A modulated signal of cos ( 2 * pi * freq * tt ) , freq = 2 ( mhz ) multiplied by a carrier with zero mean uniform phase noise . is demonstrated for 2 - d dependence of the waveform on time and trials and 2 - d dependence of spectrum on frequency and trials to show different time domain and frequency domain properties of a random process including noise and signal 以弦波电压讯号乘上含有均匀相位杂讯载波之调变讯号为例，图示含有杂讯电压讯号其波形随时间及试验之二维变动及频谱随频率及试验之二维变动，显示杂讯与讯号之随机过程在时域与频域之不同特性。
A modulated signal of uexp ( tt / pw ) added by a normal noise . is demonstrated for 2 - d dependence of the waveform on time and trials and 2 - d dependence of spectrum on frequency and trials to show different time domain and frequency domain properties of a random process including noise and signal 以单边递减波电压讯号加上准常态杂讯乘以无杂讯载波之调变讯号为例，图示含有杂讯电压讯号其波形随时间及试验之二维变动及频谱随频率及试验之二维变动，显示杂讯与讯号之随机过程在时域与频域之不同特性。
In order to verify memory effects of nonlinear power amplifier ( pa ) and to design and optimize pa with reducing memory effects , this paper analyzes existence of electrical and thermal memory effects with different tone spacing two - tone input signal and modulated signal source through mathematical derivation and advanced design system ( ads ) software simulation , and presents a method which can optimize pa with memory effects 摘要为了证实非线性功放记忆效应的存在同时为了设计和优化功放以减小记忆效应，通过理论推导和ads仿真的方法分析了不同间隔的双音输入和调制输入的情况下电记忆和热记忆效应的存在，同时提出了种优化功放记忆效应性能的方法。
In the first part of this paper , the theory of laser range and dds technology was introduced , the factors of influencing range precision were also analysed . at the same time , put forward in the paper , with using the fpga embedded technology , the wideband and high resolution sin modulating signals can be generated easily , then analysed the noise of the dds ; in the second part , the theory of phase measurement based on fft was analysed . in the phase range system , by using the fft operation , the resolution and sensibility of phase measurement can be enhanced ; then some circuits were designed and come true , also simulated and validated ; in last part , the improvement of the phase range system was brought forward , summarized and expected 论文首先阐述了激光测距和调制信号源的基本原理,分析了影响测距精度的因素,指出应用dds技术可以实现宽带、高精度的调制信号输出,说明了引起dds输出信号杂散的原因和解决的办法;同时分析了应用fft运算实现信号相位提取的基本原理及设计方法,采用这种检相技术,可以极大地提高测相精度与灵敏度;然后提出了基于fpga嵌入式系统的相位式激光测距机的整体设计,并就各部分进行了详细的分析与设计;接着介绍了激光测距系统的外围电路和基于quartusii集成软件平台的部分硬件电路的设计,并对其中的设计进行了仿真和验证;最后总结提出了对系统今后的进一步改进和完善的思路。
There are many ways of modulating signal about bpsk such as castas loop , square loop , etc . usually the carrier wave is put forward firstly , then the purified carrier wave is used to demodulate the output data ( all these things are usually completed in the same loop ) . these methods have their strong points but at same times , it is difficult to design and achieve these ways 有关bpsk调制信号的解调方法很多，例如castas环，平方环等，这些方法一般都是先提取载波，然后用提纯的载波去解调出传输的数据(大都在同一个环路内完成) ，这些方法的优点是显而易见的，但是在某些条件下，这些方法的设计和实现却很困难。
The modulating signals of firing delay angle at the rectifier and firing lead angle at the inverter , and the excitation voltage are chosen to be control variables . the offset of the current of dc line and the extinction angle and the power angle of generator are chosen to be control outputs . then a nonlinear controller is designed for the system under study according to direct feedback linearization theory 以整流侧触发延迟角的调节信号、逆变侧触发超前角的调节信号以及发电机励磁电压作为控制变量,以直流线路电流、逆变侧关断角以及发电机功角的偏移量作为目标输出,用直接反馈线性化方法设计了系统的非线性控制器。
Direct sequence spread spectrum ( ds - ss ) system modulates a data sequence to a high speed pseudorandom ( pn ) sequence , which extends the bandwidth of the modulated signal while decreasing the power spectrum density . it is an advanced communication system with many excellent properties such as multiple access , low probability of interception , anti - jamming and so widely used 直接序列扩谱通信是用一个高速的伪随机序列调制一个数据序列,以展宽并降低信号的功率谱密度的一种先进的通信体制,能获得多址接入、低截获特性和抗干扰能力,因此具有广泛的应用。
