| Summary: | 碩士 === 國立高雄第一科技大學 === 電腦與通訊工程所 === 97 === Due to the increasingly need of digital TV, and the better techniques, thedesign of the broadband tuning circuits also becomes important in RF designing.Consequently, in this thesis, we also design a low phase noise dielectronic resonate VCO of being used for the digital TV system. Therefore, we design a 1.22 GHz low noise voltage-controlled oscillator by using the model of LC-tank Oscillator to collocate dielectronic resonator. In addition, we have also combined the simulation of RF circuit software proceed with the circuit and simulation. In practical, we used ATF-55143 Low Enhancement Mode MOSFET of Agilent. As for the varactor, we used 1SV239 of TOSHIBA. The 1.22 GHz low phase noise dielectronic resonate
VCO has an output range of 1.12 to 1.24 GHz with a 8.47dBm output power. The phase noise is as good as -117 dBc/Hz at 100 kHz offset from carrier frequency.
And design a broadband VCO, the thesis is accomplished by using Balanced VCO,with the standard of the first IF that in the structure of the dual-conversion, and the range of the frequency scope must be above 815 MHz. Actually, we used 2SC5007 transistor of NEC and BB135 varactor diode of Philips. Final, it operates between 1.18 to 2.41 GHz with phase noise is -107 dBc/Hz at 100 kHz offset from carrier
frequency.
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