Amplitude Modulation of Voice signal.

This code shows how to record a sound signal and then modulate it via AM-LC and AM-DSBSC. Later, demodulation is also done.

1) Introduction:

Throughout the world, communication is a key component. For common people, talking over phone, sending voice messages is just a touch of a button but for us telecommunication Engineers, the reality is very different. We know that how communication actually works. Here we introduce the concept of modulation. Modulation is the process of passing the information on another carrier signal. There are various types of modulation but in this task, we are going to use Amplitude Modulation. AM has its sub types out which we are using the following two:

• Amplitude Modulation Double Side Band Large Carrier (also known as Full Carrier)
• Amplitude Modulation Double Side Band Suppressed Carrier (AM-DSBSC)

In this code, I have implimented the above two modulation schemes and also demodulated them using coherrent and non coherrent techniques both. Plotting is done in time domain and Frequency domain.

2) Steps:

• Take the input from users.
• Record a voice signal
• Filter the Voice signal to remove unwanted Frequencies.
• Apply Modulation (AM-DSBSC)
• Design filter for Demodulation.
• Pass signal through Filter.
• Demodulation process (AM-DSBSC).
• Apply Low Pass Filter.
• Apply Modulation (AM-LC)
• Make envelope detector for Demodulation.
• Demodulation process (AM-LC).
• Apply Low Pass Filter.
• Plot Graphs in time domain.
• Fourier Transformation of signals for Frequency Analysis.
• Shift Frequency signals to origin.
• Plot Graphs in Frequency Domain.