| 摘要 |
<p>PURPOSE: To make clear the reliability of distance measurement data by judging whether a measurement value is obtained from only the reflection signal from a target object or a signal including a reflection signal from another object in a distance measurement system using electromagnetic waves. CONSTITUTION: Angle is modulated by applying a sinusoidal wave u(t) to a transmission electromagnetic wave at the side of a transmitter 2. A reception signal r(t) including a multiple reflection wave is subjected to angle demodulation. A demodulation signal 103 is compared with a sinusoidal wave u(t) at a transmission side by a phase difference detector 6, where the phase difference between both is obtained and a propagation distance is obtained. On the other hand, a fundamental component whose frequency is equal to the sinusoidal wave u(t) at the transmission side in the demodulation signal 103 and a signal component including a number of harmonics are separated by filters 4 and 5 and then each power component is taken out by operators 8 and 9. The reliability of propagation distance measurement result is evaluated by comparing the fundamental component and the harmonic component by a distortion detector 10.</p> |
