diff --git a/include/WfAnalyzer.h b/include/WfAnalyzer.h
index 4ea1e0806c713b3e4e4b5256e13075c1ba49f721..0da299b42035c6281083ad23dd4f720d60718c90 100644
--- a/include/WfAnalyzer.h
+++ b/include/WfAnalyzer.h
@@ -153,7 +153,7 @@ public:
 
         // calculate pedestal
         if (nped <= nsamples/4) {
-            data.ped = CalcPedestal(&buffer[0], nsamples, 1.5, 3);
+            data.ped = CalcPedestal(&ybuf[0], nsamples, 1.5, 3);
         } else {
             data.ped = CalcPedestal(&ybuf[0], nped, 1.2, 3);
         }