Time division multiplexing :

Introduction:

Time-division multiplexing (TDM) is a method of transmitting and receiving independent signals over a common signal path by means of synchronized switches at each end of the transmission line so that each signal appears on the line only a fraction of time in an alternating pattern

Applications

Time division multiplexing (TDM) is mainly used in communications .in order to transmit message of different users in the same channel, we use to send this simultaneously. Simple example is TV cable lines which are subscribed to home.

Block Diagram:

Pulse width modulation :

Introduction:

Pulse witdth modulation (PWM) is a modulation technique used to encode a message into a pulsing signal. Although this modulation technique can be used to encode information for transmission, its main use is to allow the control of the power supplied to electrical devices, especially to inertial loads such as motors

Application

Ø  PWM is used to control servomechanisms; see servo control.

Ø  In telecommunications, PWM is a form of signal modulation where the widths of the pulses correspond to specific data values encoded at one end and decoded at the other

Ø  PWM can be used to control the amount of power delivered to a load without incurring the losses that would result from linear power delivery by resistive means. .

Ø  PWM is also used in efficient voltage regulators. By switching voltage to the load with the appropriate duty cycle, the output will approximate a voltage at the desired level. The switching noise is usually filtered with an inductor and a capacitor.

Ø  PWM is sometimes used in sound (music) synthesis, in particular subtractive synthesis, as it gives a sound effect similar to chorus or slightly detuned oscillators played together

Block Diagram:

Different Cases

1.    Fine frequency and Number of samples

2.    Low Frequency and Fine number of samples.

Conclusion

We performed this lab and we took following result

1.    By decreasing frequency number of pulses also decreases.

2.    By decreasing delay pulse move more slowly.

Trapezoidal Rule coding for Matlab implementation :

Clc

clear all

close all

syms x;

a=input('enter lower value')

b=input('upper value')

n=input('enter desired intervals=')

h=b-a/n

g=input('enter function=')

p=inline(g)

for i=1:n+1

   x(i)=a+h*(i-1)

   f(i)=p(x(i))

end

s=sum(f(2:n))

A=h/2*(f(1)+2*s+f(n+1))

Q) Solve the given function 1/x using trapezoidal rule:

enter lower value1

a=1

upper value2

b=2

enter desired intervals=4

n =4

h = 1.7500

enter function=1/x

g =1/x

p =Inline function:

     p(x) = 1.0./x

x =1

f = 1

x = [ 1, 11/4]

f =[ 1, 4/11]

x =[ 1, 11/4, 9/2]

f = [ 1, 4/11, 2/9]

x = [ 1, 11/4, 9/2, 25/4]

f =[ 1, 4/11, 2/9, 4/25]

x =[ 1, 11/4, 9/2, 25/4, 8]

f = [ 1, 4/11, 2/9, 4/25, 1/8]

s =1846/2475

A =362677/158400