Compare AM and FM.

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written 6.0 years ago by

AM	FM
1. In AM modulation, amplitude of the signal is varied, and frequency and phase are kept constant.	1. In FM modulation, frequency of the signal is varied, and amplitude and phase are kept constant.
2. AM has two sidebands	2. FM has infinite number of sidebands
3. The carrier of AM comprises of most of the transmitted power, which contains no information.	3. All transmitted power in FM is useful, and there is no wastage of power unlike AM.
4. Modulation index in AM varies from 0 to 1.	4. Modulation index in FM is always greater than one.
5. AM is more noisy since the AM receivers do not have amplitude limiters.	5. Noise in FM can be reduced by employing amplitude limiters to remove the amplitude variations caused by noise.
6. AM has narrow channel bandwidth which is 2fmfm.	6. The bandwidth in FM is much higher, up to 10 times as that of AM.
7. In AM if two or more signals received at same frequency, then both will be demodulated, this can lead to interference.	7. In FM if two or more signal received at same frequency, the receiver will capture the stronger signal and eliminate the weaker signal.
8. AM broadcast operates in the medium frequency (MF) and high frequency (HF).	8. FM broadcast operates in the upper VHF and UHF range, where noise effects are minimal.
9. The design of AM transmitter and receiver is not complex for the modulation and demodulation purpose.	9. The design of FM transmitter and receiver is relatively complex for the modulation and demodulation purpose.
10. AM transmission and reception equipments are not that expensive since the circuitry is relatively simple.	10. FM transmission and reception equipment is expensive as the circuitry is complex.

ADD COMMENT EDIT

1. In AM modulation, amplitude of the signal is varied, and frequency and phase are kept constant.

1. In FM modulation, frequency of the signal is varied, and amplitude and phase are kept constant.

2. AM has two sidebands

2. FM has infinite number of sidebands

3. The carrier of AM comprises of most of the transmitted power, which contains no information.

3. All transmitted power in FM is useful, and there is no wastage of power unlike AM.

4. Modulation index in AM varies from 0 to 1.

4. Modulation index in FM is always greater than one.

5. AM is more noisy since the AM receivers do not have amplitude limiters.

5. Noise in FM can be reduced by employing amplitude limiters to remove the amplitude variations caused by noise.

6. AM has narrow channel bandwidth which is 2fmfm.

6. The bandwidth in FM is much higher, up to 10 times as that of AM.

7. In AM if two or more signals received at same frequency, then both will be demodulated, this can lead to interference.

7. In FM if two or more signal received at same frequency, the receiver will capture the stronger signal and eliminate the weaker signal.

8. AM broadcast operates in the medium frequency (MF) and high frequency (HF).

8. FM broadcast operates in the upper VHF and UHF range, where noise effects are minimal.

9. The design of AM transmitter and receiver is not complex for the modulation and demodulation purpose.

9. The design of FM transmitter and receiver is relatively complex for the modulation and demodulation purpose.

10. AM transmission and reception equipments are not that expensive since the circuitry is relatively simple.

10. FM transmission and reception equipment is expensive as the circuitry is complex.