TELEMETRY FM/FM BASEBAND STRUCTURE STUDY. VOLUME 1
ELECTRO-MECHANICAL RESEARCH INC SARASOTA FL
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This final report describes an experimental evaluation program which was undertaken to investigate the technical feasibility of expanding the Inter- Range Instrumentation Group IRIG FMFM baseband to include a larger number of channels, choice of constant- or proportional-bandwidth subcarrier channels, and greater flexibility in operating parameters. The program consists of an evaluation of typical field equipment design of an expanded proportional- bandwidth baseband, a constant bandwidth baseband and a baseband composed of combinations of constant and proportional-bandwidth channels and an experimental evaluation of each baseband using typical field equipment in a complete laboratory telemeter. Results are obtained for operation of the standard IRIG baseband at deviation ratios of 1, 2, and 5, as well as operation of the baseband with higher frequency channels at 93 kc, 124 kc, and 165 kc. A 21-channel constant-bandwidth baseband with channels spaced 8 kc apart from 16 kc and deviated 2 kc is evaluated at deviation ratios of 1, 2, and 4. In addition, a baseband composed of the first 11 IRIG channels plus the 21 constant bandwidth channels is evaluated. Recommendations for expansion and operation of the FMFM baseband are given as well as a discussion of the results of the system evaluation test. This report thus provides technical information which may be used by the Telemetry Working Group TWG of IRIG for consideration of expansion of the FMFM baseband structure, but should in no way be considered to represent recommendations of the TWG or IRIG.