str += String_convert::int2hex (num, 2, '0');
str += String_convert::int2hex (intlog2 (den), 2, '0');
str += String_convert::int2hex (clocks_per_1_, 2, '0');
str += String_convert::int2hex (num, 2, '0');
str += String_convert::int2hex (intlog2 (den), 2, '0');
str += String_convert::int2hex (clocks_per_1_, 2, '0');