| 摘要 |
PURPOSE:To obtain an image of the desired region of a sample by generating a gate signal for extracting a reflected wave component on the basis of a reflected wave signal exceeding a threshold value during the gate period of the gate signal generated based on transmission timing. CONSTITUTION:When a transmission timing signal is outputted from a transmission timing signal generating circuit 1, the first gate signal is outputted from the first gate generating part 13 after a predetermined time and, when a reflected wave signal exceeds a threshold value for the first time during the gate period due to the first gate signal, a gate trigger signal is outputted from the RSFF circuit 22 of the second gate generating part 20 and the second gate signal is outputted after a predetermined time. By controlling the output timing of the second gate signal and the delay time in a signal delay part 7, gate is applied to the arbitrary place of the reflected wave signal and only the reflected wave component from the predetermined region of a sample is extracted. |
