7/31/2019 PLH22 - 2009-2010-OSS2

1/122

22

2

7/31/2019 PLH22 - 2009-2010-OSS2

2/122

To

(Baseband Communication)

(Bandpass Communication) T

.

7/31/2019 PLH22 - 2009-2010-OSS2

3/122

: To

7/31/2019 PLH22 - 2009-2010-OSS2

4/122

-

DSB To x(t)

cos2fct yDSB (t)=x(t)cos2fct

:

Y[f]=0,5X(f-fc)+0,5X(f+fc)

f>fc f

7/31/2019 PLH22 - 2009-2010-OSS2

5/122

-

DSB

7/31/2019 PLH22 - 2009-2010-OSS2

6/122

-

DSB

7/31/2019 PLH22 - 2009-2010-OSS2

7/122

7/31/2019 PLH22 - 2009-2010-OSS2

8/122

-

xDSB(t)

xDSB(t)

cos2fct ,

,

.

7/31/2019 PLH22 - 2009-2010-OSS2

9/122

.

m

.

.

-

7/31/2019 PLH22 - 2009-2010-OSS2

10/122

-

Y[f]=0,5X(f-fc)+0,5X(f+fc)

0,5 Y(f-fc) + 0,5 Y(f+fc) =

X(f-2fc) + X(f) + X(f+2fc)

7/31/2019 PLH22 - 2009-2010-OSS2

11/122

x(t)=Ac[1+x(t)]cos2fc

t=A(t)cos2fct

(t):

7/31/2019 PLH22 - 2009-2010-OSS2

12/122

7/31/2019 PLH22 - 2009-2010-OSS2

13/122

A(t)

x(t).

DSB ,

.

7/31/2019 PLH22 - 2009-2010-OSS2

14/122

Y

[f]=F{[A+x(t)]cosct}=F{Acosct}+F{x(t) cosct}=

0,5 {(-c)+(+c)}+0,5{(-c)+(+c)}

7/31/2019 PLH22 - 2009-2010-OSS2

15/122

+x(t) >0=> >=|min{x(t)}|

x(t)

H

RC

1/fc1

7/31/2019 PLH22 - 2009-2010-OSS2

16/122

7/31/2019 PLH22 - 2009-2010-OSS2

17/122

7/31/2019 PLH22 - 2009-2010-OSS2

18/122

+x(t) >0=> >=|min{x(t)}|

x(t)

H

RC

1/fc1

7/31/2019 PLH22 - 2009-2010-OSS2

19/122

DSB, AM,

,

.

,

.

7/31/2019 PLH22 - 2009-2010-OSS2

20/122

7/31/2019 PLH22 - 2009-2010-OSS2

21/122

AM

C,

AM.

AM ,

R,

.

AM , -

, .

7/31/2019 PLH22 - 2009-2010-OSS2

22/122

, .

R, C.

.

AM .., .

7/31/2019 PLH22 - 2009-2010-OSS2

23/122

-

(SSB) DSB AM

,

.

, ,

.

DSB AM

.

,

,

.

7/31/2019 PLH22 - 2009-2010-OSS2

24/122

-

(SSB) SSB

() DSB

()

.

3.12 ,

, SSB.

BPF

, .

7/31/2019 PLH22 - 2009-2010-OSS2

25/122

-

(SSB)( )

( )

( )

( )

f

f

f

f

( )X f

xfxf

( )D SBX f

cfcf

cfcf

( )B P FH f

( )S SBX f

cfcf

.

7/31/2019 PLH22 - 2009-2010-OSS2

26/122

SSB

.

3.13

SSB .

7/31/2019 PLH22 - 2009-2010-OSS2

27/122

SSB

7/31/2019 PLH22 - 2009-2010-OSS2

28/122

SSB

, ,

SSB.

(vestigialsideband VSB).

VSB , , .

VSB

, .., (facsimile).

7/31/2019 PLH22 - 2009-2010-OSS2

29/122

i

S

( )o

S N

DSB 2x

f 21

2c xA S

i

x

S

f

AM

2x

f ( )

211

2c xA S+

22

i c

x

S A

f

AM ,

( ) 1iS N

2x

f ( )2 21

12

c xA S+ 2

2i c

x

S A

f

SSBx

f 21

2c xA S

i

x

S

f

SOSSOS

.. 3.73.7

7/31/2019 PLH22 - 2009-2010-OSS2

30/122

.

, .

.

.

3.7 4 2, 2004

db, db

1 &

7/31/2019 PLH22 - 2009-2010-OSS2

31/122

1: &

, x(t) , c c .

c( ).

() x(t) ,

7/31/2019 PLH22 - 2009-2010-OSS2

32/122

() y(t)

Fourier.

y(t)=x2(t)

, x (t) &x2(t)

2 2 2 2( ) ( ) [1 ( )] cosc c ct ax t aA x t t = = + =

2 22 2 2 2

2 2 2 22 2 2 2

1 1[1 ( )] ( cos2 ) [1 ( )] [1 ( )] cos22 2 2 2

cos2 ( ) ( ) ( )cos2 ( )cos2

2 2 2 2

c cc c c

c c c cc c c c

aA aAaA x t t x t x t t

aA aA aA aAt aA x t x t aA x t t x t

ct

+ + = + + + =

+ + + + +

7/31/2019 PLH22 - 2009-2010-OSS2

33/122

() ()

Fourierx(t)

sinc

7/31/2019 PLH22 - 2009-2010-OSS2

34/122

() ()

x2(t)

[ ]

[ ]

2 2

2 2

2 2 2

2

2

2

( )

2 2

cos 2 ( 2 ) ( 2 )2 4

( ) ( ) 2

( )cos 2 ( 2 ) ( 2 )2

2 22 2 2

Fc c

Fc c

c c c

F

c c cx

F c

c c c c

c c c

x x

aA aAf

aA aAt f f f f

f

aA x t aA X f aA rect f

aAaA x t t X f f X f f

aA f f f f rect rect f f

+ +

=

+ + =

++

7/31/2019 PLH22 - 2009-2010-OSS2

35/122

() ()

x2

(t)

( ) ( ) ( ) ( )F22 2( ) sin 2 t ( )

42 = 2 rectx x

x

x t c f G ff

ff X f X f f f

x

= =

{ }

( ) ( )

{ } ( ) ( ) ( ) ( )

2 22 2

2

2 2

2 2 2

2 2

2

( ) ( )2 2

2 , 222

2 2 4

0, 2

( )cos 2 ( )cos 2 2 2 2 22 2 4

2 24

Fc c

c

x xc c

x

xx

Fc c c

c c c c c c

cx c

aA aAx t F x t

aAf f f faA aA f

X f X f f f rectf

f f

aA aA aAx t t F x t t X f f X f f X f f X f f

aA f f f

=

= = =

>

= + + + =

= 2 22 24 4c c

x c

x x

f f f frect f f f rect f f

+ + +

7/31/2019 PLH22 - 2009-2010-OSS2

36/122

() ()

-2c 2c

-2c- x -2c+ x 2c- x 2c+ x

-2c- 2x 2c+ 2x2c- 2x-2c+

2x

-2x -x x 2x

|Y(f)|

7/31/2019 PLH22 - 2009-2010-OSS2

37/122

() () |x(t)|

7/31/2019 PLH22 - 2009-2010-OSS2

38/122

2 3, 2005

.

2: &

7/31/2019 PLH22 - 2009-2010-OSS2

39/122

2: &

.

xc(t)=cos(2fct) [f1=30kHz, f2=40kHz, f3=20kHz, fc=1MHz]. (A) DSB ,

Fourier .

(B) SSB .

() 60 KHz xc(t)=cos(2fct) [fc=1 MHz] DSB, AM, SSB. .

() () 30dB

n/2=10-9 W/Hz. (DSB, SSB, AM ) 45 dB.

( ) ( ) ( ) ( )tftftftx 3212 2cos2cos2sin

2

1 +=

7/31/2019 PLH22 - 2009-2010-OSS2

40/122

()

(A) DSB , Fourier .

1.

f =60kHz f=20kHz

( ) ( ) ( ) ( )

( )[ ] ( )[ ] ( )[ ]{ }

( )[ ] ( )[ ]tftf

tfftfftf

tftftftx

LH

2cos2

12cos

2cos2cos22cos

2

1

2cos2cos2sin2

1

32321

321

2

+=

=+++=

=+=

7/31/2019 PLH22 - 2009-2010-OSS2

41/122

() ()

2. DSB

DSB

( ) ( )[ ] ( )

( ) ( ) ( )

( ) ( )( ) ( )( ) ( )( ) ( )( )tfftfftfftfftf

tftftf

txtxtx

LcLcHcHcc

LHc

cAM

++++++=

=

++=

=+=

2cos4

12cos

4

12cos

2

12cos

2

12cos

2cos2

1

2cos12cos

1

( ) ( ) ( )

( ) ( ) ( )

( )( ) ( )( ) ( )( ) ( )( )tfftfftfftff

tftftf

txtxtx

LcLcHcHc

LHc

cDSB

+++++=

=

+=

==

2cos4

12cos

4

12cos

2

12cos

2

1

2cos2

12cos2cos

7/31/2019 PLH22 - 2009-2010-OSS2

42/122

() ()

2. DSB

DSB

( )( ) ( )( ) ( )( ) ( )( )( ) ( )( ) ( )( )( )

( )( ) ( )( )( ) ( )( ) ( )( )( )LcLcLcLc

HcHcHcHccc

AM

ffffffffffff

ffffffffffffffff

fX

++++++++

+++++++++++==

8

1

8

1

4

1

4

1

2

1

( )

( )( ) ( )( )( ) ( )( ) ( )( )( )

( )( ) ( )( )( ) ( )( ) ( )( )( )LcLcLcLc ffffffffffff ++++++++

HcHcHcHc

DSB

ffffffffffff

fX

++++++++=

=

4

1

4

1

4

1

4

1

7/31/2019 PLH22 - 2009-2010-OSS2

43/122

() ()

3. DSB

DSB

1000 1020 1060940 980-1000 -980 -940-1060 -10200

1/8

1/4

1/2

f(kHz)

1000 1020 1060940 980-1000 -980 -940-1060 -10200

1/8

1/4

1/2

f(kHz)

1000 1020 1060940 980-1000 -980 -940-1060 -10200

1/8

1/4

f(kHz)

1000 1020 1060940 980-1000 -980 -940-1060 -10200

1/8

1/4

f(kHz)

fc=-1000KHz f c=1000KHz

7/31/2019 PLH22 - 2009-2010-OSS2

44/122

()

(B)

SSB . DSB

:

980 kHz 1020 KHz.

[940kHz, 980kHz]

7/31/2019 PLH22 - 2009-2010-OSS2

45/122

(B) ()

o SSB SSB

1000 1020 1060940 980-1000 -980 -940-1060 -10200

1/8

1/4

f(kHz)

1000 1020 1060940 980-1000 -980 -940-1060 -10200

1/8

1/4

f(kHz)

fc=-1000KHz f c=1000KHz

7/31/2019 PLH22 - 2009-2010-OSS2

46/122

()

() 60 KHz

xc(t)=cos(2fct) [fc=1MHz] DSB, AM, SSB.

. DSB

W=2fx=120kHz.

SSB W=fx=60kHz

7/31/2019 PLH22 - 2009-2010-OSS2

47/122

()

() ()

30dB

n/2=10-9 W/Hz. (DSB, SSB, AM

)

45 dB.

() ()

7/31/2019 PLH22 - 2009-2010-OSS2

48/122

() ()

BPF

( )DSB t

cos2 cf t

( ) ( )SS Bx t n t+

PF

)(tn

)(tyo)(ty i

)(tx

LPF

cos2 ct

( )SS Bx t

BPFBPF 22ffxx,,,,

,, ffcc,,

SSxx

SSii,N,Nii SS00,N,N00

SNR=10logSNR=10log1010(S/N)(S/N)

((--n) dB=10logn) dB=10log1010(S(Safterafter/S/Sbeforebefore))

SSafterafter/S/Sbeforebefore=10=10((--n)/10n)/10=>=>

SSii/S/Sxx=10=10((--n)/10n)/10

-30db

.

Sx

-30db

Si

45db

() ()

7/31/2019 PLH22 - 2009-2010-OSS2

49/122

( ) ()

() () DSB

SNR45db10log10(Si/nfx) 45 (Si/nfx)

104.5

n=2*10-9 W/Hz, fx=60KHz Si 2 * 10

-9 * 60000* 104.5 Watts= 12 * 10-5 * 104.5

Si

Sx 30db, SNR(Si/Sx)=-30 db 10log10(Si/Sx) =-30 (Si/Sx)=10

-3

Si= 10-3 * Sx

Si= 10

-3

* Sx 12 * 10-5

* 10

4.5

Sx 12 * 10

-2 * 104.5 =3,79 Kw

7/31/2019 PLH22 - 2009-2010-OSS2

50/122

,

[ ]( ) cos 2 ( )c c cx t A f t t = +

(t) x(t).

,

.

.

,

(t) x(t):

(phase modulation PM)

(frequency modulation FM).

PM

7/31/2019 PLH22 - 2009-2010-OSS2

51/122

FM

( ) cos ( )PM c c px t A t k x t = +

kp: .

( ) cos ( )t

FM c c fx t A t k x d

= +

kf: .

A. (PM).

. (FM).

((t)t)

x(t)x(t)

dd((t)/dtt)/dt

x(t)x(t)

PM FM

7/31/2019 PLH22 - 2009-2010-OSS2

52/122

7/31/2019 PLH22 - 2009-2010-OSS2

53/122

cos PM

( )sin FM

p x x

f x

x

x

k A t

t k At

=

( ) cosx xt A t=

[ ]( ) cos sinFM c c xx t A t t = +

f x

x

k A

=

p xk A =

{ }max i cx x

= = ==f/ff/fxx

ff

22,,

77

20042004

7/31/2019 PLH22 - 2009-2010-OSS2

54/122

( ) ( )2 1 2 1x xW f + = +

77

7/31/2019 PLH22 - 2009-2010-OSS2

55/122

7/31/2019 PLH22 - 2009-2010-OSS2

56/122

7/31/2019 PLH22 - 2009-2010-OSS2

57/122

7/31/2019 PLH22 - 2009-2010-OSS2

58/122

7/31/2019 PLH22 - 2009-2010-OSS2

59/122

7/31/2019 PLH22 - 2009-2010-OSS2

60/122

( 7, 2 2004)

Acos(20t) [cos(10t)]2 A/2

[sin(20t)]2 Asin(30t)sin(10t) FM

6.0 6.06 MHz .

,

40 KHz 80

KHz .

.

7/31/2019 PLH22 - 2009-2010-OSS2

61/122

( 7, 2 2004)

A cos(20 t) [cos(10 t)]2 A/2 [sin(20 t)]2 A

sin(30 t) sin(10 t)

= A cos(10 t) [cos(20 t) cos(10 t) - sin(20 t) sin(10 t)] - A sin(30 t) sin(10 t)

= A cos(30 t) cos(10 t) - A sin(30 t) sin(10

t) =A cos(40 t) fx=20 KHz

7/31/2019 PLH22 - 2009-2010-OSS2

62/122

( 7, 2 2004)

fx = 20 Hz

.

40 KHz 80 KHz

, 1 = / x = f / fx = 40 KHz/ 20 Hz = 2000

2 = / x = f / fx = 80 KHz/ 20 Hz = 4000

7/31/2019 PLH22 - 2009-2010-OSS2

63/122

( 7, 2 2004)

W1 = 2 (1+2000) fx = 80.04 KHz. ( 3.49 KHz).

W2 = 2 (1+4000) fx = 160.04 KHz

( )2 1 xW +

7/31/2019 PLH22 - 2009-2010-OSS2

64/122

( 7, 2 2004) X ,

. 6z

FM (6000-40.02, 6000+ 40.02) KHz = (5959.98,6040.02) KHz

6,06 z=6060 KHz

FM (6060-80.02, 6060 + 80.02) KHz = (5979.98,

6140.02) KHz.

(5959.98, 6140.02) KHz = 180.04 KHz

7/31/2019 PLH22 - 2009-2010-OSS2

65/122

Parserval

,

Parseval, P = = (

Parseval .3 .83 .

& )

=

. 2, 7, 2005

dttx+2|)(|

22| ( ) | kX f df a

+

=

7/31/2019 PLH22 - 2009-2010-OSS2

66/122

f2 ( )X f

f3( )X f

f

1( )X f 1( )x t

2 ( )x t

3( )x t

1cf

2

cf

3cf

f1c

f2c

f3c

f

1cf

2cf

3cf

1( )x t

2( )x t

3( )x t

7/31/2019 PLH22 - 2009-2010-OSS2

67/122

,

.

7/31/2019 PLH22 - 2009-2010-OSS2

68/122

T ... , .., , ,

. , , .., , , .

.. , .

.

7/31/2019 PLH22 - 2009-2010-OSS2

69/122

-

.

A/D (Analog to Digitalconversion) .

:

(Pulse Code Modulation PCM) .

7/31/2019 PLH22 - 2009-2010-OSS2

70/122

-

, , .

A/D , .

.

.

:

7/31/2019 PLH22 - 2009-2010-OSS2

71/122

x(t), fx,

x(nT), n=1,2, ,

T

7/31/2019 PLH22 - 2009-2010-OSS2

72/122

: () x(t), ()

(t), Ts , ()

x(t)=x(nTs), n=1, 2, , .

::

x(t)=x(nTs), n=1, 2, ,

x(t)=cos(2t)sin(t/2)x(nTs)=cos(2nTs)sin(nTs/2)

fs=1000 Hz,

s=1/1000,

x(nTs)=cos(2n/1000)sin(n/2*2

000)

0

x(t)

t0

(t)

ts 2s 3s 4s 5s 6s 7s

t0

xs(t)

()

()

()

Ts

7/31/2019 PLH22 - 2009-2010-OSS2

73/122

: () X(f) x(t), () Xs(f)

xs(t), , fs>2fx,

() Xs(f), fs

7/31/2019 PLH22 - 2009-2010-OSS2

74/122

(Low-pass)

f=0.

W

W fs-B

xs(t)

Xs(f)

y(t)=x(t)

X(f)

-W B B W fs-B

fs B x(t)

aliasimg

7/31/2019 PLH22 - 2009-2010-OSS2

75/122

fs 2 X(f-nfs) Xs(f), :

To

aliasing. aliasing

s(f)

-W W fs 2fs

-W W

Xa(f)

Nyquist

7/31/2019 PLH22 - 2009-2010-OSS2

76/122

Fourier.

Fourier

. 2, 5, 2005

.

7/31/2019 PLH22 - 2009-2010-OSS2

77/122

( 2, 5, 2005)

Nyquist

sinc2(100t)

.

,

(f) )(X(t) fxF

( ) ( )

( )

2

2

sin

1sin 100100 100

MF

MF

c t f

fc t

7/31/2019 PLH22 - 2009-2010-OSS2

78/122

1 ,

, 0

0,

xx ax x

tri aaa a

x a

>

-

x

( )x1

( ) ( )

2

2 sinsinFT a fx xtri a c f aa a a f

= =

1

100 100

f

=100

fmax=100 fs=2*fmax=200 Nyquist

7/31/2019 PLH22 - 2009-2010-OSS2

79/122

(

delta )

.

7/31/2019 PLH22 - 2009-2010-OSS2

80/122

: () x(t), () s(t) , ()

xs(t)

() x s(t), .

0

x(t)

t0

ts 2s 3s 4s 5s 6s 7s

()

()

t0

xs(t)

()

s(t)

Ts

t0

x's(t)

()

- Raised Cosine Pulse

7/31/2019 PLH22 - 2009-2010-OSS2

81/122

222 /41)/cos(

/)/sin()(

TtrTrt

TtTttx

=

=0.5

r = 0.35

1.35

To x(t)

7/31/2019 PLH22 - 2009-2010-OSS2

82/122

fs = 20 >> 2B = 2x1.35=2.70

To x(t)

7/31/2019 PLH22 - 2009-2010-OSS2

83/122

fs = 6 > 2B = 2.70

To

7/31/2019 PLH22 - 2009-2010-OSS2

84/122

liasing fs = 2.5 < 2B = 2.70

7/31/2019 PLH22 - 2009-2010-OSS2

85/122

7/31/2019 PLH22 - 2009-2010-OSS2

86/122

7/31/2019 PLH22 - 2009-2010-OSS2

87/122

: 300 Hz

4000 Hz

8000 samples/ sec.

:

15 kHz.

CDs 44.000samples/sec.

Video:

20

/sec

7/31/2019 PLH22 - 2009-2010-OSS2

88/122

.

.

.

PCM

PCM

K - Quantization

7/31/2019 PLH22 - 2009-2010-OSS2

89/122

Nyquist.

bits .

(Quantization) () bits.

O

(t)

7/31/2019 PLH22 - 2009-2010-OSS2

90/122

xq(t)

x(t)

xq(6Ts)xs(6Ts)

4.7 : )(tx

)(txq .

,..., 21 mm (

)( ss nTx )( sq nTx , ).

: .

7/31/2019 PLH22 - 2009-2010-OSS2

91/122

1 2 3 4 5 6 7 8 9 10 11 12 13 14

m1

m5

m4

m3

m2

1 2 3 4 5 6 7 8 9 10 11 12 13 14

m1

m5

m4

m3

m2

1 2 3 4 5 6 7 8 9 10 11 12 13 14

m1

m5

m4

m3

m2

() ()

() ()

4.8

: () , () , () , , () , .

7/31/2019 PLH22 - 2009-2010-OSS2

92/122

,

,

.

,

.

7/31/2019 PLH22 - 2009-2010-OSS2

93/122

4.9 4

x(t)

4.9

7/31/2019 PLH22 - 2009-2010-OSS2

94/122

4.9 )(tx .

a b , -. Q ,

Q

ab =

)(txq :iiiq xtxxmtx

7/31/2019 PLH22 - 2009-2010-OSS2

95/122

4.10 Gaussian.

( )+, 8 .

x(t)

( i ).

( ix )

( im ) -

.

.

,

7/31/2019 PLH22 - 2009-2010-OSS2

96/122

,

.

))(()( txgty =

)(tx )(ty , -

.

, )(ty .

(compressor), (expander).

( 1g )

)(tx .

compander (COMPressor expANDER).

7/31/2019 PLH22 - 2009-2010-OSS2

97/122

7/31/2019 PLH22 - 2009-2010-OSS2

98/122

, ,

, .

7/31/2019 PLH22 - 2009-2010-OSS2

99/122

.

, , -

.

-

,

.

4 / . 4

)( tx [ ]4,4 .

sT

,...2,1),()( == nnTxtx ss .

)( tx q .

-

0, 1, 2, , 15.

4.1 4.12

.

7/31/2019 PLH22 - 2009-2010-OSS2

100/122

4.12 . .

7/31/2019 PLH22 - 2009-2010-OSS2

101/122

, ,

.

7/31/2019 PLH22 - 2009-2010-OSS2

102/122

sT

14 bits/sec.

P C M

, P C M -

.

, L ,

L2log .

, sf , -

Lfs 2log b its/sec .

-

2 bi ts /sec/H z, , PCMB , P C M

LfB sPCM 2log2

1

PCM

7/31/2019 PLH22 - 2009-2010-OSS2

103/122

.

(DPCM-Differential PCM)

.

bits

PCM

7/31/2019 PLH22 - 2009-2010-OSS2

104/122

() . DPCM (ADPCM

Adaptive DPCM) -

.

ADPCM 32kbits/sec , (.. DECT)

bits .

7/31/2019 PLH22 - 2009-2010-OSS2

105/122

(Differential PCM

DPCM), (bits).

, , .., .

,

, PCM-

.

, -

bit .

7/31/2019 PLH22 - 2009-2010-OSS2

106/122

7/31/2019 PLH22 - 2009-2010-OSS2

107/122

)(tx

)( tx

)(ty

4.13 .

7/31/2019 PLH22 - 2009-2010-OSS2

108/122

)(1 tx)(1 tx

)(2 tx

)(2 tx

4.14

7/31/2019 PLH22 - 2009-2010-OSS2

109/122

0

)(tx

)( tx

)( tx

4.15

5:5:

7/31/2019 PLH22 - 2009-2010-OSS2

110/122

5:5:

(( ,,

))

::

7/31/2019 PLH22 - 2009-2010-OSS2

111/122

::

((unipolar):unipolar):

..

((bipolar):bipolar): g(t)g(t)

--g(t).g(t).

7/31/2019 PLH22 - 2009-2010-OSS2

112/122

..

..

..

..

..

Manchester.Manchester.

7/31/2019 PLH22 - 2009-2010-OSS2

113/122

unipolar NRZ

unipolar RZ

bipolar NRZ

AMI-RZ

Manchester

bipolar RZ

((ISI)ISI)

7/31/2019 PLH22 - 2009-2010-OSS2

114/122

((ISI).ISI).

()

ISIISI

sincsinc

7/31/2019 PLH22 - 2009-2010-OSS2

115/122

sincsinc

..

() ()

( )H f

1

2s

T

1

2s

T

()

sT sT sT

7/31/2019 PLH22 - 2009-2010-OSS2

116/122

:

raised cosine.

2

11 0

2

1 1 1

( ) cos 2 2 2 2

10

2

s

s

s s s

s

fT

T

H f f fT T T

fT

+

= +

7/31/2019 PLH22 - 2009-2010-OSS2

117/122

()

1

2s

T

1

2s

T

1

sT

1

sT

( )H f

f

()

.

,

7/31/2019 PLH22 - 2009-2010-OSS2

118/122

A/D

( )TH f

( )CH f

( )RH f

A

B

7/31/2019 PLH22 - 2009-2010-OSS2

119/122

(ASK, Amplitude Shift Keying).

(FSK, Frequency Shift Keying).

(PSK, Phase Shift Keying).

: Amplitude Shift Keying (ASK),Frequency Shift Keying (FSK) Phase Shift Keying (PSK)

7/31/2019 PLH22 - 2009-2010-OSS2

120/122

Frequency Shift Keying (FSK), Phase Shift Keying (PSK).

ASK: => 1, => 0.

FSK: freq. fc-k=> 0, freq. fc+k=> 1.

(BFSK)

FSK .

( )s t

A ft for binary

for binary( )

cos ,

,=

2 1

0 0

( )( )( )( )

s tA f k t for binary

A f k t for binary( )

cos ,

cos ,=

+

2 1

2 0

BPSK: => 1,

7/31/2019 PLH22 - 2009-2010-OSS2

121/122

=> 0.

PSK .

PSK: 1 => , 0 => .

( )

( )s t

A ft for binary

A ft for binary( )

cos ,

cos ,=

+

2 1

2 0

7/31/2019 PLH22 - 2009-2010-OSS2

122/122

ASK

BFSK BPSK

8-level QAM