diff --git a/encode.cc b/encode.cc
index d744fd5..448cf90 100644
--- a/encode.cc
+++ b/encode.cc
@@ -89,6 +89,8 @@ struct Encoder
 				if (norm(tdom[peak]) < norm(tdom[i]))
 					peak = i;
 			cmplx orig = tdom[peak];
+			if (norm(orig) <= value(1))
+				break;
 			for (int i = 0; i < peak; ++i)
 				tdom[i] -= orig * kern[symbol_len-peak+i];
 			for (int i = peak; i < symbol_len; ++i)