SpectrogramTest.py 文件源码

def stft(self, samples, window_size, overlap_factor=0.5, window_function=np.hanning):
        """
        Perform Short-time Fourier transform to get the spectrogram for the given samples

        :param samples: Complex samples
        :param window_size: Size of DFT window
        :param overlap_factor: Value between 0 (= No Overlapping) and 1 (= Full overlapping) of windows
        :param window_function: Function for DFT window
        :return: short-time Fourier transform of the given signal
        """
        window = window_function(window_size)

        # hop size determines by how many samples the window is advanced
        hop_size = window_size - int(overlap_factor * window_size)

        # pad with zeros to ensure last window fits signal
        padded_samples = np.append(samples, np.zeros((len(samples) - window_size) % hop_size))
        num_frames = ((len(padded_samples) - window_size) // hop_size) + 1
        frames = [padded_samples[i*hop_size:i*hop_size+window_size] * window for i in range(num_frames)]
        return np.fft.fft(frames)