CAJ | 학술논문

要模数转换问题的研究中,介绍了∑-△调制器的过采样和噪声整形技术,为提高转换精度和速率,提出了一个采用四阶级联结构和∑-△调制技术实现高精度的调制器的行为级模型,根据影响建模的各种非理想因素,对各种实际非理想因素(例如开关热噪声、时钟抖动、运放的有限直流增益等)通过优化系统参数之后,可以得到一个用于ADSL设计中的高精度∑-△调制器行为级模型.并在MATLAB下对其仿真验证,结果表明为实际设计提供了依据.调制器在基带带宽1.5MHz、24倍过采样率条件下,系统的信噪比达到87dB,精确度可达14比特.
요모수전환문제적연구중,개소료∑-△조제기적과채양화조성정형기술,위제고전환정도화속솔,제출료일개채용사계급련결구화∑-△조제기술실현고정도적조제기적행위급모형,근거영향건모적각충비이상인소,대각충실제비이상인소(례여개관열조성、시종두동、운방적유한직류증익등)통과우화계통삼수지후,가이득도일개용우ADSL설계중적고정도∑-△조제기행위급모형.병재MATLAB하대기방진험증,결과표명위실제설계제공료의거.조제기재기대대관1.5MHz、24배과채양솔조건하,계통적신조비체도87dB,정학도가체14비특.
This paper presents overshanping and noise-shanging techniques used in sigma-delta modulator.Behavior modeling and simulation of a high resolution Sigma-Delta modulator by using 4-rd Cascade and sigma-delta modulator technique for ADSL applications is presented.Analyzed the main non-ideal mechanism affecting the performance of Sigma-Delta modulator(such as switch thermal noise,clock jitter,finite dc gain of OPA,erc)and optimized the coefficients of the system by using MATLAB SIMULINK.In condition of various actual non-ideal performance of Sigma-Delta,simulation results show that the modulator system can achieve a SNR higher than 87dB and 14 bits accuracy with an overshaping ratio of 24.