diff --git a/src/urh/ainterpretation/AutoInterpretation.py b/src/urh/ainterpretation/AutoInterpretation.py
index 598b3e295c..53b37b5dc3 100644
--- a/src/urh/ainterpretation/AutoInterpretation.py
+++ b/src/urh/ainterpretation/AutoInterpretation.py
@@ -148,7 +148,7 @@ def detect_modulation(data: np.ndarray, wavelet_scale=4, median_filter_order=11)
     var_filtered_mag = np.var(c_auto_interpretation.median_filter(mag_wavlt, k=median_filter_order))
     var_filtered_norm_mag = np.var(c_auto_interpretation.median_filter(norm_mag_wavlt, k=median_filter_order))
 
-    if all(v < 0.1 for v in (var_mag, var_norm_mag, var_filtered_mag, var_filtered_norm_mag)):
+    if all(v < 0.15 for v in (var_mag, var_norm_mag, var_filtered_mag, var_filtered_norm_mag)):
         return "OOK"
 
     if var_mag > 1.5 * var_norm_mag:
@@ -157,7 +157,7 @@ def detect_modulation(data: np.ndarray, wavelet_scale=4, median_filter_order=11)
         return "ASK"
     else:
         # FSK or PSK
-        if var_mag > 10 * var_filtered_mag:
+        if var_mag > 5 * var_filtered_mag:
             return "PSK"
         else:
             # Now we either have a FSK signal or we a have OOK single pulse
@@ -206,14 +206,14 @@ def detect_center(rectangular_signal: np.ndarray, max_size=None):
 
     try:
         y, x = np.histogram(rect, bins=np.arange(hist_min, hist_max + hist_step, hist_step))
-    except ZeroDivisionError:
+    except (ZeroDivisionError, ValueError):
         # For a segment with zero variance (constant line) it is not possible to find a center
         return None
 
     num_values = 2
     most_common_levels = []
 
-    window_size = max(2, int(0.05*len(y)))
+    window_size = max(2, int(0.05*len(y)) + 1)
 
     def get_elem(arr, index: int, default):
         if 0 <= index < len(arr):
@@ -225,7 +225,7 @@ def get_elem(arr, index: int, default):
         # check if we have a local maximum in histogram, if yes, append the value
         if all(y[index] > get_elem(y, index+i, 0) and
                y[index] > get_elem(y, index-i, 0)
-               for i in range(1, window_size+1)):
+               for i in range(1, window_size)):
             most_common_levels.append(x[index])
 
         if len(most_common_levels) == num_values:
diff --git a/tests/auto_interpretation/test_additional_signals.py b/tests/auto_interpretation/test_additional_signals.py
index 8dee7c7f4a..33c5cffa8a 100644
--- a/tests/auto_interpretation/test_additional_signals.py
+++ b/tests/auto_interpretation/test_additional_signals.py
@@ -29,7 +29,7 @@ def test_action(self):
 
         self.assertEqual(mod_type, "ASK")
         self.assertGreaterEqual(bit_length, 400)
-        self.assertLessEqual(bit_length, 500)
+        self.assertLessEqual(bit_length, 600)
 
         print("noise", noise, "center", center, "bit length", bit_length, "tolerance", tolerance)
         demodulated = demodulate(data, mod_type, bit_length, center, noise, tolerance)
diff --git a/tests/test_advanced_modulation_settings.py b/tests/test_advanced_modulation_settings.py
index 6a7fb6472c..b37ea7cd7d 100644
--- a/tests/test_advanced_modulation_settings.py
+++ b/tests/test_advanced_modulation_settings.py
@@ -2,7 +2,9 @@
 from PyQt5.QtWidgets import QApplication
 
 from tests.QtTestCase import QtTestCase
+from urh.controller.MainController import MainController
 from urh.controller.dialogs.AdvancedModulationOptionsDialog import AdvancedModulationOptionsDialog
+from urh.controller.widgets.SignalFrame import SignalFrame
 
 
 class TestAdvancedModulationSettings(QtTestCase):
@@ -15,13 +17,24 @@ def test_pause_threshold(self):
         self.assertEqual(signal_frame.proto_analyzer.num_messages, 1)
 
     def test_message_length_divisor(self):
+        assert isinstance(self.form, MainController)
+        self.form.ui.actionAuto_detect_new_signals.setChecked(False)
         self.add_signal_to_form("pwm.coco")
-        signal_frame = self.form.signal_tab_controller.signal_frames[0]
+        signal_frame = self.form.signal_tab_controller.signal_frames[0]  # type: SignalFrame
+        signal_frame.ui.spinBoxNoiseTreshold.setValue(0.0525)
         signal_frame.ui.cbModulationType.setCurrentText("ASK")
+        signal_frame.ui.spinBoxCenterOffset.setValue(0.01807)
+        signal_frame.ui.spinBoxCenterOffset.editingFinished.emit()
+        signal_frame.ui.spinBoxInfoLen.setValue(2900)
+        signal_frame.ui.spinBoxInfoLen.editingFinished.emit()
+        signal_frame.ui.spinBoxTolerance.setValue(2)
+        signal_frame.ui.spinBoxTolerance.editingFinished.emit()
+
+
         protocol = signal_frame.proto_analyzer
 
         bits = "1000100010001110100011101000111010001000100011101000111010001110100011101000111010001110111011101"
-        pauses = [77115, 77113, 58221]
+        pauses = [77114, 77112, 58221]
         for i in range(3):
             self.assertEqual(protocol.plain_bits_str[i], bits, msg=str(i))
             self.assertEqual(protocol.messages[i].pause, pauses[i], msg=str(i))