九游会网址多少


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南京九游会网址多少视讯科技有(you)限公(gong)司(简称:九游会网址多少科技)--成(cheng)立(li)于2009年(nian)(nian),企业(ye)专注(zhu)于政府、军队、公(gong)安(an)、医疗、金融信(xin)息(xi)(xi)化领(ling)(ling)域的(de)软硬(ying)件产品(pin)的(de)研(yan)发、制造和销售,为(wei)用户提供优(you)质的(de)个性(xing)化解决方案。凭借(jie)多年(nian)(nian)在信(xin)息(xi)(xi)系统开发、产品(pin)集成(cheng)和信(xin)息(xi)(xi)安(an)全(quan)领(ling)(ling)域积累的(de)经验,企业(ye)已(yi)经成(cheng)为(wei)该(gai)领(ling)(ling)域内(nei)值(zhi)得信(xin)任的(de)信(xin)息(xi)(xi)系统解决方案提供商。


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解决(jue)方案(an)

系统集成工程中常见问题分析

  造(zao)成(cheng)模糊(hu)拖尾和变(bian)暗现象(xiang)的(de)(de)(de)(de)(de)原因从原理上可分(fen)为两部分(fen),一(yi)是(shi)(shi)信号(hao)在传输(shu)过(guo)程中(zhong)的(de)(de)(de)(de)(de)幅(fu)频特性(xing)既带(dai)(dai)宽(kuan)不够而引起的(de)(de)(de)(de)(de)模糊(hu)和变(bian)暗;二是(shi)(shi)传输(shu)过(guo)程中(zhong)的(de)(de)(de)(de)(de)群延(yan)时(shi)特性(xing)造(zao)成(cheng)的(de)(de)(de)(de)(de)拖尾现象(xiang)。幅(fu)频特性(xing),简(jian)言之(zhi)(zhi)就(jiu)是(shi)(shi)不同(tong)频率分(fen)量与(yu)幅(fu)度衰(shuai)减之(zhi)(zhi)间的(de)(de)(de)(de)(de)关系,以1024*768分(fen)辨率为例(li),一(yi)般认为其带(dai)(dai)宽(kuan)在90~120MHz之(zhi)(zhi)间,所以九游会网址多少 关心100米100MHz的(de)(de)(de)(de)(de)衰(shuai)减情况(kuang)。就(jiu)矩阵(zhen)切(qie)换器和分(fen)配器而言,本身均带(dai)(dai)有(you)一(yi)定的(de)(de)(de)(de)(de)提升和驱(qu)动能(neng)力,满(man)足信号(hao)传输(shu)不是(shi)(shi)问(wen)题,但考虑到(dao)接插(cha)件的(de)(de)(de)(de)(de)损耗,此部分(fen)的(de)(de)(de)(de)(de)提升和驱(qu)动能(neng)力在传输(shu)系统设计和分(fen)析(xi)时(shi)不予考虑。目前造(zao)成(cheng)模糊(hu)、变(bian)暗、拖尾现象(xiang)的(de)(de)(de)(de)(de)问(wen)题主(zhu)要集中(zhong)在传输(shu)的(de)(de)(de)(de)(de)电缆上,因为传输(shu)中(zhong)使(shi)用的(de)(de)(de)(de)(de)电缆,就(jiu)幅(fu)频特性(xing)而言,其衰(shuai)减呈反(fan)对数(shu)型。(如图1-1中(zhong)A曲(qu)线)

即频率越(yue)高衰减越(yue)大,具体指标祥(xiang)见下表

 

 

SYV-75-2

SYV-75-3

SYV-75-5-1

LG-RG59/5

1MHZ/100米

-3dB

-2.2dB

-1.2dB

-1dB

100MHZ/100米

-22dB

-15dB

-10dB

-8Db

200MHZ/100米

-38dB

-24dB

-15dB

-12dB

外径尺寸

 

15mm

22mm

18mm

 

  由于各频(pin)率分(fen)(fen)变(bian)量的(de)(de)(de)衰减,所以造成(cheng)图(tu)像变(bian)暗(亮度不够)和(he)模糊,为(wei)(wei)改(gai)善(shan)该(gai)种(zhong)情况,应使(shi)传(chuan)(chuan)输(shu)(shu)设备的(de)(de)(de)特性曲(qu)(qu)线(xian)呈对数(shu)型,如图(tu)1-1中的(de)(de)(de)B曲(qu)(qu)线(xian)。但在(zai)电路实践中不可(ke)能(neng)达到这种(zhong)理想(xiang)状态,一般(ban)呈抛物线(xian)型如图(tu)1-1中的(de)(de)(de)C曲(qu)(qu)线(xian)。合成(cheng)的(de)(de)(de)结果呈如图(tu)1-1中的(de)(de)(de)D曲(qu)(qu)线(xian)。九游会网址多少 一般(ban)关心合成(cheng)后的(de)(de)(de)整形带(dai)宽(kuan),:长线(xian)驱动器可(ke)保(bao)证(zheng)线(xian)路传(chuan)(chuan)输(shu)(shu)带(dai)宽(kuan)为(wei)(wei)80~120MHz,能(neng)够明显地改(gai)善(shan)变(bian)暗、模糊等情况,确保(bao)其(qi)高频(pin)分(fen)(fen)量的(de)(de)(de)传(chuan)(chuan)输(shu)(shu)与(yu)显示。

  群(qun)(qun)延(yan)时(shi)(shi)特性(xing)(xing)是指:信(xin)号(hao)传(chuan)(chuan)输(shu)(shu)(shu)过程中,由(you)(you)于分布(bu)参数(shu)的(de)存在,传(chuan)(chuan)输(shu)(shu)(shu)系(xi)统的(de)特性(xing)(xing)参数(shu)不(bu)是纯阻的(de),而(er)是由(you)(you)电(dian)(dian)阻、电(dian)(dian)容(rong)、电(dian)(dian)感(gan)组(zu)成的(de)网络,因此不(bu)同(tong)的(de)频率分量在同(tong)一介质传(chuan)(chuan)输(shu)(shu)(shu)时(shi)(shi),到达的(de)时(shi)(shi)间不(bu)同(tong)或有(you)相位差(cha),具(ju)体(ti)数(shu)学(xue)模型(xing)及分析这(zhei)里不(bu)作详细(xi)论述(shu),就其(qi)产生的(de)实际结果而(er)言(yan)。这(zhei)种群(qun)(qun)延(yan)时(shi)(shi)特性(xing)(xing)会造成信(xin)号(hao)波(bo)形的(de)后延(yan),即造成拖(tuo)尾(wei)。如(ru)图(tu)2-1。在传(chuan)(chuan)输(shu)(shu)(shu)设(she)备中,要(yao)解决(jue)群(qun)(qun)延(yan)时(shi)(shi)问题,就要(yao)对(dui)传(chuan)(chuan)输(shu)(shu)(shu)系(xi)统进行预加重(zhong),即预失真,如(ru)图(tu)2-2,合(he)成后的(de)波(bo)形将有(you)明显改善(shan),如(ru)图(tu)2-3。不(bu)同(tong)的(de)电(dian)(dian)缆和(he)不(bu)同(tong)的(de)传(chuan)(chuan)输(shu)(shu)(shu)距离其(qi)幅(fu)频特性(xing)(xing)和(he)群(qun)(qun)延(yan)时(shi)(shi)特性(xing)(xing)不(bu)同(tong),应根据不(bu)同(tong)情况进行调整。根据九游会网址多少 的(de)研究,传(chuan)(chuan)输(shu)(shu)(shu)系(xi)统幅(fu)频特性(xing)(xing)越(yue)好(hao)(hao),其(qi)群(qun)(qun)延(yan)时(shi)(shi)特性(xing)(xing)也(ye)越(yue)好(hao)(hao)。即一般(ban)而(er)言(yan)的(de)线(xian)越(yue)粗衰减和(he)拖(tuo)尾(wei)就越(yue)小。

  在无补偿情况下(xia),65HZ 1024*768分(fen)辨率的(de)(de)RGBHV信号(hao)(100MHZ)理论上用SYV-75-3的(de)(de)电缆传输(shu)仅(jin)(jin)仅(jin)(jin)为20米(mi),SYV-75-5-1的(de)(de)电缆也只(zhi)能传输(shu)30多米(mi)。但在工(gong)程(cheng)(cheng)实(shi)践中多数工(gong)程(cheng)(cheng)商和用户认(ren)为-6dB带(dai)内(nei)损耗传输(shu)的(de)(de)图像可以(yi)接受,-9dB带(dai)内(nei)损耗传输(shu)的(de)(de)图像能够(gou)容忍,但群(qun)延时特性则必须进(jin)行延时预加重调整,以(yi)解决拖(tuo)尾(wei)问题。

  长(zhang)线(xian)(xian)驱(qu)(qu)动补(bu)(bu)偿分(fen)配器(qi),可(ke)以(yi)解决工程中(zhong)对信号(hao)远距离(li)传输的(de)(de)(de)(de)(de)问题,一(yi)般认为,3+2或3+4电(dian)(dian)(dian)(dian)(dian)缆,距离(li)应(ying)控(kong)制(zhi)在20 m左(zuo)右,75-5电(dian)(dian)(dian)(dian)(dian)缆应(ying)控(kong)制(zhi)再50m左(zuo)右,如大于(yu)此距离(li),就(jiu)应(ying)用(yong)(yong)长(zhang)线(xian)(xian)驱(qu)(qu)动器(qi)进(jin)行(xing)(xing)(xing)补(bu)(bu)偿。因(yin)工程中(zhong)使用(yong)(yong)的(de)(de)(de)(de)(de)电(dian)(dian)(dian)(dian)(dian)缆规格型(xing)号(hao)不(bu)(bu)同,其直流阻抗(kang)(kang)、等效(xiao)阻抗(kang)(kang)、分(fen)布电(dian)(dian)(dian)(dian)(dian)容(rong)(rong)、电(dian)(dian)(dian)(dian)(dian)感等参数(shu)不(bu)(bu)同,因(yin)此,必须(xu)对不(bu)(bu)同的(de)(de)(de)(de)(de)情况进(jin)行(xing)(xing)(xing)补(bu)(bu)偿,理论上讲,通过(guo)对电(dian)(dian)(dian)(dian)(dian)容(rong)(rong)、电(dian)(dian)(dian)(dian)(dian)感和电(dian)(dian)(dian)(dian)(dian)阻的(de)(de)(de)(de)(de)调(diao)(diao)(diao)(diao)(diao)整(zheng)可(ke)以(yi)解决,但实际(ji)应(ying)用(yong)(yong)中(zhong),电(dian)(dian)(dian)(dian)(dian)容(rong)(rong)、电(dian)(dian)(dian)(dian)(dian)感的(de)(de)(de)(de)(de)可(ke)调(diao)(diao)(diao)(diao)(diao)范围较小,而(er)且(qie)要(yao)对R、G、B三(san)路信号(hao)同时(shi)(shi)(shi)调(diao)(diao)(diao)(diao)(diao)整(zheng),且(qie)调(diao)(diao)(diao)(diao)(diao)整(zheng)量要(yao)一(yi)致(zhi),因(yin)此要(yao)想(xiang)实现连续(xu)可(ke)调(diao)(diao)(diao)(diao)(diao)难度(du)很大,目(mu)前(qian)多(duo)(duo)采用(yong)(yong)预先设(she)(she)计好的(de)(de)(de)(de)(de)网络(luo)进(jin)行(xing)(xing)(xing)迭加(jia),即进(jin)行(xing)(xing)(xing)分(fen)档调(diao)(diao)(diao)(diao)(diao)整(zheng)而(er)不(bu)(bu)采用(yong)(yong)连续(xu)调(diao)(diao)(diao)(diao)(diao)整(zheng),但必须(xu)是可(ke)调(diao)(diao)(diao)(diao)(diao)整(zheng)的(de)(de)(de)(de)(de),如果采用(yong)(yong)固(gu)定(ding)(ding)电(dian)(dian)(dian)(dian)(dian)路进(jin)行(xing)(xing)(xing)一(yi)定(ding)(ding)的(de)(de)(de)(de)(de)补(bu)(bu)偿,不(bu)(bu)可(ke)能符合现场(chang)的(de)(de)(de)(de)(de)不(bu)(bu)同情况,不(bu)(bu)应(ying)称为长(zhang)线(xian)(xian)驱(qu)(qu)动器(qi)。该(gai)长(zhang)线(xian)(xian)驱(qu)(qu)动补(bu)(bu)偿设(she)(she)备(bei)根据不(bu)(bu)同规格电(dian)(dian)(dian)(dian)(dian)缆的(de)(de)(de)(de)(de)衰减特(te)性及电(dian)(dian)(dian)(dian)(dian)缆的(de)(de)(de)(de)(de)不(bu)(bu)同长(zhang)度(du),仿(fang)真电(dian)(dian)(dian)(dian)(dian)缆的(de)(de)(de)(de)(de)反对数(shu)曲线(xian)(xian)特(te)性,进(jin)行(xing)(xing)(xing)了分(fen)档位的(de)(de)(de)(de)(de)增益补(bu)(bu)偿和群延(yan)时(shi)(shi)(shi)调(diao)(diao)(diao)(diao)(diao)整(zheng),该(gai)设(she)(she)备(bei)补(bu)(bu)偿最多(duo)(duo)达(da)8/16级(ji)(每(mei)级(ji)约15米),设(she)(she)备(bei)带宽可(ke)达(da)200MHz(未加(jia)补(bu)(bu)偿),调(diao)(diao)(diao)(diao)(diao)整(zheng)后传输系统带宽可(ke)达(da)80~120MHz。调(diao)(diao)(diao)(diao)(diao)整(zheng)补(bu)(bu)偿器(qi)针对10dB/100米、100MHz电(dian)(dian)(dian)(dian)(dian)缆,对参数(shu)进(jin)行(xing)(xing)(xing)优化(hua),在20m时(shi)(shi)(shi)起步调(diao)(diao)(diao)(diao)(diao)整(zheng),100m时(shi)(shi)(shi)达(da)到最大,而(er)VGAD-1*2CC/LT 16档调(diao)(diao)(diao)(diao)(diao)整(zheng)设(she)(she)备(bei),在50m时(shi)(shi)(shi)起步调(diao)(diao)(diao)(diao)(diao)整(zheng),300m时(shi)(shi)(shi)达(da)到最大,从(cong)目(mu)前(qian)看能满足实际(ji)工程使用(yong)(yong)要(yao)求。

  针对(dui)图像不(bu)稳(wen)定乃至(zhi)黑频等现象,长(zhang)线(xian)补(bu)(bu)偿(chang)(chang)(chang)驱(qu)动器(qi)还对(dui)同(tong)步信号进(jin)行(xing)了数字校正。长(zhang)线(xian)补(bu)(bu)偿(chang)(chang)(chang)驱(qu)动器(qi)操作便(bian)捷,设(she)备前面板上设(she)计按(an)键进(jin)行(xing)补(bu)(bu)偿(chang)(chang)(chang)档位操作,此外(wai),还增加了RS-232接口控制,如图3-1,例中(zhong)对(dui)矩阵(zhen)切(qie)换(huan)器(qi)而(er)言,输入(ru)线(xian)的长(zhang)度(du)与输出(chu)线(xian)的长(zhang)度(du)各(ge)不(bu)相(xiang)等,进(jin)行(xing)补(bu)(bu)偿(chang)(chang)(chang)时,原则上应(ying)在输入(ru)部分(fen)采用(yong)不(bu)同(tong)的补(bu)(bu)偿(chang)(chang)(chang),以使(shi)输入(ru)信号在矩阵(zhen)入(ru)口时保持一(yi)致(zhi),由于输出(chu)线(xian)长(zhang)度(du)又(you)不(bu)一(yi)致(zhi),也应(ying)针对(dui)其采取不(bu)同(tong)的补(bu)(bu)偿(chang)(chang)(chang),设(she)备较多,如果采用(yong)图3-2的方案,在完成(cheng)切(qie)换(huan)的同(tong)时,将输入(ru)、输出(chu)线(xian)长(zhang)度(du)的信息通(tong)知长(zhang)线(xian)驱(qu)动器(qi),令其按(an)不(bu)同(tong)的长(zhang)度(du)进(jin)行(xing)补(bu)(bu)偿(chang)(chang)(chang)调整,可节省设(she)备,减(jian)少(shao)投资.