def _realwavelets(s_freq, freqs, dur, width):
    """Create real wavelets, for UCSD.

    Parameters
    ----------
    s_freq : int
        sampling frequency
    freqs : ndarray
        vector with frequencies of interest
    dur : float
        duration of the wavelets in s
    width : float
        parameter controlling gaussian shape

    Returns
    -------
    ndarray
        wavelets
    """
    x = arange(-dur / 2, dur / 2, 1 / s_freq)
    wavelets = empty((len(freqs), len(x)))

    g = exp(-(pi * x ** 2) / width ** 2)

    for i, one_freq in enumerate(freqs):
        y = cos(2 * pi * x * one_freq)
        wavelets[i, :] = y * g

    return wavelets