PURPOSE: To obtain correct positional information between clocks different in frequency band by using a ring oscillator whose oscillation frequency is synchronized with an input clock as a part for delaying an input clock by means of delay elements of many stages to form multi-phase delay clocks.

CONSTITUTION: The ring oscillator 31 is constituted of connecting gate delay element 61∼64 capable of controlling delay values in series like a loop, a phase error signal is applied from a phase comparing loop filter 30 to the delay value controlling terminals of respective elements 61∼64 and the oscillation output of th ring oscillator part 31 is synchronized with an input clock. Thereby, delay clocks 41∼44 are latched by a latch circuit 24 in accordance with the 2nd frequency clock CK2 having frequency different from that of the 1st frequency clock CK1. The latched clocks are supplied to a conversion table circuit 25 and factors (k), (1-k) are generated in accordance with the contents of the outputs of the latch circuit 24.