Broad Signal Constraints for the Management of the Spectrum in Telephone Loop Cables: Identical Constraint on All Pairs

A previous paper showed that constraining the total energy transmitted on all pairs in a cable during any time interval of a specified duration limits the maximum instantaneous near-end crosstalk voltage on any pair. This paper determines a constraint on the energy that is the same for each pair and that guarantees the same limit on near-end crosstalk. While the new constraint permits less variation of transmitted power among the pairs, it permits greater average power per pair. Thus, the constraint developed herein would be particularly useful when a cable is used principally for one type of capability, e.g., ISDN basic access.     

Spectrum Management in Telephone Loop Cables, II: Signal Constraints That Depend on Shape

Instantaneous near-end crosstalk interference depends only on the shape of the signals transmitted on the disturbing pairs during an interval of duration determined by cable properties that immediately precedes observation of the interference. It is shown that these shapes can be resolved into a linear combination of a finite number of orthonormal functions that cause significant crosstalk and a function that does not cause substantial crosstalk. The orthonormal functions are the solution of an equation that depends on the statistical properties of the crosstalk.     

宽带TWTA对信号频谱影响的估计

简要分析影响TWTA频谱特征的因素，着重探讨了TWT的供电电源对TWTA输出信号的调幅、调相作用，并就工作在连续波以及脉冲发射状态下的TWTA的频谱特征进行了初略的估计。     

Channel Requirements for a Cordless Telephone Spectrum Allocation

Planning for a permanent cordless telephone spectrum allocation requires that the number of channels necessary to meet the long-term needs of cordless telephones be estimated. To provide the analytical basis for such an estimate, we determine the relationship between the number of channels available to cordless telephones and their performance in a suburban residential environment. Multiple cordless telephones in a community can use the same channel simultaneously, so performance ultimately will be limited by cochannel interference. We therefore develop a mathematical model of the carrier-to-interference ratio. This model accounts for shadowing, polarization, and multipath propagation effects observed in field measurements, as well as the random locations of cordless telephones. A performance measure is developed and evaluated for cordless telephones that can access all available channels and are operating in a suburban residential environment. The results indicate that for carrier frequencies in the low UHF band (300 MHz to 1 GHz), an allocation of 30-40 duplex channels can accommodate universal use of cordless telephones in that environment. For lower carrier frequencies, shadowing is less severe and fewer channels would be necessary. For example, at 50 MHz, 20 duplex channels would suffice.     

三网融合中电话信号的预处理

目前,光纤入户已成为实现三网融合的最终解决方案。三网融合的关键技术是三种业务的融合,为了解决这一问题,在PPP的传输模式下,给出了三网融合框图;对公用电话网中E1帧的各路电话信号进行了提取,以满足交换模块对各种信号进行数据交换的要求。主要给出了对E1帧进行预处理的结构图及算法,最后利用QuartusⅡ软件对E1帧的15路电话信号的提取进行了仿真。仿真结果表明,对E1帧进行预处理的方法可行。     

全塑市话电缆进水排潮方法的探讨

扼要说明了全塑市话电缆进水受潮的基本途径及其对电缆电气性能的影响,阐述了电缆排潮的两种主要方法.     

基于联建端局的电话收费管理系统

介绍了一种基于联合建设的电话端局的电话收费管理系统 ,重点介绍了该收费系统的结构 ,并对该系统的主要功能作了详细阐述     

中频宽带接收机AGC电路的研究

从一种典型的AGC环路模型推导出环路的动静态特性与环路各元件参数的关系，定性定量地分析了环路的稳态误差、稳定时间以及动态范围，并利用Analog公司的AD8367和AD8361设计了符合要求的具有大动态范围、宽带放大能力的中频AGC环路，通过实际测量验证了理论分析的正确性。     

Spectrum for Pulse Interval Modulation Signal

A static approach method method is used to get the spectrum expression of the pulse interval modulation signal.The expression is simple,has a clear physical concept and it has been confirmed by a simultaneous experiment .     

电话音频信号的计算机识别

针对电话机中对多组电话号码自动拨号的要求，采用单片微型计算机自动识别电话音频信号，分析了识别原理，设计了接口电路和软件，取得了很好的识别效果，解决了电话机设计中实现这一功能的一个技术难题。     

Performance of Portable Radio Telephone Using Spread Spectrum

A 2 GHz band portable radio telephone has been fabricated using the spread-spectrum technique. We describe the fundamental performance, bit error rates with and without interference, measured using the experimental telephone. The telephone system's user density is estimated by computer simulation under relatively realistic conditions.     

用于LVDS传输系统的高速对称电缆的研制

目前LVDS(低电压差分信号)传输模式在高速数字传输领域得到了广泛应用。介绍了一种用于传输高速LVDS的对称电缆的研制,通过合理的结构及材料设计和有效的工艺措施,降低了电缆的衰减,使电缆可在2Gb/s的传输速率下进行数据传输。该电缆具有外径小、重量轻、耐高温等特点,尤其适用于航空航天领域。     

金属中激光超声信号的频谱分析

利用ＹＡＧ脉冲激光器在金属中诱导光击穿,从而产生超声脉冲。分别用５ＭＨｚ,１．２５ＭＨｚ的压电换能器接收光声信号,然后对其频谱进行分析,证明在光击穿的条件下,光声信号是一个含有多种频率的复频信号,其频谱的主峰出现在０～１００ｋＨｚ之间。     

频谱分析仪校准对信号源的要求

校准频谱分析仪通常要进行各种各样的测量,每一种测量都需要合适的输入信号。典型的校准过程一般采用一系列的信号发生器和其它设备来产生信号,并确保其准确度。本文主要介绍了频谱分析仪的校准,并讨论了最常见的校准测试及其对信号的要求,以及满足这些要求的方法。     

基于混沌振子的电话网信号检测

首先介绍了混沌检测原理和基于相关的双频信号检测方法,然后给出了检测信号模型,介绍了结合自相关和滤波预处理利用混沌振子对双频信号进行检测的新方法,分析了其检测原理。最后进行计算机仿真实验,仿真实验说明了该方法对微弱信号非常敏感,检测性能优于单纯混沌系统检测性能,同时进一步验证了所提方法具有强抗干扰等性能,有一定的实用价值。     

Mobile Agents in the Mobile Telephone Network Management

The paper discusses the application of mobile agents in the management of mobile telephone (cellular) networks. We propose the use of mobile agents for collecting subscriber information, such as location area identifier and cell identifier. By using a subscriber profile containing these data the signaling messages caused by location update could be reduced. We also propose a method to improve the quality of network coverage by collecting measurements data by a mobile agent in the mobile station (mobile phone) or at the mobile switching center. By analyzing these data the network provider would be able to discover areas without proper radio signal coverage (black holes), thereby avoiding expensive and time-consuming measurements done by specially equipped vehicles. In addition, we discuss the basic infrastructure requirements for deployment of the mobile agent technology in cellular networks.     

信号功率谱特征提取的进化规划方法

本文提出了一种提取信号功率谱中连续谱和线谱特征的新方法，该方法利用进化规划实现连续谱的最佳非线性曲线拟合，从而获得连续谱的轮廓特征及线谱的位置和相对强度，并对该方法用于被动声纳信号和振动信号的处理和分析，应用结果表明本文提出的方法能准确有效地提取信号功率谱的特征。     

非连续谱雷达信号设计综述

非连续谱雷达信号是一种特殊的认知雷达信号,其频谱由多个离散的频带组成,且能够随着外界干扰的变化自适应地调整离散频带的分布结构.因此,这种信号适用于干扰密布、频谱拥堵的工作场景.非连续谱信号设计主要研究两个问题:一是如何根据干扰环境选取最优的非连续频谱结构以满足雷达抗干扰和分辨性能要求;二是如何根据最优的非连续频谱求解出...     

一种宽带信号的多速率处理方法

相比于逐个信道接收的窄带信号而言,宽带接收机具有全概率接收的优势。为了解决接收宽带信号所需要的模／数（A／D ）转换采样率高、后续信号处理设备速度慢的问题,讨论了如何在A／D高速采样后使用多种滤波器级联的方法来进行多速率处理,最终达到降速率的目的。