| 摘要 |
A spread-spectrum CDMA communications system for locating remote units, and for communicating message data between a plurality of remote units and a base station. The spread-spectrum CDMA communications system includes a plurality of base stations and a plurality of remote units. A base station has a spread-spectrum modulator for spread-spectrum processing the message data, and a transmitter for transmitting the spread-spectrum processed-message data, combined with a generic-chip-code signal, from the base station to a remote unit. The base station also has an antenna, and spread-spectrum detectors for recovering message-data communicated from the remote-units. A remote-unit has an antenna, and a detector coupled to the antenna for recovering data communicated from the base station. The detector includes a spread spectrum demodulator. Also, the remote unit has a device for converting the format of the data into a form suitable for communicating over radio waves, a spread spectrum modulator and a transmitter. The base station has a range circuit, which comparers the generic-chip-code signal generated at the base station with the generic-chip-code signal received from the remote unit, for determining a range between the remote unit and the base station.
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