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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

The Study of ZnO/Si Layered SAW Oscillator for UV Detection

Cheng, Po-Shu 15 August 2008 (has links)
The highly c-axis oriented ZnO films were deposited on silicon substrates by reactive RF magnetron sputtering in this study. The optimal two-step deposition parameters for ZnO films, which are oxygen concentrations of 70 % (1st step) and 50 % (2nd step), RF power of 100 W and sputtering pressure of 25 mTorr, are obtained by means of XRD, SEM and AFM analysis. Al films are deposited under optimal deposition parameters, which are DC power of 100 W and sputtering pressure of 4 mTorr, to form IDT electrodes with low sheet resistances. Therefore, Al/ZnO/Si layered SAW devices were fabricated under these optimized manufacturing parameters. An oscillator based on a Al/ZnO/Si layered SAW device was fabricated for the application of UV detection and then investigating the acoustoelectric effect between surface acoustic wave and ultraviolet light illumination. Due to the fact that the sensor sensitivity is directly proportional to the resonance frequency, in this study the SAW device with high resonance frequency of Sezawa mode is adopted to form SAW oscillator for high sensitivity. The resonance frequency of SAW oscillator is 751.41 MHz. The optimal detecting zone for UV light is the center of IDT electrode with maximum sensitivity of 8.12 ppm/(£gW/cm2).
2

PC- Based S-Band Down Converter / FM Telemetry Receivers

Girija, Satyanarayana, Girija, J. 10 1900 (has links)
International Telemetering Conference Proceedings / October 28-31, 1996 / Town and Country Hotel and Convention Center, San Diego, California / In this paper design and development of a PC- Based S- Band Down Converter/ FM Telemetry Receiver are discussed. With the advent of Direct Digital Synthesis (DDS) & Phase Locked Loop (PLL) technology, availability of GaAs & Silicon MMICs, Coaxial Resonator Oscillator (CRO), SAW Oscillator, SAW Filters and Ceramic Filters, realisation of single card PC- Based Down Converter and Telemetry Receiver has become a reality. With the availability of Direct Digital Synthesis and Phase Locked Loop devices having microprocessor bus compatibility, opens up many application in Telemetry and Telecommunications. In this paper design of local oscillator based on hybrid DDS & PLL technique, Coaxial Resonator Oscillator and Front-end are discussed in detail.

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