Data Communications & Networking chapter 5. 1 ( ) (1:, 0: idle) : DC(Direct Current) Component (Synchronization) 0 1. Data Communications & Networking chapter 5. 2 1
( ), : NRZ, RZ, Biphase Zero NRZ-L, NRZ-I : 1 Data Communications & Networking chapter 5. 3 0,1. Data Communications & Networking chapter 5. 4 2
3 (,, ) 1 : 0 : 0 zero :, Data Communications & Networking chapter 5. 5 2 Manchester, Differential Manchester 0. Data Communications & Networking chapter 5. 6 3
? : 1,? : 0 RZ : 0 : 1 Data Communications & Networking chapter 5. 7 3 (,, ) : 20 : 1( ) AMI, B8ZS, HDB3 1 : 0 Data Communications & Networking chapter 5. 8 4
0 08, 0 VIOLATION 1 Data Communications & Networking chapter 5. 9 0 4 0 AMI 1 : 4 0 1 : 0 4 Data Communications & Networking chapter 5. 10 5
B8ZS 10000000000100. 1 Data Communications & Networking chapter 5. 11 HDB3 10000000000100. 1 1 Data Communications & Networking chapter 5. 12 6
, (, Sampling) Data Communications & Networking chapter 5. 13 Data Communications & Networking chapter 5. 14 7
Data Communications & Networking chapter 5. 15. (Nyquist theorem) : PAM 2. 4,000Hz 8,000 Data Communications & Networking chapter 5. 16 8
10,000Hz(1,000Hz 11,000Hz )? = 2 * (11,000) = 22,000 samples/second, 12 (+0 ~ +5, -0 ~ -5)? 4 ( 1, 3 = 2 3 = 8 ) Data Communications & Networking chapter 5. 17 = *, 8? = 4,000 * 2 = 8,000 samples/second = * = 8,000 * 8 = 64,000 bits/s = 64Kbps Data Communications & Networking chapter 5. 18 9
Data Communications & Networking chapter 5. 19 =. = / Data Communications & Networking chapter 5. 20 10
4. 1,000? = = 1,000 bauds per second = * = 1,000 * 4 = 4,000 bps 3,000. 6? = / = 3,000/6 = 500 bauds per second Data Communications & Networking chapter 5. 21 01 Data Communications & Networking chapter 5. 22 11
fc: BW = (1+d) * N baud BW:, N baud :, d: ASK? Data Communications & Networking chapter 5. 23 2,000bps ASK? ASK. 2,000, 2,000Hz 500Hz ASK? ASK. : 5,000, : 5,000 bps Data Communications & Networking chapter 5. 24 12
10,000Hz(1,000~11,000Hz) ASK.. ASKBW = 10,000/2 = 5,000Hz f c(forward) = 1,000 + 5,000/2 = 3,500Hz f c(backward) = 11,000 5,000/2 = 8,500Hz Data Communications & Networking chapter 5. 25 21 0 ASK Data Communications & Networking chapter 5. 26 13
Data Communications & Networking chapter 5. 27 2,000bps FSK., 3,000Hz. f c1 f c2 BW = + (f c1 f c0 ) BW = + (f c1 f c0 ) = 2,000 + 3,000 = 5,000Hz Data Communications & Networking chapter 5. 28 14
12,000Hz, 2,000Hz, FSK?. BW = + (f c1 f c0 ) = BW (f c1 f c0 ) = 6,000 2,000 = 4,000Hz 4,000bps Data Communications & Networking chapter 5. 29 21 0 Data Communications & Networking chapter 5. 30 15
Data Communications & Networking chapter 5. 31 Data Communications & Networking chapter 5. 32 16
Data Communications & Networking chapter 5. 33 Data Communications & Networking chapter 5. 34 17
Data Communications & Networking chapter 5. 35 2,000bps 4-PSK?. 4-PSK 1,000. PSK 1,000Hz 8-PSK 5,000Hz,? PSK 5,000 8-PSK 3 15,000bps Data Communications & Networking chapter 5. 36 18
ASKPSK ( ) Data Communications & Networking chapter 5. 37 Data Communications & Networking chapter 5. 38 19
Data Communications & Networking chapter 5. 39 Data Communications & Networking chapter 5. 40 20
Modulation Units Bits/Baud Baud Rate Bit Rate ASK, FSK, 2-PSK Bit 1 N N 4-PSK, 4-QAM Dibit 2 N 2N 8-PSK, 8-QAM Tribit 3 N 3N 16-QAM Quadbit 4 N 4N 32-QAM Pentabit 5 N 5N 64-QAM Hexabit 6 N 6N 128-QAM Septabit 7 N 7N 256-QAM Octabit 8 N 8N Data Communications & Networking chapter 5. 41 8. 4,800bps? 45 8-PSK 2 3 =8, 3 1. = 4,800/3 = 1,600 baud Data Communications & Networking chapter 5. 42 21
1,000, 16-QAM? 2 4 = 16 4 (1,000) * (4) = 4,000bps 72,000bps, 64-QAM? 2 6 = 64, 6 72,000 / 6 = 12,000 baud Data Communications & Networking chapter 5. 43 Data Communications & Networking chapter 5. 44 22
2 Data Communications & Networking chapter 5. 45 4KHz. AM? BW = 2 * 4KHz = 8KHz Data Communications & Networking chapter 5. 46 23
, Data Communications & Networking chapter 5. 47 10 Data Communications & Networking chapter 5. 48 24
4MHz. FM? BW = 10 * 4Mhz = 40Mhz Data Communications & Networking chapter 5. 49 Data Communications & Networking chapter 5. 50 25