基於改良過的Modulo- 電路和一組參考方波,設計出一個具有高效能的全新數位頻率合成器,其中該組參考方波有相同的頻率,卻各自有不同的相位。將該組參考方波通過一個多工器,並藉由一漸增器(Incrementer)運作,可由該組參考波組合得到最大的輸出頻率,其中使用一格雷編碼器(Gray encoder),得以控制多工器的輸出,而達到消除脈衝干擾(Glitch)問題的目的,最後加上特殊設計的Modulo- 電路,將該多工器的輸出頻率重新組合成所欲的輸出頻率。藉由Cell-Based設計實現流程,使用TSMC 0.18um製程以圖形方式來驗證電路設計的Pre-Layout和Post-Layout模擬結果。
With an improved omodulo-N arithmetic and a set of reference square waveforms, a new architecture of high-performance digital frequency synthesizer is devised, where the reference square waveforms with the same frequency but different phases are passed through a multiplexer to obtain the maximal frequency with an incrementer. A Gray encoder is designed to eliminate the glitch problem. Finally, the special Modulo-N circuit synthesizes the desired output frequency by the output of the multiplexer. Pre- and post-layout simulation results based on the TSMC 0.18um cell-based implementation are illustrated to validate the design, which can be used for TSMC 0.18 um realization.