Multiple-Channel Same-Frequency Repeater Study.
Abstract
The study determines and describes an optimum technique for a multiple channel same frequency repeater (SFR) system for airborne range extension of amplitude-modulated voice communications in the 225 to 400 MHz band. Analyses are performed and tradeoff studies conducted on the large number of factors relating to multiple channel operation of both sampling and nonsampling SFR's having from 2 to 12 channels. An optimum configuration is defined for both the sampling and nonsampling techniques, and the merits of the two are compared. The recommended system employs sampling SFR's in a synchronous configuration, such that all transmitters and all receivers are alternately gated at a 13 kHz rate. Channels are combined through tunable cavity bandpass filters into a single standard aircraft antenna. Channel spacing may be as close as 1.25 percent of the operating frequency. Unlimited channel selection is possible without repeater self-interference or generation of excessive intermodulation products so long as the minimum required channel spacing is maintained. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1969
- Accession Number
- AD0863794
Entities
People
- Lionel D. Freeman
- W. Henry Horne
Organizations
- Martin Marietta