亚洲精品大全,亚洲午夜精品一区二区,国产精品爽爽爽爽爽爽在线观看

Multiplexing

數據通信系統或計算機網絡系統中，傳輸媒體的帶寬或容量往往會大于傳輸單一信號的需求，為了有效地利用通信線路,希望一個信道同時傳輸多路信號，這就是所謂的多路復用技術(Multiplexing)。采用多路復用技術能把多個信號組合起來在一條物理信道上進行傳輸，在遠距離傳輸時可大大節省電纜的安裝和維護費用。頻分多路復用FDM(FrequencyDivisionMultiplexing)和時分多路復用TDM(TimeDivisionMultiplexing)是兩種最常用的多路復用技術。

OFDM系統中降低峰均功率比的研究

正交頻分復用技術（Orthogonal Frequency Division Multiplexing， OFDM）非常適合高速通信系統，但存在高峰均功率比（PAPR）的問題。對OFDM系統中如何降低PARR的問題進行了研究，討論了降低PAPR的主要方法，重點分析了選擇性映射法（SLM），并在此基礎上提出了一種基于預編碼矩陣的改進算法，最后通過matlab進行了算法仿真，仿真結果表明，改進算法在使得OFDM系統在降低峰均功率比的性能上得到了進一步的改善。

標簽： OFDM 峰均功率比

上傳時間： 2014-01-23

上傳用戶：zwei41
克服了正交頻分復用(OFDM)和IEEE 1901.2智能電網通信的挑戰

Abstract: While many questions still surround the creation and deployment of the smart grid, the need for a reliablecommunications infrastructure is indisputable. Developers of the IEEE 1901.2 standard identified difficult channel conditionscharacteristic of low-frequency powerline communications and implemented an orthogonal frequency division Multiplexing (OFDM)architecture using advanced modulation and channel-coding techniques. This strategy helped to ensure a robust communicationsnetwork for the smart grid.

標簽： 1901.2 OFDM IEEE 正交頻分復用

上傳時間： 2013-10-18

上傳用戶：myworkpost
降低OFDM信號PAPR的方法研究

正交頻分復用（Orthogonal Frequency Division Multiplexing，OFDM）是一種多載波調制技術，由于具有良好的抗多徑干擾性能，適用于高速數據傳輸，OFDM成為近年來人們研究的熱點。但是其峰均比較高，應用受到了限制，因此有必要研究降低PAPR的方法。本文首先介紹了OFDM的基本原理和PAPR的基本概念，然后討論了目前常用的降低PAPR的方法，最后對SLM和PTS方法進行了MATLAB仿真。

標簽： OFDM PAPR 信號方法研究

上傳時間： 2013-11-19

上傳用戶：moshushi0009
XAPP740利用AXI互聯設計高性能視頻系統

This application note covers the design considerations of a system using the performance features of the LogiCORE™ IP Advanced eXtensible Interface (AXI) Interconnect core. The design focuses on high system throughput through the AXI Interconnect core with F MAX and area optimizations in certain portions of the design. The design uses five AXI video direct memory access (VDMA) engines to simultaneously move 10 streams (five transmit video streams and five receive video streams), each in 1920 x 1080p format, 60 Hz refresh rate, and up to 32 data bits per pixel. Each VDMA is driven from a video test pattern generator (TPG) with a video timing controller (VTC) block to set up the necessary video timing signals. Data read by each AXI VDMA is sent to a common on-screen display (OSD) core capable of Multiplexing or overlaying multiple video streams to a single output video stream. The output of the OSD core drives the DVI video display interface on the board. Performance monitor blocks are added to capture performance data. All 10 video streams moved by the AXI VDMA blocks are buffered through a shared DDR3 SDRAM memory and are controlled by a MicroBlaze™ processor. The reference system is targeted for the Virtex-6 XC6VLX240TFF1156-1 FPGA on the Xilinx® ML605 Rev D evaluation board

標簽： XAPP 740 AXI 互聯

上傳時間： 2013-11-23

上傳用戶：shen_dafa
This paper considers semiblind channel estimation and data detection for orthogonal frequency-divis

This paper considers semiblind channel estimation and data detection for orthogonal frequency-division Multiplexing (OFDM) over frequency-selective fading channels.

標簽： frequency-divis estimation orthogonal considers

上傳時間： 2014-12-07

上傳用戶：coeus
This project aim was to build wireless software modem for data communication between two computers

This project aim was to build wireless software modem for data communication between two computers using an acoustic interface in the voice frequency range (20Hz– 20,000Hz). The transmitting antenna is a speaker (frequency response of: 90Hz – 20,000Hz) and the receiving antenna is a microphone (frequency response of: 100Hz – 16,000Hz). The test files used as information files were text files. This goal was attained both in an incoherent scheme and in a coherent scheme. Build under Matlab code, our modem uses OFDM (orthogonal frequency division Multiplexing) modulation, synchronization by LMS sequence, channel estimation (no equalizer) via pilot tones. The symbols are either PSK or ASK for a constellation size of 2 or 4. To optimize the probability of error, these symbols were mapped using Gray mapping. Report

標簽： communication computers software wireless

上傳時間： 2014-05-29

上傳用戶：wangdean1101
OFDM Modem Applications • Digital Video Broadcast (DVB) • Digital Audio Broadcast (DAB)

OFDM Modem Applications • Digital Video Broadcast (DVB) • Digital Audio Broadcast (DAB) • Broadband Wireless Access (802.16x) • Wireless LAN (802.11x & HiperLAN) Orthogonal OFDM Sub-carriers Orthogonal Frequency Division Multiplexing (OFDM)

標簽： Broadcast Digital 8226 Applications

上傳時間： 2016-03-23

上傳用戶：cc1
OFDM仿真及實現

OFDM(Orthogonal Frequency Division Multiplexing)即正交頻分復用技術，實際上OFDM是多載波調制的一種。其主要思想是：將信道分成若干正交子信道，將高速數據信號轉換成并行的低速子數據流，調制到在每個子信道上進行傳輸。正交信號可以通過在接收端采用相關技術來分開，這樣可以減少子信道之間的相互干擾 ICI 。每個子信道上的信號帶寬小于信道的相關帶寬，因此每個子信道上的可以看成平坦性衰落，從而可以消除符號間干擾。而且由于每個子信道的帶寬僅僅是原信道帶寬的一小部分，信道均衡變得相對容易。

標簽： OFDM

上傳時間： 2015-02-17

上傳用戶：hongyun288
TJA1040

The TJA1040 is an advanced high speed CAN transceiver for use in automotive and general industrial applications. It supports the differential bus signal representation described in the international standard for in-vehicle high speed CAN applications (ISO11898). CAN (Controller Area Network) is the standard protocol for serial in-vehicle bus communication, particularly for Engine Management and Body Multiplexing. The TJA1040 provides a Standby mode, as known from its functional predecessors PCA82C250 and PCA82C251, but with significantly reduced power consumption. Besides the excellent low-power behavior the TJA1040 offers several valuable system improvements. Highlights are the absolute passive bus behavior if the device is unpowered as well as the excellent EMC performance.

標簽： CAN

上傳時間： 2015-03-23

上傳用戶：Yuan Lo
Advances+in+Mobile+Radio+Access+Networks

This book gives a comprehensive overview of the technologies for the advances of mobile radio access networks. The topics covered include linear transmitters, superconducting filters and cryogenic radio frequency (RF) front head, radio over fiber, software radio base stations, mobile terminal positioning, high speed downlink packet access (HSDPA), multiple antenna systems such as smart antennas and multiple input and multiple output (MIMO) systems, orthogonal frequency division Multiplexing (OFDM) systems, IP-based radio access networks (RAN), autonomic networks, and ubiquitous networks.

標簽： Advances Networks Access Mobile Radio in

上傳時間： 2020-05-26

上傳用戶：shancjb

亚洲欧美第一页_禁久久精品乱码_粉嫩av一区二区三区免费野_久草精品视频