第10講 基帶傳輸：ISI、奈氏準(zhǔn)則、眼圖、部分相應(yīng)系統(tǒng)

1、 ( )() ns n m tatnT ( )() nTs n s ta gtnT ( )()( ) nsw n r ta g tnTnt ( )( )( ) T g tc tgt ( )()( ) ns n y ta x tnTt ( )( )( )( )( )( ) RTR x tg tgtc tgtgt ( )( )( ) wR tntgt 00 0 0 00 ()()() ( )() sn ns m n sss n ns m n y mTta x mTtnTmTt a xa x mn TtmtTt 0000 ()( )() ns m n sns m n a x mn Tty mTta

2、x tmTt ( )() ns n m tatnT ( )( ) ( )( ) TR HGCG 1 ( )( ) 2 j t h tHed ( )() ns n y ta h tnT ()()(0)() snsnns m n nm n y mTa h mn Ta ha h mn T ()0 ns m n a h mn T 1 () 0 s mn h mn T mn 1 0 () 0 0 s k h kT k 1 ()( ) 2 s j kT s h kTHed 2 s T (21) (21) 1 ()( ) 2 s s s iT j kT s iT i h kTHed 2 s i T dd 2

3、 12 () 2 12 2 s s s s s s T jkTjik s T i s T jkT T i s i h kTHeed T i Hed T ss TT 12 () 2 s s s T jkT s T i s i h kTHed T 0 2 ( ) jn n n Ff e 0 0 0 2 2 2 0 1 ( ) jn n fFed 0 2 s T ( ) 2 ss s Tjn T s n T T fFed 2 s T 12 () 2 s s s T jkT s s T i ss Ti h kTHed TT () s h kT 12 i ss i H TT () s h kT 12 (

4、) 2 s s s T jkT s s T i bs Ti h kTHed TT 12 () s j kT s ii ss i Hh kT e TT 12 1 i ss i H TT 2 , s i sss i HT TTT )(H2 s T(,) ss TT 2 , s i sss i HT TTT 2 , s i sss i HT TTT 1 2 s W T 1/ s T 1 2 s W T , ( ) 0 s TWfW H f 1 2 s T W 1 2(Baud) s s RW T 1 2 s W T ( ) 0 s s s T T H T sin() ( )Sinc() s s s

5、t T h tt T t T s T (1) , 0 (1)(1) ( )1 sin, 22 (1) 0, s s ss sss s T T TT H TTT T 2 22 sincos ( ) 1 4 ss ss t Tt T h t t TtT 2 , s i sss i HT TTT 1 2 Baud/Hz 2 s f ssf R WW TTW cos 1 22 ss W TT cos 2 1 ( )( ) ( )( ) 1 ( )( )( ) ( ) 0 TR TR HGCG WHGG C W 升余弦 升余弦 ( ) ( )( )HTH 2 , s i sss i HT TTT s T

6、2),( ss TT 2 ( ), 2 s sss i s Ti TT TTTi H T 222 s ii sss iii HHTT TTT s T2 ( ) s jnT n n Te 1式 ( ) 222 ss jnTjnT sss n i s TTT Teded i H T 2式 1 ( )() 2 ss s TjnT Tnns T nn h tedtnT ( )() N is iN e ttiT ( ) s N jiT i iN Ee ( )( )( )() N is iN y tx te tx tiT 000 ()()() NN sissis iNiN y kTtx kTtiTx ki

7、 Tt , N kik iik i k i iN k i yxx 0 0 1 k k k Dy y 22 2 0 0 1 k k k y y 0 0000 1 ()() NN kik iikkik iik kiNkiN kiki Dxxx xxxx x y 0 zeros 0 1 0 zeros 0 N Y N 1 0 1 N N N N N A N N kik i iN yx 01212 102221 212201 22110 NN NN NN NN xxxx xxxx X xxxx xxxx YXA ( ) 0 s s s T T H T sin() ( )Sinc() s s s t T

8、 h tt T t T 1 sin() 2 ( ) () 2 s s s s T t T g t T t T 2 sin() 2 ( ) () 2 s s s s T t T g t T t T 2 2 sin()sin() 22 ( ) ()() 22 cos() 4 4 1 ss ss ss ss s s TT tt TT g t TT tt TT t T t T 2cos, 2 ( ) 0, s s s s T T T G T 2 1 t 2 t 1 t 1 s T 1 2 s T 1 sin() 2 ( ) () 2 s s s s T t T g t T t T 2 2 cos() 4 ( ) 4 1 s s t T g t t T kkk aac 1 1 kkk aca 1 1 kkk kkk bab bba 1 kkk bbc 2mod kk ca 1 0 1 1 0 1 0 0 1 1 0 0 0 1 1 0 1 1 0 1 2 2 1 1 2 2 2 1 1 0 1 1 0 1 2 2 1 1 2 2 2 1 k b k