def nb_samples_per_dit_decim(Fs=8000, code_speed=13, decim=7.69):
    """ One dit of time at w wpm is 1.2/w.
        Returns a tuple (raw samples per dit, expected decimation factor)
        Overlap is nfft - decimation factor
    """
    t_dit = 1.2 / code_speed
    return int(t_dit * Fs), int(t_dit * Fs) / decim