background:url(2、png),url(1、jpg),url(3、png),url(4、jpg);},表示哪张图片处在最上层() A: 2、png B: 1、jpg C: 3、png D: 4、jpg

三角形连接的三相对称负载，接于三相对称电源上，线电流与相电流之比为（ ） A: [img=25x26]1803817c12771ee.png[/img] B: [img=25x26]1803817c1b1cfcb.png[/img] C: 1 D: 0

background: url(2、png),url(1、jpg),url(3、png),url(4、jpg);},表示哪张图片处在最上层（）。

设.向量可表示为的线性组合:,则() A: a=-1,b=-1,c=-1 B: a=1,b=-1,c=-1 C: a=-1,b=1,c=-1 D: a=-1,b=-1,c=1

<img src="data:image/png;base64,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" />=（ ） A: (atan(x^(1/2))+C B: (atan(x)^2+C C: (atan(x^(1/2))^2+C D: (atan(x^2)^(1/2)+C

共有4个站进行码分多址通信。4个站的码片序列为：a：（-1 -1 -1 +1 +1 -1 +1 +1） b：（-1 -1 +1 -1 +1 +1 +1 -1）c：（-1 +1 -1 +1 +1 +1 -1 -1） d：（-1 +1 -1 -1 -1 -1 +1 -1）现收到这样的码片序列：（+1 +1 -1 +3 +1 +1 -3 +1），则（ ）发送1。 A: a和d B: a C: b和c D: c

【判断题】对于维持阻塞结构的D触发器，当CP=1期间，输入信号D由1跳转到0，则由于=D，输出状态Q也由1跳转到0。 data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAGMAAAAwCAYAAAAFIcTMAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAKNSURBVHhe7Zk/jw1RGMYHH0BEu4XQSiT A.对 B.错

A、B、C三个站点采用CDMA技术进行通信，A、B要向C发送数据，设A的码片序列为+1，-1，-1，+1，+1，+1，+1，-1。则B可以选用的码片序列为: -1，+1，-1，+1，-1，+1，+1，+1|-1，+1，-1，+1，-1，+1，-1，+1|-1，+1，-1，-1，-1，+1，+1，+1|-1，-1，-1，+1，-1，+1，+1，+1

下列哪个码片序列不能用于CDMA通信 A: ( -1 -1 -1 +1 +1 -1 +1 +1 ) B: ( -1 -1 +1 -1 +1 +1 +1 -1 ) C: ( -1 +1 -1 +1 +1 -1 -1 -1 ) D: ( -1 +1 -1 -1 -1 -1 +1 -1 )

不支持动画，支持透明背景，支持真彩色，网上只要下载1/64就可以显示出低分辨率的预览图像的是（）格式。 A: JPEG B: GIF C: PNG D: PSD