接收前端信道设计分析

介绍了接收信道前端在微波接收设备中的重要性，给出了信道前端设计的框图，介绍了各分电路在接收信道中起的作用，讨论了接收机中混频器／本振、放大器性能和系统噪声系数设计、组合干扰产生等方面对接收机性能的影响，同时强调了设计中应该注意和兼顾考虑的地方。     

双频三模接收前端(LNA+Mixers)

本文主要讨论如何根据CDMA系统指标要求确定接收前端的指标,以及如何设计接收机前端,优化接收机性能。     

双频三模接收前端（LNA＋Mixers）

本文主要讨论如何根据CDMA系统指标要求确定接收前端的指标,以及如何设计接收机前端,优化接收机性能。     

基于IEEE UWB标准信道模型的RAKE接收机性能分析

超宽带信号经多径信道传播会产生严重的时间弥散。采用RAKE接收是提高超宽带接收机性能的重要手段。介绍了Intel的UWB多径信道模型。对采用TH-PPM调制的超宽带系统在Intel多径信道模型下A-RAKE，S-RAKE和P-RAKE的误码率性能和对系统复杂性的要求进行了分析。在实际的RAKE接收机设计中，S-RAKE和P-RAKE的性能与支路数有关，S-RAKE要优于P-RAKE。S-RAKE和P-RAKE的性能随着支路的增加而减小。     

一种新型最佳接收机设计方法

提出了一种提高接收机性能的新方法。该方法通过对信道传输信号波形的特征参数测量,分析传输信号的成形方式,根据成形参数设计最佳接收滤波器,有效降低码间串扰和信道噪声对接收机性能的影响,并在噪声信道环境下进行了仿真研究,使用了采样统计方差、信噪比和眼图3种方法对接收机性能进行分析,结果表明,该方法能够有效提高接收机的性能。     

宽带一体化接收前端技术的研究

本文构建了一个通用化、标准化、模块化的带射频接收前端,结合指标要求,进行了系统指标的规划及方案 的可行性论证,利用ADS 软件对其关键指标进行了仿真验证,阐述了宽带射端的设计方法及步骤。通过对各个功能模 块的设计、选择、及调试,最终在200MHz-3200MHz 的频率范围内,采用二次变频技术设计了一种超外差接收前端。 介绍了宽带射频前端系统仿真研究、接收机系统的方案选择、大动态范围接收机的实现接收机技术指标的计算与仿真 和发射机系统的设计与仿真。介绍了宽带一体化接收前端技术的系统设计与实现以及2～6GHz 通用接收机研究及关键 电路的设计与实验。     

基于判决自相关超宽带接收机研究

首先介绍了基于判决自相关(简称DDA)超宽带接收机的接收原理和结构,理论分析了接收误码率特点;比较了基于判决自相关接收机与Rake接收机和基本TR接收机的基本参数要求,并在标准信道模型下仿真对比了它们的接收性能;考察了窗口宽度因子N对基于判决自相关接收机接收性能和结构的影响;通过提高判决自相关系统脉冲功率可在相同能量效率条件下获得与平均TR系统相近的接收性能,且具有更高传输率的优点。     

扩频通信系统中Rake接收性能仿真研究

在扩频通信中,Rake接收是抵抗多径衰落的有效方法。本文首先介绍无线移动通信的信道特性,然后对Rake接收的基本原理和接收机结构进行详细描述,并对Rake接收性能进行了仿真比较。仿真结果表明,在多径信道条件下,Rake接收方式能很好的改善接收系统误码性能;采用GOLD序列扩频比m序列扩频方式时,Rake接收方法性能提高的更明显。     

电子战数字接收机设计中的性能匹配分析

电子战数字接收系统的前端由信号放大链及数字A/D模块组成,接收系统所能达到的极限灵敏度和瞬时动态范围将取决于两者的匹配性能。研究了接收系统为获得接收前端模拟级联放大链与数字A/D模块的匹配问题,推导了有关设计公式,给出了实验验证结果,并给出了在接收系统前端和A/D性能允许范围内获得设计师希望得到的接收机灵敏度和动态范围的设计方法。     

一种VDL mode 2高动态接收前端的设计

针对VDL mode 2接收机前端信号强度变化大、容易造成信道失真的问题,本文设计了一种高线性的动态接收前端。射频前级利用数字增益控制实现增益的快速控制响应,中频则采用模拟自动增益控制电路,进一步提高动态范围。实验结果表明,动态范围达到110dB,并实现了±1dB的线性精度,满足VDL mode 2数据链系统对接收前端的要求。     

Iterative Joint Tone-Interference Cancellation and Decoding for MIMO-OFDM

In this paper, multi-input–multi-output orthogonal frequency-division multiplexing (MIMO-OFDM) is considered in the presence of multipath fading and multitone interference (MTI). The MIMO-OFDM system makes joint use of channel coding and orthogonal space–frequency block coding (OSFBC) on the transmit side and iterative processing on the receiver side for robustness and improved performance against the fading and MTI effects of the channel. The new iterative receiver is implemented by either an optimal a posteriori probability (APP) space–frequency detector or a soft-information-aided minimum-mean-squared-error (MMSE) combiner at its front end and a soft-input–soft-output channel decoder at its back end. An approximate error performance analysis is provided for the OSFBC-OFDM system under maximum-likelihood decoding to illustrate the interference mitigation efficiency of the system. Then, the two iterative receivers are compared in terms of their computational complexities and bit error rate (BER) performances. As depicted in the BER graphs, both iterative receivers provide an improvement in performance after only a few detection/decoding iterations. It is also shown that despite its suboptimality, the MMSE receiver has the potential to achieve a BER performance close to that of the APP detector at a significantly lower cost.      

Multilevel Optical Systems With MLSD Receivers Insensitive to GVD and PMD

This paper analyzes optical transmission systems based on high-order modulations such as phase-shift keying signals and quadrature amplitude modulations. When the channel is affected by group velocity dispersion (GVD), polarization mode dispersion (PMD), and phase uncertainties due to the laser phase noise, the optimal receiver processing based on maximum-likelihood sequence detection and its practical implementation through a Viterbi processor is described without a specific constraint on the receiver front end. The implementation issues are then faced, showing that at least a couple of widely known front ends, with proper modifications, can be used to extract the required sufficient statistics from the received signal. The aspects related to the receiver adaptivity, the complexity reduction of the Viterbi processor, and the possibility of employing polarization diversity at the transmitter end are also discussed. It is demonstrated that, as long as a sufficient number of Viterbi processor trellis states is employed, GVD and PMD entail no performance degradation with respect to the case of no channel distortions (the back-to-back case).     

双波段软件无线电接收机射频前端设计与仿真

射频前端是无线电接收机的重要组成部分,目前常用的超外差结构射频前端虽然性能良好,但结构复杂、不易集成、便携性不高。因此文中从结构出发,采用直接变频的零中频结构设计了一种可以兼容接收短波、超短波射频信号,同时也能达到一般超外差接收机的性能指标的射频前端。并通过multisim软件仿真验证,该设计具备跨波段、高灵敏度、大动态范围等性能特点。     

Modeling and analysis of nonlinearities and mismatches in AC-coupled direct-conversion receiver

This paper analyzes the effects of circuit nonlinearities and mismatches on the performance of an AC-coupled direct-conversion receiver (DCR). An analytical solution is necessary, since quantifying the DCR performance by simulation can be prohibitively slow. Our analysis approach first transforms the receiver front end to an equivalent baseband continuous-time receiver model with all of the noise sources referred to just before the sampler. Accurate approximations were made throughout this process to make the analysis tractable. The baseband continuous-time model can be further simplified and combined with the baseband equivalent propagation channel model. The resulting model allows the end-to-end performance of an ac-coupled DCR to be quickly and accurately quantified.     

一种超宽带雷达系统接收前端的实验研究

较详细地介绍了一种VHF/UHF频段超宽带接收前端的设计,实验系统带内具有良好的线性相位和幅度平坦特性,文中给出了接收前端及主要部件研制结果的性能指标。     

多通道相位一致性高温超导滤波器组

利用高温超导薄膜材料的低插损特性,实现了具有相位一致性的新型高温超导高性能三通道滤波器组,该器件置于接收机前端系统的低噪声放大器前可以使接收机前端系统同时具有带外抗干扰特性和带内低损耗特性,并具有极高的灵敏度。     

Ka波段混合集成前端

介绍最近研制成功的8毫米波混合集成前端的设计方法和测试结果，该前端由本征模块、发射机和接收机组成，具有高指标、小型化、轻量化和高可靠等优点，测量结果表明，在工作频带内，发射功率大于350mW，接收机噪声系数小于3.0dB。     

Noncoherent decorrelative detection for nonorthogonal multipulsemodulation over the multiuser Gaussian channel

This paper introduces the problem of noncoherent detection for nonorthogonal multipulse modulation in the context of the synchronous multiuser Gaussian channel. Each user sends an M-ary information symbol by transmitting one of M possibly nonorthogonal waveforms. Furthermore, the M signals of one user are allowed to be correlated with the signals of all other users. A key idea proposed here is that of a noncoherent decorrelative receiver front end. Like its counterpart in single-pulse modulation, this front end eliminates multiuser interference. It therefore reduces the multiuser detection problem into decoupled single-user problems over equivalent noise-enhanced single-user channels. Each equivalent single-user channel is rather general and can be described as one where the waveforms employed are not only correlated, but are also of unequal energies. Several new results pertaining to the design and analysis of optimum and suboptimum noncoherent detectors for this single-user channel are obtained. In the multiuser channel, these detectors constitute the post-decorrelative processing units for each user     

多任务载荷中共用接收射频前端设计

介绍了机载载荷的现状与发展趋势,特别是多任务载荷的发展方向.提出了多任务载荷中接收前端方案,描述了共用接收射频前端的系统构成,对接收分系统的性能及关键技术进行了分析与仿真,结果表明接收射频前端可同时满足通信与通信情报侦察的需求.