Telecommunication involves transmitting information over a distance using technology. There are two main types of modulation used: analog and digital. Analog modulation includes amplitude modulation (AM), frequency modulation (FM), and phase modulation (PM). Digital modulation includes amplitude-shift keying (ASK), phase-shift keying (PSK), and frequency-shift keying (FSK). Modulation is the process of altering a carrier wave to allow it to carry information. Key concepts in telecommunication also include frequency, wavelength, bandwidth, transmission media, signaling, switching, and multiple access.

1. Fundamentals of
Telecommunication
Eng. Mohammed Eldaw
https://twitter.com/Mo7ammedEldaw

2. Brief Contents
• Telecommunication definition
• Modulation and demodulation
.Analog modulation
. Digital modulation
• Transmission Media
• Signaling
• Switching
• Multiple access

4. what is Telecommunication ?
• Telecommunication has been defined as a
technology with communication from a
distance .
• The simplest form of telecommunications
takes place between two stations.
However, it is common for multiple
transmitting and receiving stations to
exchange data among themselves.

6. Frequency
Frequency is the number of complete
cycles per second in alternating current
direction.
The standard unit of frequency is the hertz,
abbreviated Hz.
One (1) Hz is the frequency at which the
current complete one cycles.

7. • Kilohertz (kHz) thousand of cycles
• Megahertz (MHz)�������� million
of cycles
• Gigahertz
(GHz)���������� billion of
cycles
• Terahertz
(THz)����������� zillion of
cycles
•

9. Wavelength
• Wavelength is the distance between
identical points in the adjacent cycles of a
waveform.
• � In Radio Frequency (RF), the
wavelength length is usually in meters,
centimeters, or millimeters ranges.

11. Bandwidth
• Bandwidth is a broad term defined as the bit-
rate measure of the transmission capacity
over a network communication system .
• Bandwidth also refers to a range
of frequncies used to transmit a signal.
• bandwidth is measured in hertz and is often
referenced in signal processing applications.

12. Bandwidth Diagram

13. Modulation
• What is Modulation ?
• Modulation is the process by which a carrier
wave is altered in such a way that it is able to
carry information on it.
• There are tow types of modulation:
1.analog modulation includes: FM,PM,AM
2.Digital modulation includes: ASK,PSK,FSK

14. Modulation process

15. Analog Modulation
• In this chapter we will discuss about the
types of analog modulation and you will be
able to know the difference between them
.

16. Amplitude Modulation AM
• When an amplitude modulated signal is
created, the amplitude of the signal is
varied in line with the variations in intensity
of the sound wave. In this way the overall
amplitude or envelope of the carrier is
modulated to carry the audio signal. Here
the envelope of the carrier can be seen to
change in line with the modulating signal.

18. • ts most basic form as a function of time (t)
is:

19. • A, the amplitude, is the peak deviation of the
function from zero.
• f, the ordinary frequency, is the number of
oscillations (cycles) that occur each second
of time.
• ω = 2πf, the angular frequency, is the
rate of change of the function argument in
units of radians per second

20. • , the phase, specifies (in radians) where in
its cycle the oscillation is at t = 0.

21. Amplitude Modulation advantages &
disadvantages
• ADVANTAGES:
• It is simple to implement
• It can be demodulated using a circuit
consisting of very few components
• AM receivers are very cheap as no
specialised components are needed.

22. • DISADVANTAGES :
• An amplitude modulation signal is not
efficient in terms of its power usage.
• It is not efficient in terms of its use of
bandwidth.
• An amplitude modulation signal is prone to
high levels of noise because most noise is
amplitude based and obviously AM
detectors are sensitive to it.

23. Frequency Modulation
FM
• Frequency modulation uses the
information signal, Vm(t) to vary the carrier
frequency within some small range about
its original value. Here are the three
signals in mathematical form:

24. • Here are the three signals in mathematical
form:
•
• Information: Vm(t)
• Carrier: Vc(t) = Vco sin ( 2 p fc t + f )
• FM: VFM (t) = Vco sin (2 p [fc + (Df/Vmo)
Vm (t) ] t + f)

26. Advantages and disadvantages of
FM
• Advantages :
• Resilient to signal strength variations
• Resilient to noise
• Does not require linear amplifiers in the
transmitter
• Enables greater efficiency than many
other modes

27. disadvantages
• Requires more complicated demodulator
• Some other modes have higher data
spectral efficiency.
• Sidebands extend to infinity either side

28. pm
• PM changes the phase angle of the
complex envelope in direct proportion to
the message signal.
• Suppose that the signal to be sent (called
the modulating or message signal) is and
the carrier onto which the signal is to be
modulated is

31. Advantages and disadvantages of
PM
• Advantages :
• 1. Phase modulation is easy matched against
Frequency modulation.
•
• 2. Phase modulator makes it easy in finding
velocity of acting target by pulling out Doppler
info.
• .

32. • 3. Doppler info needs unchanging carrier
which will be fairly easy in phase
modulation but not really in frequency
modulation

33. • Disadvantages :
• 1. Phase ambiguity comes up if we
surpass its transition index pi rad (180
degree).
• 2. We require frequency multiplier to
maximize phase modulation index.