diff --git a/Delay.cpp b/Delay.cpp
index fa0b4ea..eda70a6 100644
--- a/Delay.cpp
+++ b/Delay.cpp
@@ -23,8 +23,10 @@ void Hilbert::filter_block(const double* pIn, cmplx* pOut)
 		const double* IKptr = IHilbertBPFirCoef+HILBPFIR_LENGTH-m_hilbert_ptr;
 		const double* QKptr = QHilbertBPFirCoef+HILBPFIR_LENGTH-m_hilbert_ptr;
 		cmplx acc{0., 0.};
-		for (int j = 0; j < HILBPFIR_LENGTH; ++ j, ++ Firptr)
-			acc += (*Firptr) * (*IKptr++);
+		for (int j = 0; j < HILBPFIR_LENGTH; ++ j, ++ Firptr) {
+			acc.r += Firptr->r * (*IKptr++);	// in-phase: band-pass (I) taps
+			acc.i += Firptr->i * (*QKptr++);	// quadrature: Hilbert (Q) taps
+		}
 		pOut[i] = acc;
 		if (-- m_hilbert_ptr < 0)
 			m_hilbert_ptr = HILBPFIR_LENGTH - 1;