frequency shift transmission

Remote sensing image fusion method based on wavelet packet frequency-shift;

基于小波包移频算法的遥感图像融合技术

Design of detector for frequency-shift track signal;

移频轨道信号测试仪的设计

A plan of frequency-shift equipment with microcomputer on railway signal is proposed, which replace the old frequency-shift equipment.

介绍了一种以单片机为核心实现铁路信号移频发送设备电子化的方案 ,用来替代由分离元件构成的移频发送盒 ,从方案设计思想、设备的硬件组成框图和软件设计流程等方面进行了详细的论述 。

Research and Development of the monitor system of shifting frequency signals;

移频信号监测系统的研究与开发

In terms of the disadvantages of the two presently comparatively advanced interval automatic blocking technologies: ZPW-2000A jointless shifting frequency automatic blocking and microcomputer axle counter technology,this paper combines them based on actual projects to complement each other so as to improve the efficiency and safety of rail transport.

针对ZPW-2000A型无绝缘移频和微机计轴这2种目前比较先进的区间自动闭塞技术的弊端,结合工程实际,将二者结合起来,互相弥补不足之处,以改善区间列车的行车效率及安全性。

The traditionnal frequency shifting automatic block systems are disadvantages involved behindhand technology,small information,bad credibility.

为改变传统移频自动闭塞系统存在技术落后、信息量少、可靠性差,不能满足现代运输生产的发展需求状况,应用先进的单片机技术,可编程逻辑芯片(FPGA)和高性能CPU,通过逻辑结构设计和时序控制,实现了移频自动闭塞设备的集成化、通用化,大幅度提高了列车运行的可靠性,并为实现机车信号主体化创造了条件。

Precision of phase demodulation in practical 3D detection using the projected grating phase method was improved by recognizing that spectrum mixing and inaccurate frequency moving greatly affected the accuracy of phase demodulation.

为提高投影栅相位法在三维检测实际应用中的解相精度 ,分析了频谱混叠及移频方法的不准确对解相精度造成的影响 ,建立了一种新的频域相对解相技术。

The problems are analysed in practical 3D detection by phase approaching of projected grating that frequency moving in frequency domain and the correspondence between measured surface and reference plane have great effect on the accuracy of phase demodulating.

根据投影栅相位法三维检测实际应用中所遇到的频域处理的移频问题和被测物体与参考面的对应关系问题，分析了它们对解相精度的影响，提出了不移频和全场参考面的解决方法。

The realization of frequency shift signal based on railway circuit;

轨道电路移频信号解调实现

Digital realization of frequency shift signal with continuous phase;

相位连续移频信号的数字化实现

The investigation of technical solution based orthogonal frequency shift signal;

基于正交性移频信号技术方案的研究

The phase of the Frequency-Shift Keying(FSK) signal transmitted in frequency-shift track circuits is continuous.

移频轨道电路信号是一种相位连续的移频键控(FSK)信号,它的载频和低频信息通过FFT可以很容易的检测出来,但上下边频的高精度检测,一直是比较棘手的问题。

The paper analyzes non detection zone(NDZ) of active frequency drift(AFD) and active frequency drift with positive feedback(AFDPF) .

该文通过对主动移频式孤岛检测方法的检测盲区进行分析,推导了带线性正反馈主动移频式(active frequency drift with positive feedback,AFDPF)孤岛检测方法的盲区大小与反馈增益间的关系,并得出特定负载下孤岛检测无盲区AFDPF反馈增益的取值范围,从而为AFDPF孤岛检测方法的参数优化提供了理论指导。