FM Modulation:

Type the following keyword in the command prompt window.

Expt.No. Simulink Modeling of basic modulation systemsDate:

Aim:

To know and understand basic modulation techniques using Simulink tool.

Softwares Required:

Matlab R2015a

Hardware Required:

A personnel Computer.

Procedures:

1. Open Simulink library from Matlab tool.2. Draw the model in the Simulink model window.3. Save the file with .mdl Extension and run the program.4. Verify the output in the command Window.

Theory:

Amplitude Modualtion:

Amplitude modulation (AM) is one of the conventional technique used to transmit message

signals using a carrier wave. The amplitude or strength of the high frequency carrier wave is

modified in accordance with amplitude of the message signal.

The basics of AM are:

Carrier signal (Sc) = Acsin(2π fct)

Message signal (Sm) = Amsin(2πtfm)   # fm must be smaller than fc

# em must be smaller than ec

When carrier amplitude is altered with respect to message signal,

Modulated Signal = (Ac+ Amsin(2 πfmt))*sin(2 π fct)

In terms of modulation index (m,= Am / Ac) the equation becomes

Modulated signal= (1+ msin(2 πfmt))* Ac sin(2 π fct), where,

Ac = Carrier signal amplitude

Am = Message signal amplitude

fc= Carrier frequency

fm =Message frequency

AMPLITUDE MODUALATION:

QPSK

Result: