1
Nhập môn Kỹ thuật Truyền thông
Phần 2: Các kỹ thuật điều chế số
(Digital Modulations)
Bài 10: Không gian tín hiệu PSK
(Phase Shift Keying)
PGS. Tạ Hải Tùng
2
1. Bandpass modulation
2. One-dimensional signal space and antipodal binary
constellation (equal to 2-PAM)
3. TX filter p(t)cos(2
f0t)
4. Information associated to the carrier phase =
Phase Shift Keying
2-PSK: characteristics
3
SIGNAL SET
Information associated to the impulse amplitude
BUT
we can also write
SIGNAL SET
Information associated to the carrier phase
2-PSK: constellation
1 0 2 0
{ ( ) ( ) cos(2 ) , ( ) ( ) cos(2 ) }M s t p t f t s t p t f t
1 0 2 0
{ ( ) ( ) cos(2 ) , ( ) ( ) cos(2 ) }
M s t p t f t s t p t f t
4
Versor b1(t)=p(t)cos(2πf0t) (d=1)
VECTOR SET
2-PSK: constellation
1 2
{ ( ) , ( )}
M s s R
1
s
1
( )b t
2
s
0
5
(example)
2-PSK: binary labeling
1
:
e H M
1
(1)
e s
2
(0)
e s
1
( )b t
0
2
0 / s
1
1/ s
