AM (or Amplitude
Modulation) and FM (or Frequency Modulation) are ways of broadcasting radio
signals. Both transmit the information in the form of electromagnetic waves.
| Attributes | AM | FM |
|---|---|---|
| Stands for | AM stands for Amplitude Modulation | FM stands for Frequency Modulation |
| Origin | AM method of audio transmission was first successfully carried out in the mid 1870s. | FM radio was developed in the United states in the 1930s, mainly by Edwin Armstrong. |
| Modulating differences | Carrier wave is modulated in amplitude by the signal that is to be transmitted. | Carrier wave is modulated in frequency by the signal that is to be transmitted. |
| Frequency Range | AM radio ranges from 535 to 1705 KHz | FM radio ranges in a higher spectrum from 88 to 108 MHz |
| Zero crossing in modulated signal | Equidistant | Not equidistant |
| Noise | AM is more susceptible to noise | FM is less susceptible to noise |
