【摘要】 提出了一种适合于宽带应用的单环高阶双采样ΣΔ调制器系统结构。该结构采用双采样技术,在不提高系统时钟频率的条件下,可使系统的过采样率增至原来的两倍。提出了一种新的实现噪声传递函数fs/2处零点的双采样电路,使得该系统结构能够灵活实现优化了的噪声传递函数和信号传递函数。采用SIMULINK对包含了电容失配的调制器进行了建模和仿真,仿真结果表明该结构能有效地抑制采样支路失配引起的折叠噪声,提高了调制器的性能。更多还原

【Abstract】 A single-loop high-order double-sampling ΣΔ modulator architecture for broadband applications was proposed.The architecture employs the technique of double-sampling,and can double the oversampling ratio of the ΣΔ modulator without increasing the clock frequency.A new simple circuit was proposed,and the circuit can realize the zero at the half of the sampling frequency in the noise transfer function.The proposed architecture can easily implement the optimized noise transfer function and signal transfer function of the modulator.A system model was built and simulated by SIMULINK.Simulation results show that the ΣΔ modulator architecture can degrade the folded noise caused by the mismatch of sampling capacitance and improve the modulator’s performance.更多还原