|  | 4.1 |
| Background for Studying Frequency-Based Cable Testing
|  | 4.1.8 |
| Bandwidth
Bandwidth is an extremely important concept in communications systems. Two ways of considering bandwidth that are important for the study of LANs are analog bandwidth and digital bandwidth. Analog bandwidth typically refers to the frequency range of an analog electronic system. Analog bandwidth could be used to describe the range of frequencies transmitted by a radio station or an electronic amplifier. The units of measurement for analog bandwidth is Hertz, the same as the unit of frequency. Examples of analog bandwidth values are 3 kHz for telephony, 20 kHz for audible signals, 5 kHz for AM radio stations, and 200 MHz for FM radio stations. Digital bandwidth measures how much information can flow from one place to another in a given amount of time. The fundamental unit of measurement for digital bandwidth is bits per second (bps). Since LANs are capable of speeds of millions of bits per second, measurement is expressed in kilobits per second (Kbps) or megabits per second (Mbps). Physical media, current technologies, and the laws of physics limit bandwidth. During cable testing, analog bandwidth is used to determine the digital bandwidth of a copper cable. Analog frequencies are transmitted from one end and received on the opposite end. The two signals are then compared, and the amount of attenuation of the signal is calculated. In general, media that will support higher analog bandwidths without high degrees of attenuation will also support higher digital bandwidths.
Web Links
Bandwidth Basics – A Comparison of Connection Speeds http://www.wesonline.com/techsystems/ bandwidth.htm