diff --git a/lib/__init__.py b/lib/__init__.py
index ef29685..2f667d7 100644
--- a/lib/__init__.py
+++ b/lib/__init__.py
@@ -1,7 +1,7 @@
 from .util import *
 from .bq import *
 from .data import *
-from .butterworth import *
+from .nsf import *
 from .sweeps import *
 from .smoothfft import *
 from .plot import *
diff --git a/lib/butterworth.py b/lib/nsf.py
similarity index 98%
rename from lib/butterworth.py
rename to lib/nsf.py
index 159aa54..7cb4309 100644
--- a/lib/butterworth.py
+++ b/lib/nsf.py
@@ -1,3 +1,5 @@
+# network synthesis filters
+
 import numpy as np
 
 def LPB(n):