本文選題：可視對(duì)講 + i.MX27��； 參考：《南京理工大學(xué)》2014年碩士論文

【摘要】：隨著國(guó)民經(jīng)濟(jì)的增長(zhǎng)和科技水平的提高,人們對(duì)家居環(huán)境的要求也日益升高,可視對(duì)講系統(tǒng)已經(jīng)成為住宅小區(qū)必不可少的基礎(chǔ)設(shè)施。傳統(tǒng)的對(duì)講系統(tǒng)采用模擬音視頻信號(hào)傳輸,存在施工布線復(fù)雜、成本高、容易占線、傳輸距離有限、抗干擾能力差、穩(wěn)定性差、無(wú)法兼容等局限性。而數(shù)字化技術(shù)的導(dǎo)入彌補(bǔ)了以上缺陷。 本文對(duì)模擬可視對(duì)講系統(tǒng)進(jìn)行數(shù)字化改造,設(shè)計(jì)完成了數(shù)字可視對(duì)講系統(tǒng)的核心部分——數(shù)字聯(lián)網(wǎng)切換器。首先研究了目前可視對(duì)講系統(tǒng)發(fā)展趨勢(shì)以及網(wǎng)絡(luò)音視頻傳輸?shù)南嚓P(guān)技術(shù),對(duì)比了多種音視頻編解碼標(biāo)準(zhǔn)以及系統(tǒng)架構(gòu),結(jié)合本系統(tǒng)的設(shè)計(jì)需求,提出了以多媒體SoC處理器i.MX27為核心的總體設(shè)計(jì)方案。 其次,本文詳細(xì)介紹了聯(lián)網(wǎng)切換器各功能模塊的工作原理與實(shí)現(xiàn)方法,包括H.264視頻編解碼、音頻處理、DDR內(nèi)存、RTC實(shí)時(shí)時(shí)鐘、RS-232/485通訊、以太網(wǎng)通訊等,并根據(jù)各模塊外設(shè)芯片的功能特性完成原理圖設(shè)計(jì)。 然后本文基于高速電路信號(hào)完整性理論,考慮信號(hào)反射、串?dāng)_、電源完整性等因素,結(jié)合高速PCB設(shè)計(jì)經(jīng)驗(yàn),對(duì)PCB層疊、器件布局、傳輸線寬、線間距等進(jìn)行規(guī)則設(shè)定,最終完成了PCB設(shè)計(jì)。 另外,本文根據(jù)應(yīng)用需求,在Linux系統(tǒng)開(kāi)發(fā)環(huán)境下對(duì)Bootloader以及GPIO、RS485等設(shè)備驅(qū)動(dòng)程序進(jìn)行設(shè)計(jì)與修改,為應(yīng)用程序提供API。 最后對(duì)聯(lián)網(wǎng)切換器進(jìn)行模塊化調(diào)試以及系統(tǒng)聯(lián)調(diào),驗(yàn)證設(shè)計(jì)的正確性。 經(jīng)過(guò)調(diào)試,數(shù)字化改造后的可視對(duì)講系統(tǒng)實(shí)現(xiàn)了門口機(jī)與室內(nèi)機(jī)之間的雙向視頻通話、視頻監(jiān)控、拍照、錄音、開(kāi)鎖、報(bào)警等功能。系統(tǒng)運(yùn)行穩(wěn)定,視頻通話效果良好。
[Abstract]:With the growth of the national economy and the improvement of science and technology, people's requirements for the home environment are also increasing day by day. Visual intercom system has become an essential infrastructure in residential areas. The traditional intercom system uses analog audio and video signal transmission, which has the limitations of complex construction wiring, high cost, easy busy, limited transmission distance, poor anti-interference ability, poor stability and incompatibility. The introduction of digital technology makes up for the above defects. In this paper, the analog visual intercom system is digitized and the core part of the digital visual intercom system is designed and completed. Firstly, this paper studies the development trend of visual intercom system and the related technology of network audio and video transmission, compares various audio and video coding and decoding standards and system architecture, and combines the design requirements of the system. An overall design scheme based on multimedia SoC processor i.MX27 is presented. Secondly, this paper introduces the working principle and implementation method of each function module of the network switch in detail, including H.264 video coding and decoding, audio processing DDR memory RTC real-time clock RS-232 / 485 communication, Ethernet communication, etc. According to the functional characteristics of each module peripheral chip, the schematic design is completed. Then, based on the theory of signal integrity of high-speed circuit, considering the factors of signal reflection, crosstalk, power integrity and so on, combined with the design experience of high-speed PCB, this paper sets the rules of PCB stack, device layout, transmission line width, line spacing and so on. Finally, the PCB design is completed. In addition, according to the application requirements, this paper designs and modifies the Bootloader and GPIO RS485 device drivers in the Linux system development environment, so as to provide the application program with API. Finally, modularization debugging and system tuning are carried out to verify the correctness of the design. After debugging, the digital video intercom system realizes the functions of two-way video communication, video surveillance, photography, recording, unlock, alarm and so on between the door machine and the indoor machine. The system runs stably and the effect of video communication is good.
【學(xué)位授予單位】：南京理工大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類號(hào)】：TN929.54

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本文編號(hào)：1970975