Oscillation circuit, phase synchronization circuit, phase interpolation circuit, the phase adjustment circuit and the phase coupling circuit

摘要

PROBLEM TO BE SOLVED: To improve a phase resolution of a oscillation circuit more than a limit level of the resolution determined by a specific delay of delay elements being components of the circuit. SOLUTION: Phase coupling circuits 13a-13f make a relation of phases of output signals of two corresponding delay elements. For example, an output of the delay element 12a of a ring oscillator 12 is controlled by phase coupling circuits 13a, 13b so that a relation of a phase of outputs of delay elements 11a, 11b of the ring oscillator 11 is stably controlled. Thus, first and second ring oscillators 11, 12 maintain the oscillation so that the state of the phase is temporally shifted by a half of the delay time of each delay element. As a result, a time interval of the state of phase during the oscillation is nearly a half of the delay time of each delay element so that the resolution of the oscillation circuit in the state of phase can be improved up to about twice a limit level depending on the delay time of the delay elements.