VISVESVARAYA TECHNOLOGIAL UNIVERSITY
BELAGAVI - 590018
Project Synopsis on
“AM and FM modulation and demodulation using
Multisim software ”
BACHELOR OF ENGINEERING
In
ELECTRONICS AND COMMUNICATION ENGINEERING
Submitted by
GEETHA O S (4GH19EC020)
KAVANA K M (4GH20EC403)
MADHU C (4GH20EC404)
PRARTHANA A D (4GH20EC407)
Under the Guidance
Mrs.SHRUTHI K N.B.E,M.Tech
Assistant Professor, Dept of E&CE
GEC, Hassan
DEPARTMENT OF ELECTRONICS AND COMMUNICATION ENGINEERINGGOVERNMENT
ENGINEERING COLLEGE,
DAIRY CIRCLE, HASSAN-573201
ABSTRACT :
In a communication transmission system modulation and demodulation process greatly
affect the signal transmission process, in order to signal to the destination information.
Modulation is laying event information signal to the carrier signal, demodulation is the
process of converting the signal to return to normal after modulated. One example is the
analog modulation AM. At the moment there is no a simulator learning analog signals,
therefore made an AM signal simulation for learning analog signals. Frequency modulation
highlights the significant basics of the telecommunications and signal processing which
revolves around modulation and demodulation. The modulator and demodulator circuits
were simulated later on using multisim.
INTRODUCTION:
Amplitude modulation :
Amplitude modulation or AM as it is often called is a form of modulation used for radio
transmissions for broadcasting and two way radio communication applications. One of the
key reason for the use of amplitude modulation was its was of use. The system simply
required the carrier amplitude to be modulated, but more usefully the detector requires in
the receiver could be a simple diode based circuit. This means that AM radios did not need
complicated demodulators. In order that a radio can carry audio or other information for
broadcasting or for two way radio application, it must be modulated or changed in some
way. Although there are number of ways in which a radio may be modulated, one of the
easiest is to change its amplitude in line with variation of sound.
Frequency modulation :
Frequency modulation is a very important process that is used a lot in radio broadcasting
stations. After frequency modulation happens, the message signal will be modulated or
changed in transmission. Indeed, understanding the process of modulation and
demodulation and observing the concept of FM signals is very important in communication
systems. The project was achieved by applying the knowledge that has been gained from
the previous lab sessions and theoretical discussions.
“We have used multisim simulator demonstrating AM and FM modulation and
demodulation.”
COMPONENTS REQUIRED (Software):
• Multisim simulator
Dept of ECE,GEC Hassan 1
OBJECTIVE OF THE PROJECT
The objective of the project are to:
➢ Understand the process of generating the AM and FM signal
➢ Design and simulate a modulator and demodulator by building a circuit using
Multisim based on the given components.
ADVANTAGES AND DISADVANTAGES
ADVANTAGES OF AM :
• It is easy to implement.
• It can be demodulated using a circuit consisting=g of very few components
• AM receivers are very cheap as no specialized components are needed.
DISADVANTAGES OF AM:
• It is not efficient in terms of its power usage
• It is not efficient in terms of its use of bandwidth, requiring a bandwidth equal to twice
that of the highest audio frequency.
• It is prone to high levels of noise because most noise is amplitude based and obviously
AM detectors are sensitive to it.
APPLICATIONS OF AM :
• Picture transmission in T.V
• Broadcasting. (Point to multipoint communication)
• long distance communication.
• Ground wave communication.
ADVANATGES OF FM :
• It gives noiseless reception. Noise is a form of amplitude variation and a FM receiver
will reject such noise signals.
• The operating range is quite large.
• The efficiency of transmission is very high.
•
DISADVANTAGE OF FM :
• A much wider channel is required by FM.
Dept of ECE,GEC Hassan 2
• FM transmitting and receiving equipment’s tends to be more complex.
APPLICATION OF FM :
• Telemetry, radar and seismic prospecting, EEG monitoring of new-born’s etc. also
use the technique of frequency modulation.
• Frequency modulation can be used for the broadcasting of FM radio. This helps in
larger signal to noise ratio.
• It is also used in music synthesis, some systems that use video-transmission and also
for magnetic tape-recording systems.
CONCLUSION:
In amplitude modulation, the carrier frequency is constant, on the other hand, the
value of the carrier amplitude varies depending on the amplitude the modulating signal.
The envelope of the modulated signal is the same shape as the modulating signal. Hence
the Amplitude Modulation Wave is generated using Multisim Software.
As we know, that both the amplitude and phase of the carrier wave remains unchanged and
only the change in frequency is noticed in case of frequency modulation. Hence, we can
say information is transmitted by the frequency variation in the case of FM using Multisim
software.
REFERNCE :
https://www.degruyter.com/document/doi/10.1515/9783110593822-004/html?lang=en
https://ieeexplore.ieee.org/document/8043221
Dept of ECE,GEC Hassan 3
