| 摘要 |
A very narrow band multipoint communication system suitable for use in an automatic meter reading (AMR) system having a communication protocol that divides each main channel of a frequency or digital code hopping system into multiple sub-channels and applies frequency division multiplexing among the sub-channels. Each sub-channel exhibits a very narrow band characteristic that allows gain increase to increase the transmission range of the meters. In addition, frequency division multiplexing among the sub-channels greatly increases the number of meters that can communicate on each main channel. The data collection device demodulates and decodes the multiplexed meter signals at an intermediate frequency with electronic circuitry. The resulting very narrow band AMR system exhibits greater transmission range, greater bandwidth and can accommodate a much larger number of meters per data collection device in comparison to a conventional narrow band AMR system.
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