[通信] 瞬时频率
The local energy and instantaneous frequency of the signal can be derived from the IMFs.
信号的局部能量和瞬时频率都可以从其本征模函数中推导出来。
This paper proposed the theory of digital counting instantaneous frequency measurement and analyzed the error of frequency measurement.
文章介绍了一种用直接数字计数测量瞬时频率的原理，并进行了测频误差分析。
The physical meaning of instantaneous frequency is analyzed. Its application in the evaluation of the bandwidth of IR scanning systems is discussed.
分析了瞬时频率的物理概念，指出在红外扫描系统中，用瞬时频率来计算系统带宽是值得讨论的。
Firstly the estimation of instantaneous frequency is discussed.
首先是瞬时频率的估计问题。
On the basis of comparatively systematic research to the computing technology of signal instantaneous frequency, a new computing technology of instantaneous frequency is present.
对信号瞬时频率计算方法进行了较为系统的研究，提出了一种新的瞬时频率计算方法；
All the conventional vibrators use the sweep signal of which the instantaneous frequency shows linear change with time.
常规可控震源都是采用瞬时频率随时间线性变化的扫描信号。
An algorithm based on the magnitude and phase angle of the generalized phasor to measure instantaneous frequency and swing frequency while the power swing occurred is presented.
提出了一种基于综合相量幅值和相位变化规律实时测量电力系统振荡中振荡频率及瞬时频率的算法，利用三相电流经相应变换获得综合相量。
The method of computing single frequency signal's instantaneous frequency (IF) is unsuitable to the multi component signal.
计算单分量信号瞬时频率的方法不适合于多分量信号。
In the paper, the method to estimate instantaneous frequency of AM-FM signals using the peak of the WVD and its performances are stu***d.
该文研究了应用WVD谱峰检测估计AM-FM信号的瞬时频率的方法及其性能。
The algorithm can be realized in computer completely, it measures the instantaneous frequency of signal, and implements code synchronization through the jumping of frequency.
这种算法完全可以在微机上软件编程实现，它通过实时估计信号的频率，根据频率的跳变来提取同步信息。
It stems from the concept of instantaneous frequency, and it can describe accurately the local properties of dynamic data in the time-frequency plane.
该方法源于瞬时频率的概念，它能把动态信号的局部特征正确地在时频域内予以描述。
It has the properties of high time-frequency resolution and energy concentration as well as tracking instantaneous frequency etc.
它具有很高的时频分辨率、能量集中性和跟踪瞬时频率等特性。
If a proper non- linear change of the instantaneous frequency is realized, we can get a frequency spectrum whose input is the mean of the reciprocals of bed attenuation coefficients.
如果把瞬时频率作适当的非线性变化，就可以得到一个以地层衰减率的倒数的平均值为输入的频谱。
Instantaneous frequency measurement(DIFM) receiver is one of important component part of EW system.
瞬时测频接收机是电子战系统的重要组成部分之一。
In this method, the main conceptual innovations are the introduction of IMF based on local properties of the signal, which makes the instantaneous frequency meaningful;
这种方法最主要的概念创新是引入了基于信号局部特征的内在模式函数（IMF）的概念，从而使瞬时频率变得有实际意义；
Experimental simulation yielded the relation of the partial mode's instantaneous frequency and vortex frequency without noise.
实验模拟，得到无噪音的部分模式的瞬时频率的关系和涡流频率。
Its adaptability and good local performance of signal instantaneous frequency and amplitude, thus make the signal expressed as a real physical form.
它的自适应性和局域性能很好的表征信号的瞬时频率和幅度，从而将信号表示成具有实际物理意义的形式。
Time-Frequency Analysis is applied to instantaneous frequency estimation;
时频分布应用于瞬时频率的估计；
A method for identifying the instantaneous frequency of a linear time-varying structure was proposed.
提出了一种识别线性时变结构瞬时频率的方法。
Instantaneous attributes including amplitude, instantaneous frequency, bandwidth, dominant frequency and decay rate are used to analyze thin interbeds.
利用地震瞬时谱的属性（包括瞬时振幅、瞬时频率、瞬时带宽、瞬时主频及瞬时品质因数等）进行地震薄互层分析。
According to Hilbert-Huang transform, order tracking analysis of a speed-up signal of gearbox, which is based on instantaneous frequency estimation, is presented.
提出了基于瞬时频率估计的齿轮箱升降速信号阶次跟踪的新方法。
In the paper, a novel instantaneous frequency measure method, which is applicable for the frequency measure system of frequency hopping radar, is presented according to the digital phase-shift theory.
本文根据时钟数字移相原理，提出了一种新的瞬时测频方法，适用于捷变频雷达测频系统。
Using 750 wave-guide in a certain reconnaissance equipment causes the frequency measurement error over the index in the instantaneous frequency measurement receiver.
在某侦察设备中使用750波导引起宽带瞬时测频接收机测频误差偏大。
Three features parameters derived from the instantaneous amplitude, instantaneous phase, instantaneous frequency and power spectrum of analogue modulated signals are presented in this article.
首先介绍从信号幅度、相位、频率及功率谱等特性中提取的三种特征参数，应用这三种参数采用人工神经网络对模拟调制信号进行了识别。
Introduction to the physical concept, classical definition and application scope of instantaneous frequency(IF) is given.
首先介绍了瞬时频率的物理概念、经典定义及其适用范围。
Then using them to research the HH neuron model's transient section and calculate the instantaneous frequency.
在HH神经元模型中分析时间序列的暂态过程部分，求出了暂态过程的频率成分。
Supposing the LFM signals had been sorted and selecting the instantaneous frequency as identification character, the closest method is used to distinguish the signals.
在对LFM信号实现分选的基础上，选取待识信号的瞬时频率作为识别特征，利用最近邻方法对信号进行识别。
Of the basic measures: instantaneous frequency and original frequency, their relationship is given qualitative analysis in earthquake data.
同时对变换之间基本量瞬时频率及傅立叶频率联系，给出在地震动数据方面定性分析；
瞬时频率（Instantaneous Frequency）是信号处理领域的关键概念，特指信号在某一特定时刻的瞬时相位变化率。它描述了信号频率随时间变化的特性，尤其适用于频率成分随时间变化的非平稳信号（如调频信号）。以下是详细解释：
对于任意实信号 ( s(t) ) 或其对应的解析信号 ( z(t) )（由希尔伯特变换构造），瞬时频率 ( f_i(t) ) 定义为： $$ f_i(t) = frac{1}{2pi} frac{dphi(t)}{dt} $$ 其中：
物理意义：瞬时频率反映了信号在时刻 ( t ) 附近微小时间窗口内的局部振荡速率 。
频率的局部化描述
传统傅里叶变换的频率定义适用于稳态信号，而瞬时频率通过相位导数捕捉信号的瞬时频谱特性，适用于分析雷达、声呐、通信中的调频信号 。
调频信号的直接表征
以调频广播（FM）为例，若载波相位 ( phi(t) = 2pi int_0^t f_c + k_f m(tau)dtau )（( m(t) ) 为调制信号），则瞬时频率为： $$ f_i(t) = f_c + k_f m(t) $$ 直接体现调制信号控制的频率偏移 。
非平稳信号分析的基石
在时频分析（如短时傅里叶变换、小波变换）中，瞬时频率是刻画信号时变特性的核心参数，用于故障检测、生物医学信号处理等领域 。
（注：链接指向公开可访问的权威文献来源，部分需订阅权限的书籍标注了标准引用格式）
瞬时频率（instantaneous frequency）是信号处理与物理学中的重要概念，用于描述信号在某一时刻的瞬时频率特性。以下为详细解释：
瞬时频率是一个时变信号在某一特定时刻的频率值。它突破了传统频率（如周期信号的固定频率）的限制，适用于分析非平稳信号（频率随时间变化的信号，如语音、雷达脉冲等）。
数学上，对于解析信号（analytic signal）( s(t) = a(t)e^{jphi(t)} )：
瞬时频率公式为： $$ f(t) = frac{1}{2pi} frac{dphi(t)}{dt} $$ 即相位对时间的导数除以( 2pi )，单位为赫兹（Hz）。
| 普通频率 | 瞬时频率 |
|---|---|
| 适用于周期性平稳信号 | 适用于非平稳、时变信号 |
| 固定值（如50Hz交流电） | 随时间变化的函数( f(t) ) |
| 描述整体周期性 | 描述局部时间点的频率特性 |
假设一个调频信号相位为( phi(t) = 2pi f_0 t + pi k t )：
瞬时频率的提出，使得对复杂时变信号的分析更加精细化，尤其在非线性系统和非平稳信号处理中具有核心意义。
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