Delay clock generating apparatus and delay time measuring apparatus

摘要

A standard clock 34 is input to a phase comparator 52 and a phase controller 56. The ring oscillator 50 oscillates a shift clock 70 having a same cycle as the standard clock 34. The phase comparator 52 matches the downward shift of the shift clock 70 with the downward shift of the standard clock 34 to output a shift clock 72. The shift clock 72 is supplied to the pulse inserter 54. The phase controller 56 receives the standard clock 34 and generates a phase control signal 74 indicating cycles of the shift clock 72 to which the insert-pulses are inserted among a plurality of cycles of the shift clock 72. The pulse inserter 54 inserts the insert-pulses to the cycles of the shift clock indicated by the phase control signal 74. The phase-lock unit 58 generates a delay clock 82 by delaying the phase of the shift clock 70 oscillated by the ring oscillator 50 with respect to the phase of the standard clock, based on the standard clock and the shift clock 76 including the insert-pulses.