EE4209/EE5809 Digital Audio Technology--The 3 meanings of bandwidth

EE4209/EE5809 Digital Audio Technology
The 3 meanings of bandwidth :

1. Bandwidth as maximum rate of change in digital data communication. How fast can the signal be changed.

Assume that a signal is sent with two possible signal levels and a bandwidth of b Hz. Then the data rate, d, in bits/s is

d = 2b.

Allowing more than two signal levels such that more than one bit can be communicated at a time is called multilevel coding.

2. Bandwidth of a signal in terms of frequency.

For a signal that can be represented as a periodic waveform , let fmax be the frequency of the highest-frequency component and let fmin be the frequency of the lowest-frequency component.
Then, the width of the signal ,w is :

w = fmax - fmin

3. Bandwidth of a communication channel in terms of frequency. The range of frequencies allocated to a band constitutes the bandwidth of a channel., also called the width of a channel, since it correlated with the width of a signal.

Modulation adds frequency components called sidebands to the original carrier signal, and these sidebands must lie within the designated channel. So, the bandwidth of a channel affects the amount of information that can be communicated.

但是，身為「 普選聯 」核心成員的蔡耀昌和 單仲偕( 民主黨副主席 )，不久前在一個網台的論壇中，竟然對 5月16日 會否去投票一事上支吾以對。

我們認為，這顯示「 普選聯 」正處於進退維谷之境地：「 五一六投票 」等於支持「 五區公投 」，妨礙溝通大業。

SRW LIVE 勇者王誕生
http://www.youtube.com/watch?v=7Hou0zeofVs&feature=related

《青台友香聞》訪問黃毓民 Part 6/8
http://www.youtube.com/watch?v=wlI1_ZMqK6U&feature=related