CHAPTER 2
Modulation:-
Modulation is the process of superimposing a low frequency signal on a high frequency signal.
OR
The process of modulation can be defined as varying the RF carrier wave in accordance with the
information in a low frequency signal.
Need of Modulation:-
If two musical programs were played at the same time within distance, it would be
difficult for anyone to listen to one source and not hear the second source, since all
musical sound have same frequency range, from about 50 Hz to 10 kHz.
The second reason for modulating a high frequency carrier is that RF energy will travel a
great distance then same amount of energy transmitted as sound
Types of modulation:-
There are two types of modulation are as follows:-
Analog Modulation.
Digital modulation.
ANALOG MODULATION:- Analog modulation refers to the process of transferring analog low
frequency baseband signal, like TV signal over a higher frequency carrier signal such as radio
frequency band.
There are three type of analog modulation:-
Frequency modulation (FM)
Amplitude modulation (AM)
Phase modulation (PM)
Frequency modulation (FM):- Frequency modulation (FM) is the process of varying the
instantaneous frequency of carrier signal accordingly with instantaneous amplitude of the
message signal.
, FM Advantage
Modulation and demodulation does not catch any channel noise.
FM Disadvange:
Circuit needed for FM modulation and demodulation is bit complicated than AM
Application:
1) FM radio broad cast is an example
Amplitude Modulation:: -Amplitude modulation or AM is the process of varying the
instantaneous amplitude of carrier signal accordingly with instantaneous amplitude of message
signal.
Modulation:-
Modulation is the process of superimposing a low frequency signal on a high frequency signal.
OR
The process of modulation can be defined as varying the RF carrier wave in accordance with the
information in a low frequency signal.
Need of Modulation:-
If two musical programs were played at the same time within distance, it would be
difficult for anyone to listen to one source and not hear the second source, since all
musical sound have same frequency range, from about 50 Hz to 10 kHz.
The second reason for modulating a high frequency carrier is that RF energy will travel a
great distance then same amount of energy transmitted as sound
Types of modulation:-
There are two types of modulation are as follows:-
Analog Modulation.
Digital modulation.
ANALOG MODULATION:- Analog modulation refers to the process of transferring analog low
frequency baseband signal, like TV signal over a higher frequency carrier signal such as radio
frequency band.
There are three type of analog modulation:-
Frequency modulation (FM)
Amplitude modulation (AM)
Phase modulation (PM)
Frequency modulation (FM):- Frequency modulation (FM) is the process of varying the
instantaneous frequency of carrier signal accordingly with instantaneous amplitude of the
message signal.
, FM Advantage
Modulation and demodulation does not catch any channel noise.
FM Disadvange:
Circuit needed for FM modulation and demodulation is bit complicated than AM
Application:
1) FM radio broad cast is an example
Amplitude Modulation:: -Amplitude modulation or AM is the process of varying the
instantaneous amplitude of carrier signal accordingly with instantaneous amplitude of message
signal.
