| 摘要 |
Communication system for vehicle wheel alignment apparatus includes transceivers for each wheel sensor and a plurality of transceivers disposed at a control console or control remote unit. Communication is accomplished with any particular sensor transceiver by switching among the control transceivers as follows: (1) If the sensor transceiver does not respond, switch the transmitter portions of the control transceivers sequentially until the sensor transceiver does respond, and (2) if the signal from the sensor transceiver is garbled, switch the receiver portions of the control transceivers sequentially until the message is ungarbled. The transmitter and receiver portions of the control transceivers are controlled independently, so that for a particular message transmission may use a first control transceiver and reception may use a second control transceiver. The communication between sensor transceivers and the control transceivers is cross-band, with all sensor transceivers using the same transmission frequency and a second, different reception frequency. Each transceiver uses the receiver mixer stage as the final, power amplification stage for the transmitter. Transmission is via an AM modulated FM subcarrier.
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