On the occasion of the 12th session of the Comite Consultatif pour la
Definition de la Seconde (CCDS) a report is given on the state of the
realization of the second at PTB. New results of the CS1, CS2, CS3 and
CS4 primary atomic clocks are presented. In addition, the subjects of
current research in this field are outlined. The report also covers t
he realization of the Universal Coordinated Time, UTC, of UTC(PTB) and
the important methods of time comparisons.