频率偏差

进一步根据区域控制偏差（ACE）和频率偏差的大小与方向，对区域总调节功率予以修正，以进一步提高CPS指标。

Based on the area control error ( ACE ) and frequency deviation , the total regulation power is corrected to be more suitable for CPS .

首先分析了时钟频率偏差对OFDM子载波造成的相位旋转和载波间干扰，并针对试验系统进行偏差测试，验证了理论推导的结论。

First it analyzes the phase rotation and inter-carrier interference of the OFDM sub-carriers caused by the clock frequency deviation , and carries on a deviation test for the trial system which verifies the conclusions of theoretical derivation .

高精度GPS时间传递测定和校准原子钟频率偏差

Frequency deviation of atomic clock determined and calibrated by GPS time transfer with high precision

然而，OFDM系统对频率偏差和相位噪声比较敏感。

However , OFDM is sensitive to frequency offset and phase noise .

码元定时和频率偏差估计是OFDM系统的关键技术之一。

Symbol timing and frequency offset estimation are key techniques in OFDM systems .

OFDM的主要缺点是对载波频率偏差很敏感。

One of the principal disadvantage of OFDM is sensitivity to frequency offset .

基于差分空时调制的OFDM系统中的载波频率偏差估计算法

An Algorithm for Estimating Carrier Frequency Offset in the DSTM Based OFDM System

通过MATLAB仿真，分析了载波频率偏差与相位偏差对系统性能的影响。

Analysis on how carrier frequency bias and phase bias influence the system performance is achieved by the Matlab emulation .

但是OFDM系统对于包括符号定时偏差和频率偏差在内的同步偏差非常敏感。

However , OFDM is very sensitive to synchronization errors which include timing offset and frequency offset .

在载波同步模块的设计过程中，本论文改进设计了ML载波同步算法，提出通过联合相关平均和角度平均来进行载波频率偏差估计。

In the frequency synchronization , we design a combined correlation average and angle average structure to estimate the frequency offset accurately .

通过连续重发两个相同的OFDM符号，应用最大似然估计方法确定采样频率偏差。

At last , a maximum likelihood estimating method of sampling frequency offset by transmitting two identical OFDM symbol was proposed .

部分相关ML算法首先利用子空间分解技术动态跟踪多径信道变化，再实时计算出最佳相关长度用于码元定时和频率偏差估计。

The partial correlation algorithm tracks maximum multipath length by subspace decomposition and calculates optimal correlation length subsequently for symbol timing and frquency offset estimation .

CPS考核中区域频率偏差系数的动态特性仿真分析

Emulation Analysis of Dynamic Performance of Area Fequency Error Factor in CPS Appraisal

其次本文分析了符号定时误差、采样时钟偏差、频率偏差对解调信号的影响。针对符号定时同步问题，阐述了利用OFDM帧头训练序列同步的方法；

Secondly , the effects of carrier frequency offset , sampling clock offset , and symbol timing offset on OFDM signals are exploited .

3）研究了同时利用CP（循环前缀）集相关特性和能量差分特性的符号定时同步方法，这种方法可以消除频率偏差对符号同步的影响，提高了同步效果，系统性能得到很大改善。

3 ) The symbol timing synchronization method combining the cyclic prefix ( CP ) energy difference and set correlation is adopted .

在分析国外研究状况及中国AGC实际运行的基础上提出了一种频率偏差系数确定方法。

A frequency bias coefficient setting technique is proposed by analyzing the investigative status abroad and AGC performance in China .

该技术的主要特点是各子信道具有很高的频谱约束性，对系统频率偏差不敏感，从而克服了OFDM易受频率偏差影响的弱点。

The main character of this technique is the high-spectral constraint of each subcarrier which results in its non-sensitivity to frequency offset where OFDM enduring .

针对LEO信道多径衰落的特性，提出了OFDM系统频率偏差估计算法。

On the basis of the characteristics of the LEO channel , a pilots-aided frequency offset estimation algorithm for OFDM systems is proposed .

尤其在高速移动环境下，多普勒频移和多普勒扩展明显，频率偏差使OFDM系统子载波间的正交性遭到破坏，产生子载波间干扰（ICI），这将大大降低系统性能。

Frequency offset destroys the orthogonality between OFDM sub-carriers , which brings about inter-carrier interference ( ICI ), resulting in performance degradation .

分析了载波频率偏差、符号定时偏差和样值频率偏差对OFDM系统性能的影响。

This thesis analyzes some influences on the performances of OFDM digital communications , which include carrier frequency offset , symbol timing offset and sampling clock offset .

然而OFDM系统对于符号定时偏差和载波频率偏差十分敏感，因此精确的符号定时和频偏估计对于OFDM系统是极其必要的。

However , OFDM system is very sensitive to symbol timing offset and carrier frequency offset , so accurate timing synchronization and frequency synchronization are necessary to OFDM system .

OFDM系统自身的正交多载波调制特点，决定了其对定时误差和载波频率偏差十分敏感。

The orthogonal multicarrier modulation , which is the main character of OFDM , determines that it is very sensitive to both timing synchronization error and carrier frequency offset .

如何克服这两个问题是OFDM技术研究的主要方向之一，本文主要是研究OFDM技术中的频率偏差估计问题。

How to eliminate the two problems is the main task of the research of OFDM . In this thesis , we mainly discuss the problem of frequency offset estimation .

以基于Blackman-Harris窗的加窗插值FFT算法推导出关于频率偏差的9次方程。

The 9th order equation of the frequency offset based on Blackman-Harris window and interpolated FFT is derived .

分析指出，ip-iq谐波电流检测方法坐标变换过程中，C变换矩阵的频率偏差对检测结果不构成影响。

It is concluded that the detection results will not be influenced by frequency offset in the C matrix transformation process of i_p-i_q harmonic current detecting method .

而产生ISI和ICI的主要原因是在OFDM系统接收端产生的符号定时偏差和载波频率偏差。

The most critical causes yielding the ISI as well as ICI are symbol timing and carrier frequency offset which are occurred in the OFDM receiver .

因此，在OFDM系统接收机中，定时的确定、载波频率偏差和采样频率偏差的纠正是信号恢复的关键。

So , in an OFDM system , finding the symbol timing , the carrier frequency offset , and the sampling rate offset the receiver is important in the recovery of the signal .

经过仿真，从星座图、误码率（Bit-Error-Rate，BER）及信噪比（Signal-to-NoiseRatio，SNR）损失等角度对采样频率偏差的影响做了揭示和验证。

In the simulation , constellation , Bit-Error-Rate ( BER ) and Signal-to-Noise Ratio ( SNR ) performance degradation are analyzed taking into account the effect of sampling frequency offset .

其次介绍了OFDM技术的基本原理，给出了OFDM信号的特性以及一般OFDM系统的构成模型，仔细分析了三种同步误差（定时偏差、载波频率偏差、采样时钟频偏）对OFDM解调性能的影响。

Secondly , the basic theory of OFDM system and the system model are introduced , and the errors of timing synchronization , frequency synchronization and the sampling rate synchronization are discussed in detail .

论文针对OFDM技术峰值平均功率比高以及易受频率偏差和时变信道的影响的缺点进行研究，给出有效的解决措施。

In the dissertation , researching the defects that Peak-to-Average Ratio ( PAR ) is high and influenced greatly by frequency offset and time-varying channel in OFDM system , providing the effective settlement measures .