Channel Models it describes a channel models in which the bandwidth of the message does not significantly exceed the channel’s coherence bandwidth of the channel.In the study of wireless communication channels narrow band channels implies that the channel under consideration is sufficiently narrow that is frequency response can be considered flat of that signal. The message bandwidth is therefore be less than the coherence bandwidth of the channel of the signal. This is usually used as an idealizing assumption as no channel has perfectly flat fading but if the analysis of many aspects of wireless systems is greatly simplified then flat fading can be assumed quickly .Narrowband can be used with the audio spectrum so as to describe sounds which occupy a narrow range of frequencies. The telephony channel has narrowband which is usually considered to cover frequencies 300–3400 Hz.
A system is wideband when the message bandwidth exceeds the bandwidth of the coherence channel in the communication. In some communication channels links have a high data rate so that they are forced to use a wider bandwidth and other links may have low data rates but use a wider bandwidth that is “necessary” for that data rate in order to gain more advantages in communication.
It is also known as aerial. It is an electrical device which helps in converting the electric power into radio waves & vice versa. Usually uses a radio transmitter or radio receiver. During transmisson of sgnal a radio transmitter supplies an oscillating frequency of radio signal in the form of electric current to the terminal of the antenna and the antenna radiates the energy from the current as radio waves in the transmission.During reception an antenna intercepts some of the power of an electromagnetic wave in order to produce a tiny voltage at its terminals which is applied to a receiver for amplification of the signal.
Antennas for base station
There are mobile phone base station antennas situated on towers and buildings throughout the area. These antennas are part of the mobile telephone network which emit radiation consisting radio frequency through the signal. The fact i.e. the radiation provides the possibility of adverse health effects arising from exposure to this radiation.
Antennas for mobile station
There are mobile station antennas on towers and buildings throughout the locations. These type of antennas are part of the mobile telephone network and they emit radiation consisting radio frequency.
Some related question and answer
1. What does the narrow band channel band implies?
Ans. In wireless communication channels narrow band channels implies that the channel under consideration is sufficiently narrow where a frequency response can be considered flat.
2. when a system has wideband?
Ans. A system has wide band when the message bandwidth exceeds the bandwidth of the coherence channel.
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