diff --git a/filters.py b/filters.py
new file mode 100644
index 0000000..0a350bd
--- /dev/null
+++ b/filters.py
@@ -0,0 +1,15 @@
+import scipy.signal as signal
+
+def design_butterworth(order, cutoff, fs, btype='low'):
+    """Designs a digital Butterworth filter."""
+    nyq = 0.5 * fs
+    normal_cutoff = cutoff / nyq
+    b, a = signal.butter(order, normal_cutoff, btype=btype, analog=False)
+    return b, a
+
+def design_chebyshev(order, rp, cutoff, fs, btype='low'):
+    """Designs a digital Chebyshev Type I filter."""
+    nyq = 0.5 * fs
+    normal_cutoff = cutoff / nyq
+    b, a = signal.cheby1(order, rp, normal_cutoff, btype=btype, analog=False)
+    return b, a