Hi Hao,
Since the digital age, the word Bandwidth is used and heard more and more in adverting. In the old analog age, most people couldn’t tell the difference between AM and FM bands. Nowadays, the word “Broadband” is everywhere. To understand what a band is in telecommunication terms, perhaps, it’s helpful to know a little bit about AM and FM on the radio. The AM band (amplitude modulation ) on your radio sounds horrible because each channel is limited to a bandwidth of 5000 hertz (5 KHZ). In this frequency, the signals don’t travel very far and are prone to static interference. The sound quality is poor.
FM (frequency modulation) on the other hand, is stereophonic and has better sound quality because each channel has a broader bandwidth at 150,000 hertz which can carry more audio information much further with less vulnerability to electrical interference, like high voltage power line.
In the frequency spectrum, data can travel further, faster with a lot more information at the higher the bandwidth. For instance, Satellite radio operates in Giga hertz which is 1,000,000,000 cycle per second. Since it’s completely digital, its noise ratio is almost non-existent, that’s why it’s also called High Def. Radio.
As various commercial application such as HDTV and computer connection for data transfer increase, the demands for higher bandwidth is insatiable. On-line video games consume a tremendous amount of bandwidth because of the graphics and color details. In true technical terms, the game performance depends on“ higher bandwidth”. But in layman’s term, it also is called “bigger bandwidth”.
If you are interested, this information may be helpful:
http://www.tvtower.com/Commercial%20Television%20Frequencies.html