Computer Aided Design (CAD) Engineering/2460... · 2015. 11. 16. · Computer Aided Design (CAD) Lecture 11 Dr.Eng. Basem ElHalawany Simulation of Analog Communication Systems using

Computer Aided Design (CAD)

Lecture 11

Dr.Eng. Basem ElHalawany

Simulation of Analog Communication Systems

using Simulink (3)

2

Schedule (Updated 28-10)

CAD - Basem ElHalawany

Topics Estimated Duration (# Lectures)

Introduction 1

Introduction to Matlab Environment 1

Matlab Programing (m-files) (1) 5

Modeling using Matlab Simulink Tool (1) 3

Midterm 7th Week

Communication Systems Simulation (Applications) 3 (1/3)

Introduction to FPGA + Review on Digital Logic/Circuits 2

VHDL Modeling Language 4

VHDL Application 2

Introduction to OPNET Network Simulator ( Projects ) 2

Course Closeout / Feedback/ project (s) Delivery 1

CAD - Basem ElHalawany 3

The Lecture is based on :

1. Modeling of Digital Communication Systems using simulink

2. Online Tutorials, You can find complete links on Instructor “External Links” on University website

www.bu.edu.eg/staff/basem.mamdoh-external-Links

4

The spectrum Analyzer is used to find the frequency content of a signal How much power in each frequency

Spectrum Analyzer

Two-sided Spectrum

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One versus Two-Sided Spectrum:

One-sided Spectrum

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Spectrum of 2 multiplied sinusoidal

F =100 Hz

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Amplitude Modulation

Amplitude Modulation is a process where the amplitude of a carrier signal is altered according to information in a message signal.

The frequency of the carrier signal is usually much greater than the highest frequency of the input message signal.

CAD – Dr.Eng. Basem ElHalawany 8

The AM signal

The modulating signal:

The Carrier Signal:

tAtc cc cos

ttmkAts cc cos 1

tm

0 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 0.1-5

0

5

0 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 0.1-1

0

1

0 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 0.1-1

0

1

AM - Basic Definitions

CAD – Dr.Eng. Basem ElHalawany 9

The Envelope:

The AM Signal

ttmkAts cc cos 1

tmkAts c 1

0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18 0.2-5

-4

-3

-2

-1

0

1

2

3

4

5

AM - Basic Definitions

CAD – Dr.Eng. Basem ElHalawany 10

0 500 1000 1500 2000 2500 3000 3500 4000 4500 50000

0.5

1

1.5

Frequency (Hz)

|M(f

)|

0 500 1000 1500 2000 2500 3000 3500 4000 4500 50000

0.5

1

1.5

Frequency (Hz)

|Y(f

)|

tm ts

Carrier

Side Bands

AM Spectrum

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Block Diagram of the simulation Environment

AM Modulation Scheme

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AM Modulation Scheme Results

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AM Demodulator (Square-Law Demodulator)

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AM Modulator/Demodulator

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AM Demodulator sub-blocks

17 AM Demodulator sub-blocks

Select ”Digital Filter Design” and add it to the model Double click and configure as the next slide

18

AM Demodulator sub-blocks

Since the carrier frequency (fc) is 15 KHz and the maximal frequency of the information is 1 KHz,

The filter will be designed to pass frequencies below 5 KHz, and rejects frequencies higher than 10 KHz.

19

AM Demodulator sub-blocks