N-GEN Communications Web-based Seminars ©NGCS

Seminar - An Overview of Communications Technologies

Module 2 - Data Communications Basics and Legacy Technologies                                                Slide 13 of 45 _________________                                                                                  __________

                    Building Blocks - Transmission Media Capabilities

                                                Channel

                                                Bandwidth

_________________                                                                                  __________

A channel and the bandwidth terms were originally used with voice transmission in an analogue form over the copper wire facilities in the public telephone network.

A channel, voice grade, is defined by a frequency range of 300 to 3200 Hz suitable to transmit speech or data in an analogue form.
                A channel capacity is measured by the amount of information which can be sent
                through it - bits per second (digital)
                A voice channel bandwidth    - 2900 Hz
                A basic analogue communications channel    - 4 K Hz

- Bandwidth is defined as the frequency range between the lowest and highest frequencies passed through a media with acceptable attenuation.