Analog modulation:-
1) Transmitted modulated signal is analog in nature.
2) Amplitude , frequency or phase variations in the transmitted signal represented the information or message.
3) Noise immunity is poor for AM , but improved for FM and PM.
4) It is not possible to separate out noise and signal.
Therefore, reperaters cannot be used.
5) Coding is not possible.
6) Bandwidth required is lower than that for the digital modulation methods.
7) FDM is used for multiplexing.
8) Not suitable for transmission of secret information in military applications.
9) Analog modulation systems are AM , FM , PM , PAM , PWM , etc.
Digital modulation:-
1) Transmitted signal is digital , i , e. train of digital pulses.
2) Amplitude , width or position of the transmitted pulses is constant . The message is transmitted in the form of code words.
Noise immunity is excellent.
3) It is possible to separate signal from noise.
4) Therefore , repeaters can be used.
5) Coding techniques can be used to detect and correct the errors.
6) Due to higher bit rates , higher channel bandwidth is required.
7) TDM is used for multiplexing.
8) Due to coding techniques , it is suitable for militray applications.
9) Digital modulation systems are PCM , DM , ADM , FPCM ,etc.
1) Transmitted modulated signal is analog in nature.
2) Amplitude , frequency or phase variations in the transmitted signal represented the information or message.
3) Noise immunity is poor for AM , but improved for FM and PM.
4) It is not possible to separate out noise and signal.
Therefore, reperaters cannot be used.
5) Coding is not possible.
6) Bandwidth required is lower than that for the digital modulation methods.
7) FDM is used for multiplexing.
8) Not suitable for transmission of secret information in military applications.
9) Analog modulation systems are AM , FM , PM , PAM , PWM , etc.
1) Transmitted signal is digital , i , e. train of digital pulses.
2) Amplitude , width or position of the transmitted pulses is constant . The message is transmitted in the form of code words.
Noise immunity is excellent.
3) It is possible to separate signal from noise.
4) Therefore , repeaters can be used.
5) Coding techniques can be used to detect and correct the errors.
6) Due to higher bit rates , higher channel bandwidth is required.
7) TDM is used for multiplexing.
8) Due to coding techniques , it is suitable for militray applications.
9) Digital modulation systems are PCM , DM , ADM , FPCM ,etc.
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