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The defense date of the thesis is 2011-08-17
The current date is 2019-07-19
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URN etd-0812111-175515 Statistics This thesis had been viewed 1077 times. Download 4 times. Author Yuan-Jen Cheng Author's Email Address No Public. Department Communication Engineering Year 2010 Semester 2 Degree Master Type of Document Master's Thesis Language zh-TW.Big5 Chinese Page Count 94 Title A Study of Interference over Manufactory Equipments in Clean Room and Voice Quality for PHS Keyword MOS Multipath Effect PHS PHS Multipath Effect MOS Abstract In semiconductor FAB clean rooms, due to the heavy metal wall surrounding the FAB building the reflected signals almost have no loss upon hitting the metal walls such that the reflected signal and direct path signal have a similar strength but opposite phase. Under such conditions, those interacting electromagnetic waves will cancel each other and produce near-zero combined signal strength .Those Fast fading spots exist in many places in the FAB clean rooms and when people move into those spots while making wireless phone calls a discontinuous voice noise will occur.
In order to reduce clean room voice noise issue and guarantee PHS system does not impact exist service equipments when set up a trial PHS system in FAB building. Measure Power density and Check Voice quality (MOS) is the essential testing items.
Base on the testing result that we measure Power density are followed up NCC standard specification ( 0.95 mW/cm2),and observed customer manufactory machine also running well.
To improve clean room voice noise issue, we try to adjust PHS System parameter (TCH Switching Ratio & TCH Switching-type Handover Process Level)that the average MOS value is 4 .
Advisor Committee Chau-Yun Hsu - advisor
Files Date of Defense 2011-07-27 Date of Submission 2011-08-17