The new method is a modified pts method , and can make good compromise between performance and computational complexity . the dissertation explores , by means of computer simulation , how the conventional method based on amplitude - limiting and filtering affects the performances of wavelet packet modulation signals , and presents a new method , namely , selective mapping / amplitude limiting / filtering method , which proves to be effective , simple , and have better ber performance 并基于自子波变换和时间、尺度分辨率的概念,从理论和仿真实验两方面对信道建模和时间/尺度rake接收机进行了分析,并与传统的kake接收机进行了比较,结果表明时间/尺度联合分集能有效地克服高速衰落多径信道的影响。
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。