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  • ·高速下行分組接入的接收端設計挑戰分析2005.11.13
  • 高速下行分組接入(HSDPA)能提供比通用移動通信系統(UMTS)更高的速率,但要求更強的處理能力、更大存儲容量和高階調制等新的性能,這些要求對接收端的設計帶來挑戰。本文分析了這些技術挑戰,并提出了采用均衡器、雙天線等解決思路。 許多有關HSD… [閱讀全文]
  • 評論:0 推薦:0 點擊:645
  • ·3G基站發射機性能測試與分析2005.11.7
  • 在當前快速發展的第三代無線通信系統中,為了達到更高的傳輸率需要采用高度復雜的調制系統,這給工程師帶來了新的挑戰,本文向中國測試和測量工程師簡要介紹了3G基站發射機需要測試和分析的關鍵參數及其意義。 在當前快速發展的第三代無線通信系… [閱讀全文]
  • 評論:1 推薦:5 點擊:3128
  • ·通過誤差向量分析優化接收機性能2005.10.30
  • 誤差向量分析是一種用幅度誤差和相位誤差定量表示發射機或接收機性能的方法。通過采用具有誤差向量分析功能的向量信號分析儀,工程師可以在線研究信號空間的幅度值和相位誤差,同時可以調整接收機鏈路參數。 為了調整接收機參數以獲得最佳性能,… [閱讀全文]
  • 評論:3 推薦:2 點擊: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, … [閱讀全文]
  • 評論:0 推薦:1 點擊: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… [閱讀全文]
  • 評論:0 推薦:0 點擊: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… [閱讀全文]
  • 評論:0 推薦:1 點擊: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… [閱讀全文]
  • 評論:0 推薦:1 點擊: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… [閱讀全文]
  • 評論:0 推薦:2 點擊: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… [閱讀全文]
  • 評論:0 推薦:1 點擊: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]. … [閱讀全文]
  • 評論:0 推薦:0 點擊: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… [閱讀全文]
  • 評論:0 推薦:0 點擊:432
  • ·快速分析儀器可望加快3G手機測試2005.9.25
  • 針對技術越來越復雜、利潤越來越薄的手機市場,測試必須快速、靈活和有效才能保證生產線達到維持利潤的批量,通過采用具有先進軟硬件和不同測試模式的測試儀器,可以對各種手機實現快速、精確地測量,從而確保3G產品所需的質量。 當今的無線手機… [閱讀全文]
  • 評論:1 推薦:3 點擊: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… [閱讀全文]
  • 評論:0 推薦:0 點擊:778
  • ·為今天的多模手機選擇最恰當的發射架構2005.9.6
  • 在競爭激烈的GSM電話終端市場上,終端制造商開始期待可以加快開發速度和縮短開發周期的解決方案。由于越來越多功能豐富的新型手機開始集成百萬像素數字相機、藍牙技術和多媒體功能,設計者開始尋找尺寸更小和集成度更高的發射和接收RF模塊,它們能… [閱讀全文]
  • 評論:2 推薦:1 點擊:2203
  • ·MAX2395輸出匹配SAW濾波器輸入,獲得最佳的級聯增…2005.8.30
  • 發射機(TX) SAW濾波器輸出阻抗易受輸入端看進去的源阻抗的影響。MAX2395與SAW濾波器和下一級PA互相作用引起輸出端口阻抗的變化易導致在整個頻段上3dB凈增益波動。在MAX2395和TX SAW之間的修訂版本的匹配電路表明在整個頻段上增益平坦性得到改善-大概… [閱讀全文]
  • 評論:0 推薦:1 點擊:1525
  • ·3GPP直接轉換接收器中雙音及W-CDMA調制阻塞的有效I…2005.8.30
  • 近年來隨著第3代(3G)無線網絡在日本(IMT-2000)、歐洲(UMIST)和美國(CDMA2000)的推廣,在3G移動手機的商業開發中,對低成本、低功耗與小型化的用戶設備(UE)的需求正在變得日益重要。通過硅處理工藝的正確使用、適當的電路設計技術和架構的實現,直接… [閱讀全文]
  • 評論:1 推薦:0 點擊: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 … [閱讀全文]
  • 評論:1 推薦:3 點擊: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… [閱讀全文]
  • 評論:3 推薦:2 點擊:1968
  • ·應用于手機的TD-SCDMA無線芯片集框圖2005.8.25
  • 中國對3G蜂窩電話的選擇是TD-SCDMA系統。本文列出了一個詳細的手機收發信機框圖,其中,MAX2361作為發射機集成電路,MAX2291作為功率放大器(PA),MAX2388和MAX2309構成接收器,一個VCO緩沖放大器提供良好隔離性能以保持一個無干擾的LO信號。 引言 … [閱讀全文]
  • 評論:0 推薦:3 點擊:2816
  • ·Maxim無線/射頻功率放大器選擇指南2005.8.25
  • 本文概括了Maxim針對蜂窩、PCS、802.11b、無繩電話以及Bluetooth等應用提供的射頻(RF)功率放大器(PA)。列出了工作電壓、電源電流、輸出功率、封裝、功效等參數的對照表,并給出了Maxim PA IC的特點。另外,還提供了一個根據市場應用選擇的參考表。 … [閱讀全文]
  • 評論:0 推薦:0 點擊:2694
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