| 摘要 |
A combined motion detector/transmitter device for a traffic information warning system is disclosed. The device includes first and second oscillators for transmitting first and second carrier signals, respectively. The first carrier signal has a first carrier signal frequency and the second carrier signal has a second carrier signal frequency. The carrier signals are used to transmit a message regarding a traffic situation based upon either the magnitude of the frequency difference between the first and second carrier signal frequencies or the specific frequency locations of the carrier signals. The first and second oscillators also set up first and second disturbance fields, respectively. A first reflected signal receiver is associated with the first oscillator and receives a first reflected signal when a target is within the first disturbance field. A second reflected signal receiver is associated with the second oscillator and receives a second reflected signal when a target is within the second disturbance field. First and second detector circuits are provided for detecting the presence or absence of a moving target in the first and second disturbance fields, respectively. Finally, the device includes an indicator for indicating the detected presence of a moving target in either the first or second disturbance fields.
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