| 摘要 |
<p>An instrument for facilitating accurate nondestructive measurements of physical properties using a noncontact sensor. A noncontact measurement instrument (1) includes a transmitter (21) and a receiver (22). The transmitter (21) sends a wave to an object under test (41) in a medium (100), whereas the receiver (22) receives a wave reflected by the object (41) and a coating on the object (42). The transmitter (21) and the receiver (22) are connected to a gain control circuit (13) to form a self-excited oscillator (11) serving as a feedback loop. The gain control circuit (13) increases gain based on the phase difference between the transmitted wave and the reflected to facilitate accurate measurements of changes due to the difference in physical properties of the object (41).</p> |
