| 摘要 |
PURPOSE:To enable a highly accurate measurement of distance and speed even in a short range, by using a sound modulated by more than one signals simultaneously as transmission wave. CONSTITUTION:The frequency of signals generated with signal generation circuits 1 and 2 rises in the circuit 1 with the time and falls in the circuit 2. The signals are combined with a sum circuit 3 and generated with a signal generation circuit 5 in a multiplication circuit 4. A carrier wave is modulated in the amplitude. A modulation signal is released from a transmission electricity-sound converter 6 while reflected waves from an object 7 are converted into electrical signals with a receiving converter 8. The signals are passed through phase difference circuits 10 and 11 through a detection circuit 9 and changes in the phase difference between signals generated from the circuits 1 and 2 is outputted in terms of time. An information processing section 12 recognizes the distance to the object and the shape thereof and the relative speed as two signal waves having the frequency components corresponding thereto. |
