基于混合滤波器组的时间交替采样技术

时间交替采样技术对通道失配误差十分敏感，而基于混合滤波器组的采样技术降低了对通道失配误差的敏感，但前端模拟分析滤波器的稳定性难于设计限制了其工程应用。结合时间交替和混合滤波器组采样技术，提出了一种易于工程实现的基于混合滤波器组的时间交替采样技术。仿真结果表明，该技术能显著提高采样系统的精度。     

过采样Delta—Sigma调制器原理及实现

随着超大规模集成电路(VLSI)技术的发展，基于过采样Delta—Sigma转换技术的ADC得到了飞速发展。本文重点对过采样Delta—Sigma ADC技术中的Delta—Sigma调制器进行了研究，分析了一阶过采样Delta—Sigma调制器的原理和量化噪声，并推广到高阶。根据理论分析，设计了二阶过采样Delta—Sigma调制器电路，给出了与理论分析相同的仿真结果。     

快速纹理映射技术

本文提出一种利用区域求和表对纹理图案进行采样的正向纹理映射技术。通过使用二叉村图象分割算法以及Ｇｕｅｓｓ采样函数对图形进行采样和滤波，有效地解决了纹理映射过程中存在的图形走样问题；使用纹理图案的区域求和表和正向纹理映射技术，提高了纹理图案的采样效率，避免了逆映射过程中出现的对同一纹理元素多次采样的问题；正向映射简化了计算复杂性，为并行处理提供了条件，加快了纹理映射速度。     

多率信号处理中的重采样技术

本文从基本原理、实现电路两个方面对多率信号处理中的重采样技术进行了详细分析，既分析了固定变换率重采样电路，又分析了自适应重采样电路。由于实现重采样技术的关键是求模运算的实现，所以文中对如何用累加器实现求模运算也进行了详细分析。     

信号的双相采样处理技术及其应用

依据奈奎斯特采样定理分析信号的双相采样处理技术原理，双相采样处理技术的优点是对一定的信号带宽可使采样率降低一半，或者当采样率一定时，利用信号的双相采样处理技术可使信号的处理带宽增加一倍。因此双相采样处理技术在通信、雷达、电子战、微波数字化接收技术和高频数字存储示波器等领域将得到广泛应用。     

利用S-B自适应采样方法加速基于空间映射技术的神经网络建模

将空间映射技术用于辅助神经网络的建模可以帮助降低神经网络的复杂程度，从而达到降低训练成本的目的。但是，不论是空间映射技术还是神经网络的训练，需要大量的采样是这一技术中一个关键问题。本文将一种灵活高效的自适应采样技术运用在基于空间映射技术的神经网络建模过程中，大大减少了建模需要的采样时间，提高了最终得到模型的精度。     

基于DSP的过采样技术

在使用DSP进行数字信号处理时，应用过采样技术可以增加其内置模数转换器的分辨率。讨论了应用过采样技术的原理、如何使用TMS320LF2407来实现过采样，以及在软件上的实现方法。     

新型CMOS采样/保持电路的设计研究

讨论了目前各种先进的采样／保持电路结构，基于底极板(BottomPlate)采样技术和引导开关技术，设计了一种新型的全差分开关电容双采样保持放大器，有效地消除了电荷注入和时钟馈通效应，并保证了较高的单位增益频率、采样速率和信号建立时间。电路设计基于TSMC 0．35μm CMOS工艺Bsim3模型，并采用Hspice工具对设计进行了仿真验证。     

欠采样系统的SYSTEMVIEW仿真研究

欠采样技术是软件无线电的核心技术之一，目前被广泛用于雷达、移动等通信系统中，本文利用SYSTEMVIEW软件对该技术进行了仿真，并通过对AM和FM两种调制信号的欠采样研究，解释了新采样体制对部分系统参数的影响并寻求解决途径。     

基于星历信息的星地链路补偿关键技术及FPGA实现

针对星地链路中的多普勒频偏和采样点漂移问题，分析了多普勒频偏和采样点漂移产生的原因，提出了一种基于星历信息的补偿技术，采用 Farrow 滤波补偿采样点漂移，并在 FPGA 中进行实现验证，对滤波前后的波形进行对比，性能基本保持一致。     

基于软件无线电的DS/DQPSK调制解调器

一种基于软件无线电的数字DS/DQPSK调制和解扩解调器的FPGA实现方案。采用了调制前的基带成形处理、正交调制、数字匹配滤波解扩和延时差分解调等技术,直接对中频模拟已调信号进行带通采样,然后使用FPGA进行数字信号处理,完成基带数据的解扩解调以及基带时钟提取,不需要进行数字下变频,也不需要进行伪随机码同步捕获和载波提取,简单易行,具有一定的新意和较高的实用价值。     

A Novel Receiver Architecture for DBF Antenna Array

The developments of the high speed analog to digital converters （ADC） and advanced digital signal processors （DSP） make the smart antenna with digital beamforming （DBF） a reality. In conventional M-elements array antenna system, each element has its own receiving channel and ADCs. In this paper, a novel smart antenna receiver with digital beamforming is proposed. The essential idea is to realize the digital beamforming receiver based on bandpass sampling of multiple distinct intermediate frequency （IF） signals. The proposed system reduces receiver hardware from M IF channels and 2M ADCs to one IF channel and one ADC using a heterodyne radio frequency （RF） circuitry and a multiple bandpass sampling digital receiver. In this scheme, the sampling rate of the ADC is much higher than the summation of the M times of the signal bandwidth. The local oscillator produces different local frequency for each RF channel The receiver architecture is presented in detail, and the simulation of bandpass sampling of multiple signals and digital down conversion to baseband is given. The principle analysis and simulation results indicate the effectiveness of the new proposed receiver.     

A Wideband ΔΣ Digital-RF Modulator for High Data Rate Transmitters

A wideband software-defined digital-RF modulator targeting Gb/s data rates is presented. The modulator consists of a 2.625-GS/s digital DeltaSigma modulator, a 5.25-GHz direct digital-RF converter, and a fourth-order auto-tuned passive LC RF bandpass filter. The architecture removes high dynamic range analog circuits from the baseband signal path, replacing them with high-speed digital circuits to take advantage of digital CMOS scaling. The integration of the digital-RF converter with an RF bandpass reconstruction filter eliminates spurious signals and noise associated with direct digital-RF conversion. An efficient passgate adder circuit lowers the power consumption of the high-speed digital processing and a quadrature digital-IF approach is employed to reduce LO feedthrough and image spurs. The digital-RF modulator is software programmable to support variable bandwidths, adaptive modulation schemes, and multi-channel operation within a frequency band. A prototype IC built in 0.13-mum CMOS demonstrates a data rate of 1.2 Gb/s using OFDM modulation in a bandwidth of 200 MHz centered at 5.25 GHz. In-band LO and image spurs are less than -59 dBc without requiring calibration. The modulator consumes 187 mW and occupies a die area of 0.72 mm².     

Review of saw devices and their signal processing applications in space communications

An increasing number of advanced signal processing techniques are being investigated in satellite communications systems as the ground and space segments require more and more sophisticated, light-weight, low-power-consumption and cost-effective equipment. RF signal processing techniques based on surface acoustic wave (SAW) devices can be suitably exploited in these systems, constituting a valid alternative to digital baseband processing. This paper aims at presenting the most recent applications of SAW devices to RF signal processing in satellite communication systems. They span the frequency range from about 10 MHz to 10 GHz. Interaction of SAWs with laser beams is also illustrated.     

Digital complex sampling

Complex sampling is often employed in digital signal processing schemes where the input signal is bandpass in origin and is to be processed using lowpass techniques. Conventionally the signal is first mixed to zero centre frequency in two quadrature channels, filtered to remove the high-frequency mixing products and then digitised in two A/D convertors. A method is proposed that employs only one A/D convertor followed by digital mixing to produce the required pair of signals, thus allowing a considerable saving in hardware.     

数据传输系统的FPGA一体化设计与实现

当前的差分相移键控（DPSK）数据传输系统大多是采用独立的数据调制解调终端设备和收发信设备组成的,集成度低、可靠性较差,存在内部信号量化噪声。通过应用现场可编程门阵列（FPGA）加高速数字信号处理设计技术,将数据传输系统中的信号进行DPSK调制,基带到射频信号的数字上变频,以及信号的解调与射频到基带信号数字下变频进行一体化设计,解决了DPSK调制解调终端设备与射频信道设备相互独立所带来的集成度低、可靠性差,以及设备间信号变换引起信号受损等问题。     

Frequency synthesis based on bandpass sigma-delta modulation

A PLL frequency synthesiser using a bandpass sigma-delta digital oscillator as the frequency reference is described. The system emphasises digital signal processing and allows the use of a wideband loop filter     

Signal processing challenges for applying software radio principles in future wireless terminals: an overview

The general idea of software radio is to develop highly integrated radio transceiver structures with high degree of flexibility and multimode capabilities, achieved through increased role of digital signal processing software in defining the functionalities which have traditionally been implemented with analog RF techniques. This paper explores the software radio concept from the receiver architecture and signal processing points of view, with mainly the wireless terminal application in mind. We first discuss the critical issues in alternative receiver architectures with simplified analog parts and increased configurability. We also introduce certain advanced digital signal processing techniques which could potentially relieve some of the essential problems and pave the way towards DSP‐based, highly integrated, and highly configurable terminals. Big emphasis is on efficient digital multirate signal processing methods and complex (I/Q) signal processing. Copyright © 2002 John Wiley & Sons, Ltd.     

基于QPSK的智能天线固定多波束基带DBF算法

射频(RF)波束形成算法,难以直接采用数字信号处理(DSP)技术,实时完成数字波束形成(DBF)计算.对于相移键控(PSK)调制方式,本文认为RF波束形成算法可等效在基带实现.针对四相相移键控(QPSK)调制方式,本文提出了一种新的智能天线固定多波束基带DBF算法.与RF波束形成算法相比,提出的算法可实现同样的辐射方向图,但需要的计算量却大幅度地降低.基带DBF算法,使智能天线的实现更为简单、应用更为灵活、性能更为优良,对推动智能天线技术实用化发展具有重大意义.     

一种宽频带可配置数字射频调制的实现方法

针对航空电子系统能力提升和体积重量功耗的矛盾,提出了一种宽频带可配置数字射频调制的设计与实现方法,使用数字信号处理的方法实现调制和上变频,将数字化推进到天线接口单元.首先,对比分析了3种发射信道的实现架构;其次,基于数字射频调制信道架构设计了宽频带可配置发射信道;然后,针对宽频带可配置数字射频调制在实现过程遇到的问题,一一给出了解决方法,即N次谐波调制技术、多相采样降速技术、最优本振选择方法.实现结果表明,相比传统二次发射信号的产生方案,本设计能够产生高质量的射频发射信号,幅度误差仅为1.7%RMS(Percent Root Mean Square),相位误差小于1°,误差向量幅度(EVM)仅为2.345%RMS,并具有宽频带优良的谐杂波抑制能力.