| 摘要 |
PROBLEM TO BE SOLVED: To provide a mobile unit detection apparatus which can expand a space to be monitored while suppressing an increase in the scale of circuitry. SOLUTION: Since a plurality of transmitters 3 are provided, a continuous energy wave (an ultrasonic wave) is allowed to reach a place which has been conventionally a blind spot (for example, the vicinity of the third-row seats in a minivan type car), thereby expanding a space to be monitored. In addition, when compared to a case in which a plurality pairs of transmitters 3 and receivers 4 are provided, an increase in the scale of circuitry can be suppressed, since there is no need to increase circuits for processing a received signal output from the receiver 4 (phase detection circuits 6A, 6B, low-pass filters 7A, 7B, comparators 9A, 9B, or the like). COPYRIGHT: (C)2010,JPO&INPIT |
