Lecture 41 Mobile Communication 24-04-2007
1
Cellular Telephone Systems
2
History & Evolution
1921 Radio Dispatch Service was introduced for Police cars in Detroit. 1934 AM mobile communication system used by hundreds of state & municipal forces. The majo
The Noise objective was 3pW/km. The total noise power measured at the end of 6400 km was 8000 pW, which is less than 3pW/km. The (S/ N)O was 40 dB. 2 coaxial tubes required for 10,800 channels, one for Go and the other for Return. For L5 - 22 tubes are th
Lecture 8
Frequency Modulation FM Generation
FM Generation
1.Direct Method 2.Indirect Method (Armstrong Method)
Narrowband FM Generation (NBFM) Wideband FM Generation Combination of NBFM and Frequency multipliers
Narrow Band FM:
x (t) = Ac cos[ct + (t)] F
Types of AM :
1.Ordinary AM Carrier and both sidebands. 2. DSB-SC Double Sideband Suppressed Carrier. 3. SSB-SC Single sideband suppressed Carrier. 4. VSB Vestigial Sideband. VSB is a compromise between DSB & SSB.
VSB Signal :
VSB modulation is used for t
Fourier transform of an Impulse train
An impulse train in time domain is transformed into another impulse train in the frequency domain.
Sampling Theorem(contd.)
Impulse train and
its spectrum
Rayleighs Energy Theorem:
x(t)x*(t)dt = X ( ) X *( )d Sxx( )
Lecture-2
Review of Signals and Systems
Classification of signals: 1. Deterministic or Random (Stochastic ) Also Classified as Discrete-time(digital) Continuous time(analog) Further Classified as 1. Periodic 2. Aperiodic Also classified as Energy signal 0
BIRLA INSTITUTE OF TECHNOLOGY & SCIENCE, PILANI INSTRUCTION DIVISION SECOND SEMESTER 2003-2004 Course Handout ( Part- II ) Date : 07-01-2006 Course No. Course Title Instructor-in-Charge 1. : EEE C383 : Communication Systems. : S. BALASUBRAMANIAN.
Scope an
Lecture - 22 Quantization 27-02-2007
1
2
PCM Generation
3
Problem with Uniform Quantization
SNR is an indication of the quality of the received signal SNR is directly proportional to signal power and varies from talker to talker by as much as 40 dB. The
Lecture - 23 DPCM , DM & Line Codes. 1-03-2007
1
Delta Modulation
2
D Modulator
3
Two versions of D Modulator
4
Line Codes PCM Signaling Formats
Unipolar Signaling: A binary 1 is represented by high level ( +5 Volts or A Volts) and a binary 0 by zero lev
Lecture 39 Analog Comm. System Noise Performance Comparison, Bandwidth Efficiency etc. 19-04-2007
1
Comparison of Noise Performance of Analog Systems
2
Bandwidth Efficiency Diagram
3
Comparison of M-ary PSK with Ideal System
4
Bandwidth Efficiency Plane f
Lecture - 26 Equalizer, Eye Pattern 10-03-2007
1
2
Inter-symbol Interference (ISI)
3
Zero forcing equalizer: cks are the tap gains. The time delay is chosen to be the symbol interval Tb. pO(t) must satisfy the Nyquist criteria.
4
Received Pulse
After Equa
Lecture - 25 Line Codes. 8-03-2007
1
Power Spectral Density of NRZ Line Code
2
PSD of RZ and Manchester NRZ Codes
3
Inter-symbol Interference (ISI)
4
Raised Cosine Filter
5
Response for different roll-off factors.
6
Response for different roll-off factors
Iterativecomputationsofthe Transportationalgorithm
Iterative computations of the Transportation algorithm After determining the starting BFS by any one of the three methods discussed earlier, we use the following algorithm to determine the optimum solutio
DeterminationofStarting BasicFeasibleSolution
Determination of the starting Solution In any transportation model we determine a starting BFS and then iteratively move towards the optimal solution which has the least shipping cost. There are three methods
Dual simplex met hod for solving t he pr imal
I n thi s l ectur e we descr i be the i mpor tant Dual Si mpl ex method and i l l ustr ate the method by doi ng one or t wo pr obl ems.
Dual Simplex Method
Suppose a basic solution satisfies the optimality con
D ualit y t heor ems Finding t he dual opt imal solut ion fr om t he pr imal opt imal t ableau
Dual problem in Matrix form In this lecture we shall present the primal and dual problems in matrix form and prove certain results on the feasible and optimal s
Dual Problem of an LPP Given a LPP (called the primal problem), we shall associate another LPP called the dual problem of the original (primal) problem. We shall see that the Optimal values of the primal and dual are the same provided both have finite fea
Deterministic Dynamic Programming
Dynamic Programming (DP) determines the
optimum solution to an n-variable problem by
decomposing it into n stages with each stage
constituting a single-variable sub problem.
Recursive Nature of Computations in DP
Computat
The Assignment Model " The best person for job" is an apt description of the assignment model. The general assignment model with n workers and n jobs is presented below: Jobs 1 2 . n 1 c11 c12 c1n Workers 2 c21 c22 c2n n cn1 cn2 cnn
The element cij is the
Formation of CCITT Group
DEMODULATION
The process of extraction or recovery of the message signal from the modulated waveform 1. COHERENT 2. NON-COHERENT
m(t) cosct m(t) cosct 2 Cosct LPF m(t)
To demodulate a DSB-SC signal a product modulator is employed
Spectrum of AM:
x AM (t) = Ac[1+ cosmt]cosct
= Ac cosct +(1/ 2)Ac cos(c m)t +(1/ 2)Ac cos(c +m)t
Taking the Fourier transform
x
Along with the carrier there are two frequency components fc-fm is called the LOWER SIDEBAND(LSB) f +f is called the UPPER SIDE
Lecture 42 Satellite Communication 26-04-2007
1
Concept of Extra-terrestrial Relays
2
Timeline Of the Events in the Satcom Industry
3
Two-way Satellite Link
4
Communication Satellite
5
Satellite Communication Systems - Properties
6
Satellite Communication
Some problems illustrating the principles of duality
I n this le cturewelook at som proble s that use e m s t he re sults from Duality the (as discusse in ory d C hapte 7). r
Problem 7. Problem Set 4.2D Page 130 Consider the LPP Maximize z = 5 x1 + 2 x2 +