04 综合布线设计基础.ppt

Chapter 4 Foundation of Generic Cabling Design 4.1 Channel transmission performance 4.2 Composition of Generic Cabling system 4.3 Foundation of Generic Cabling system 4.1 Channel transmission performance Review : Why choice laser in Gigabit Ethernet 1)The maximum modulation speed is not enough for Gigabit Ethernet applications 2)coupling coefficient: Laser LED(30%~80% )versus LED ( 5%~15%) 3) VCSEL: Laser performance at the LED’s price Review Q: In IEEE 802.3ae, 10GBase-SR/SW, MM fiber:26 m or 33 m depending on fiber bandwidth. Why ? A: 1)mininum modal bandwidth 2) Maximum (MHz ? km) attenuation Example: modal bandwidth of a MM fiber is 200 MHz*km So, when the length of Fiber is 1km,the maximum frequency of signal that can transmit is 200 MHz. Also, when when the length of Fiber is 500m,the maximum frequency is 200*1km/0.5km=400 MHz Review:GB50311-2007(Safety)Indoor and Outdoor Link performanceof connectors 1) Insertion loss 2) Return loss Goals: How to Choice network media ,Why? How to test transmission performance? 4.1 Channel transmission performance 4.1.1 Concept 4.1.2 The performance of Copper Cable Channel 4.1.3 The performance of Optic fiber Channel 4.1.1 Channel and link  1、Concept 2、Cabling channel、Permanent link、CP Link 3、Types of Optic Fiber Channel 4、Theory of Shannon 1、 Concept Channel link 2、Cabling channel、Permanent link、CP Link GB50311-2007 3、Type of Optic Fiber Channel 1 Type of Optic Fiber Channel 2 Type of Optic Fiber Channel 3 4、Shannons Theory the maximum data rate of a noisy channel whose bandwidth is B Hz, and whose signal-to-noise ratio is S/N, is given by For example, a channel of 3000-Hz bandwidth with a signal to thermal noise ratio of 30 dB (typical parameters of the analog part of the telephone system) can never transmit much more than 30,000 bps, no matter how many or how few signal leve