@staticmethod
def time_base_to_nr3(n, s):
    """
        converts the time base into the nr3 format
        Args:
            n: time base value (1, 2, 5)
            s: time base (ns, us, ms, s)

        Returns:
            a string in nr3 format that represents the time for example, 1.0E-9, 2.0E-9, 5.0E-9, ... 1.0E+00, 2.0E+00, 5.0E+00)

        """
    if s == 'ns':
        nr3 = 'E-9'
    if s == 'us':
        nr3 = 'E-6'
    if s == 'ms':
        nr3 = 'E-3'
    if s == 's':
        nr3 = 'E+00'
    return str(n) + '.0' + nr3
