1 8 de febrero del 2001. 2 chapter 5 encoding 3 figure 5-1 different conversion schemes

1

8 de febrero del 20018 de febrero del 2001

2

Chapter 5

Encoding

3

Figure 5-1

Different Conversion Schemes

4

Figure 5-2

Digital to Digital Encoding

5

Figure 5-3

Types of Digital to Digital Encoding

6

Figure 5-4

Unipolar Encoding

7

Figure 5-5

Types of Polar Encoding

8

NRZL

Especificación del Protocolo:

( )

( )−

+

→=

→=

V DD

V DD

transmiter

0 ::

1 ::

()

( )

( ) 0::

1 ::

()

=→

=→−

+

DD V

DDV

reciever

9

Figure 5-6

NRZ-L and NRZ-I Encoding

10

Figure 5-7

RZ Encoding

11

Bifase (Auto-Sincronizados)Bifase (Auto-Sincronizados)

Siempre hay una transición a mitad del intervalo de duración del bit.

TécnicasManchester: La transición de mitad del intervalo

sirve para sincronización y transmisión de datos.Manchester Diferencial: La transición de mitad del

intervalo solo sirve para sincronización

12

Manchester

( ) ( )

( ) ( )+−

−+

→=

→=

V V DD

V V DD

transmiter

,0 ::

,1 ::

()

( )

( )

( )

( )+

+

+

−

=→

=→

V

DD V

V

DDV

reciever

1::

0 ::

()

Especificación del Protocolo:

13

Figure 5-8Manchester and Diff. Manchester Encoding

14

1. ¿Cuál es la capacidad de un canal de 5kHz que utiliza codificación Manchester?

2. ¿Y si utilizara codificación MLT-3?

)2(log)58(2log2.1 22 kHzVHC ==bps000,10=

)3(log)5(2log2.2 22 kHzVHC ==bps850,15=

15

Figure 5-9

Types of Bipolar Encoding

16

Binario MultinivelBinario Multinivel

Técnicasbiploar-AMI (“Alternate Mark Inversion”)pseudoternarioMLT-3 (Multi-Level Transmit - 3 Levels)2B1Q

17

Bipolar-AMI

( )

( )

( )

( )00 ::

~1 ::

':

()

V DD

VB

B, V DD

VBci

transmiter

c

c

→=

=

=→=

= +

( ) ( )

( ) 0::

1|| ::

()

0 =→

=→−+

DD V

DDVV

reciever

Especificación del Protocolo:

18

Figure 5-10

Bipolar AMI Encoding

19

Figure 5-11

B8ZS Encoding

20

Figure 5-12

HDB3 Encoding

21

Figure 5-13

Solution to Example 5.1

22

Figure 5-14

Solution to Example 5.2

23

Figure 5-15

WCB/McGraw-Hill The McGraw-Hill Companies, Inc., 1998

Analog to Digital Encoding

24

Figure 5-16

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PAM

25

Figure 5-17

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Quantized PAM Signal

26

Figure 5-18

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Quantizing Using Sign and Magnitude

27

Figure 5-19

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PCM

28

Figure 5-20

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From Analog to PCM

29

Figure 5-20-continued

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From Analog to PCM

30

Figure 5-20-continued

WCB/McGraw-Hill The McGraw-Hill Companies, Inc., 1998

From Analog to PCM

31

Figure 5-20-continued

WCB/McGraw-Hill The McGraw-Hill Companies, Inc., 1998

From Analog to PCM

S k

S k ~

S (t) ~

S(t)

⎩⎨⎧

=≥

=fsTs

fwfsfwTs

Nyquist

/1

22/1

76.102.6 += nSNRdB

32

Figure 5-21

WCB/McGraw-Hill The McGraw-Hill Companies, Inc., 1998

Nyquist Theorem

33

Figure 5-22

WCB/McGraw-Hill The McGraw-Hill Companies, Inc., 1998

Digital to Analog Encoding

34

Figure 5-23

WCB/McGraw-Hill The McGraw-Hill Companies, Inc., 1998

35

ASKASK

Especificación del Protocolo:

1

0

1 ::

0 ::

()

A DD

A DD

transmiter

→=→=

DDA

DD A

reciever

1 ::

0::

()

1

0

=→=→

36

Figure 5-24

WCB/McGraw-Hill The McGraw-Hill Companies, Inc., 1998

ASK

37

Figure 5-25

WCB/McGraw-Hill The McGraw-Hill Companies, Inc., 1998

Bandwidth for ASK

38

FSKFSK

Especificación del Protocolo:

1

0

1 ::

0 ::

()

f DD

f DD

transmiter

→=→=

DDf

DD f

reciever

1 ::

0::

()

1

0

=→=→

39

FSKFigure 5-27

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40

Bandwidth for FSKFigure 5-28

WCB/McGraw-Hill The McGraw-Hill Companies, Inc., 1998

41

PSKPSK

Especificación del Protocolo:

1

0

1 ::

0 ::

()

ϕϕ DD DD

transmiter

→=→=

DD

DD

reciever

1 ::

0::

()

1

0

=→=→

ϕϕ

42

PSKFigure 5-29

WCB/McGraw-Hill The McGraw-Hill Companies, Inc., 1998

43

PSKConstellation

Figure 5-30

WCB/McGraw-Hill The McGraw-Hill Companies, Inc., 1998

44

4-PSKFigure 5-31

WCB/McGraw-Hill The McGraw-Hill Companies, Inc., 1998

45

4-PSKCharacteristics

Figure 5-32

WCB/McGraw-Hill The McGraw-Hill Companies, Inc., 1998

46

8-PSKCharacteristics

Figure 5-33

WCB/McGraw-Hill The McGraw-Hill Companies, Inc., 1998

47

PSKBandwidth

Figure 5-34

WCB/McGraw-Hill The McGraw-Hill Companies, Inc., 1998

48

QAM (4)QAM (4)

Especificación del Protocolo

30

20

10

00

11 ::

10 ::

01 ::

00 ::

()

ϕϕϕϕ

A DD A DD A DD A DD

transmiter

→=→=→=→=

49

QAM(Quadratura Amplitude Modulation)

QAM(Quadratura Amplitude Modulation)

Re00

01

10

1101

00

01

10

11

11 00 01 1010

50

4-QAM and 8-QAMConstellations

Figure 5-35

WCB/McGraw-Hill The McGraw-Hill Companies, Inc., 1998

51

QAM (8)QAM (8)

Especificación del

protocolo

31

21

11

01

30

20

10

00

111 ::

110 ::

101 ::

100 ::

011 ::

010 ::

001 ::

000 ::

()

ϕϕϕϕϕϕϕϕ

A DD A DD A DD A DD A DD A DD A DD A DD

transmiter

→=→=→=→=→=→=→=→=

52

Re000

001

010

011

100101

110 111

000

001

010

011

011011000110

100

101

110

111

53

8-QAM SignalFigure 5-36

WCB/McGraw-Hill The McGraw-Hill Companies, Inc., 1998

54

16-QAMConstellation

Figure 5-37

WCB/McGraw-Hill The McGraw-Hill Companies, Inc., 1998

55

Bit Rate and Baud Rate

Figure 5-38

WCB/McGraw-Hill The McGraw-Hill Companies, Inc., 1998

56

Figure 5-38-continued

WCB/McGraw-Hill The McGraw-Hill Companies, Inc., 1998

Bit Rate and Baud Rate

57

Datos Digitales-Señales Análogas

Datos Digitales-Señales Análogas

Aplicación en Redes Públicas de Datos

Aplicación en Redes de Área Local

58

Problema 1. Problema 1.

¿Cuál es el periodo de muestreo que necesita una señal análoga que tiene un ancho de banda de 20 Khz?

.40

)025.0(1

)20*2/(1

msegT

T

KhzT

s

s

s

===

59

Problema 2. Problema 2.

¿Cuál es la razón de señal de ruido, si se utilizan 8 niveles para discretizar linealmente la amplitud de la señal?

82.19

76.106.18

76.1)3(02.6

=+=+=

dB

dB

dB

SNRSNRSNR

60

Problema 3. Problema 3.

¿Cuál es la razón de datos de una señal discretizada a 8 niveles (3 bits) con un periodo de muetreo de 0.1 mseg.?

bpsRD

msegbitsRD

000,30

1.0/3

==

61

Figure 5-39

WCB/McGraw-Hill The McGraw-Hill Companies, Inc., 1998

Analog to Analog Modulation

62

Figure 5-40

WCB/McGraw-Hill The McGraw-Hill Companies, Inc., 1998

63

Figure 5-41

WCB/McGraw-Hill The McGraw-Hill Companies, Inc., 1998

Amplitude Modulation

64

Figure 5-42

WCB/McGraw-Hill The McGraw-Hill Companies, Inc., 1998

AM Bandwidth

65

Figure 5-43

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AM Band Allocation

66

Figure 5-44

WCB/McGraw-Hill The McGraw-Hill Companies, Inc., 1998

Frequency Modulation

67

Figure 5-45

WCB/McGraw-Hill The McGraw-Hill Companies, Inc., 1998

FM Bandwidth

68

Figure 5-46

WCB/McGraw-Hill The McGraw-Hill Companies, Inc., 1998

FM Band Allocation

69

Cap. 6

70

Figure 6-19

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Modem

71

Bandwidth for Telephone LineFigure 6-20

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72

Baud Rate for Half-Duplex ASK

Figure 6-21

WCB/McGraw-Hill The McGraw-Hill Companies, Inc., 1998

73

Baud Rate for Full-Duplex ASK

Figure 6-22

WCB/McGraw-Hill The McGraw-Hill Companies, Inc., 1998

74

Baud Rate for Half-Duplex FSK

Figure 6-23

WCB/McGraw-Hill The McGraw-Hill Companies, Inc., 1998

75

Baud Rate for Full-Duplex FSK

Figure 6-24

WCB/McGraw-Hill The McGraw-Hill Companies, Inc., 1998

76

Bell Modems

Figure 6-25

WCB/McGraw-Hill The McGraw-Hill Companies, Inc., 1998

77

Bell Modems

Figure 6-25-continued

WCB/McGraw-Hill The McGraw-Hill Companies, Inc., 1998

78

ITU ModemsFigure 6-26-continued

WCB/McGraw-Hill The McGraw-Hill Companies, Inc., 1998

79

V.22bis 16-QAM ConstellationFigure 6-27

WCB/McGraw-Hill The McGraw-Hill Companies, Inc., 1998

80

V.32 ConstellationFigure 6-28

WCB/McGraw-Hill The McGraw-Hill Companies, Inc., 1998

81

V.33 ConstellationFigure 6-29

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