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信号源的合成技术按频率合成的方法可分为三大类:直接式频率合成,锁相式频率合成和直接数字式频率合成.以Peregrine公司的一款高性能单片锁相环频率合成器PE3236为例,介绍了微波信号源发生器研制中的关键实现技术,并给出部分实验测试数据. 相似文献
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频率合成技术发展浅析 总被引:3,自引:0,他引:3
王兵 《电子信息对抗技术》2009,24(3):74-77
通过跟踪国内外频率合成技术的发展现状、趋势及其新理论、新方法,对目前典型的几种频率合成体制,如直接模拟式频率合成技术(DAS)、直接数字式频率合成技术(DDS)和间接锁相式频率合成技术(PLL)分别进行分析、研究,探索其在雷达、通信、电子战等领域的应用需求。 相似文献
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频率合成理论自20世纪30年代提出以来,得到了迅速的发展,目前主要包含四种技术:直接模拟频率合成、锁相频率合成、直接数字频率合成和混合式频率合成技术. 相似文献
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基于FPGA的直接数字频率合成系统的仿真 总被引:1,自引:1,他引:0
频率源是雷达、通信、电子对抗与电子系统实现高性能指标的关键之一,被喻为众多电子系统的"心脏".而当今高性能的频率源均通过频率合成技术实现.传统的频率合成器有直接频率合成器和锁相环两种.直接数字式频率合成(Difeet Digital Frequency Synthesis,即DDFS,一般简称DDS),是从相位概念出发直接合成所需波形的一种新的频率合成技术.它将先进的数字处理理论与方法引入信号合成领域,标志着第三代频率合成技术的出现. 相似文献
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基于EP1K30QC208的直接数字频率合成器设计 总被引:1,自引:0,他引:1
讨论了几种不同类型的数字频率合成技术,对比了直接数字频率合成(DDS)和其他频率合成方法的优缺点.以FPGA为基础,采用硬件描述语言来设计一种新型的频率合成器.实验结果证明该直接数字频率合成器具有带宽很宽、相位噪声低、频率分辨率很高的优点.在各种仪器或设备中使用该频率合成器,整体上可降低系统成本,提高系统的集成度和可靠性. 相似文献
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A novel circular aperture pattern synthesis technique is presented, which enables a linear line-source distribution to be converted to a rotationally symmetric circular aperture distribution, of which any /spl phi/-cut radiation pattern is ideally the same as the principal plane pattern of the line-source distribution. Line-source pattern synthesis techniques are numerous and versatile and the technique presented here allows these techniques to be applied to circular apertures as well. This new synthesis method is most compatible with line-source distributions which have zero edge illumination. 相似文献
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随着数字技术的发展 ,近十几年来 ,直接数字频率合成 ( DDS)技术发展很快 ,已发展成为主要的频率合成技术之一。现代许多频率合成器在设计中采用了 DDS和 PLL的混合式频率合成技术 ,可以将 DDS的高分辨率及快速转换时间特性与 PLL的输出功率高、寄生噪声和杂散低的特点有机地结合起来。文中研究了应用于正交频分复用 ( OFDM)通信系统的 DDS+ PPL混合式频率合成器设计 ,给出了系统方案、电路实现及测试结果 ,输出信号功率为 -5 d Bm,带内相位噪声可以达到 -76d Bc/Hz@1 k Hz,频率分辨率为 1 Hz,跳频速度可以达到 1 0 4 跳 /秒的数量级 ,实验表明其性能指标满足 OFDM通信系统的要求。 相似文献
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《Antennas and Propagation, IEEE Transactions on》2009,57(2):452-459
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Personal communications services (PCS) require low-power radio technologies. One such transceiver architecture employing frequency-hopped spread-spectrum techniques is presented. System features such as antenna diversity with equal-gain combining and sequential hop combining are incorporated into the transceiver design to achieve robust wireless digital data transmission over fading channels. A direct-conversion architecture from radio frequency (RF) to baseband reduces the overall power consumption by eliminating intermediate frequency (IF) components. High-rate frequency hopping with frequency-shift keying (FSK) modulation is implemented using a direct digital frequency synthesis technique. A multiplierless correlation FSK detector, suitable for direct-conversion receivers, has been designed for quadrature noncoherent detection. Robust acquisition algorithms based on energy detection and pattern matching and tracking architectures using digital phase-locked loops are also described for system synchronization. The proposed transceiver is well-suited for low-power PCS applications and other portable wireless communications 相似文献
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一种适于散射自适应选频通信的信号分析 总被引:1,自引:1,他引:1
根据对流层散射信道的时变衰落特性,提出了散射自适应选频通信的技术思想,分析了其可行性以及相对传统分集接收技术所具有的优势。使用自适应选频通信方式,可以集中所有发射功率在最佳频率上发射信号,避免传统分集技术使用固定频率发射信号衰落时产生的信号功率浪费。散射自适应选频信道,可以看作是能量和带宽双受限信道,通过对多种信号形式的时域和频域特性分析,提出了自适应选频散射通信的信号形式选取原则,分析结果表明α=0·6时的IJF-OQPSK信号形式非常适合于散射自适应选频通信。 相似文献
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Bech M.M. Pedersen J.K. Blaabjerg F. Trzynadlowski A.M. 《Power Electronics, IEEE Transactions on》1999,14(3):578-586
The analysis of random pulsewidth modulation (PWM) techniques has matured into a state where analytical expressions have been derived to aid in understanding the frequency domain characteristics. Derivations of the formulae require a lot of algebra, and the expressions must be verified by laboratory measurements. It is shown, however, that factors originating from digital signal processing techniques make the comparison difficult if proper measures against misinterpretation are not taken. A methodology to overcome the problems is presented. Novel expressions for the random lead-lag pulse position technique and the random switching frequency technique are also presented as well as their verifications by laboratory measurements on a full-bridge DC/DC power converter 相似文献
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Rapid frequency offset estimation is required in burst communication systems. The performance of traditional open loop frequency estimation techniques is severely degraded by multipath propagation. We present a new data-aided technique for frequency offset estimation in the presence of strong multipath. The technique allows estimation of the frequency offset with no knowledge of the channel parameters. Results comparing the new technique with the maximum-likelihood estimation technique in a frequency selective Ricean fading environment are presented 相似文献
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This paper develops a new formal technique to verify the frequency response of analog circuits using global optimization techniques. Since simulation-based approaches are unable to cover the design space, there is a need for formal approaches to verify large circuits. Drawing parallels from the digital domain, the verification problem in the analog domain is modeled as a non-linear optimization problem and solved using global optimization techniques by ensuring that the implementation response is bounded within an envelope around the specification. We also address the problem of verifying frequency response under the influence of parameter variations. Direct as well as indirect techniques are illustrated using accurate frequency response models. Experimental results are presented to show the effectiveness of the proposed methodology. 相似文献