Initial numpy FM demod

1 files changed, 33 insertions, 0 deletions

diff --git a/numpy_fm_demod.py b/numpy_fm_demod.py
new file mode 100644
index 0000000..fb2c46b
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+++ b/numpy_fm_demod.py
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+import numpy as np
+import scipy.signal as signal
+
+from rtlsdr import RtlSdr
+
+
+class NumpyFmDemod():
+    '''
+    Numpy-based FM signal demodulation
+    Based on the great tutorial by Fraida Fund
+    https://witestlab.poly.edu/blog/capture-and-decode-fm-radio/
+    '''
+    def __init__(frequency, sample_rate=1140000, sample_count=8192000, dc_offset=250000):
+        self.freq = int(frequency)
+        self.sample_rate = sample_rate
+        self.sample_count = sample_count
+        self.dc_offset = dc_offset
+
+    def capture_samples(self):
+        sdr = RtlSdr()
+        sdr.sample_rate = self.sample_rate
+        sdr.center_freq = self.freq - self.dc_offset
+        sdr.gain = 'auto'
+
+        samples = sdr.read_samples(self.sample_count)
+        sdr.close()
+
+        self.raw_samples = np.array(samples).astype('complex64')
+
+
+if __name__ == '__main__':
+    nfd = NumpyFmDemod(frequency=96.3e6)
+    nfd.run()