低谐波失真的CMOS正弦波振荡器设计  

Design of CMOS sine-wave oscillator with low output harmonic distortion

作　　者：陈思远[1] 高明伦[1] 肖飞[1] 何书专[1] 

机构地区：[1]江苏省光电信息功能材料重点实验室南京大学微电子设计研究所,南京210093

出　　处：《电子测量技术》2008年第4期13-16,共4页Electronic Measurement Technology

基　　金：江苏省高技术研究资助项目(BG2005030)

摘　　要：本文设计了一种具有低谐波失真输出的CMOS正弦波振荡器。该振荡器以RC有源微分电路作为选频回路。在实际电路设计中应计及运算放大器的频率特性,由此可得RC有源微分电路为二阶高Q电路。该电路具有良好的选频特性,大幅降低了振荡器输出的谐波失真,并配合移相和可变增益电路以满足振荡器起振条件。使用本文设计的CMOS运算放大器,该振荡器可起振的带宽可达200Hz～2MHz,其谐波失真小于通带噪声。以输出正弦波频率为100kHz为例,给出了Hspice仿真结果。A design of CMOS sine-wave oscillator with low output harmonic distortion is presented. The oscillator uses active RC differentiator as its frequency selecting loop. In practice designs, the frequency characteristic of OpAmps should be taken to account, and then the active RC differentiator could be found operating as a narrow-bandpass filter. This reduces the harmonic distortion of the output signal of the oscillator largely. This paper modifies the active RC differentiator and adds phase lag loop and voltage controlled amplifier to meet the oscillating set up condition. Using the CMOS OpAmps shown in this paper, the operation range of this oscillator could achieve 200 Hz^2 MHz. An example circuit with output frequency at 100 kHz and its simulation results by Hspice are presented. The harmonic distortion of its output is less than the pass-band noise.

关 键 词：CMOS正弦波振荡器 RC有源微分电路 谐波失真 运算放大器频率特性 

分 类 号：TN752.1[电子电信—电路与系统]