def resample_factor_str(sig_sample_rate_hz: float,
                        wav_sample_rate_hz: float) -> str:
    """
    Compute file string for oversample and downsample options

    :param sig_sample_rate_hz: input signal sample rate
    :param wav_sample_rate_hz: wav sample rate; supports permitted_wav_fs_values
    :return: string with resample factor
    """
    resample_factor = wav_sample_rate_hz / sig_sample_rate_hz
    # If resample factor is unity, no change
    resample_str = '_preserve'
    if resample_factor > 1:
        resample_str = '_upsample_' + str(int(10.*resample_factor)/10) + 'x_to'
    elif 1 > resample_factor > 0:
        resample_str = '_decimate_' + str(int(10./resample_factor)/10) + 'x_to'
    elif resample_factor < 0:
        print("Resample factor is negative: address")
    return resample_str