【摘要】 设计了一个用于GSM系统的Sigma-Delta调制器.GSM系统要求信号带宽大于200kHz,动态范围大于80dB.为了能取得较低的过采样率以降低功耗,采用了级联结构(MASH)来实现,与单环高阶结构相比,它具有稳定及易于实现的优点.设计工作时钟为16MHz,过采样率为32,基带带宽为250kHz,电路仿真可以达到最高82dB的SNDR和87dB的动态范围.芯片采用SMIC0.18μm工艺进行流片,面积为1.2mm×1.8mm.芯片测试效果最高SNDR=74.4dB,动态范围超过80dB,测试结果与电路仿真结果相近,达到了预定的设计目标.芯片工作在1.8V电源电压下,功耗为16.7mW.更多还原

【Abstract】 We propose a Sigma-Delta modulator for a GSM system,whose channel bandwidth is wider than 200kHz and dynamic range is more than 80dB.A multi-stage noise shaping structure,rather than a single-loop structure,is chosen to achieve lower OSR and higher stabilization.The design parameters are:f_ CLK=16MHz,OSR=32,and baseband width=250kHz.Simulation at the circuit level achieves a peak SNDR of 82dB and DR of 87dB.The chip is implemented in SMIC 0.18μm CMOS technology,and the area is 1.2mm×1.8mm.Measurement at 16MHz clock frequency and OSR of 32 achieves a peak SNDR of 75dB and DR over 80dB,which are close to the values obtained by the circuit level simulation.The chip operates under a 1.8V power supply with a power dissipation of 16.7mW.更多还原