24th January 2007, 10:54 #1
Member level 1
advantages of am
What are the advantages and disadvantages of AM and FM modulation?
Ajish Babu S
24th January 2007, 10:54
24th January 2007, 12:34 #2
Member level 2
advantages of fm over am
- Advantage of AM
1- Corverage area of AM Reciever is wider than FM because atmospheric propagation
2- AM is long distance propagation because λ
3- AM Circuit is cheapter and non complex than FM.
4- AM have bandwidth limited and FM unlimited
- Disadvantage of AM
1- The only one way to withance to noise happen is increasing power transmite
2- Signal of AM is not stronger than FM when it propagate to obstacle. (Urband)
3- Only one sideband of AM transmites Information Signal, So it loss power on other sideband and Carrier.
4- Noise mixes AM Signal in amplitude when it propagates in free space that it make difficulty to recover Original Signal at reciever.
24th January 2007, 12:34
25th January 2007, 16:13 #3
Advanced Member level 5
disadvantages of am
Originally Posted by RatanaRETH
I am sorry, but I can agree only with point 3 from Disadvantage.
In my opinion all the others are wrong.
25th January 2007, 16:13
25th January 2007, 16:40 #4
Advanced Member level 2
advantages of fm
One big advantage of FM is that you can run the PA in Compression and/or
Saturation Mode. With AM you care about the linearity
25th January 2007, 17:25 #5
Member level 1
disadvantages of fm
one main advantage of the FM is low noise compare to AM
and we dont need any amplitude limitter circuit in AM where as in FM we need an amplitude limitter ckt.
25th January 2007, 21:54 #6
Full Member level 6
disadvantages of frequency modulation
For AM, linear amplifiers are rarely used because of their poor efficiency. Most high level AM modulation transmitters use a class C (non-linear) RF amplifier. Newer ones use switcher PA (Class E, F, etc) which are also non-linear. In the non-linear cases, the audio is injected by modulating the DC power supply of the non-linear RF amplifier.
So a class C amplifier works equally well for AM or FM. However, if you are high level AM modulating the class C amplifier, you would need an audio amplifier that supplies the additional audio sideband power. This is not needed for FM.