() C (t) I (t) Q (t), . :
- , s (t) ( QPSK QASK);
- ( : QPSK 0 → h, 1 → h; QASK 00 → 3 h, 01 → h, 10 → h, 11 → 3 h);
- , QASK, .
:
1. .
) )
. 3.4.1. QASK () QPSK ()
) )
2. c (t) C (t)
( ) 16 (. 3.4.2).
. 3.4.2.
.
, , , , , ; - 0, + h ( - ).
3. QPSK
( QASK) TS (. 3.4.3). .
;
TS.
(36)
, , , , , ; , , (. 3.4.1) :
QPSK h, + h 0,5 , . .
;
QSK 3 h, h, + h, +3 h
QPSK ( 00)
QSK ( 01)
. 3.4.3. i (t) q (t)
4.
.
C (t) . [1]
,
,
= .
B C(τ) GC (f) . 3.4.4.
. 3.4.4. B C(τ) () GC (f) ()
|
|
C (t)
5.
BI (τ) BQ (τ), GI (f) GQ (f) I (t) Q (t). .
I (t) Q (t) C (t) (TS = 2 TB QPSK TS = 4 TB QSK), QSK BI (0) = BQ (0) = D [ I (t)] = D [ Q (t)] GI (0) = GQ (0) = D [ I (t)]/ TS = D [ Q (t)]/ TS
B I(τ) GI (f) QSK . 3.4.5.
. 3.4.5. B I(τ) ()
GI (f) () I (t)
6.
. , , , .
(!) 7. TS.
TS = 2 TB QPSK,
TS = 4 TB QPSK,
TB - ).
TS = 2 TB = 22,78 = 5,56 (. 0) TS = 4 TB = 21,39 = 5,56 (. 1)
:
- U cosω t,
- U sinω t,
- 1 2, SI (t) = I (t)cosω t SQ (t) = Q (t)sinω t, I (t) Q (t), ;
-
S (t) = SI (t) + SQ (t) = I (t)cosω t + Q (t)sinω t.
:
; , Q . , (. Q)
:
. 1 , 2 3 . 1.
1. TS ( , ):
;
;
;
( ). . 3.5.1 -4, -16 3.5.2.
. 3.5.1. sI (t), sQ (t) s (t) ( QPSK . 02 -4)
. 3.5.2. sI (t), sQ (t) s (t) ( QASK . 01 -16)
2. BSI (τ), BSQ (τ) GSI (f) GSQ (f) SI (t) SQ (t) (!) .
, [2, . 41 42],
,
|
|
GSI (f) GSQ (f) SI (t) SQ (t) - [2, .43]
,
.
3. BS (τ) GS (f) S (t) . .
, S (t) SI (t) SQ (t)
S (t) = SI (t) + SQ (t) = I (t)cosω t + Q (t)sinω t,
BS (τ) = BSI (τ) + BSQ (τ) =
GS (f) S (t) GSI (f) GSQ (f) SI (t) SQ (t), ,
.
BS (τ) GS (f) . 3.5.3.
. 3.5.3. BS (τ) GS (f)
4. FS S (t)
720 ( 0); 720 ( 1).
s (t)
().
z (t) = μ s (t) + n (t),
μ . μ = 1. N
( N ).
:
1. F .
F = FS = 720 (. 0); F = FS = 720 (. 1)
2. .
= N O Fk = 2,510-7720103 = 0,18 2 (. 0, 1)
3. s (t) / .
(. -4)
(. -16)
(. 0)
(. 1)
4. ( ) .
(. 0)
5. .
z (t) = μ s (t) + n (t), , . ().
:
1. ,
(. 3.7.1).
. 3.7.1. -16
2. 1 2 .
(1) 4 (77), (80) , (76).
:
.
1 ( 2) , , :
00 = 1, 10 = 2, 01 = 3, 11 = 4.
3. 1 2 In Qn, h, h, 3 h, 3 h (. 3) [2]:
,
,
PIn = x () PQn = x () In = x Qn = x, ,
|
|
3
In Qn | 1 2 |
In = h, Qn = h | , Q (x) , 1 - 1cosωc t, 1 = 0,512 TS N O |
In = 3 h, Qn = 3 h |
=
=
4.
() [2]:
In = h, Qn = h (4 QPSK QASK)
P In=h,Qn=h() = PIn=h () + PQn=h () PIn=h () PQn=h (),
In = 3 h, Qn = 3 h (4 QASK)
P In=3h,Qn=3h() = PIn= 3 h () + PQn= 3 h () PIn= 3 h () PQn= 3 h (),
In = 3 h, Qn = h In = h, Qn = 3 h (8 QASK)
P In=3h,Qn=h() = PIn= 3 h () + PQn=h () PIn= 3 h () PQn=h ().
5. :
QPSK:
P () = 4 P In=h,Qn=h() / 4 = P In=h,Qn=h(),
QASK:
P () = [4 P In=h,Qn=h() + 4 P In=3h,Qn=3h()+ 8 P In=3h,Qn=h()] / 16.
, (, ), , .
:
1. [1, . 253-256].
2. , . 4 3.3
c (iTb) = 110110101001001011.
3. b (k) q ( )
â (k) = 010110101001001011 ( q = 1).
4. : t 1 t 4, t 1 t 5, t 1 t 6, t 1 t 7, t 1 t 8, t 1 t 9, t 1 t 10, t 1 t 4 (. 3.8.1). , , , â (k). , â (k) = b (k), .. q.
. 3.8.1, . t 1 t 4
. 3.8.1, . t 1 t 6
. 3.8.1, . t 1 t 7
. 3.8.1, . t 1 t 8
. 3.8.1, . t 1 t 11
1. .. : / . ., 2007. 273 .: .
2. : / . . , . . , . . . .: , 2012. 80 .
:
(Times New Roman, 12 , , ; 1 ).
: 2,5 , 3 , 2,5 , 2 .
. .
, . .
|
|
, , .
, .
. .
- 15
!
+ | |
+ | |
+ + | |