convert knee to knee frequency

neurodsp-tools · Feb 2, 2022 · 503688d · 503688d
1 parent 79b1a7d
commit 503688d
Showing 1 changed file with 5 additions and 3 deletions.
diff --git a/neurodsp/sim/aperiodic.py b/neurodsp/sim/aperiodic.py
@@ -142,7 +142,6 @@ def sim_knee(n_seconds, fs, exponent1, exponent2, knee):
         Power law exponent after the knee.
     knee : float
         Location of the knee in Hz.
-
     Returns
     -------
     sig : 1d array
@@ -177,8 +176,11 @@ def sim_knee(n_seconds, fs, exponent1, exponent2, knee):
     sig = np.zeros(n_samples)
 
     for f in freqs:
-        sig += np.sqrt(1 / (f ** -exponent1 * (f ** (-exponent2 - exponent1) + knee))) \
-            * np.cos(2 * np.pi * f * times + 2 * np.pi * np.random.rand())
+
+        knee_term = knee**(-2*exponent1 - exponent2)
+
+        sig += np.sqrt(1 / (f ** -exponent1 * (f ** (-exponent2 - exponent1) + knee_term))) * \
+            np.cos(2 * np.pi * f * times + 2 * np.pi * np.random.rand())
 
     return sig