Overview of DCS &
Review of Math
2
Sistem Komunikasi Digital Digital Communication
Dr. Eng. Wahyul Amien Syafei
Block Diagram
SOURCE Info.
Transmitter
Transmitted signal
Received signal
Receiver
Received info.
Noise
Channel
Source User
Formatter Source encoder
Channel
encoder Modulator
Formatter Source decoder
Channel
decoder Demodulator
Transmitter
Receiver
Digital Communication System
4 important features:
1. Transmitter sends a waveform from a finite set of possible waveforms during a limited time
2. Channel distorts, attenuates the transmitted signal, and adds noise to it.
3. Receiver decides which waveform was transmitted from the noisy received signal
4. Probability of erroneous decision is an important measure for the system
performance
Digital v.s. Analog
Advantages of digital communications:
Regenerator receiver
Different kinds of digital signal are treated identically.
Data
Voice Media
Propagation distance Original
pulse
Regenerated pulse
A bit is a bit!
Terminology
Information source
Textual
Character
Bit
Bit stream
Symbol
Digital waveform
Data rate
Signal Processing in DCS
Advantages of DCS
Less distortions
Less interferences
Reliable
Economic in mass production
More flexible in hardware implementation
Easier synchronization
Performance Criteria
Analog CS:
SNR (power signal to noise rasio)
Digital CS:
BER: bit error rate
SER: symbol error rate
PER: packet error rate
HW 2
Test Formatif
Wi-fi 802.11g (54 Mbps) Kel. A
Wi-fi 802.11n (>150 Mbps) Kel. B
Hitung / buktikan
