio/interpolation/Farrow.hpp b/radio/interpolation/Farrow.hpp
index 8aee679..10d30c2 100644
--- a/radio/interpolation/Farrow.hpp
+++ b/radio/interpolation/Farrow.hpp
@@ -68,6 +68,8 @@ public:
 
 	size_t feed(ComplexScalar const *x, uint32_t size=1)
 	{
+		m_w = (m_w + size) % m_N;
+		m_fifo[m_w] = *x;
 		return m_bufferIn.write(x, size);
 	}