| 摘要 |
PURPOSE:To contrive higher accuracy and reliability, by aranging fluctuation values in such a way that, it is applied to either one of two signals applied to a time difference detecting circuit and by these fluctuation values, estimating the mean value of propagation time in an ultrasonic wave propagation path. CONSTITUTION:By a successive approximation, a higher-rank datum W1 is determined, a lower-rank datum W2 is scanned and a detecting signal F of the time difference detecting circuit 5 is integrated by an integrating device 6. After repeating this operation several times, the lower-rank datum W2 relaive to the propagation time from the integrated value Fs is determined. Assuming a time distance Ts1 of a dividing signal S1 is expressed as follows: Ts1(t)=T<0>s1+ deltaTs1W2(t), where, fluctuation time =deltaTs1; mean value of Ts1=T<0>s1. This value is compared with the propagation time of received signal V by the time difference detecting circuit 5. The result is integrated by an integrating means 6 and the mean value T<0>v of the propagation time Tv is estimated from Fs. |
