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  • ·高速下行分组接入的接收端设计挑战分析2005.11.13
  • 高速下行分组接入(HSDPA)能提供比通用移动通信系统(UMTS)更高的速率,但要求更强的处理能力、更大存储容量和高阶调制等新的性能,这些要求对接收端的设计带来挑战。本文分析了这些技术挑战,并提出了采用均衡器、双天线等解决思路。 许多有关HSD… [阅读全文]
  • 评论:0 推荐:0 点击:645
  • ·3G基站发射机性能测试与分析2005.11.7
  • 在当前快速发展的第三代无线通信系统中,为了达到更高的传输率需要采用高度复杂的调制系统,这给工程师带来了新的挑战,本文向中国测试和测量工程师简要介绍了3G基站发射机需要测试和分析的关键参数及其意义。 在当前快速发展的第三代无线通信系… [阅读全文]
  • 评论:1 推荐:5 点击:3128
  • ·通过误差向量分析优化接收机性能2005.10.30
  • 误差向量分析是一种用幅度误差和相位误差定量表示发射机或接收机性能的方法。通过采用具有误差向量分析功能的向量信号分析仪,工程师可以在线研究信号空间的幅度值和相位误差,同时可以调整接收机链路参数。 为了调整接收机参数以获得最佳性能,… [阅读全文]
  • 评论:3 推荐:2 点击:2068
  • ·Create a flexible EDGE data receiver(Part 3)2005.10.23
  • EDGE in softwareEnabling a fully-software EDGE data receiver implementation has many advantages. Design can be iterated without effecting the terminal''s hardware design while optimizing for performance in the FTA and IOT process, … [阅读全文]
  • 评论:0 推荐:1 点击:759
  • ·Create a flexible EDGE data receiver(Part 2)2005.10.23
  • EDGE data receiverA typical EDGE handset receiver consists of an RF front end, a mixed-signal portion, and a baseband receiver. The RF portion impacts the baseband receiver''s performance and design by various imperfections/effects… [阅读全文]
  • 评论:0 推荐:0 点击:916
  • ·Create a flexible EDGE data receiver(Part 1)2005.10.23
  • Today''s integrated solutions don''t necessarily have to result in a high level of complexity. The introduction of new wireless standards often places tremendous pressure on the underlying technologies, especially the data receive… [阅读全文]
  • 评论:0 推荐:1 点击:670
  • ·Merging GSM with WLAN in a mobile handset needn…2005.10.17
  • When GSM is transmitting, the WLAN subsystem can''t receive WLAN packets (Fig. 1). Likewise, when GSM is in receive or monitor mode, the WLAN can'' transmit, as it will desensitize the GSM receiver. In addition, one radio chain mus… [阅读全文]
  • 评论:0 推荐:1 点击:798
  • ·Merging GSM with WLAN in a mobile handset needn…2005.10.17
  • Multi-mode handsets are designed to work in conventional wireless LAN (WLAN) hotspots as well as in GSM cellular networks. Multi-mode communication is important to consumers for applications such as GSM/WLAN voice-over-IP (VoIP) Vo… [阅读全文]
  • 评论:0 推荐:2 点击:420
  • ·Quenching the thirst of RF power amps and exten…2005.10.7
  • In tracking the average power, high peak-to-average power ratio (PAPR) signals are clipped and therefore distorted (i.e., linearity is compromised), which is why this method is most attractive for low PAPR and infrequent above-aver… [阅读全文]
  • 评论:0 推荐:1 点击:890
  • ·Quenching the thirst of RF power amps and exten…2005.10.7
  • State-of-The-Art in Efficient Linear PAsThere have been several techniques proposed to improve the average efficiency of linear PAs, and most notable are the dual PA (Doherty), envelope following, and power tracking schemes [5-6]. … [阅读全文]
  • 评论:0 推荐:0 点击:440
  • ·Quenching the thirst of RF power amps and exten…2005.10.7
  • Battery life or rather runtime is crucial in portable wireless systems such as cell phones, PDAs, laptop computers, and so on because it ultimately defines the device''s mobility. With decreasing form factors and increasing functio… [阅读全文]
  • 评论:0 推荐:0 点击:432
  • ·快速分析仪器可望加快3G手机测试2005.9.25
  • 针对技术越来越复杂、利润越来越薄的手机市场,测试必须快速、灵活和有效才能保证生产线达到维持利润的批量,通过采用具有先进软硬件和不同测试模式的测试仪器,可以对各种手机实现快速、精确地测量,从而确保3G产品所需的质量。 当今的无线手机… [阅读全文]
  • 评论:1 推荐:3 点击:1010
  • ·Resistive tap monitors and sets W-CDMA power le…2005.9.16
  • In a cell phone it''s important to set the power level of a power amplifier (PA) precisely. This is necessary to compensate for the temperature variation and to set the correct power, which is dictated by the base station. A well-e… [阅读全文]
  • 评论:0 推荐:0 点击:778
  • ·为今天的多模手机选择最恰当的发射架构2005.9.6
  • 在竞争激烈的GSM电话终端市场上,终端制造商开始期待可以加快开发速度和缩短开发周期的解决方案。由于越来越多功能丰富的新型手机开始集成百万像素数字相机、蓝牙技术和多媒体功能,设计者开始寻找尺寸更小和集成度更高的发射和接收RF???,它们能… [阅读全文]
  • 评论:2 推荐:1 点击:2203
  • ·MAX2395输出匹配SAW滤波器输入,获得最佳的级联增…2005.8.30
  • 发射机(TX) SAW滤波器输出阻抗易受输入端看进去的源阻抗的影响。MAX2395与SAW滤波器和下一级PA互相作用引起输出端口阻抗的变化易导致在整个频段上3dB净增益波动。在MAX2395和TX SAW之间的修订版本的匹配电路表明在整个频段上增益平坦性得到改善-大概… [阅读全文]
  • 评论:0 推荐:1 点击:1525
  • ·3GPP直接转换接收器中双音及W-CDMA调制阻塞的有效I…2005.8.30
  • 近年来随着第3代(3G)无线网络在日本(IMT-2000)、欧洲(UMIST)和美国(CDMA2000)的推广,在3G移动手机的商业开发中,对低成本、低功耗与小型化的用户设备(UE)的需求正在变得日益重要。通过硅处理工艺的正确使用、适当的电路设计技术和架构的实现,直接… [阅读全文]
  • 评论:1 推荐:0 点击:722
  • ·Understanding MIMO Antennas: Part 22005.8.26
  • With MIMO, systems use multiple transmit and multiple receive antennas. Looking at various MIMO techniques (specifically the receive techniques) that use different approaches to antenna and signal optimization, note that each type … [阅读全文]
  • 评论:1 推荐:3 点击:2408
  • ·Understanding MIMO Antennas: Part I2005.8.26
  • The use of multiple transmit and receive antennas is defined as MIMO, or multiple-input-multiple-output. This technology has garnered a fair amount of attention of late. As wireless systems become more popular, the need to ensure r… [阅读全文]
  • 评论:3 推荐:2 点击:1968
  • ·应用于手机的TD-SCDMA无线芯片集框图2005.8.25
  • 中国对3G蜂窝电话的选择是TD-SCDMA系统。本文列出了一个详细的手机收发信机框图,其中,MAX2361作为发射机集成电路,MAX2291作为功率放大器(PA),MAX2388和MAX2309构成接收器,一个VCO缓冲放大器提供良好隔离性能以保持一个无干扰的LO信号。 引言 … [阅读全文]
  • 评论:0 推荐:3 点击:2816
  • ·Maxim无线/射频功率放大器选择指南2005.8.25
  • 本文概括了Maxim针对蜂窝、PCS、802.11b、无绳电话以及Bluetooth等应用提供的射频(RF)功率放大器(PA)。列出了工作电压、电源电流、输出功率、封装、功效等参数的对照表,并给出了Maxim PA IC的特点。另外,还提供了一个根据市场应用选择的参考表。 … [阅读全文]
  • 评论:0 推荐:0 点击:2694
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