BOOK_CONTENT
From Telecom Basics, Second Edition

Overview

Transmission systems interconnect communication devices (end nodes) by guiding signal energy in a particular direction or directions through a transmission medium such as copper, air, or glass. A transmission system will have at least one transmitting device, a transmission medium, and a receiving device. The transmitting communication device is capable of converting an information signal into a form of electrical, electromagnetic wave (radio), or optical signal that allows the information to be transferred through the transmission medium. The receiving communication device converts the transmitted signal into another form that can be used by the device or other devices that are connected to it. Transmission systems can be unidirectional (one direction) or they can be bi-directional (two directions).

The basic types of transmission mediums include copper wire, coaxial cable, free space/air, fiber optic cable, and mechanical transmission line. Copper and coaxial wire is primarily used for low to moderate frequency transmission over a few miles. Free space/air systems can transmit hundreds of miles but have limited bandwidth and are susceptible to noise interference. Fiber optic cable is capable of carrying high-speed data signals (as light pulses) over thousands of miles. Mechanical (acoustic wave) transmission lines transmit over very short distances (only a few millimeters) and are used for signal filtering components.

Different types of transmission lines have varying performance characteristics and may be susceptible to interference during signal transmission. These characteristics include the available frequency bandwidth (frequency response), how much signal leakage that occurs (cross talk), and the susceptibility of...

Copyright APDG Publishing 2002 under license agreement with Books24x7

Products & Services
Fiber Optic Cables
Fiber optic cables are composed of one or more transparent optical fibers enclosed in protective coverings and strength members. Fiber optic cables are used to transmit "light" data.
GPIB Extenders
GPIB extenders are used to remove the restrictions on cable length specified in the IEEE 488 (GPIB) standard, while maintaining optimal performance (e.g., maximum data rate, transmission quality, etc.).
Fiber Optic Polarizers
Fiber optic polarizers (FOP) are placed inline to improve the extinction characteristics of fiber optic cable. They allow the transmission of only one polarization, blocking light in unwanted polarization states.
Fiber Optic Attenuators
Fiber optic attenuators are devices that reduce signal power in fiber optic links by inducing a fixed or variable loss. They are used to control the power level of optical signals at the outputs of light sources and electrical-to-optical (E/O) converters. They are also used to test the linearity and dynamic range of photo sensors and photo detectors.
Specialty Optical Fiber
Specialty optical fiber is modified, usually by doping, for a specialized function. It consists of one or more transparent fibers enclosed in a protective covering.

Topics of Interest

Switching is the process of connecting two (or more) points together within a network or communication devices. These connections can be physically connected (mechanical switch) or connected logically...

Absorption: The portion of optical attenuation in an optical fiber resulting from the conversion of optical power to heat; caused by impurities such as hydroxyl ions in the fiber. A/B Switch: A...

Transmission feed line system performance plays an important role in wireless network coverage. Insertion loss measurement is one of the critical measurements used to analyze transmission feed line...

Exam Essentials List the main considerations when designing a basic fiber optic system. Remember that there are many ways to approach fiber optic system design and there are many different fiber optic...

The TereScope 3000, from SystemSupportSolutions, is an example of the type of sending/receiving device used in FSO technology. Photo Courtesy of SystemSupportSolutions, Inc. One relatively...