The catch is that because low-frequency waves can travel great distances, when they do bounce off cavities or objects underground, they often end up far from the detection equipment at the surface.
捕捉过程是这样的，因为低频波可以传输到更远的距离，当它们遇到地下的空穴或其他物体反射回来的时候，已经距地面的接收装置很远了。
The simulation result shows that the dynamic response and the detection precision in detection circuit can be greatly influenced by the cut-off frequency, order and type of low pass filter.
结果表明，低通滤波器的截止频率、阶数和类型对检测电路的动态响应过程、检测精度都有很大影响。
The detection probability calculating method about low pulse repetition frequency(LPRF) PD radar against air vehicle is studied.
提出了低脉冲重复频率（LPRF）PD雷达探测飞行器目标的发现概率计算方法。
In intelligent peripheral subsystem, Radio Frequency Front Modules include linear power amplifier, low noise amplifier and detection control circuit.
智能天线子系统中，射频前端模块包括线性功率放大器，低噪放大器，检测控制电路。
The U. S. Navy plans to deploy a new submarine detection system, known as Low Frequency Active Sonar (LFA), throughout 80% of the world's oceans.
在世界的 80% 的大海各处，美国海军计划部署一个新的海中发现系统，即是低的频率活跃的声纳 （LFA） 。
A broadband, high resolution and low phase noise frequency synthesizer used in electronic detection and electronic countermeasure system is described in detail.
详细介绍了一种用于电子侦察与对抗系统中的宽带、高分辨率、低相位噪声频率合成器。
The reasons of low detection accuracy are analyzed in detail and the improved methods are proposed. A fault detection approach based on frequency distance comparison is presented.
通过对造成电动机断条故障检测准确度不高的各种原因进行深入的分析，针对这些原因提出了具体的改进方法，并提出了一种基于频距比较的故障检测新方法。
Therefore, supergain hydrophone array, particularly the small-sized circular array, is very good for improving the detection performance of low frequency passive sonar.
由于超增益阵具有尺度小、空间增益高的特点，对于改进低频被动声纳的检测性能具有重要的意义。
In chapter six, the application of higher order statistics in detection low-frequency noise of transistor is discussed.
第六章研究了高阶统计量在晶体管低频噪声检测中的应用。
The method was Correlate search and FFT carrier detection, which could solve the problem of the capture of the spread spectrum code under the condition of low SNR and big frequency offset.
方案中提出了：相关搜索、FFT检测信号载波的方法，解决了低信噪比、大频差条件下扩频码的同步捕获难题；
The mix-lookin detection technique for high frequency signal measurement with low frequency look-in amplifier is presented.
本文提出一种利用低频锁相放大器测量高频信号的混频-锁相检测技术。
Results 40 cases appendicitis patients, low frequency probe with 35% detective rate, and high frequency probe for the detection rate of 87.5%.
结果40例阑尾炎患者，低频探头超声论断符合率为35%，而高频探头检测符合率为87.5%。
The system comprises low frequency-difference two-frequency laser interferometer measuration module, micro-detection device and two dimension platform.
系统由低频差双频激光干涉度量模块和微探头及二维工作台两部分组成。
The detection method of low frequency signal injection, which is widely used, is easily influenced by the capacitors between ground and each branch and by the ring net.
目前广泛使用的低频信号检测法容易受到直流系统支路中存在的对地分布电容和环网的影响。
A new method for height finding using monopulse measurement based on stepped-frequency system is discussed in this paper for enhancing low-altitude detection of metric-wave radar.
为了提高米波雷达低空探测性能，本文讨论步进频率体制下，单脉冲测角的米波雷达测高方法。
High frequency surface wave radar is an important tool of the over horizon detection of sea and low-altitude targets.
高频地波雷达是对海面、低空目标进行超视距探测的重要手段。
Method: to use Model HKY06A heart vibration sensor for the detection of the heart sound, and to form the heart sound envelope with two way hardware rectification and low frequency passed filter.
方法：使用HKY06 A心音传感器提取心音信号，使用双向检波及低通滤波实现心音包络的提取。
With analyzing the detecting procedure of Low-frequency active sonar and emulating about it, the Optimum Detection frequency Band of Low-frequency active sonar were researched.
本文通过对低频主动声纳的主动声纳方程的分析与声学探测过程的仿真，初步研究了低频主动声纳在不同距离上的最优探测频率问题。
In the process of bearing defect detection and diagnosis, the faulty bearing vibration signals are scattered in a wide frequency range, which can be easily masked by noise and low-frequency effects.
在轴承缺陷检测和诊断的过程中，有缺陷的轴承振动信号分散在一个较宽的频带范围，很容易被噪声和低频信号所掩盖。
Stochastic resonance can only be applied to low-frequency signal or the known high-frequency signal detection. So the applications of the system are severely constrained.
现有的随机共振系统只能应用于低频率信号检测或待测信号频率已知的高频率信号检测，这束缚了系统的实用范围。
Target characteristics and high frequency scattering mechanism are summarized. RCS analysis methods, RCS reduction approaches and low RCS target detection techniques are discussed.
本文概述军用飞行目标对微波雷达的散射特性，讨论了目标的高频散射机理，雷达截面(RCS)分析方法及减缩途径，以及低rcs目标探测技术等。
Finally, error detection and concealment algorithms for low and high frequency coefficients are presented respectively.
最后，对低频和高频系数，分别提出了相应的差错检测和掩盖算法。
Cloge detection system of pigging and extrusion tools is adopting very-low-frequency radiowave emission and reception.
清管及挤涂工具的阻卡探测系统是采用甚低频无线电波发射、接收。
As far as cased-hole formation resistivity logging, the key problems needed to be solved are detection of ultra-low frequency and extremely weak signals, as well as reduction of strong interferences.
超低频、纳伏级信号的检测以及强干扰的抑制是过套管地层电阻率测井需要解决的关键问题。
The detection of Pre-P wave was affected by the heart rate, respiratory, artefact and low frequency waves.
前波的表达受心率、呼吸、伪差及低频波等因素干扰。
The detection of Pre-P wave was affected by the heart rate, respiratory, artefact and low frequency waves.
前波的表达受心率、呼吸、伪差及低频波等因素干扰。
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