MICROMODULE LIFE TEST PROGRAM.
RADIO CORP OF AMERICA CAMDEN N J COMMUNICATIONS SYSTEMS DIV
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Based on over 26 million micromodule hours, the observed MTTF for micromodules is approximately 300,000 hours with continuous operation 65 or 75C. Handling of modules and the physical movement of the test setup during test had a dramatic effect on the reliability of the modules. There is a learning curve or familiarization period associated with new operators and test facilities. There was a positive or upward drift in center frequency of the analog modules. This coupled with the fact that Modules which are tunable should receive periodic center frequency adjustments. On the other hand, if modules are to be completely sealed, they should be tuned to a center frequency slightly below the specified center frequency to allow an upward frequency drift. The variable capacitor used with the DM-3 micromodule is inadequate to withstand the stresses imposed on it in this test. Inadequate mechanical strength may have been a contributing factor to many failures. Improved protection against mechanical stress should be provided. Environmental testing was not effective as a screen to eliminiate potential failures. The reliability of the micromodules tested is probably a function of the amount of experience each vendor had accumulated prior to the production of material for this test. Reliability estimates for the Vendor A modules are probably most nearly representative of what one would achieve in the long run. Analog modules are more subject to degradation failures than digital modules. Author
- Electrical and Electronic Equipment