Need of modulation
1)The baseband transmission has many limitations which can be overcome using modulation.
2)In the modulation ,the baseband signal is translated i.e.,shifted from low frequency to high frequency.
4)Avoids mixing of signals:
If the baseband sound signals are transmitted without using the modulation by more than one transmitter,then all the signals will be in the same frequency range i.e. 0 to 20 kHz. therefore,all the signal get mixed together and a receiver cannot separated them from each other.
hence,if each baseband sound signal is used to modulate a different carrier then they will occupy different slots in the frequency domain(different channels).
If the baseband sound signals are transmitted without using the modulation by more than one transmitter,then all the signals will be in the same frequency range i.e. 0 to 20 kHz. therefore,all the signal get mixed together and a receiver cannot separated them from each other.
hence,if each baseband sound signal is used to modulate a different carrier then they will occupy different slots in the frequency domain(different channels).
5)Improves quality of reception:
with frequency modulation (FM),and the digital communication techniques like PCM,the effect of noise is reduced to a great extent. this improve quality of reception
with frequency modulation (FM),and the digital communication techniques like PCM,the effect of noise is reduced to a great extent. this improve quality of reception
6)Multiplexing is possible:
Multiplexing is a process in which two or more signal can be transmitted over the same communication channel simultaneously.this is possible only with modulation.the multiplexing allows the same channel to be used by many signals.Hence,many TV channels can use the same frequency range,without getting mixed with each other or different frequency signals can be transmitted at the same time.
Multiplexing is a process in which two or more signal can be transmitted over the same communication channel simultaneously.this is possible only with modulation.the multiplexing allows the same channel to be used by many signals.Hence,many TV channels can use the same frequency range,without getting mixed with each other or different frequency signals can be transmitted at the same time.
7)Increases the range of communication:
The frequency of baseband signal is low,and the low frequency signals can not travel a long distance when they are transmitted.they get heavily attenuated(suppressed).the attenuation reduces with increase in frequency of the transmitted signals,and they travel longer distance.the modulation process increases the frequency of the signal to be transmitted.therefore,it increases the range of communication.
The frequency of baseband signal is low,and the low frequency signals can not travel a long distance when they are transmitted.they get heavily attenuated(suppressed).the attenuation reduces with increase in frequency of the transmitted signals,and they travel longer distance.the modulation process increases the frequency of the signal to be transmitted.therefore,it increases the range of communication.
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