Browse Prior Art Database

Microwave Linking of VHF Repeater Stations

IP.com Disclosure Number: IPCOM000043012D
Original Publication Date: 1984-Jun-01
Included in the Prior Art Database: 2005-Feb-04
Document File: 2 page(s) / 52K

Publishing Venue

IBM

Related People

Gay, CJ: AUTHOR

Abstract

Mobile radios and other portable radios typically are low-power VHF stations communicating through higher-power VHF repeaters. The drawing illustrates a system to extend communications over long distances by linking repeaters by microwave. The microwave stations operate on non-interfering frequencies and communicate only with two other stations in a loop, as shown in Fig. 1. The microwave communications are digital, employing standard differential phase-shift keying which may be readily decoded without external synchronization. Time periods in a fixed time period or frame are allocated to station addressing and messages, all digitized. Synchronization is first established employing frames blank except for the predetermined synchronization pattern.

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Microwave Linking of VHF Repeater Stations

Mobile radios and other portable radios typically are low-power VHF stations communicating through higher-power VHF repeaters. The drawing illustrates a system to extend communications over long distances by linking repeaters by microwave. The microwave stations operate on non-interfering frequencies and communicate only with two other stations in a loop, as shown in Fig. 1. The microwave communications are digital, employing standard differential phase- shift keying which may be readily decoded without external synchronization. Time periods in a fixed time period or frame are allocated to station addressing and messages, all digitized. Synchronization is first established employing frames blank except for the predetermined synchronization pattern. Subsequently, the microwave loop is continuously operated with each station observing for the synchronization pattern only during the limited period corresponding to when the pattern should appear. This prevents synchronization on a similar, false pattern. Time division multiplexing is employed. The frames have portions allocated to station-selection patterns, which address one or more of the microwave stations, and to data. The data typically will be digitized audio. Each frame has a time period allocated for passing commands among stations. These commands are used to establish links among the stations. The high frequencies of microwave permit the broad signal band necessary to carry all of that data. Each of the microwave stations receives the audio from all of the other stations and responds to it when it is addressed by a command to decode the aud...