diff --git a/sdrbase/CMakeLists.txt b/sdrbase/CMakeLists.txt
index da49b3469..c3ac5e833 100644
--- a/sdrbase/CMakeLists.txt
+++ b/sdrbase/CMakeLists.txt
@@ -30,7 +30,7 @@ set(sdrbase_SOURCES
     dsp/dspdevicesinkengine.cpp
     dsp/fftcorr.cpp
     dsp/fftengine.cpp
-    dsp/fftfilt.cxx
+    dsp/fftfilt.cpp
     dsp/fftwindow.cpp
     dsp/filterrc.cpp
     dsp/filtermbe.cpp
diff --git a/sdrbase/dsp/fftfilt.cxx b/sdrbase/dsp/fftfilt.cpp
similarity index 100%
rename from sdrbase/dsp/fftfilt.cxx
rename to sdrbase/dsp/fftfilt.cpp