carat.features.spectrogram

carat.features.spectrogram(signal, fs, window_length=0.02, hop=0.01, windowing_function=<function hanning at 0x7f5b23b4b0d0>, dft_length=None, zp_flag=False)

Calculates the Short-Time Fourier Transform a signal.

Given an input signal, it calculates the DFT of frames of the signal and stores them in bi-dimensional Scipy array.

Args:

• window_len (float):length of the window in seconds (must be positive).
• window (callable): a callable object that receives the window length in samples and returns a numpy array containing the windowing function samples.
• hop (float): frame hop between adjacent frames in seconds.
• zp_flag (bool): a flag indicating if the Zero-Phase Windowing should be performed.

Returns:

• spec (numpy array): spectrogram data
• time (numpy array): time in seconds of each frame
• frequnecy (numpy array): frequency grid