AMPLITUDE MODULATION (AM)
If the amplitude of the carrier signal is modified in proportion to the instantaneous amplitude of the baseband signal, then it is called amplitude modulation. Here the frequency and the phase of the carrier signal remain constant. Amplitude modulation is used in radio and TV broadcasting.
The signal shown in Figure 10.1(a) is the basebandsignalthatcarries information. Figure 10.1(b) shows the high-frequency carrier signal and Figure 10.1(c) gives amplitude modulated signal. We can see that amplitude of the carrier is modified in proportion to the amplitude of the baseband signal.
• Easy transmission and reception
• Lesser bandwidth requirements
• Low cost
• Noise level is high
• Low efficiency
• Small operating range