數(shù)字電視按傳輸方式分為地面、衛(wèi)星和有線三種。其中，DVB-S和DVB-C這兩個(gè)全球化的衛(wèi)星和有線傳輸方式標(biāo)準(zhǔn)，目前已作為世界統(tǒng)一標(biāo)準(zhǔn)被大多數(shù)國家所接受。而對于地面數(shù)字電視廣播標(biāo)準(zhǔn)，經(jīng)國際電訊聯(lián)盟(ITU)批準(zhǔn)的共有三個(gè)，包括歐盟的DVB-T(Digital Video Broadcasting-Terrestrial，數(shù)字視頻地面廣播)標(biāo)準(zhǔn)、美國的ATSC(Advanced Television System COMMITTEE，先進(jìn)電視制式委員會)標(biāo)準(zhǔn)和日本的ISDB-T(Terrestrial Integrated Services DigitalBroadcasting，綜合業(yè)務(wù)數(shù)字廣播)標(biāo)準(zhǔn)。綜合比較起來，歐洲的DVB-T標(biāo)準(zhǔn)在技術(shù)及應(yīng)用實(shí)踐上都更加成熟。 本論文首先介紹了DVB-T系統(tǒng)的主要結(jié)構(gòu)，針對DVB-T標(biāo)準(zhǔn)中各模塊的實(shí)現(xiàn)進(jìn)行了闡述，并根據(jù)發(fā)射機(jī)端各個(gè)模塊討論了接收機(jī)端相關(guān)模塊的算法設(shè)計(jì)。 隨后，論文給出了基于Microsoft Visual Studio 2005平臺實(shí)現(xiàn)的數(shù)字電視基帶信號產(chǎn)生與接收的軟件仿真系統(tǒng)的總體設(shè)計(jì)流程，重點(diǎn)討論了內(nèi)編解碼器和內(nèi)交織/解交織器的算法與實(shí)現(xiàn)，并在實(shí)現(xiàn)的多參數(shù)可選的數(shù)字電視基帶信號產(chǎn)生與接收軟件仿真平臺上，重點(diǎn)分析了內(nèi)編/解碼模塊在接收端Viterbi譯碼算法中采用硬判決、簡化軟判決以及不同調(diào)制方式時(shí)對DVB-T系統(tǒng)整體性能的影響。 最后，論文討論了內(nèi)碼譯碼算法的實(shí)現(xiàn)改進(jìn)，使得Viterbi譯碼更適合在FPGA上實(shí)現(xiàn)，同時(shí)針對邏輯設(shè)計(jì)進(jìn)行優(yōu)化以便節(jié)省硬件資源。論文重點(diǎn)討論了對幸存路徑信息存儲譯碼模塊的改進(jìn)，比較了此模塊三種不同的實(shí)現(xiàn)方式帶來的硬件速率和資源的優(yōu)劣，通過利用4塊RAM對幸存路徑信息的交互讀寫，完成了對傳統(tǒng)回溯算法的改進(jìn)，實(shí)現(xiàn)了加窗回溯的譯碼輸出，同時(shí)實(shí)現(xiàn)了回溯長度可配置以實(shí)現(xiàn)系統(tǒng)不同的性能要求。
his folder contains the following files:
1. 02490rxP802-15_SG3a-Channel-Modeling-SubCOMMITTEE-Report-Final.doc: This is the final
report of the channel modeling sub-COMMITTEE.
2. cmx_imr.csv (x=1, 2, 3, and 4) represent the files containing the actual 100 channel
realizations for CM1, CM2, CM3, and CM4. The columns are organized as (time, amp, time, amp,...)
3. cmx_imr_np.csv (x=1, 2, 3, and 4) represent the files containing the number of paths in
each of the 100 multipath realizations.
4. cmx_imr.mat (x=1, 2, 3, and 4) are the .mat files that can be loaded directly into
Matlab (TM).
5. *.m files are the Matlab (TM) files used to generate the various channel realizations.
DIGITAL IMAGERY is pervasive in our world today. Consequently,
standards for the efficient representation and
interchange of digital images are essential. To date, some of
the most successful still image compression standards have resulted
from the ongoing work of the Joint Photographic Experts
Group (JPEG). This group operates under the auspices of Joint
Technical COMMITTEE 1, SubCOMMITTEE 29, Working Group 1
(JTC 1/SC 29/WG 1), a collaborative effort between the International
Organization for Standardization (ISO) and International
Telecommunication Union Standardization Sector (ITUT).
Both the JPEG [1–3] and JPEG-LS [4–6] standards were
born from the work of the JPEG COMMITTEE. For the last few
years, the JPEG COMMITTEE has been working towards the establishment
of a new standard known as JPEG 2000 (i.e., ISO/IEC
15444). The fruits of these labors are now coming to bear, as
JPEG-2000 Part 1 (i.e., ISO/IEC 15444-1 [7]) has recently been
approved as a new international standard.
RTEMS (Real-Time Executive for Multiprocessor Systems) is a free open source real-time operating system designed for embedded systems.
The acronym RTEMS initially stood for Real-Time Executive for Missile Systems, then became Real-Time Executive for Military Systems before changing to its current meaning. RTEMS development began in the late 1980s with early versions of RTEMS available via ftp as early as 1993. OAR Corporation is currently managing the RTEMS project in cooperation with a Steering COMMITTEE which includes user representatives.
On Sunday, April 27, 2003, Fresno will celebrate Earth Day in downtown Fresno at Courthouse Park. The event will begin at noon.
This year we will include music, speakers, and vendors, plus activities for children.
Fresno Earth Day is recognized as the only Earth Day festival that happens in Fresno, and the largest in the Central Valley.
The Fresno Earth Day COMMITTEE is a small group of environmental activists hoping to broaden the appeal of a better planet and environment. We are a non-profit organization whose fiscal fiduciary is the Fresno Center for Nonviolence.
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