adding filtes and gitignore

code/modules/filters.py

@@ -0,0 +1,36 @@
+from scipy.signal import butter, sosfiltfilt
+import numpy as np
+
+
+def bandpass_filter(data, rate, lowf=100, highf=1100):
+    sos = butter(2, (lowf, highf), "bandpass", fs=rate, output="sos")
+    fdata = sosfiltfilt(sos, data)
+    return fdata
+
+
+def highpass_filter(
+    data,
+    rate,
+    cutoff=100,
+):
+
+    sos = butter(2, cutoff, "highpass", fs=rate, output="sos")
+    fdata = sosfiltfilt(sos, data)
+    return fdata
+
+
+def lowpass_filter(
+    data,
+    rate,
+    cutoff=100,
+):
+
+    sos = butter(2, cutoff, "lowpass", fs=rate, output="sos")
+    fdata = sosfiltfilt(sos, data)
+    return fdata
+
+
+def envelope(data, rate, freq=100):
+    sos = butter(2, freq, "lowpass", fs=rate, output="sos")
+    envelope = np.sqrt(2) * sosfiltfilt(sos, np.abs(data))
+    return envelope