Matakuliah
Tahun
Versi
: H0174/Jaringan Komputer
: 2006
: 1/0
Pertemuan 03
Transmisi Data
1
Learning Outcomes
Pada akhir pertemuan ini, diharapkan mahasiswa
akan mampu :
• Menjelaskan transmisi data
2
Outline Materi
• Mode transmisi
• Metode transmisi
• Media Transmisi
3
KOMPONEN
• Transmitter
• Receiver
• Medium
– Guided medium
• twisted pair, optical fiber
– Unguided medium
• air, water
4
TEKNIK TRANSMISI DATA
• MODE TRANSMISI DATA:
– PARALEL
– SERIAL
• ASINKRON
• SINKRON
• METODE TRANSMISI
–
SIMPLEX
–
HALF DUPLEX
–
FULL DUPLEX
• BENTUK FISIK
– BOUNDED/GUIDED MEDIUM (KABEL, SERAT
OPTIK)
– UNBOUNDED/UNGUIDED MEDIUM (MICROWAVE)
5
TEKNIK TRANSMISI DATA
•
KARAKTERISTIK
– MEMBERIKAN LEBAR RENTANG FREKUENSI
(BANDWIDTH) YANG DAPAT DILAYANI
• GANGGUAN
– RANDOM:
THERMAL NOISE, IMPULSE, CROSS TALK, ETC
– SYSTEMATIC:
–
ATTENUATION, DELAY, ETC.
6
LST/FASKD/CINQ
Paralel Transmission
7
Serial transmission
8
ASINKRON
TRANSMISI ASINKRON:
– PENGIRIMAN INFORMASI BIASANYA DILAKUKAN PER
UNIT DATA ( 5 - 8) BIT
– SINKRONISASI DAN RESINKRONISASI DENGAN
START/STOP BIT
– TIMING HANYA PERLU DIJAGA PADA TIAP UNIT DATA
– START/STOP MERUPAKAN OVERHEAD YANG TINGGI
– DIGUNAKAN TERUTAMA UNTUK TERMINAL DAN DATA
BERUPA KARAKTER
9
LST/FASKD/CINQ
Synchronous Transmission
10
TRANSMISI SINKRON
TRANSMISI SINKRON
– PENGIRIMAN INFORMASI DILAKUKAN PER BLOK DATA
DENGAN PERINTAH PENGENDALIAN TERMASUK
DALAM BLOK INFORMASI
– OVERHEAD SANGAT RENDAH
– MEMBUTUHKAN SINKRONISASI YANG RUMIT:
• SINKRONISASI BIT
• SINKRONISASI KARAKTER/OKTET
• SINKRONISASI FRAME
11
Metode Transmisi
• Simplex
– One direction
• e.g. Television
• Half duplex
– Either direction, but only one way at a
time
• e.g. police radio
• Full duplex
– Both directions at the same time
• e.g. telephone
12
MEDIA TRANSMISI
• UNBOUNDED/UNGUIDED:
– GELOMBANG
ELEKTROMAGNETIK
• GELOMBANG VHF
• GELOMBANG UHF
• GELOMBANG MIKRO
• SPREAD SPEKTRUM
• SATELIT
• BOUNDED/GUIDED:
– KABEL TEMBAGA
TWISTED PAIR
– UNSHIELDED
– SHIELDED
– KABEL KOAKSIAL
– SERAT OPTIK
• MONO MODE
• MULTI MODE
13
Guided Transmission Media
• Twisted Pair
• Coaxial cable
• Optical fiber
14
Matakuliah
Tahun
Versi
: H0174/Jaringan Komputer
: 2006
: 1/0
Pertemuan 04
Transmisi Data - Lanjutan
15
Learning Outcomes
Pada akhir pertemuan ini, diharapkan mahasiswa
akan mampu :
• Menjelaskan transmisi data
16
Outline Materi
• Media
• Gangguan
17
Coaxial Cable
18
Coaxial Cable Applications
• Television distribution
– Antenna to TV
– Cable TV + Cable Modem
19
Optical Fiber
20
Optical Fiber Transmission Modes
21
Optical Fiber - Characteristic
• Greater capacity (Data rates of
hundreds of Gbps)
• Smaller size & weight
• Lower attenuation
• Electromagnetic isolation
• Greater repeater spacing
22
Spektrum untuk Communication
23
Transmission Frequencies
• 2GHz to 40GHz
– Microwave
– Highly directional
– Point to point
– Satellite
• 30MHz to 1GHz
– Omnidirectional
– Broadcast radio
• 3 x 1011 to 2 x 1014
– Infrared
– Local
24
Bands
Band
Range
Propagation
Application
VLF
3–30 KHz
Ground
Long-range radio navigation
LF
30–300 KHz
Ground
Radio beacons and
navigational locators
MF
300 KHz–3 MHz
Sky
AM radio
HF
3–30 MHz
Sky
Citizens band (CB),
ship/aircraft communication
VHF
30–300 MHz
Sky and
line-of-sight
VHF TV,
FM radio
UHF
300 MHz–3 GHz
Line-of-sight
UHF TV, cellular phones,
paging, satellite
SHF
3–30 GHz
Line-of-sight
Satellite communication
EHF
30–300 GHz
Line-of-sight
Long-range radio navigation
25
Wireless Propagation
Signal travels along three routes
– Ground wave
• Follows contour of earth (up to 2MHz, AM radio)
– Sky wave
• Amateur radio, BBC world service, Voice of America
• Signal reflected from ionosphere layer of upper
atmosphere (actually refracted)
– Line of sight
• Above 30Mhz
26
Satellite Point to Point Link
27
Satellite Broadcast Link
28
Transmission Impairments
• Signal received may differ from signal
transmitted
• Analog - degradation of signal quality
• Digital - bit errors
• Caused by
– Attenuation and attenuation distortion
– Delay distortion
– Noise
29
Attenuation
• Signal strength falls off with distance
• Depends on medium
• Received signal strength:
– must be enough to be detected
– must be sufficiently higher than noise to be
received without error
• Attenuation is an increasing function of
frequency
30
Noise
• Additional signals inserted between transmitter
and receiver
• Thermal
– Due to thermal agitation of electrons
– Uniformly distributed
– White noise
• Intermodulation
– Signals that are the sum and difference of
original frequencies sharing a medium
31
Noise
• Crosstalk
– A signal from one line is picked up by another
• Impulse
– Irregular pulses or spikes
• External electromagnetic interference
• Short duration
• High amplitude
32