The chip can be widely used in mp3 player , pda , digital camera , cells phone and portable products etc . this thesis first introduces the basic theory of switching power supply . the operating theory of this circuit has been demonstrated . the operating principle and simulation analysis about band gap reference , self - biased current source , one shot circuit , hysteresis comparator , and current - limit circuit have been particularly expounded in this thesis 本文首先阐述了开关电源的工作原理,详细介绍了本电路的整体工作原理,最后重点介绍了自偏置电流源电路、基准源电路、单稳态触发器电路、峰值电流限制及低电池电压迟滞比较器的工作原理,并利用eda工具larker ? ams 、 hspice对电路进行了完整的设计和模拟仿真,给出了合理的电路数据,各子模块电路的电特性参数均达到或优于设计所需指标。
This paper goes on with analysis of the phased array radar calibration theory and compare of different schemes , then the best is adopted . 2 mhz digital circuit mainly composed of dds ( direct digital synthesis ) chip , which carries out the shift of the phase and the limit of the amplitude , has been designed and debugged successfully . it is used to substitute for the conventional phased shift circuit and amplitude limiting circuit which work at the radio frequency , so the all - digital transmit channel of phased shift array radar is achieved 本论文研究的重点是:针对传统相控阵雷达系统收发( t r )组件中的移相和限幅功能均在射频段完成,大胆利用直接数字合成( dds )芯片组成频率在2mhz左右的数字电路代替传统相控阵雷达在射频段进行移相和限幅的电路,从而组成全数字发射通道,使对相位和幅度的控制和调试更方便快捷,并设计具体的电路验证此方案的可行性。