ISDN,which stands for Integrated Services Digital Network, is a system of digital phone connections, which has been available for over a decade.This system allows data to be transmitted simultaneously across the world using (1) digital connectivity.With ISDN,voice and data are carried by bearer channels occupying a bandwith of (2) (bits per second).Some switches limit B channels to capacity of 56 Kbps.A data channel (3) handles signaling at 16Kbps or 64Kbps,depending on (4) .Note that,in ISDN terminology,”k” means (5),and not 1024(2^10) as in many computer applications;therefore,a 64Kbps channel carries data at a rate of 64000bps. A new set of standard prefixes has recently been created to handle this. Under this scheme,”K”(Kilo) means 1000(10^3),”M” (Mega) means 1000000(10^6),and soon ,and “Ki”(Kibi) means 1024 (2^10),”Mi” (Mebi) means 1048576(2^20).and soon。
1 曼彻斯特编码的一个主要优点是_____________。(含自同步信号)
2 在一条频分多路复用线路中，若要同时传输24路话音，最低的载频是64KHZ，则线路上传输24路话音的频率范围是________,若在一条时分数字线路上传输，采样频率是8000次/秒，一个信号用7位表示，则线路的传输比特率应该是_____。(60kHZ-156kHZ,1.344Mb/s)
3 计算机网络中常用的纠错法有两种，在单向传输信道中，宜采用_____方法。 (正向纠错法)
4 在现有的传输检错技术中，最精确、最常用的检...[查看详情]
