提出了一种基于二次差频测距的新方法。
A new ranging method based on quadric difference frequency is presented.
给出了用差频延时法测距的距离折射误差计算公式。
A formula of atmospheric refraction error of range measured by difference frequency delay method is presented.
提出一种通过矢量控制和差频控制原理控制的双电机传动系统。
This paper provides both vector control and frequency difference control to modulate the system of double motors transmission.
多频测距解模糊的实现方式通常有两种：二次差频和参差双频。
The realization mode of solving ambiguity for multiple frequency ranging usually has two kinds:quadric difference frequency and uneven dual frequency.
它主要由二次谐波产生、和频产生、差频产生、光参量振荡等构成。
It mainly consists of harmonic generation, sum-frequency generation, difference-frequency generation, optical parametric oscillation and etc.
通过对波导中差频耦合方程的简化，推导出了转换效率的解析表达式。
By simplifying the coupled equations of DFG in waveguides, we provide analytical expressions of the conversion efficiency.
除此之外，在本文也介绍此差频技术所产生光源之基本特性以及相关的应用。
Moreover, the characteristics and applications of coherent terahertz radiation sources will be introduced in this paper.
本文给出了一种计算无噪声时具有正弦鉴相器的二阶锁相环捕捉特性的新方法，求得了每个差频周期的平均角频率牵引量。
A new method is presented for analyzing the acquisition behavior of second-order PLL with sinusoidal phase detector in the absence of noise.
通过理论分析和数值模拟研究了在双脉冲泵浦情况下的级联和频与差频的二阶非线性效应，探讨了走离效应对波长转换的影响。
Through theoretical analysis and numerical simulations, the walk-off effect between sum-frequency pulse and pump pulse caused by Group Velocity Mismatch (GVM) was discussed.
随机周期长度偏差对准相位匹配波导中差频效率的影响要比随机占空比偏差的影响来得大，这与单块周期极化晶体中的情况类似。
With the same magnitude, random period error casts much larger effect on the conversion efficiency than random duty cycle error, which is similar with the case in bulk crystals.
差分跳频是一种新型的跳频通信技术。
Differential frequency hopping (DFH) is a kind of new frequency hopping (FH) technique.
频率转移函数设计和信号的检测方法是差分跳频中的关键技术。
The frequencies transition function and the method of signal detection are the key technologies in this system.
结果证实了，差分跳频通信技术和按序列检测方法的结合，使通信系统在瑞利衰落信道条件下的性能得到了比较显著的提升。
The simulation results presented prove that the performance of DFH system with signal detecting by sequence is much better than the conventional frequency hopped systems over Rayleigh fading channels.
提出了一种频差估计的新算法，该算法结合观测序列的周期图和自相关函数进行频率估值。
A simple algorithm for frequency offset estimation is proposed, which estimates the frequency offset with the periodogram and the correlation function of the observation samples.
提出一种适合软件无线电的载波相位和频差估计算法。
An algorithm suitable for carrier phase and frequency offset estimation in software radio is proposed.
采用集成电路实现舰船电站自动频载调节，从理论上分析了并联运行机组间的有功功率分配以及频差调节原理。
In this paper, we theoretically analyses the distribution of the active power and the regulation principle of the frequency differences between the parallel operating generators.
本文研究了收发双方存在载波频差时利用累积量实现调制分类这一实际问题，提出一种改进的基于累积量的信号分类算法。
An improved algorithm for classification of MDPSK signals based on cumulants is presented in this paper, which is robust to the error of the carrier synchronization.
在数字通信系统中，发送端和接收端的载波往往存在一定的频差。
In a digital communication system, usually there exist carrier frequency offset between the sender and the receiver.
基于仿射密码的加密原理，构造了一种差分跳频的频转移函数。
Based on the encryption principle of affine cipher, a frequency transition function of DFH is designed.
由于外差或频差效应，能够得到多普勒频率。
The Doppler frequency can be obtained as a heterodyne or beat effect.
小管径频差法超声波流量计的测量精度受各种因素的影响，因而获得较高精度比较困难。
The precision of the ultrasonic flowmeter with small tube diameter and frequency difference method is affected by several factors, so to gain more accuracy is difficult.
可估计的载波频差范围是大的，约为符号率的，并且算法所需的计算负载非常低，适合数字硬件实现。
Its estimation range is large, about of the symbol rate, while the algorithm proposed requires a very low computational load and is very easy to implement with digital hardware.
利用时间窗数据和频率窗数据所进行的联合时-频反演，缩小了拟合差，提高了定量解释精度。
The fitting difference is reduced and the precise of quantitative interpretation is improved by means of joint TF inversion with time and frequency window data.
仿真试验表明，该方法能够精确地估计调频非线性剩余频差，具有较高的运算效率，并给出了一个实际试验结果。
Simulations demonstrate that this method provides an accurate estimation of nonlinear residual frequency errors with high computation efficiency. An experimental result was also given.
通过与有限差分计算的频散曲线的比较验证了算法和程序的正确性。
The method is validated by comparing the results obtained by this method with those obtained by the finite-difference method.
结果表明，用该算法可以精确估计载波相位和频差，有效地降低系统的误码率。
The simulation for QPSK shows that the algorithm can estimate the carrier phase and frequency offset accurately and reduce the system BER effectively.
结果表明，用该算法可以精确估计载波相位和频差，有效地降低系统的误码率。
The simulation for QPSK shows that the algorithm can estimate the carrier phase and frequency offset accurately and reduce the system BER effectively.
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