1. User needs analysis
The HFC cable TV network is composed of optical fiber as the trunk line and coaxial cable as the distribution network to form the optical fiber coaxial hybrid network. It gives full play to the excellent characteristics of optical fiber and cable, and organically combines to complete the high-quality transmission and distribution of cable TV signals. This constitutes this unique fiber / coax hybrid network structure. HFC is a fiber-optic star layout with the front end as the center, the optical fiber extending to the receiving point and the optical node as the end point, and at the same time, a star tree coaxial cable network extends from the optical node to cover users. Therefore, the HFC cable TV network topology is a star-one tree structure.
Second, the cable TV optical transmission and transmission system scheme design according to the cable TV optical transmission and transmission system split structure, the fiber optic link is specifically designed to ensure that the link transmission quality meets the design requirements.
2.1 Determine the topology of the optical fiber trunk draw a schematic diagram of the structure of the optical cable trunk; determine the length and number of cores of each optical cable.
2.2 Identify the optical transmitter.
The selection of cable TV optical transmitters will be determined according to the specific locations (such as communities, enterprises, and villages) where fiber optic cable (HFC) transmission systems are constructed.
Choose 1310 nm cable TV optical transmitter or 1510 nm cable TV optical transmitter;
Calculate fiber loss and optical power at each point;
Calculate the split ratio of the optical splitter;
Calculate the power of the optical transmitter;
Select the model of the optical transmitter and list the main parameters
2.3 Determine the optical receiver set the average received optical power of the optical receiver Select the type of optical receiver, list the main parameters
2.4 Determining the performance of the designed optical link Write the specific process of optical link index estimation in detail; determine the main performance of the designed optical link.
Optical fiber link loss: formula αL × residual optical transmission level: αL + 1-receiving end level optical transmission power: Calculate the required CATV optical transmitter transmission power for each optical link according to the required split ratio and optical fiber link length.
Use the formula to calculate the score ratio K = Pn / (Ptotal)
3. Schematic diagram of cable optical transmission system
Our hair bonnets with soft elastic drawstring strap will make you feel comfortable. Easily fit it to your head, nice and comfy and stays on all night while you sleep. Won`t be tight, also doesn`t slip off, won`t give you headaches or leave an annoying marks on your forehead.
Premium Satin double-layered reversible silk bonnets helps maximally maintain moisture of hair, doesn`t add any extra heat. help your hair not to get tangled up during the tossing and turning while you sleep. Besides, it prevents hair loss, reduce frizz breakage and split ends. Super Soft, Smooth, Lightweight, Breathable and Skin-friendly.
Extra Large & Roomy great for holding natural hair, dreadlocks, braids, weaves, waves, long, dry, tangled, perms, rollers, afros, buns, short, shoulder length wavy, and up-dos. Keeping your various hairstyles when sleeping.
This silky head cover is really convenient in daily use. Not only it used as sleeping cap at home for preserving certain hairstyles and keep your hair healthy, but also when wash your face, skin care, hair beauty, makeup, do housework, cook, take shower or relax at home.
Wig Thread,Nylon Sewing Thread,Best Thread For Wig Making,Hair Extension Thread
Xuchang Le Yi De Import And Export Trade Co., Ltd. , https://www.synthetichairs.com