diff --git a/src/rabifun/analysis.py b/src/rabifun/analysis.py
index 933e57b..e9bb2f7 100644
--- a/src/rabifun/analysis.py
+++ b/src/rabifun/analysis.py
@@ -2,12 +2,17 @@ import numpy as np
 
 
 def fourier_transform(
-    t: np.ndarray, signal: np.ndarray, window: tuple[float, float] | None = None
+    t: np.ndarray,
+    signal: np.ndarray,
+    window: tuple[float, float] | None = None,
+    low_cutoff: float = 0,
+    high_cutoff: float = np.inf,
 ):
     """
     Compute the Fourier transform of a signal from the time array
     ``t`` and the real signal ``signal``.  Optionally, a time window
-    can be specified through ``window = ([begin], [end])`` .
+    can be specified through ``window = ([begin], [end])`` .  The
+    ``low_cuttof (high_cutoff)`` is the lower (upper) bound of frequencies returned.
 
     :returns: The (linear) frequency array and the Fourier transform.
     """
@@ -20,4 +25,5 @@ def fourier_transform(
     freq = np.fft.rfftfreq(len(t), t[1] - t[0])
     fft = np.fft.rfft(signal)
 
-    return freq, fft
+    mask = (freq > low_cutoff) & (freq < high_cutoff)
+    return freq[mask], fft[mask]