| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To solve the problem wherein the peak position of an analog signal cannot be detected accurately because a relative position to the peak position of a phase detection point is changed following an amplitude change of the analog signal. <P>SOLUTION: A circuit for detecting a specific phase position includes a measuring part for detecting two time positions where a signal level of the analog signal agrees with the first threshold as the first and second reference positions respectively in each cycle of the analog signal, and measuring respectively the time length between the first and second reference positions as a reference period; a calculation part for calculating a period having a fixed ratio to the reference period as an additional period based on the reference period measured in the preceding cycle in each cycle of the analog signal; and a detection part for detecting a time position shifted as much as the additional period calculated by the calculation part as a specific phase position from the first reference position detected in the present cycle, and outputting a detection signal showing the specific phase position. <P>COPYRIGHT: (C)2006,JPO&NCIPI</p> |
