Patent ID: 7257508
Filing Date: 2007-08-14
Classification: G01R

Abstract:
1. A timing generator that outputs a second periodic signal having a predetermined phase difference to a first periodic signal, comprising: a voltage-controlled oscillating unit for outputting an oscillation signal with frequency according to a given control voltage as the second periodic signal; and a timing controlling unit for superimposing a superimposed voltage according to the phase difference of the second periodic signal to the first periodic signal on the control voltage in order to supply the voltage to said voltage-controlled oscillating unit, wherein said timing controlling unit comprises: an initializing unit for measuring a timing shift gain indicative of a ratio of a timing shift amount of the oscillation signal output from said voltage-controlled oscillating unit to a change of the superimposed voltage; and a voltage generating unit for generating the superimposed voltage based on a timing shift amount according to the predetermined phase difference of the second periodic signal and the timing shift gain, and the initializing unit comprises: a first phase adjusting means for shifting a phase of at least one of the first periodic signal and the second periodic signal with respect to a phase of the other and harmonizing the phase of the first periodic signal with the phase of the second periodic signal; a second phase adjusting means for sequentially changing the superimposed voltage supplied by the voltage generating unit to said voltage-controlled oscillating unit and detecting an amount of change of the superimposed voltage when the phase of the first periodic signal and the phase of the second periodic signal are identical with each other once more, on condition that an amount of phase shift by the first phase adjusting means is held; and a gain computing unit for computing the timing shift gain based on an amount of change of phase of the second periodic signal to the first periodic signal caused by changing the change amount of the superimposed voltage detected from the second phase adjusting means and the superimposed voltage.