Modulation Techniques
Modulation Block Diagram
Demodulation Block Diagram
AM Modulation FM Modulation
Phase Modulation Amplitude Shift Keying
Frequency Shift Keying Phase Shift Keying
Modulation
Advantages Disadvantages Application
Technique
• Simple to implement
Amplitude • AM radio broad cast is an
• Robust against noise • AM is very susceptible to noise.
Modulation example
• Inexpensive receivers
• Higher fidelity audio
• Circuit needed for FM modulation
Frequency • Less susceptible to static and noise • FM radio broad cast is an
and demodulation is bit
Modulation • Wider bandwidth allows for stereo and example
complicated than AM
more channels
• Higher spectral efficiency • Low noise immunity
Phase Modulation • Less susceptible to distortion and noise • Low signal to noise ratio • Satellite communication
• Can achieve higher data rates • Complex circuitry
• Less Bandwidth as compared.
Amplitude Shift • Simple Implementation • Poor Noise immunity.
Keying • Synchronization is not required • More power required • Military Communication
• Effect of DC is more Systems
• More Bandwidth as compared • Moderately complex • Mobile Communication
Frequency Shift
• Better Noise immunity Implementation Systems,
Keying
• Synchronization is not required • Moderate power required • Digital Broadcasting,
• Less-moderate power required • Radar Systems,
• Synchronization is essential.
Phase Shift Keying • Better Noise immunity
• Very complex Implementation.
• High bit rate application.
