  The dipole mode synchrotron frequency is a basic beam parameter; it and a few
similarly basic quantities measured at small time intervals serve to
characterize the longitudinal beam dynamics throughout the acceleration cycle.
The effective accelerating voltage, in conjunction with the amount of rf
voltage required for the acceleration, is important for the estimate of the
beam energy loss per turn. The dipole mode frequency can be used to obtain the
effective accelerating rf voltage, providing that it can be measured precisely.
The synchrotron frequency measured from the synchrotron phase detector signal
(SPD) generally agrees well with calculation, and it can be applied for such
purposes as inferring the effective rf voltage.
