In Double Side Band Amplitude Modulation DSB-AM, the amplitude of the modulated signal is proportional to the message signal. This means that time domain representation of the modulated signal is given by

where

is the carrier and  is the message signal. A typical speech signal and its corresponding amplitude modulated signal are shown in figure 1:

Figure 1: Speech segment and its corresponding AM-SC signal

At the end of this experiment, students instructed to observe the changes on the AM-SC modulated wave by varying the duty cycle. The students can also observe the spectrum of AM-SC modulated signal.