diff --git a/utils/freqwave.c b/utils/freqwave.c
index cba0f89f844e5967616ccf5b80aa77ba280de3e7..591537747f614f86337fb3c25144ad32cbf1b318 100644
--- a/utils/freqwave.c
+++ b/utils/freqwave.c
@@ -396,7 +396,8 @@ void freqwave(float *wave, int nt, float dt, float fp, float fmin, float flef, f
     }
     //fprintf(stderr,"scaling factor back FFT=%e\n", max);
     for (i = 0; i < nt; i++) {
-		wave[i]= rwave[i]*max*exp(-alpha*i*dt);
+        tt=(float)i*dt;
+		wave[i]= rwave[i]*max*exp(-alpha*tt);
 	}
 
     free(cwave);