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1、1 2 1 2 2 2 3 2 4 2 5 2 6 2 2 1 3 4 4kHz 64Kbps 5 2 1 1 6 PC PC 7 2 1 2 8 2 2 0 1 9 2 2 1 10 x t Asin 2 ft A f T T T 11 1 0实拥 0实拥 1 0实拥11实拥2 12 1 0实拥 0 0实拥 1 00实拥11实拥2 1 0实拥 0 0实拥 1 00实拥11实拥2 1 0实拥 0 0实拥 1 00实拥11实拥2 S t sin 2 ft S t 1 3 sin 2 3f t S t sin 2 ft 1 3 sin 2 3f t 13 1s 效 效连ps 1s 11100000
2、 1 bps 14 15 S bit s bps B Baud 16 Hz Hz bps 17 S B log2N N 2 W log2N 1 2 2 3 3 18 1924 Nyquist B W B 2 W Baud W Hz Baud 1 1 19 Shannon C C W log2 1 S N bps W S N S N dB 10 log10 S N dB 20 1 3 5kHz 16 Nyquist S 2 W log2N 2 3 5k log216 2 3 5 4 28kbps 21 2 30dB 3 5kHz Shannon C W log2 1 S N 3 5kHz log
3、2 1 1000 35kbps 22 modulation 23 modulation AM FM PM 24 010011100 25 26 2 2 2 0 1 27 1 0 11100000 28 1 NRZ 2 RZ 3 29 11100000 1 NRZ L NRZ I 1 0 30 31 MPE 1 0 DME 0 1 32 01110000 0 1 MPE DME 0 MPE DME 33 3 0 0 1 AMI 8 B8ZS 3 HDB3 34 AMI 0 0 1 01110100 35 2 2 3 1 0 ASK Amplitude Shift Key FSK Frequenc
4、y Shift Key PSK Phase Shift Key QAM Quadrature Amplitude Modulation 36 1 4 x t Asin 2 ft 37 ASK Amplitude shift key 0 1 0 1 1001 AM ASK 38 FSK Frequency shift key 0 1 0 1 FSK ASK 1001 39 PSK Phase shift key 0 1 0 0 180 1 1001 40 PSK PSK 0 00 90 01 180 10 270 11 00110110 41 2 PSK 10 4 PSK 1000 01 11
5、8 PSK 100000 010 110 001 011 101 111 42 QAM Quadrature Amplitude Modulation ASK PSK 000110010100001111011101 43 16 QAM 44 Modem V 32 QAM 32 4 1 x2400 9600bps V 32bis QAM 128 6 1 x2400 14400bps V 34 12x2400 28800bps V 34bis 14x2400 33600bps V 90 7x8000 56000bps 45 A D 3 2 2 PCM 2 46 001 010 011 100 1
6、01 110 111 001 010 011 100 101 110 111 47 20Hz 20kHz 300Hz 3000Hz 48 2 3 49 2 3 1 50 2 3 2 51 52 8 1 并 性 并 性 53 1 1 0 0 0 1 1 0 0 01 0 1 0 0 1 1 0 0 01 1 1 0 0 1 1 0 0 0 123 54 并 性 control syn syndataerrorend 55 2 4 multiplexing 56 FDM TDM WDM CDM 57 2 4 1 FDM TDM FDM Frequency Division Multiplexing
7、 58 FDM 报 戒 息 性 并 59 TDM Time Division Multiplexing TDM B C DA A TDM TDM B C DAB C DAB C DA TDM TDM TDM TDM 60 TDM TDM TDM 61 TDM D C B A AAAA 1 BBBB 2 CCCC 3 DDDD 4 AAAA 1 BBBB 2 CCCC 3 DDDD 4 D C B AD C B A 62 TDM 1 2 3 4 a ab b c d b ca t t t t t 4 1 a c b cd 2 3 4 63 TDM D4 D4 AA 1 BB 2 C 3 DDD
8、4 AA 1 BB 2 C 3 DDD 4 B2 A1 D4C3 B2 A1 TDM STDM 64 TDM 1 2 3 4 a b c d t t t t t 3 STDM 3 a c b ab bcacd 2 1 65 TDM vs TDM 66 2 4 2 WDM Wavelength Division Multiplexing WDM 67 DWDM 1550 nm 0 1551 nm 1 1552 nm 2 1553 nm 3 1554 nm 4 1555 nm 5 1556 nm 6 1557 nm 7 0 1550 nm 1 1551 nm 2 1552 nm 3 1553 nm
9、 4 1554 nm 5 1555 nm 6 1556 nm 7 1557 nm 8 2 5 Gb s 1310 nm 20 Gb s EDFA 120 km 68 2 4 3 CDM Code Division Multiplexing CDMA Code Division Multiple Access CDMA 69 2 5 70 Circuit Switch Packet Switch Message Switch ATM 71 2 5 1 72 A B C 1 2 3 D E F G 73 74 A B A B B D C A 75 2 5 2 76 2 5 3 packet 77
10、78 79 A CF D B E 3 4 2 1 1212 1 2 3 4 4 3 1 2 3 4 B A F EC D 80 A CF D B E 1 3 2 1 13 1 2 1 3 2 2 1 2 1 2 3 B A D C 1 2 81 H2 H1 H3 H5 H4 B D E C A VC1 VC2 82 SVC PVC 83 84 P1 P2 P3 P4 P1 P2 P3 P4 P3 P4 A B C D A B C DA B C D t P2 P1 85 2 6 86 2 6 1 Parity checking 1 m b1b2b3 bm r b1 b2 b3 bm m b1b2
11、b3 bm r b1 b2 b3 bm 1 r 87 11100111110111010011100110101001 11001111011101011100101010010101010 1100111101110101110010101001 88 1100111101110101110010101001 11100111 11011101 00111001 10101001 10101010 1110011111011101001100011010100110101010 89 2 6 2 CRC G x m G x x4 x3 1 11001 m 4 U x 1101011 xmU
12、x G x m R x U x m G x R x U x 90 CRC G x 0 2 1 1 0 1 0 1 0 0 0 0 1 1 91 U x 1101011 G x x4 x3 1 11001 11010111010 1 1 1 0 0 1 1 1 0 1 0 1 1 0 0 0 0 1 1 0 0 1 1 0 0 1 0 1 0 0 0 1 1 1 1 0 1 0 G x 4 0 0 0 0 0 0 0 1 1 1 1 0 0 0 0 0 1 1 1 1 0 1 1 0 0 1 0 1 1 1 0 0 0 0 0 0 1 1 1 0 0 1 1 0 0 1 0 1 0 1 0 0
13、0 0 0 0 R x 92 U x 10010110 G x x5 x2 x 100110 1001011000010 1 0 0 1 1 01 0 0 1 0 1 1 0 0 0 0 0 0 1 0 0 1 1 0 1 0 0 0 1 1 1 1 0 0 0 1 1 1 0 0 0 1 0 0 1 1 0 1 1 1 1 0 0 1 0 0 1 1 0 1 1 0 1 0 0 1 0 0 1 1 0 1 0 0 1 0 0 1 0 0 1 1 0 0 0 0 1 0 G x R x 5 0 2 93 2 6 3 n 16 n n n n n 1 94 1 1000100 1100111 1011101 1000101 0111001 1111110 0101001 1 0100111 1 0101000 1010111 1 1010111 1 1 1000100 1100111 1011101 1000101 0111001 1111110 0101001 1 0100111 1 0101000 1111111 1 1100111101110101110010101001 10101111100111101110101110010101001 10101111100111101110101110010101001 95
