| 摘要 |
An integrated value ( DELTA tsum) of pulse time intervals ( DELTA t) during one rotation of a signal rotor is computed (S110), and the integrated value ( DELTA tsum) is updated by replacing the pulse time interval achieved one rotation ago with a newly obtained pulse interval ( DELTA t(m)) after exceeding one rotation (S210-S260), while determining an average pulse interval ( DELTA tave) which is an average value of the integrated value ( DELTA tsum) (S420). That is, the pulse information is extracted on the basis of time information required for one rotation of the tire. After the one rotation of the tire, pulse information having the same uniformity as one rotation ago is regained. A running average of n tooth segment times is formed and non-uniformities of individual teeth are filtered out. Additionally, tire pressure may be detected using a Fourie transform. <IMAGE> |
