Amplitude Modulation- In A.M. the amplitude of the carrier wave is made to vary in accordance with the audio frequency.
The Frequency and the Phase of the carrier remains unchanged.
Factors affecting Amplitude Modulation-
1. Construction of the Receiver equipment is simple, but the Transmitter is complicated.
2. Single Side Band mode is possible.
3. It has more bandwidth, and is subjected to more noise and interference.
4. Requires high power Transmitter.
Frequency Modulation- In Frequency Modulation, the Frequency of the carrier wave is made to vary in accordance with the Audio wave.
The Amplitude of the carrier wave remains unchanged.
Factors affecting Frequency Modulation-
1. Construction of the Receiver equipment is complicated, but the Transmitter is simple.
2. Single Side Band mode is not possible.
3. It has wider bandwidth, because the frequency is made to vary in accordance with the audio wave, and is not subjected to noise or interference.
4. It does not require high power Transmitters.
Pulse Modulation- is used in the Radar, in this the pulses are sent in short intervals.
RADAR = Radio Detection and Ranging
Factors affecting Pulse Modulation-
1. It uses shorter Wavelengths, which can reflect the beams more efficiently.
2. It has narrow beams, which can be used at shorter Wavelengths, and is not subjected to noise or interference.