The Design of Modular Telemetry Transmitters for Satellite Applications

摘要

All solid-state telemetry transmitters of APL design were first used in APL satellites in place of commercially designed units in 1961. A second-generation transmitter composed of individual functional modules was designed to replace the original units beginning with the GEOS satellite launched in 1965. A total of fifteen satellites have used APL designed transmitters, of which four are of the newer modular configuration. As of January 1967, ten of these satellites were operational. Modular TM transmitters can be constructed with more confidence because the assembler works on a less complex unit. Testing is simpler. Quality control inspections are more rigorously defined. Six standard modules, comprising a crystal oscillator, phase modulator, frequency multiplier, and power amplifiers, are discussed in detail. In addition, present and future special-purpose modules are presented. Particular emphasis is placed on the analysis of linear phase modulators and the engineering philosophy that led to the modular concept, including packaging, testing procedures, quality control, and thermal design.