| 摘要 |
A method for determining the starting instant (to) of a periodically oscillating signal response (E2; E2'), wherein the signal response comprises a first set of half periods (E2a-d; E2'a-d) having a polarity equal to a polarity of the first half period (E2a; E2'a) in the signal response, and a second set of half periods (E2e-h; E2'e-h) having a polarity opposite to the polarity of the first half period (E2a; E2'a) in the signal response. The method comprises the steps of: determining a peak half period (E2e; E2'f) as the half period with the highest amplitude in a selected one of the first and second sets; determining a zero-crossing instant (ZC1; ZC'1) of the signal response occurring a known time distance from the peak half period (E2e; E2'f); determining the starting instant (to) of the signal response (E2; E2') based on the zero-crossing instant (ZC1; ZC'1) and a relationship between the peak half period (E2e; E2'f) and the starting instant (to). |
