GSM (Gaussian Minimum Shift Keying - GMSK). , - , , - :
f0 - , ; F=1/T - .
Δf=fB-fH=F/2 - , fB fH . fB fH π. . F/2, F/4, :
(F/4)/(F/2)=0,5.
. GMSK MSK(Minimum Shift Keying - MSK - ).
MSK , 2 .
MSK , , ( ) n- , n- (n-1)- :
, ω0 =2πf0 - , :
(cos) | (sin) | (cos) | (πt/2T) | |||
- | - | - | - | fH | ||
+ | - | + | + | fB | ||
- | - | - | - | fH | ||
- | - | - | + | fB |
, , , , : , ; , - .
, :
:
:
- fB fH, .
fB fH . π, .
|
|
MSK.
.8.24 MSK
.
1 2 , , 2- , , 1 a2 +1 -1 ( -1 0 ).
1 2 , .
' 1 2, 1 2 sin(πt/2T) cos(πt/2T). π; 1 2.
ʳ
sin(ω0t) cos(ω0t) . MSK - ( - G).
-
, φ MSK - , φH(t) , . , , φH(t) . 3 :
B = 0,3F,
= 0,3.
GSM F=270,833 , =81,3 .
, .
( diversity) , , , , , , . , , . , , .
' :
- (time diversity). , . , ';
|
|
- (frequency diversity). , , ;
- (direction diversity). ( ) . , , ( , ), , ;
- (polarization diversity). . , ;
- (space diversity). , . , , , .
, , , . , , , . . . .
. , . , , . , , . , , .
' , :
- () ;
- () ;
- , /.
, - .
(frequency hopping) . , , . -, , , 100...300 . , , , .
. , , - . GSM .
|
|
- . , , : f0, f1, f2. . (. 8.25).
.8.25
(), , 63 . , '. , : , . ; 6 .
: . , , . , . , , .