北邮考研信号与系统专业课试卷及答案2003A.pdf

A 1 7321 1.( ) f t()F j +3 2 t f A 2 3 22 1 j eF B 2 3 22 1 j eF C() 6 22 j eF D() 6 22 j eF 2. tf()jF= + 3 4cos( )tf A() + 3 4 2 1 j etB()() + + 33 44 2 1 jj etet C()() + + 33 44 2 1 jj etetD()() + 33 44 2 1 jj etet 3.( )()dtutf= 0 A S 1 B 2 1 S C 3 1 S D 4 1 S 4.( )( )tuetf t 2 = A:( ) 2Re 2 1 + =S S SF B:( ) 2Re 2 1 =S S SF D:( ) 2Re 2 1 + =S S SF 5.( ) () + = + s e sF Ts A: () ()Ttue Tt B:()Ttue t C:() tue t D: () ()Ttue t 6. ( )( )nunf n = 3 1 Z( )F Z A: 13 1 z z ,B: 13 z z ,C: 13 3 z z ,D: 13 3 +z z ( ) njnj eenx 3 . 02 . 0 += A10 B20 C0.2 D0.3 8324 1.( )6,5,4,3 =nx,( )ng=()=12nx 2. 3.() = = n T nTtt)(, 4.( )tf,( )ty, ()jH= 5.( )tfBHz( )tf 2 = N f= N T A 3 6.( ) () 1 1 22 + = s es sF s ()= + 0f( )=f 7.( ) X nZ ( ) 212 61 +=ZZzZX( )nx ( )nx= 8.( )H ZZ 5840 1.( )tf 3 2 t f ( )tf A t ( )1 O 2.( ) + + += 3 40cos4 6 30cos6 4 20cos16ttttx (1) (2) 3.8 22 1 )( ta tx + = Ot 2 1a ( )tf ( )a 4. ( )f t A B A 4 5.( ) 5 . 0 = z z zH12 3 765 18 ( )0,1,2= nf( )0,1,2,1 =nh ( )( )( )nhnfny= 28( )( )( )tftftf 21 = ( )tf1 ( )tf2 tt tsin OO 38 )()( 1 tuth=) 1()( 2 =tth)()( 3 tth=)(th ( )( )tuete t = )( 2 th)( 1 th)( 3 th )(tr ( )te )( 1 th 48 A 5 ( ) () ( ) ( )( )txty t ty k t ty 36 d d 2 d d 2 2 =+ 1( )sH 2,K 580=t( )( )tuetx t2 2 = 0t( )t c ( )tx H1 1 F1 1 A1 L i + ( )t C 0=t 615 1 z 1 z ( )nx( )ny 2 1 3 10 3 7 4 1 1 2 3 710LTI( )( )( )IRHj+= )(th( )( )IR ( ) ( ) d 1 = I R( ) ( ) d 1 = R I 1 2003(A) 7321 1.D 2.D 3.C 4. C 5.B 6.C 8324 1.( )ng=()6,412 =nx 2. 3.( ) =+= = T tn TT t n T 2 cos 21 1 1 1 4.()jH= 0 tj Ke 5.= N fHz4B= N Ts 4 11 BfN = 6.()= + 0f1( )=f0 7.( )nx=()( )()()2612+nnnn 8. 5840 1. 2 3 2 t f A ( )3 Ot 2.1 2 343 42 3 8 n F 2 02 3 4 3 1 n 2 4 3 0 4 6 3 210: O ( ) 203040 64 9 4 203040 64 9 4 3.8 a e ata + 22 1 a O ( )F ( )b 4.( )()() 000 33 2 1 3cos+FFttf ( )( )()()( )HFFthttf 000 33 2 1 3cos+ 3 ( )ttfF 0 cos 2 1 0 3 0 300 0 5 0 5 ( )Y 2 1 0 3 0 300 5. Imzj Rez o 5 . 01 o 2 3 2 232 )( j eH 765 18( )1,0,5,2= ny 28 ( ) () ()() () = 0 4312cos 1 321cos2cos 1 211cos1 1 tt ttt tt tf 38( )( )( )( )( )( )()1 3121 =+=tutuththththth ( )( )( )()1= tututuety t = () tee te tt t 1 101 1 481( ) ()62 3 2 + = sks sH22k 58( )()( ),23 2 tueetu tt C = 4 ( )()( )tueetu tt zs C 2 2 =( )0= tetu t Czi 615