Pc_clock Spread Spectrum Technology

The dissertation describes the principle of PC clock generator and its application on the PC mother board.Especially analyzes mother board structure,PLL,random N divider,high speed divider.The spread spectrum technology is introduced to reduce EMI on the mother board.A novel six-segments synthesis method is proposed to synthesize varied modulation waveform,such as Lexmark waveform,square waveform,tooth waveform,and triangle waveform etc.Delta-Sigma modulation is implemented to shape noise to high frequency,which is expatiated in this paper.The spread spectrum technology is a simple,applied,small die size solution.The prototype is fabricated in a 0.18μm standard CMOS process.The measurement result is consistent with the calculation.