| Summary: | 碩士 === 大同大學 === 通訊工程研究所碩士班 === 94 === ABSTRACT
In this thesis, a case study relating to the third order harmonic emission from an
IEEE 802.11a WLAN card is investigated. The WLAN card contains many circuit
subsystems. Among them, the transceiver block, the filter block, the power amplifier
block and the diplexer block are the main block under study. We carefully investigate
electric performances of each block to understand if the harmonic emission may come
from these blocks. In this test, each block is detached from the mainboard. We found that
harmonic emission exists even through each block is individually well functioned.
In addition to the block test, we also use the near field scan method to locate the
nearest possible spots which may cause the harmonic emission. We found that this
method is an efficient way. In our case, the emission is determined to come from the PA
block as it contributes the highest radiation intensity by way of this near field test. After
locating the source of emission, we can prevent them by way of shielding.
|
|---|
