1. PGT110 – MULTIMEDIA TECHNOLOGY
Lecturer/PLV : Mohd Fisol Bin Osman
Mobile :

2. Date and Time Lecture Monday : 5 PM to 7 PM (2 Hours)
Laboratory/Tutorial Session (3 Hours)
Divided into two groups :
Group 1 : Friday 4 PM to 7 PM
Group 2 : 12 Noon to 3 PM
Attendance will be recorded !

3. Course Outcomes (Cos) CO1 :
Ability to identify the fundamentals and concepts of data, voice and video communications and the criteria for choosing a communications medium.
CO2 :
Ability to explain how networking media, devices and software work together to provide data, voice and video networking services and describes the benefits of various types of media.

4. COs Continue..
CO3 :
Ability to list and analyze wireless telecommunications technologies and its structure
CO4 :
Ability to evaluate and propose basic telecommunication design structure based on conditions given

5. Course Contents

6. Chapter 1 – Overview of Multimedia Systems (Concepts and Definations)
Dedicated, switched, and virtual circuits
Two wires vs four wires circuits
Analog vs Digital
Amplifiers, Repeaters
Modem and Codecs
Multiplexers and Switchers
Signaling and Controls

7. Preface
“What is the transmitter? It is an electrical ear which receives the shock of the dancing molecules, just as does the membrane of the human ear What is the receiver? It is an electric mouth which can utter human sounds. “
John Mills, The Magic of Communication: A Tell - You - How Story, Information Department, American Telephone and Telegraph Company

8. Telecommunications General definition:
Telecommunications is the transfer of information ( communications ) from a transmitter or sender to a receiver across a distance ( tele ) through a transmission medium
Electromagnetic energy is employed to represent the data, usually through a physical/transmission medium,
such as:
copper wire or glass fibre
What else?.
wired/ wireless ?
NEXT : INFORMATION

9. Information Information can be in many form - electromagnetic energy
Electric impulse
Radiated energy
The information can retain its original, or native, form during transmission.
Alternatively, the transmission process can alter the data in some way in order to effect compatibility between the transmit and receive devices and with various intermediate network elements.
List several types/forms of information :

10. Information (Cont.) Audio/Voice
Human voice, CDs, tape, records, radio etc
Video
movies, graphics and animation
Data
s, messages etc
Image
Combinations/Multimedia

11. Intermediate devices
to establish and maintain the connection and to support the information transfer.
Examples:
modems or codecs,
controllers,
multiplexers
bridges, switches, routers,
Gateways
ETCs..

12. Communication System

13. Transmitter
The transmitter is a collection of electronic components and circuits that converts the electrical signal into a signal suitable for transmission over a given medium.
Transmitters are made up of oscillators, amplifiers, tuned circuits and filters, modulators, frequency mixers, frequency synthesizers, and other circuits.

14. Communication Channels/ Transmission Mediums
The communication channel is the medium by which the electronic signal is sent from one place to another.
Types of media include
Electrical conductors
Optical media
Free space

15. Receivers
A receiver is a collection of electronic components and circuits that accepts the transmitted message from the channel and converts it back into a form understandable by humans.
Receivers contain amplifiers, oscillators, mixers, tuned circuits and filters, and a demodulator or detector that recovers the original intelligence signal from the modulated carrier

16. Transceivers
A transceiver is an electronic unit that incorporates circuits that both send and receive signals.
Examples are:
Telephones
Fax machines
Handheld CB radios
Cell phones
Computer modems

17. Noise
random, undesirable electronic energy that enters the communication system via the communicating medium and interferes with the transmitted message.

18. Communication Systems – In Depth

19. Souce Other words for transmitter
Device that originates the information transfer.
Transmitters include voice telephones, data terminals, host computer systems, and video cameras.

20. Sink Other word for receiver/ destination
target device, or destination device, that receives the information transfer.
Receivers can include telephones, data terminals, host computers, and video monitors.
Most devices are capable of both transmitter and receiver functions (source/sink)

21. Circuit
a communications path, over an established medium, between two or more points, from end to end, between transmitter and receiver
logical connection over a physical line
Might include path, link, line , and channel , although such usage can be specifi c to the underlying technology
Circuits also may be for purposes of either access (from the customer premises to the edge of the carrier network) or transport (circuits are employed in the core , or backbone , of the network for purposes of long - haul transmission)
simplex (one - way), half - duplex (two - way, but only one way at a time), or full - duplex (simultaneous two - way)

22. Link
two - point segment of an end - to - end circuit (e.g., from terminal to switch or from switch to switch)
Either single link or multiple links
Example:
between a host computer and a peripheral, such as a printer

23. Line Has several definitions
In a Private Branch eXchange (PBX) environment, a station line refers to the connection between the PBX switch and the station user ’ s terminal equipment, such as telephone, fax machine etc.
In rate and tariff terminology, line refers to a local loop connection from the telephone company Central Office (CO) switch to the user premises in support of Customer Premises Equipment (CPE) other than a switch.

24. Trunk
a communications circuit, available to share among multiple users, on a pooled basis and with contention for trunk access managed by an intelligent switching device
trunks interconnect switches
Trunks are directional in nature, with the options being one - way outgoing (originating), one – way incoming (terminating), or two - way (combination).

25. Dedicated, Switched and Virtual Circuits
Dedicated Circuits between Seattle terminal and
New York Mainframe

26. Dedicated Circuits
physical circuits dedicated to directly connecting devices (e.g., PBXs and host computers) across a network
Advantages:
serve a single - user organization only, rather than serving multiple users
Ability to condition dedicated circuits to deliver specific levels of performance by adding amplification or other signal processing enhancements to the line to optimize its transmission characteristics, whereas you generally cannot do so with switched circuits (not from end to end).

27. Dedicated circuits Disadvantages:
In terms of network efficiency because that circuit is taken out of shared public use and, therefore, is unavailable for use in support of the traffic of other users
rather expensive - with their costs being sensitive to distance and capacity
susceptible to disruption, backup circuits often are required to ensure effective communications in the event of either a catastrophic failure or serious performance degradation.
Could be difficult and lengthy design and configuration process. – for huge connections

28. Example of circuit switched connections
Switched Circuits
Example of circuit switched connections

29. Switched Circuits
More flexible

30. Virtual Circuits logical, rather than physical, circuits.
are established through the network based on options and instructions defined in software routing tables
Divided into two:
- Permanent Virtual Circuits (PVCs)
- Switched Virtual Circuits (SVCs)
Will learn more in chapter 10 !..Broadband Network Services

31. Two wires vs Four wires Circuit
Comparison of Two wires and Four wires Circuits

32. Two wires circuit
carry information signals in both directions over the same physical link or path
The use of a single twisted pair, copper wire connection
two wires are required to complete the electrical circuit, with the current in one wire opposite to the current in the other, and both wires carry the information signal
generally cover a short distance
gener-ally they are analog in nature; therefore, error performance (quality) is relatively poor

33. Four wire circuit
carry information signals in both directions over separate physical links or paths and in support of simultaneous, two - way transmission.
Traditional – used copper wires, nowadays over a variety of transmission media, including twisted pair, coaxial cable, or fiber optic cable
can be established without the use of any wires at all, as in the case with a circuit established over microwave, satellite, or infrared transmission systems.

34. Four wire circuit Advantages :
Can accommodate multiple, simultaneous communications in a full - duplex mode, all multichannel circuits are four wire. Multichannel capability
greater bandwidth, or capacity
digital, rather than analog – improve error performance

35. Bandwidth measure of the capacity of a circuit or channel
the total frequency on the available carrier for the transmission of data.
While the information signal (bandwidth usable for data transmission) does not occupy the total capacity of a circuit, it generally and ideally occupies most of it.
The balance of the capacity of the circuit may be used for various signaling and control (overhead ) purposes

36. Carrier
continuous signal on a circuit that is at a certain frequency or within a certain frequency range
support of the information bearing signal (i.e., it carries the information signal), which the transmitter impresses on the carrier by varying the signal in some fashion and which the receiver must detect and interpret
support signaling and
control information used to coordinate and manage various aspects of network operations

37. Types of CommunicationsTX RX
Simplex:
One-way
Channel
Channel(s)
Two-way Half duplex: Alternate TX/RX Duplex: Full duplex: Simultaneous TX/RX

38. Types of Communication Signals
Digital - binary or two voltage levels.
Time
Analog - smooth and continuous voltage variation.

39. Communications Signal Variations
Baseband - The original information signal such as audio, video, or computer data. Can be analog or digital.
Broadband - The baseband signal modulates or modifies a carrier signal, which is usually a sine wave at a frequency much higher than the baseband signal.

40. Basic analog communications system
Baseband signal (electrical signal)
EM waves (modulated signal)
Transmitter
Input transducer
Transmission Channel
Modulator
EM waves (modulated signal)
Carrier
Baseband signal (electrical signal)
Receiver
Output transducer
Demodulator

41. MODULATION
An electronic technique in which a baseband information signal modifies a carrier signal (usually a sine wave) for the purpose of frequency translation and carrying the information signal via radio.
The common types of modulation are amplitude, frequency and phase.

42. Why modulation is needed?
To generate a modulated signal suited and compatible to the characteristics of the transmission channel.
For ease radiation and reduction of antenna size
Reduction of noise and interference
Channel assignment
Increase transmission speed

43. Modulation at the transmitter

44. AMPLITUDE MODULATION higher than the baseband frequency
The modulating (baseband) signal is a sinusoid in this example.
High-frequency carrier, normally much
higher than the baseband frequency

45. FREQUENCY MODULATION
The baseband signal controls the carrier’s frequency and the carrier’s amplitude remains constant.

46. FM Resting fc Increasing fc Decreasing fc Increasing fc Resting fc
Modulating signal
Carrier

47. MULTIPLEXING
Multiplexing (MUX or MPX) - the process of simultaneously transmitting two or more baseband information signals over a single communications channel.
Demultiplexing (DEMUX or DMPX) - the process of recovering the individual baseband signals from the multiplexed signal.

48. MULTIPLEXING AND DEMULTIPLEXING
Single communications channel (radio or cable)
MUX
DEMUX
Recovered baseband
information signals
Original baseband
information signals

49. Modulation and Multiplexing

50. FREQUENCY AND WAVELENGTH
Cycle - One complete occurrence of a repeating wave (periodic signal) such as one positive and one negative alternation of a sine wave.
Frequency - the number of cycles of a signal that occur in one second.
Period - the time distance between two similar points on a periodic wave.
Wavelength - the distance traveled by an electromagnetic (radio) wave during one period.

51. PERIOD AND FREQUENCY COMPARED
T = One period
time
One cycle
Frequency = f = 1/T

52. Frequency and wavelength compared+ T
time
f = 1/T 
distance

53. CALCULATING WAVELENGTH AND FREQUENCY
 = wavelength in meters
f = frequency in MHz

54. THE ELECTROMAGNETIC SPECTRUM FROM 30 HZ TO 300 GHZ
Wavelength
( = 300/f)
107 m
106 m
105 m
104 m
103 m
102 m
10-1 m
10-2 m
10-3 m
10-4 m
10 m
1 m
Millimeter
waves
ELF VF
VLF LF MF HF
VHF
UHF
SHF
EHF
30 Hz
3 kHz
300 Hz
30 kHz
3 MHz
3 GHz
300 kHz
30 MHz
30 GHz
300 MHz
300 GHz
(f = 300/)
Frequency

55. LOW AND MEDIUM FREQUENCIES
Extremely Low Frequencies - 30 to 300 Hz
Voice Frequencies to 3000 Hz
Very Low Frequencies - 3 kHz to 30 kHz
Low Frequencies - 30 kHz to 300 kHz
Medium Frequencies kHz to 3 MHz

56. HIGH FREQUENCIES High Frequencies - 3 MHz to 30 MHz
Very High Frequencies
- 30 MHz to 300 MHz
Ultra High Frequencies
- 300 MHz to 3 GHz
(1 GHz and above = microwaves)
Super High Frequencies
- 3 GHz to 30 GHz
Extremely High Frequencies
- 30 GHz to 300 GHz

57. THE ELECTROMAGNETIC SPECTRUM ABOVE 300 GHZ
Wavelength
0.8 x 10-6 m
0.4 x 10-6 m
10-3 m
10-4 m
10-5 m
Millimeter
waves
Ultraviolet
Infrared
X-rays
Visible
Gamma rays
Cosmic rays
300 GHz

58. OPTICAL FREQUENCIES
Infrared to 10 micron
Visible light to 0.8 micron
Ultraviolet - Shorter than 0.4 micron
Note: A micron is one millionth of a meter. Light waves are measured and expressed in wavelength rather than frequency.

59. Limitations in communication system
Physical constraint
-Delay, attenuation, bandwidth limitation, etc
Technological constraint
hardware.
Expertise
- economy, law

60. Frequency Spectrum &Bandwidth
The frequency spectrum of a waveform consists of all frequencies contained in the waveform and their amplitudes plotted in the frequency domain.
The bandwidth of a frequency spectrum is the range of of frequencies contained in the spectrum.It is calculated by subtracting the lowest frequency from the highest.

61. Frequency Spectrum &Bandwidth (cont’d)
Bandwidth of the information signal equals to the difference between the highest and lowest frequency contained in the signal.
Similarly, bandwidth of communication channel is the difference between the highest and lowest frequency that the channel allow to pass through it