| 摘要 |
The efficient and secure operation of facilities such as roads, pipelines, etc., will increasingly require reliable and low cost means for distribution and collection of operational data along the facility. A method using simplex, party-line transmission of electromagnetic signals for distributing and collecting data packet messages is described which, in the case of random failures, automatically seeks out alternate routes. The system incorporates double and single end-of-message codes that cue the insertion of new messages, primary and secondary routes that are pre-determined by relative path losses and no-message timing signals, transmitted for phase locking and received signal level referencing purposes. The alternate routes are established by adjustable, enhanced antenna, or lens, side lobes. Alternate routing is triggered by an automatic gain control circuit. A preferred binary modulation, message format and station design are described. A method for automatically bridging in-line failed stations that use microwave transmissions is also described.
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