Bandwidth
Sabtu, 14 Agustus 2010
A term you will meet often in radio physics is bandwidth. Bandwidth is simply
a measure of frequency range. If a range of 2.40 GHz to 2.48 GHz is
used by a device, then the bandwidth would be 0.08 GHz (or more commonly
stated as 80MHz).
It is easy to see that the bandwidth we define here is closely related to the
amount of data you can transmit within it - the more room in frequency
space, the more data you can fit in at a given moment. The term bandwidth is
often used for something we should rather call a data rate, as in “my Internet
connection has 1 Mbps of bandwidth”, meaning it can transmit data at 1
megabit per second.
Frequencies and channels
Let us look a bit closer at how the 2.4GHz band is used in 802.11b. The
spectrum is divided into evenly sized pieces distributed over the band as individual
channels. Note that channels are 22MHz wide, but are only separated
by 5MHz. This means that adjacent channels overlap, and can interfere
with each other. This is represented visually
a measure of frequency range. If a range of 2.40 GHz to 2.48 GHz is
used by a device, then the bandwidth would be 0.08 GHz (or more commonly
stated as 80MHz).
It is easy to see that the bandwidth we define here is closely related to the
amount of data you can transmit within it - the more room in frequency
space, the more data you can fit in at a given moment. The term bandwidth is
often used for something we should rather call a data rate, as in “my Internet
connection has 1 Mbps of bandwidth”, meaning it can transmit data at 1
megabit per second.
Frequencies and channels
Let us look a bit closer at how the 2.4GHz band is used in 802.11b. The
spectrum is divided into evenly sized pieces distributed over the band as individual
channels. Note that channels are 22MHz wide, but are only separated
by 5MHz. This means that adjacent channels overlap, and can interfere
with each other. This is represented visually
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