From 6fcdf1eee03e9b4edb7be1831c0ff54404e150f6 Mon Sep 17 00:00:00 2001
From: "a.ott" <a.ott@student.uni-tuebingen.de>
Date: Fri, 24 Jan 2020 13:39:12 +0100
Subject: [PATCH] sinusoidal stimulus with beat

---
 stimuli/SinusAmplitudeModulation.py | 30 +++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)
 create mode 100644 stimuli/SinusAmplitudeModulation.py

diff --git a/stimuli/SinusAmplitudeModulation.py b/stimuli/SinusAmplitudeModulation.py
new file mode 100644
index 0000000..2296d28
--- /dev/null
+++ b/stimuli/SinusAmplitudeModulation.py
@@ -0,0 +1,30 @@
+from stimuli.AbstractStimulus import AbstractStimulus
+import numpy as np
+
+
+class SinusAmplitudeModulationStimulus(AbstractStimulus):
+
+    def __init__(self, carrier_frequency, amplitude, contrast, modulation_frequency, start_time=0, duration=np.inf):
+        self.contrast = contrast
+        self.modulation_frequency = modulation_frequency
+        self.amplitude = amplitude
+        self.carrier_frequency = carrier_frequency
+        self.start_time = start_time
+        self.duration = duration
+
+    def value_at_time_in_s(self, time_point):
+        if time_point < self.start_time or time_point > self.start_time + self.duration:
+            return 0
+
+        am = (1 + self.contrast * np.sin(2*np.pi*self.modulation_frequency * time_point))
+        carrier = np.sin(2*np.pi*self.carrier_frequency*time_point)
+        return self.amplitude * am * carrier
+
+    def get_stimulus_start_ms(self):
+        return self.start_time
+
+    def get_stimulus_duration_ms(self):
+        return self.duration
+
+    def get_amplitude(self):
+        return self.contrast