Conventional phase processing is only for the continuous phase comparison at the same nominal frequency. In this case the processing resolution is limited, PLL and synthesizer are complicated, and linking between ultra high and ultra low frequency signals is very difficult. In most cases the comparison and control of frequency signals occur between the different nominal frequencies. To two signals with different nominal frequencies, one is the reference signal and another is the measured and controlled signal. The phase variation period of them is their least common multiple period, T minc (LCMP), and also expresses the phase variation of the measured signal against its nominal frequency signal. In T minc between two period groups of the signals the average variation full period of all different phase differences is equal to the group phase variation between any two most adjacent phase coincidences. It is also equal to 1/AB T minc , the equivalent phase comparison period T equ =T minc /AB. Here A and B are the divider between nominal frequency of the signals and their greatest common factor frequency (GCFF) respectively.