摘要
为了能处理X-ray安检系统中微弱的探测信号,需要设计一款精度高达14 bit的调制器。文中采取了三阶Sigma-Delta调制器结构,该调制器采用过采样和噪声整形技术来实现高精度,在信号带宽20 kHz,过采样率256,时钟10.24 MHz的情况下,Matlab Simulink建模仿真结果表明,该调制器SNR可以达到104.6 dB,精度可达17 bit。通过对调制器非理想性分析,采用TSMC0.25μm工艺实现整个调制器的管级电路,并通过Cadence Spectre后仿真,仿真结果 SNR可达到98 dB,即精度为16 bit,满足X-ray安检系统14 bit的精度要求。
In order to deal with the weak signal in the X-ray security system, a 14-bit modulator is needed. This paper adopts a third-order Sigma-Delta modulator structure, the modulator adopts the oversampling and noise shaping technology to realize high precision, with the 20 kHz signal, 256 over- sample rate and 10.24 MHz clock, Matlab Simulink modeling simulation results show that the SNR of modulator can achieve 104.6 dB and the pre-cision can reach 17 bit. After analyzing the non-ideal conditions of the modulator,The tube circuit of the modulator adopts TSMC0.25 um technology and simulates by Cadence Spectre, The results show that the SNR of the mo-dulator can reach 98 dB and the precision is 16 bit, which can satisfy the precision requirements of the X-ray security system.
出处
《电子设计工程》
2017年第10期110-113,119,共5页
Electronic Design Engineering
