advanced simulation lab

1

EXPERIMENT NO. 1

AIM:- TO STUDY VARIOUS OPERATIONS ON SIGNALS ( +,*,-,/,mux, demux, integration, diffrentiation) USING SIMULINK. SIMULINK LIBRARY :- Simulink→Common Used Blocks→Math operations→Add, Simulink→Common Used Blocks→Math operations→ Sub , Simulink→Common Used Blocks→Mux, Simulink→Common Used Blocks→Demux, Simulink→Common Used Blocks→ Product, Simulink→Common Used Blocks→ Div, Simulink→Common Used Blocks→Integrator, Simulink→Common Used Blocks→Contineous→Derivative, Simulink→Common Used Blocks→Contineous→Sine wave , Simulink→Common Used Blocks→ Constant Simulink→Common Used Blocks→Sink→ Scope. MODEL:-

Differentiation is a method to compute the rate at which a dependent output y changes with respect to the change in the independent input x. This rate of change is called the derivative of y with respect to x. In more precise language, the dependence of y upon x means that y is a function of x. This functional relationship is often denoted y = f(x), where f denotes the function. If x and y are real numbers, and if the graph of y is plotted against x, the derivative measures the slope of this graph at each point.

The derivative of y with respect to x", "d y by d x", or "d y over d x". The oral form "d y d x" is often used conversationally, although it may lead to confusion.

Integration is an important concept in mathematics and, together with its inverse, differentiation, is one of the two main operations in calculus. Given a function f of a real variable x and an interval [a, b] of the real line, the definite integral is defined informally to be the area of the region in the xy-plane bounded by the graph of f, the x-axis, and the vertical lines x = a and x = b, such that area above the x-axis adds to the total, and that below the x-axis subtracts from the total.

Addition is a mathematical operation that represents combining collections of objects together into a larger collection. It is signified by the plus sign (+). Addition can also represent combining other physical and abstract quantities using different kinds of numbers: negative numbers, fractions, irrational numbers, vectors, decimals and more.

Multiplication (often denoted by the cross symbol "×") is the mathematical operation of scaling one number by another. It is one of the four basic operations in elementary

2

arithmetic (the others being addition, subtraction and division).

Subtraction is one of the four basic binary operations; it is the inverse of addition, meaning that if we start with any number and add any number and then subtract the same number we added, we return to the number we started with. Subtraction is denoted by a minus sign in infix notation, in contrast to the use of the plus sign for addition.

Since subtraction is not a commutative operator, the two operands are named. The traditional names for the parts of the formula

c − b = a

are minuend (c) − subtrahend (b) = difference (a). subtraction = value1 - value2

In mathematics, especially in elementary arithmetic, division (÷) is an arithmetic operation. Specifically, if b times c equals a, written:

where b is not zero, then a divided by b equals c, written:

a ÷ b = c

For instance,

6 ÷ 3 = 2

since

6 = 3 × 2

In the expression a ÷ b = c, a is called the dividend or numerator, b the divisor or denominator and the result c is called the quotient.

IN electronics, a multiplexer (or MUX ) is a device that selects one of several analog or digital input signals and forwards the selected input into a single line. A multiplexer of 2n inputs has n select lines, which are used to select which input line to send to the output. Multiplexers are mainly used to increase the amount of data that can be sent over the network within a certain amount of time and bandwidth. A multiplexer is also called a data selector. They are used in CCTV, and almost every business that has CCTV fitted, will own one of these.

An electronic multiplexer makes it possible for several signals to share one device or resource, for example one A/D converter or one communication line, instead of having one device per input signal.

On the other hand, a demultiplexer (or demux) is a device taking a single input signal and selecting one of many data-output-lines, which is connected to the single input. A multiplexer is often used with a complementary demultiplexer on the receiving end.

An electronic multiplexer can be considered as a multiple-input, single-output switch, and a demultiplexer as a single-input, multiple-output switch. The schematic symbol for a multiplexer is an isosceles trapezoid with the longer parallel side containing the input pins and the short parallel side containing the output pin. The schematic on the right shows a 2-to-1 multiplexer on the left and an equivalent switch on the right.

3

SIMULINK DIAGRAM

Subtract

Sine Wave

Scope7

Scope5

Scope3

Scope2

Scope1

Scope

Product

1s

Integrator

Divide

du/dt

Derivative

3

Constant1

1

Constant

Add

4

OUTPUT PLOTS

DIFFERENTIATION

INTEGRATOR

5

ADDITION

MULTIPLICATION

6

SUBTRACTION

DIVISION

7

S in e Wa ve5

S in e Wa ve4

S in e Wa ve3

Sine W ave2

S in e Wave1

Sine Wa ve

Sco pe 1

1

Con stan t

MULTIPLEXER

RESULT

Various types of signals ( +,*,-,/,mux,demux,integration, diffrentiation) has been studied.

8

EXPERIMENT NO. 2 AIM: To study design of Amplitude Modulation & Demodulation. AMPLITUDE MODULATION : SIMULINK LIBRARY:

Signal Processing Blockset→ DSP Sources→ DSP Constant

Signal Processing Blockset→ DSP Sources→ DSP Sine wave

Simulink→ Maths Operations→ Adder

Simulink→ Maths Operations→ Product

Signal Processing Blockset→ DSP Sinks→Vector Scope

MODEL AMPLITUDE MODULATION Modulation is defined as the process by which some characteristics of a carrier signal is varied in accordance with a modulating signal. The base band signal is referred to as the modulating signal and the output of the modulation process is called as the modulation signal. Amplitude modulation is defined as the process in which is the amplitude of the carrier wave is varied about a means values linearly with the base band signal. The envelope of the modulating wave has the same shape as the base band signal provided the following two requirements are satisfied 1. The carrier frequency fc must be much greater then the highest frequency components fm of the message signal m (t) i.e. fc >> fm 2. The modulation index must be less than unity. If the modulation index is greater than unity, the carrier wave becomes over modulated

9

Simulink Diagram Of Amplitude Modulation

Time

VectorScopeDSP

Sine Wave1

DSP

Sine Wave

Product

5

DSPConstant

Add

Output Plot

Amplitude Modulated Output

10

AMPLITUDE DEMODULATION SIMULINK LIBRARY:

Signal Processing Blockset→ DSP Sources→ DSP Constant

Signal Processing Blockset→ DSP Sources→ DSP Sine wave

Simulink→ Maths Operations→ Adder

Simulink→ Maths Operations→ Product

Signal Processing Blockset→ DSP Sinks→Vector Scope

Simulink→Math Operations→Matrix Concatenation

Simulink→Math Operations→Math Function

Signal Processing Blockset→Filtering→Filter Designs→ Digital Filter Design

MODEL

AMPLITUDE DEMODULATION The process of detection provides a means of recovering the modulating Signal from modulating signal. Demodulation is the reverse process of modulation. The detector circuit is employed to separate the carrier wave and eliminate the side bands. Since the envelope of an AM wave has the same shape as the message, independent of the carrier frequency and phase, demodulation can be accomplished by extracting envelope. An increased time constant RC results in a marginal output follows the modulation envelope. A further increase in time constant the discharge curve become horizontal if the rate of modulation envelope during negative half cycle of the modulation voltage is faster than the rate of voltage RC combination ,the output fails to follow the modulation resulting distorted output is called as diagonal clipping : this will occur even high modulation index.

11

Time

VectorScope2

Time

VectorScope1

Time

VectorScope

DSP

Sine Wave1

DSP

Sine Wave

Product1

Product

Horiz Cat

MatrixConcatenation

sqrt

MathFunction1

u2

MathFunction

FDATool

DigitalFilter Design

2

DSPConstant2

1

DSPConstant1

5

DSPConstant

Add1

Add

Simulink Diagram Of Amplitude Demodulation

Amplitude Demodulated Output RESULT

Amplitude modulation and demodulation is studied.

12

EXPERIMENT NO. 3 AIM :- To study Digital Modulation Scheme(PAM) SIMULINK LIBRARY : Communication Blockset→ Random Data Source→ Random Integrator Generator Communication Blockset→ Modulation→ Digital Baseband Modulation→ AM→ M-PAM Modulator Baseband Communication Blockset→ Channels→ AWGN Channel Communication Blockset→ Modulation→ Digital Baseband Modulation→ AM→ M-PAM Demodulator Baseband Communication Blockset→ Comm Sinks→ Error Rate Calculation Simulink→ Sinks→ Scope Communication Blockset→ Comm Sinks→ Discrete-Time Scatter Plot Scope Simulink Extras→ Additional Sinks→ Power Spectral Density Simulink→ Math Operations→ Complex to Real-img Simulink→ Sinks→ XY Graph Simulink→ Sinks→ Display MODEL :- PAM stands for Pulse amplitude modulation; it is a form of signal modulation where the message information is encoded in the amplitude of a series of signal pulses. It is an analog pulse modulation scheme in which the amplitude of train of carrier pulse is varied according to the sample value of the message signal. The signal is sampled at regular intervals and each sample is made proportional to the magnitude of the signal at the instant of sampling. These sampled pulses may then be sent either directly by a channel to the receiving end or may be made to modulated using a carrier wave before transmission.

13

There are two types of pulse amplitude modulation: • Single polarity PAM: In this a suitable fixed dc level is added to the signal to

ensure that all the pulses are positive going. • Double polarity PAM: In this the pulses are both positive and negative going.

Pulse-amplitude modulation is widely used in baseband transmission of digital data.

SIMULINK DIAGRAM :-

14

OUTPUT PLOTS:-

TIME SCATTER PLOT SCOPE

TIME SCATTER PLOT SCOPE1

15

INPUT POWER SPECTRAL DENSITY

16

POWER SPECTRAL DENSITY1

17

XY GRAPH

XY GRAPH 1

18

SCOPE

SCOPE 1

RESULT:- The experiment was performed successfully.

19

EXPERIMENT NO. 4 AIM:- TO STUDY DIGITAL MODULATION SCHEME(BPSK) SIMULINK LIBRARY :- BPSK modulator, AWGN channel, Scope, I/P & O/P spectral density-P,BPSK Demodulator, Transient time scale plot scope, Complex to real image,Trans X-Y plot, Error rate calculation,Display,Rx X-Y plot and O/P scope MODEL:- BPSK (also sometimes called PRK, Phase Reversal Keying, or 2PSK) is the simplest form of phase shift keying (PSK). It uses two phases which are separated by 180° and so can also be termed 2-PSK. It does not particularly matter exactly where the constellation points are positioned, and in this figure they are shown on the real axis, at 0° and 180°. This modulation is the most robust of all the PSK s since it takes the highest level of noise or distortion to make the demodulator reach an incorrect decision. It is, however, only able to modulate at 1 bit/symbol (as seen in the figure) and so is unsuitable for high data-rate applications. BPSK is functionally equivalent to 2-QAM modulation. Output Plots:-

BPSK SIMULINK DIAGRAM

20

TIME SCATTER PLOT SCOPE 1

TIME SCATTER PLOT SCOPE

21

INPUT SPECTRAL DENSITY 1

XY GRAPH

22

XY GRAPH 1

SCOPE

23

SCOPE 1

RESULT:- BPSK has been studied.

24

EXPERIMENT NO:-5 AIM :- Design simulink model for Frequency Shift Keying. APPARATUS USED: - MATLAB 7.0, MATLAB R2011b

SIMULINK LIBRARY :- Communication block sets→communication sources-→random data sources→Random integer generator Simulink Extras→Additional sinks→Power spectral density Communication blocksets→modulation→Digital baseband modulation→FM→M-FSK Modulator baseband M-FSK Demodulator Communication blocksets→Channels→AWGN Channel Communication blocksets→Communication sinks→Discrete time scatter plot scope Math Operations→ Complex to real-imag Communication blocksets→ Communication sinks→Error rate calculation MODEL :- FREQUENCY SHIFT KEYING FSK is a digital bandpass modulation technique. In this frequency of the carrier signal which is analog in nature is modulated in accordance with digital baseband signal. Frequency is shifted according to the logic states as in case of 32 FSK 5 logical bits are transmitted in a single bit duration. In this technique amplitude and phase remain constant.

25

SIMULINK DIAGRAM :- FSK MODULTOR AND DEMODULATOR

OUTPUT PLOTS:- TRANSMITTER XY GRAPH

26

RECEIVER XY GRAPH

27

INPUT POWER SPECTRAL DENSITY

OUTPUT POWER SPECTRAL DENSITY

28

FSK TRANSMITTER DISCRETE TIME SCATTER PLOT SCOPE

FSK RECEIVER DISCRETE TIME SCATTER PLOT SCOPE

Result:- The Simulink design for M-FSK Modulator and Demodulator is successfully designed.

29

EXPERIMENT No. 6 AIM :-To Design SIMULINK model for quadrature amplitude modulation (QAM)

APPARATUS USED: - MATLAB 7.0, MATLAB R2011b SIMULINK LIBRARY :- Communication blocksets→communication sources→random datasources→Random integer generator Simulink Extras→Additional sinks→Power spectral density Communication blocksets→Modulation→Digital baseband modulation AM → General QAM Modulator baseband General QAM Demodulator Communication blocksets-→Channels→ AWGN Channel Communication blocksets→ Communication sinks→Discrete time scatter plot scope Math Operations → Complex to real-imag Communication blocksets→Communication sinks→Error rate calculation MODEL :- QUADRATURE AMPLITUDE MODULATION: QAM is both analog and digital modulation technique. In this technique amplitude of two carrier waves are modulated using ASK or AM . In this case the digital signal can be analog or can be a digital bit of streams. It is called quadrature because the two carrier waves have a phase difference of 90 degrees. In digital QAM the modulated waveform is a combination of both ASK and PSK and in analog QAM modulated waveform is a combination of both AM and PM. In digital QAM a finite number of atleast two amplitude and phase is necessary.

30

SIMULINK DIAGRAM :- QAM MODULATOR AND DEMODULATOR

OUTPUT PLOTS:- TRANSMITTER XY GRAPH

31

RECEIVER XY GRAPH

INPUT POWER SPECTRAL DENSITY

32

OUTPUT POWER SPECTRAL DENSITY

33

TRANSMITTER DISCRETE TIME SCATTER PLOT

RECEIVER DISCRETE TIME SCATTER PLOT

RESULT:- The Simulink design for AM Transmitter and AM Reciever was successfully designed.