Accession Number : AD0863794

Title :   Multiple-Channel Same-Frequency Repeater Study.

Descriptive Note : Final rept. Mar-Dec 69,

Corporate Author : MARTIN MARIETTA AEROSPACE ORLANDO FL

Personal Author(s) : Horne, W. Henry ; Freeman, Lionel D.

Report Date : DEC 1969

Pagination or Media Count : 160

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)

Descriptors :   (*RADIO REPEATERS, ULTRAHIGH FREQUENCY), RADIO RELAY SYSTEMS, VOICE COMMUNICATIONS, AMPLITUDE MODULATION, MULTIPLE OPERATION, SAMPLING, AIRBORNE.

Subject Categories : Radio Communications

Distribution Statement : APPROVED FOR PUBLIC RELEASE