06-08-2014, 10:15 AM
Degree of Bachelor of Engineering in
Electronics and Communication
Engineering
[attachment=66615]
INTRODUCTION
Communication systems have undergone a fast growth
during the last few years, giving rise to a huge support
infrastructure. Further developments in the domain of
wideband systems are expected to sustain the expansion of
this segment of the telecommunication and electronic
market, linking it more closely to the world of data
communication and Internet. In the next future, a substantial
amount of skilled personnel will be engaged in running
communication systems both at a network level and in the
maintenance and organization of field apparatus. At the
same time, short time-to-market is becoming a must for
companies engaged in the development and design of
communication system hardware, which requires advanced
skills in terms of analog and digital design, but also a broad
vision of all problems related to the world at largeSo looking at all the latest trends we have tried to
develop a system which is able to remove the limitations of a
normal communication system. Therefore we have used
fiber optics as the communication media. Some of the salient
features of this communication technique are :-
- This method of communication is relatively noise free and
transmits the signals over a long range without any
appreciable attenuation.
- The size of the optical fibers is very small and their
diameter is comparable to the human hair. This helps in
reducing the congestion of electrical wires.
- Optical fibers are very good electrical insulators and
therefore immune to electrical interference.- Optical fibers are also free from electromagnetic
interference and thus immune to crosstalk.
- The optical fiber provides excellent signal security as one
can't simply obtain the information by invading the fiber.
- The optical fibers have high strengths and they can be
twisted without any damage.
- The optical fibers are reliable and require less
maintenance.
- Also the system where on the one hand is very simple to
use and is very cheap. On the other hand this gives a very
good accuracy for the data and command communication.
The project also include all the aspects of interfacing the
communication system with the physical ports of a PC and
controlling that devices using interrupts and port
programming .The same switching concept is used in our
telecommunication industries where the switching is used to
switch over the bandwidth to every channel on the TDMA ,
FDMA CDMA or any other bases.
The main function of the project is to transfer data and voice
from one point to another which are at a distance from each
other and the switching of electrical appliances through
optical fiber. The data to be transmitted, is outputted from
the PC itself.
So looking at all the latest trends we have tried to
develop a system which is able to remove the limitations of a
normal communication system. Therefore we have used
fiber optics as the communication media. Some of the salient
features of this communication technique are :-
- This method of communication is relatively noise free and
transmits the signals over a long range without any
appreciable attenuation.
- The size of the optical fibers is very small and their
diameter is comparable to the human hair. This helps in
reducing the congestion of electrical wires.
- Optical fibers are very good electrical insulators and
therefore immune to electrical interference.- Optical fibers are also free from electromagnetic
interference and thus immune to crosstalk.
- The optical fiber provides excellent signal security as one
can't simply obtain the information by invading the fiber.
- The optical fibers have high strengths and they can be
twisted without any damage.
- The optical fibers are reliable and require less
maintenance.
- Also the system where on the one hand is very simple to
use and is very cheap. On the other hand this gives a very
good accuracy for the data and command communication.
The project also include all the aspects of interfacing the
communication system with the physical ports of a PC and
controlling that devices using interrupts and port
programming .The same switching concept is used in our
telecommunication industries where the switching is used to
switch over the bandwidth to every channel on the TDMA ,
FDMA CDMA or any other bases.
The main function of the project is to transfer data and voice
from one point to another which are at a distance from each
other and the switching of electrical appliances through
optical fiber. The data to be transmitted, is outputted from
the PC itself.
DATA COMMUNICATION
The data communication through an optical fiber consists of
a switch panel.when the user presses any particular switch
(for example :- switch no 5) then the DTMF encoder IC UM
91214 will generate a unique pair of frequencies which will
be passed to the optical source as the input and accordingly
the signals of different frequencies for different keys, from
the transmitter is passed through the fiber . This code
sequence will be fed to an LED which will emit the light
according to the sequence generated i.e. it will turn on for
logic 1 and turn off for logic 0
VOICE COMMUNICATION
In this model we show the working of the optical fiber with
the help of two-amplifier circuit. In this model we transmit the
data in analogue form. Firstly we convert the sound signal
into light signal. This light signal is coupled to the optical
fiber and end of the optical fiber is connected to photodiode.
Photodiode convert the light signal into electrical signal and
this electrical signal is now reproduced in to sound signal
with the help of amplifier and speaker.
In this project we use IC 741 as a amplifier component. Pin
no 7 of the IC is connected to the positive supply. Pin no 4 of
the IC is connected to the negative supply. Pin no 6 is output
pin. Pin no 2 and 3 is input pin.
Positive and negative voltage is supply to the IC through
battery. In this project we use 9-volt dc voltage as a supply
voltage. Pin no 3 is act as a reference voltage pin, for this
purpose we connect two resistance to pin no 3 via positive
terminal and negative terminal. Input signal is applied to the
pin no2 via capacitor and input resistance. Input signal is
applied to the pin no2 through condenser mike. Condenser mike converts the sound signal into small electrical signal.
This electrical signal is coupled to the pin no 2 via capacitor
and resistance. Here capacitor works as a DC blocking
capacitor and pass only AC signal from the mike. This input
signal after coupling to the pin no2 is amplified by the IC 741
and available on the pin no 6. Here we connect a one
feedback resistance between pin no 6 and pin2. This
resistance is work as a feedback resistance. Feedback
resistance acts as a very important part in this amplifier,
After increasing the value of this resistance we change the
level of the sound. Now output from the pin no 6 is coupled
to the two transistor circuit. Here both transistor works as
push pull amplifier network circuit.
Output of the transistor is connected to the L.E.D through
one resistance. Now sound is converted into light with the
help of this L.E.D Variations in the intensity of the light is as
per the intensity of the sound. We coupled this light of the
LED to the optical fiber in proper way. We connect it in
optical fiber, so that all the light is passed through the optical
fiber in other end. Now optical fiber is connected to the photodiode in proper
way, so that all the light is from optical fiber is connected to
the photodiode is not wasted. Photodiode is light sensitive
component. Photodiode convert this light into the small
voltage. This small electrical signal is coupled to the pin no 2
of the IC. Here again we use one operational amplifier as a
amplifier circuit. Pin no 7 of this IC is connected to the
positive. Pin no 4 is connected to the negative voltage. Pin
no 6 is the output pin. Electrical signal amplify by the IC is
available on the pin no 6. Output from the IC is again
amplified by the pushpull amplifier circuit. Output from the
push pull amplifier is now connected to the speaker via
capacitor. We use capacitor for block the dc voltage from the
IC and pass only AC signal to the speaker
CONCLUSION
Achievment is finding out what you would
be and then doin what you have to. The higher the submit,
The higher is to climb. The goal was determined and we
began with a determined resolve and put in ceaseless
sustained effort.