共查询到16条相似文献,搜索用时 93 毫秒
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介绍了一种适用于数字通信系统的中频调制方案。该方案基于正交调制、DDS、数字内插技术和ARM微处理器技术,使用数字上变频器AD9856和ARM926EJ—S微处理器S3C24AOA设计通用硬件平台,可以生成多种中频调制信号,可用于移动通信和数字化电台等通信系统项目的研发和验证。 相似文献
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介绍了数字可变增益放大器(DVCA)AD8369的电路结构及其关键技术指标,并用该芯片为数字中频接收机设计了全数字自动增益控制(DAGC)系统,给出了其控制回路及其实现算法。该DAGC系统具有收敛速度快、工作稳定性好和抗饱和能力强等特点。 相似文献
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介绍了AD9858在超短波无线电通信领域中的一种应用.基于AD9858设计一种频率合成器,该频率合成器采用"DDS 倍频"的方案,具有相噪低、跳速快等优点,可用于超短波无线电通信系统. 相似文献
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简要比较了超高速数字鉴频鉴相器AD9901和数字鉴频鉴相器E12540的性能,并突出了AD9901的性能优点。另外,对E12540中存在的鉴相"死区"问题进行了简要分析。最后,重点介绍了AD9901在基本锁相环路中的设计及相关注意事项,并给出了试验结论。 相似文献
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拄要介绍了集成温度传感器AD590和大规模集成电路ICL7107的特性,分析了AD590的原理详细介绍基于集成温度传感器AD590的数字温度计的温度采集电路和A/D转换及显示电路的设计方法。 相似文献
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AD9856是美国AD公司新近推出的功能强大的通用正交数字上变频器,本文提出了一种基于该芯片设计的数字调制方案,该方案具有结构简单、精度高,并且可灵活设置调制方式、符号速率、中频频率。 相似文献
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本文介绍了直接数字频率合成(DDS)芯片AD9852与可编程门阵列(FPGA)相结合采用数字方法实现中频线性相位调制(PM)及试验结果。 相似文献
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The literature on antidumping (AD) has documented various aspects of this protectionist tool. However, a peculiar feature of AD has not received much attention: these measures are endogenous to the behaviour of the exporting firms, which can adjust the dumping margin by changing their export price and ask the authority to amend the AD measures accordingly. The objective of this paper is to fill part of this gap in the literature by analysing the AD reviews conducted by the European Union for affirmative petitions initiated in 1980–2009. To this end, a novel data set of all such reviews has been assembled. Summary statistics reveal that more than a third of all petitions concluded with the imposition of AD measures are reviewed at least once before their expiration, and most reviews lead to lower AD duties (although, almost 20 per cent of the firms investigated through interim reviews see their duties increase). There are significant differences in the outcome of the reviews depending on the party requesting them (i.e. reviews lodged by European producers are less likely to lead to lower duties). These conclusions are confirmed by the econometric analysis, which also shows that Chinese firms see their duties reduced significantly less than those of firms from other countries. 相似文献