ATOMIC CLOCKS AND THEIR APPLICATIONS

Abstract : Atomic clocks consist of electronic frequency dividers and electromechanical integrators which are driven by an atomic frequency standard. The following topics are reviewed: criteria for the selection of useful atomic spectral lines; conversion of output frequencies from one to other time scales; advantage of integral over proportional servo control; criteria for performance description of atomic frequency standards; perturbations of output frequencies; tunability of atomic standards; synchronization errors caused by frequency offset and instability; perturbing influences of dividers and measurement techniques; principles and performance data on various atomic frequency standards, namely, conventional NH3 maser, hydrogen maser, other maser schemes, Rb and Cs gas cell standards, and Cs beam standards; and applications for frequency measurement and for time measurement both with single and separated synchronized clocks. (Author)