全概率截获信道化接收机的设计

文章重点研究了基于多相滤波技术实现全概率截获的信道化接收机,推导了实信号的多相滤波器组信道化接收机数学模型,并基于模型利用MATLAB针对四路信号进行了仿真分析,仿真结果证明了接收机模型的正确性和可操作性,为通信系统具体应用该接收机提供了重要的理论依据.     

多相滤波宽带信道化数字接收机

宽带雷达电子战数字接收机是当前国内外研究的重点,信道化接收机能够处理同时到达的多个信号并有较高的截获概率。多相滤波信道化接收机运算量小且易于实现。为克服因D倍抽取而产生的多相滤波信道化数字接收机的接收盲区,引入了重叠一半的多相滤波信道化数字接收机。利用瞬时自相关接收机,可在消除信道化接收机虚假输出的同时提高信道化接收机的测频精度。文中给出了上述数字接收机的实现方法,并通过仿真实验证明了以上结论的有效性。     

宽带数字信道化接收机的FPGA实现

为解决现代电子战对接收机处理带宽宽、灵敏度高及实时性处理的要求,提出一种数字信道化接收机的设计方法。在推导高效信道化接收机模型的基础上,采用多相滤波器结构实现的数字信道化接收机。该接收机利用超高速A/D对数据进行高速采样,然后由高性能FPGA进行数据抽取、多相滤波、CORDIC算法等信道化实时处理。为了提高实时性,采用并行IFFT实现。该信道化接收机不仅能稳定输出载频及相位信息,还能处理三路同时到达的不同信号。实际的性能测试结果表明该接收机的功能正确并达到预定指标。     

一种大带宽高分辨力数字信道化接收机

阐述了两种基于多相滤波器结构的数字信道化模型，就电子对抗领域中雷达侦察接收机的实际应用，提出了一种大带宽数字信道化接收机的方案，该方案采用文中阐述的两种信道化模型级联的方式，具有瞬时带宽大，频率分辨力高等特点，能够在单片FPGA中实现。     

基于FPGA的数字信道化接收机的研究及实现

本文讨论了软件化电子战侦察接收机多信号处理问题。使用多相滤波的宽带数字化接收设计技术，可以提高接收机的实时处理能力，提高全概率截获能力。本文讨论基于多相滤波的信道化接收机的基本原理及实现方案，给出了基于FPGA的数字信道化接收机的实现方法，实验结果证明了该方法是有效的。     

基于多相DFT结构数字信道化接收机的仿真研究

雷达侦察接收机已进入了数字时代,本文推导了一种多相滤波器实现方法,并建立一种基于多相DFT结构数字信道化接收机数学模型,使用MATLAB对其可行性进行仿真验证。这种结构结合了信道化接收机和数字接收机的特点,既能处理同时到达的信号,又具备较高数据处理速度,具有一定的研究价值。     

DSP的软件信道化接收机的设计与实现

基于传统信道化接收机以硬件划分信道为主，无法实时处理大量的宽带信号，提出了软件结合硬件来实现宽带信号中子信道的划分；采用多相滤波算法实现信道化，介绍了软件信道化接收机实现的硬件平台，对该接收机硬件设计中每个电路模块的功能及实现分别作了说明，并从整体上描述了软件的信道化接收机的工作流程。     

一种高效的宽带数字信道化接收方法

宽带雷达对抗侦察数字接收机具有较宽的瞬时频率覆盖特性和较高的截获概率,并能处理同时到达的多个信号。多相滤波信道化接收机是实现宽带接收的一种方法,其抽取运算在滤波运算之前,运算量小,输出速率低,便于后续处理,是一种高效结构。给出了多相滤波信道化数字接收机的基本原理和实现方法,采用重叠一半多相滤波信道化数字接收机能够有效消除接收盲区,实现全概率接收并消除虚假输出,通过仿真试验证明了其有效性。     

信道化接收处理方法研究

现代雷达接收机要求具有瞬时频带宽,良好的灵敏度和动态范围,检测同时到达信号的能力等特点。针对这些问题,采用多相滤波组信道化接收的处理方法,将两个线性调频脉冲信号通过多相滤波组信道化接收机,经信道划分、采样、移频等处理后,实现对多路信号的信道分离,并成功检测到同时到达的信号,降低了信号处理的复杂度,提高了接收机实时处理能力,尤其是提高了雷达接收机全概率截获目标的能力。     

双/多基地综合脉冲孔径地波雷达的信道化接收技术研究

双/多基地综合脉冲孔径地波雷达在发射站为多载频信号同时辐射,在接收站综合形成发射方向图之前需要对各发射信号分量进行分离.尽管采用数字混频和低通滤波器组可以对各发射分量进行分离,但运算量太大,难以实时实现.为此提出采用多相滤波器组信道化接收技术,设计该雷达的多相滤波器组信道化接收机.这种多相滤波器组信道化接收机与低通滤波器组信道化接收相比,运算量减少N²倍(N为信道数).最后给出了该雷达试验系统的实测数据处理结果,验证了这种多相滤波器组信道化接收技术在该雷达信号处理中的有效性.     

MIMO iterative receiver SNR estimation strategies for link to system interfacing

This paper presents link to system (L2S) interfacing technique for multiple input and multiple output (MIMO) iterative receivers. In L2S interfacing, usually the post detection signal to noise ratio (SNR)‐based frame error rate lookup tables (LUT) are used to predict the link level performance of receivers. While L2S interfacing for linear MIMO receivers can be conveniently implemented, it is more challenging for MIMO iterative receivers due to unavailability of the closed form SNR expressions. In this paper, we propose three methods for post detection SNR estimation for MIMO iterative receivers. The first is based on the QR decomposition of the channel matrix, the second relies on the residual noise calculation based on the soft symbols, and the third exploits the closed form SNR expressions for linear receivers. A link to system interface model for iterative receivers is developed for evaluating the reference curves for different modulation and coding schemes, and results are validated by comparing the simulated and predicted frame error rates. It is shown that linear and residual noise‐based SNR approximations result in a very good prediction performance whereas the performance of QR decomposition‐based method degrades for higher order modulations and coding schemes. This paper presents link to system interfacing technique for MIMO iterative receivers. A link to system interface model for iterative receivers is developed for evaluating the reference curves for different modulation and coding schemes, and results are validated by comparing the simulated and predicted frame error rates. Three post detection SNR evaluation schemes have been proposed for link to system interfacing all of which give good prediction performance especially at lower order modulation.     

Coding for Frequency-Hopped Spread-Spectrum Communication with Partial-Band Interference--Part II: Coded Performance

The performance of codes in a frequency-hopped spreadspectrum communication system with partial-band interference is investigated. The performance measure considered is the decoded bit error probability. A simplified interference model and worst-case partial-band Gaussian noise interference model is considered with the interference noise statistically independent of the transmitted signal. We consider soft decision receivers with side information and hard decision receivers with and without side information.     

一种基于多相滤波的高效信道化算法研究及改进

本文对基于多相滤波技术的信道化算法做了仿真和优缺点分析.针对其存在盲区的问题,以降低抽取率为基础,对该算法进行了改进,建立了无盲区信道化接收机模型.并由此模型设计了四信道仿真系统,实验结果验证了模型的正确性.最后,在Tiger SHARCTS101上实现了改进算法,运行结果证明了算法的高效性.     

Theoretical analysis of heterodyne optical receivers for transmission systems using (semiconductor) lasers with nonnegligible linewidth

We present a general theoretical model of receivers for coherent optical communication systems where transmitters and local oscillators having nonzero linewidth are used. Key issues in the model are the concept of single realization measurements of a stochastic intermediate frequency, and development of the probability density function for this stochastic process. Analytical results are derived for heterodyne ASK and dual filter FSK receivers and include the shot-noise limit, the asymptotic error-probability limits in ASK and FSK receivers, the influence of the IF on receiver noise, and the effective local oscillator strength. Detailed numerical results for typical p-i-n-FET wide-band receivers illustrate the influence on receiver sensitivity of IF filter bandwidth and relative threshold setting in ASK systems and of modulation index and IF filter bandwidth in FSK systems. A receiver sensitivity penalty for nonzero linewidth is found to be, for IF linewidths of 0.1 to 0.3 of the bit-rate, 3 to 9 dB in optimum ASK receivers, and 2 to 8 dB in optimum FSK receivers. Thus DFB lasers of linewidth 5 to 20 MHz could be used without external cavities in simple systems with near-ideal performance, which could find application wherever the great multiplexing advantage of coherent systems is a prime advantage. We present some guidelines for system design based on the results of this work.     

Design considerations for wide-band p-i-n/HBT monolithictransimpedance optical receivers

A comprehensive circuit and device model was developed for the design of wideband transimpedance optical receivers using heterojunction bipolar transistors (HBTs). This model is used to determine the device and circuit design that gives the highest combination of bandwidth, sensitivity, and stability. For optoelectronic integration, it is convenient to use the collector-base junction of the HBT device structure to fabricate the p-i-n detector. A resulting transistor transit-time effect is shown to cause shunt peaking in the closed-loop response or, at worst, instability. It is shown that the photodiode stray capacitance is not a major source of sensitivity degradation in flip-chip transimpedance receivers. Optimum device structures are determined for InP- and GaAs-based HBT receivers with fine-line as well as relaxed geometries     

Analysis of the performance of time-spread optical code-division multiple access systems with integrate-and-dump receivers

The BER performance of asynchronous time-spread optical code-division multiple access (TS-OCDMA) systems employing integrate-and-dump receivers with partially coherent optical sources was analyzed. Monte-Carlo simulations of the system were performed to verify the validity of the model. Using the developed analytic model, the TS-OCDMA systems with integrate-and-dump receivers were compared with those employing optical thresholders. It was found that: (1) as the integration time (or gating time) increases, the systems with optical thresholders outperform those using integrate-and-dump receivers, (2) while the performance of both systems is improved as the optical sources become more incoherent, those with integrate-and-dump receivers benefit more, (3) when the systems are spectral-efficiency limited, the performance does not improve by using partially coherent sources.     

Low-complexity tensor-based blind receivers for MIMO systems

In the tensor-based MIMO receivers, the multidimensional MIMO signals first are expressed as a third-order tensor model, wherein the factor matrices of tensor model are corresponding time/frequency, symbols, code/diversity of signals. A algorithm then is used for fitting this tensor mode, in which the symbols are estimated as a independent factor matrix. Although the performance of tensor-based receivers strongly depends on the initializations of the factor matrices. However, due to the absence of a priori on channels, these initializations are done randomly in alternating least squares (ALS), a basic algorithm for fitting the tensor models. In order to avoid these random initializations, this paper proposes two algorithms for fitting the tensor models. The first one, called delta bilinear ALS (DBALS) algorithm, where we exploit the increment values between two iterations of the factor matrices, refine these predictions by using the enhanced line search and use these refined values to initialize for two factor matrices. The second one, called orthogonal DBALS algorithm that takes into account the potential orthogonal in factor matrix for the DBALS algorithm, to provide the initialization for this factor matrix. By this way, we avoid random initializations for three factor matrices of tensor model. The performance of proposed receivers is illustrated by means of simulation results and a comparison is made with traditional ALS algorithm and other receivers. Beside a performance improving, our receivers give a lower complexity due to avoid random initializations.     

Receiver Power Allocation and Transmitter Power Control Analysis for Multiple-Receiver Wireless Power Transfer Systems

As different power has its own receivers, this paper analyzes and designs a multiple-receiver wireless power transfer (WPT) system systematically. The equivalent circuit model of the system is established to analyze the key parameters including transmitter power, receiver power, transmission efficiency, and each receiver power allocation. A control circuit is proposed to achieve the maximum transmission efficiency and transmitter power control and arbitrary receiver power allocation ratios for different receivers. Through the proposed control circuit, receivers with different loads can allocate appropriate power according to its power demand, the transmitter power and system efficiency do not vary with the change of the number of receivers. Finally, this control circuit is validated using a 130-kHz WPT system with three receivers whose power received is 3:10:12, and the overall system efficiency can reach as high as 55.5%.     

Enhancing multicast security of cognitive radio networks with antenna correlations over Nakagami-m fading channels

In this paper, we investigate the impact of diversity and antenna correlations on the secrecy capacity and outage performance of a cognitive radio multicast network over Nakagami-m fading channels analytically. The proposed network consists of single primary and secondary user, multiple primary and secondary receivers, and multiple eavesdroppers. It is assumed that each user is equipped with single antenna while all the primary and secondary receivers, and eavesdroppers are equipped with multiple antennas. The primary and secondary users transmit their common messages to the respective receivers in the presence of multiple eavesdroppers. A mathematical model is developed to ensure successful reception of confidential information to the primary receivers protecting the activities of eavesdroppers neglecting the effect of interference due to secondary user. In order to analyze the security of the proposed model, closed-form analytical expressions have been derived for the secrecy multicast capacity, the secure outage probability for multicasting and the probability of non-zero secrecy multicast capacity. Analytical results are justified via Monte-Carlo simulations.

     

基于频谱偏移的GEO星机多基SAR提高距离分辨率方法

该文给出了发射端固定的单发多收地球同步轨道(GEO)星机多基SAR几何模型,推导了不同接收端回波之间的频谱偏移.基于该频谱偏移,提出了通过合成不同接收端的频谱实现提高距离分辨率的方法.详细分析了谱合成过程中产生的重叠干扰项,及其对距离分辨率的影响,并提出了权值滤波的方法进行抑制.最后通过仿真验证了方法的有效性.