Amplitude modulation

# Amplitude modulation - For amplitude modulation

This preview shows pages 1–23. Sign up to view the full content.

Communications 1 ELCN 306 Hebat-Allah M. Mourad Professor Cairo University Faculty of Engineering Electronics & Communications Department

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
Text Book Modern Digital and Analog Communication Systems Third edition B.P.Lathi - Chapters: 4 – 5 – 6 – 11 Communication systems, S. Haykin, John Wiley and Sons inc., 4 th edition
Course Contents - Introduction to modulation - Different analog modulation techniques: Amplitude, Frequency and Phase -Transformation from analog to digital: Sampling, Quatization, PCM, DM, ADM -Random process

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
Grading system Mid term 20 Quiz 20 Lab + section participation + attendance 20 Final 40 Total 100
Intended Learning Outcomes (ILO’s ( To know the function of different components of a communication system , to understand the different types of modulation (AM, FM, PM, PAM, PCM, DM, DPCM( and demodulation techniques . Calculate two main communication system parameters: power and bandwidth. Design FDM and TDM systems. Solve problems. Choose the best modulation/ demodulation technique for a practical engineering system and analyze the system . How to represent mathematically a random process

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
Why Modulation ? Mainly for two reasons 1 - Practical antenna dimensions light velocity Wavelength frequency Dimension is in the order of a quarter wavelength f c λ =

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
Baseband Power Spectrum

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
Why Modulation ? 2- Multiplexing Better utilization of the available frequency band Spectrum Frequency M 1 (f( M 2 (f( M 3 (f( M N (f(
Basic Modulation Types s (t( = A (t( cos [ Ө (t( ] Ө (t( = ω t + φ (t( ‘ A c cos ω c t ‘ is called un-modulated carrier Analog Modulation Digital Modulation

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
Modulator m(t) Acos(2 f π c t + ) φ modulated signal: s(t) Un-modulated carrier
Modulation Types (Analog Modulation (

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
Modulation Types (Digital Modulation (
Analog Modulation - Different analog modulation techniques - For each type:- - Mathematical presentation * Bandwidth * transmitted power - Modulators - Demodulators - Applications

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
1 - Amplitude Modulation (A.M( Conventional Amplitude Modulation Consider a sinusoidal Carrier wave c(t( the un- modulated carrier. c(t( = A c cos 2 π f c t = A c cos ω c t A c = carrier amplitude f c = carrier frequency A.M is the process in which the amplitude of the carrier wave c(t( is varied about a mean value, linearly with the base band signal
1 - Amplitude Modulation s(t( = A c cos 2 π f c t + m(t( cos 2 π f c t = [A c + m(t( ] cos 2 π f c t = modulated signal S(ω( = π A c [ δ(ω + ω c ( + δ(ω - ω c ( ] + (1/2( [ M(ω + ω c ( + M(ω - ω c ( ]

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
1 - Amplitude Modulation s(t(= un-modulated carrier + upper side band (U.S.B( + lower sideband (L.S.B.( Bandwidth (B.W.( = 2W | M(ω( | | S( ω ( | 0 0 W - W - ω c + ω c

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
Condition : A c + m(t( > 0 for all t A c ≥ m(t( min (absolute –ve peak amp.( Define: μ = modulation index = m(t( min / A c 0 ≤ μ 1 since there is no upper bound on A c and A c ≥ m(t( min The envelope has the same shape of m(t( Over modulation : μ > 1 μ x 100 = percentage modulation
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

### What students are saying

• As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

Kiran Temple University Fox School of Business ‘17, Course Hero Intern

• I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

Dana University of Pennsylvania ‘17, Course Hero Intern

• The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

Jill Tulane University ‘16, Course Hero Intern