應用於射頻訊號產生器中具功率微調功能之寬頻輸出模組研製

Abstract

本文研發射頻訊號產生器中之輸出模組。此模組包括寬頻之調變器、射頻 放大器、分功率器、檢波器及其溫度補償電路、迴路濾波器及後級衰減電 路。在電路製做時，特別考慮元件本身之特性、寄生效應以及實際電路佈 線時對頻寬之影響，以達到 1.3 GHz 之寬頻要求。此外，對準位控制之 迴路穩定度、檢波器與調變器之線性化考量，也有詳細之分析與探討，使 本模組具有消除前級合成器之波動、穩定控制輸出至所需之準位，同時產 生低失真振幅調變訊號之功能。其輸出準位，最大可至+13dBm，準確度 達+-1.5dB;同時振幅調變頻寬可至50KHz;調變指數在70% 內，調變失真小 於4% ;調變指數在30% 內，調變失真小2%，已達到目前國外現有訊號產生 器之水準。 The fabrication of wideband automatic level control(ALC) module with applications to RF signal generator is pre- sented in this thesis. The module has the capability of eliminating the fluctuation from the synthesizer,adjusting the output level precisely and generating low distortion amplitude modulation. The wideband design is under consid- eration when fabricates each sub-module.The module consists of the modulator,RF amplifier,power splitter,detector,loop filter and post attenuator.The features of PIN diodes, Schottky diodes and other passive components are charact- ized to achieve the broadband circuit design from 160 MHz to 1280MHz.In addition, the close-loop stability of the ALC and the linearization of the detector and modulator are also analyzed for further exploration.The output module with frequency range up to 1280 MHz,+13dBm maximum output ,stable and precise control of the output power level,50k Hz modulation bandwidth, less then 2% AM distortion under 30% AM index and less then 4% AM distortion under 70% AM index has been successfully fabricated.