def preprocess_signals(signals):
    """
    Preprocess signals as Torch Tensors with gradients.

    Arguments
    ---------
    signals: numpy.ndarray

    Returns
    -------
    processed_signals: torch.Tensors
    """
    preprocessed_signals = signals.squeeze(0).view((signals.shape[0], 15, -1))
    return preprocessed_signals.requires_grad_(True)