Browsing by Author "Yang, Hui Chun"

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Fabrication of Portable HSDPA USB Dongle
(2009)
Kao, Yao Huang
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Yang, Hui Chun
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電信工程研究所
;
Institute of Communications Engineering
The construction of portable HSDPA USB dongle is studied. Of course, data service such as GPRS and EDGE are also supported. In the multi-mode operation of GPRS & EDGE exit GSM850, EGSM, GSM1800 and GSM1900. For WCDMA & HSDPA, Band I, II, and V are treated in our dongle. So, the dongle must fulfill the requirements for multi-mode and multiband services. The power regulator with LDO is indicated to have the heat problem and leads to adjacent channel leakage ratio (ACLR) fail even drop the call. Change LDO to Bulk can overcome the temperature rising, but produce switching noise, which will cause the in-band noise and sensitivity degradation. The solutions to the wireless in-band noise are proposed. Also the transient peak current for GSM transmitter is solved.
Interferences of GPS Reception in PDA Phone
(2010-01-01)
Kao, Yao Huang
;
Yang, Hui Chun
;
電信工程研究所
;
Institute of Communications Engineering
Recently, wireless industry is moving towards convergence of radio technology to cater for multi standards on a single platform-personal digital assistant (PDA). In the meantime, the platform have to satisfy small size, light weight, and low power consumption. The wireless sensitivity is by no questions affected by the digital and analog functions. The determents are from conductive and coupling noises. In this study, the sensitivities in GPS and 2G/3G are tested. The sources are identified step by step turning on each application function. It is found that the most deteriorated factors are from digital functions of camera and SD card, which are allocated near the GPS antenna. The solutions are nothing but improving the grounding, noise bypassing, and slit closure. Same phenomena are also found in the reception of 2G/3G operation. The GPS receiver sensitivity is affected not only by the digital noise but also by analog noise. GPS noise radiating from system digital noises (LCM driver IC/FPC, camera, light sensor, G-sensor, IR-sensor, SD-card, SIM card, processor or memory noise when running map).