def setUp(self):
"""Create a time-domain signal comprised of two frequencies.
"""
# Setup a 11kHz 1V signal in time domain
# Signals are sampled at 96 kHz (common for LX-10) for 10 seconds
sampling_rate = 96000
num_samples = 960000
time_array = (1.0 / sampling_rate) * np.arange(num_samples)
signal_1_frequency = 11000
self.signal_1_amplitude = 1
signal_1 = self.signal_1_amplitude * np.sin(
2 * np.pi * signal_1_frequency * time_array)
test_signal = signal_1
# Setup variables needed for the STFT
frame_size_sec = 1
hop_size_sec = 0.5
use_hamming_window = False
self.data_stft, self.time_array_stft, self.freq_array_stft, \
freq_bin_size = \
siganalysis.stft(test_signal,
sampling_rate,
frame_size_sec,
hop_size_sec,
use_hamming_window)
def test_stft_freq_bin_size(self):
data_stft, time_array_stft, freq_array_stft, freq_bin_size = \
siganalysis.stft(self.test_signal,
self.sampling_rate,
self.frame_size_sec,
self.hop_size_sec,
self.use_hamming_window)
self.assertEqual(freq_bin_size, 1 / self.frame_size_sec)
def test_stft_another_freq_bin_size(self):
frame_size_sec = 0.5
correct_freq_per_bin = 1 / frame_size_sec
data_stft, time_array_stft, freq_array_stft, freq_bin_size = \
siganalysis.stft(self.test_signal,
self.sampling_rate,
frame_size_sec,
self.hop_size_sec,
self.use_hamming_window)
self.assertEqual(freq_bin_size, correct_freq_per_bin)
def test_stft_shape_size(self):
data_stft, time_array_stft, freq_array_stft, freq_bin_size = \
siganalysis.stft(self.test_signal,
self.sampling_rate,
self.frame_size_sec,
self.hop_size_sec,
self.use_hamming_window)
known_freq_size = int(self.frame_size_sec * self.sampling_rate / 2)
self.assertEqual(data_stft.shape[1], known_freq_size)
self.assertEqual(data_stft.shape[1], freq_array_stft.size)
self.assertEqual(data_stft.shape[0], time_array_stft.size)
