数字信号课件：DSP第八章1

1、( )01h nnN10( )( )NnnH zh n z()()jjH ee ( )dd 0( ) ( ) 10()( )Njj nnH eh n e()( )jHe ()()jjH ee 10()( )Njj nnH eh n e( ) ()jjH ee 10() coscosNjnH eh nn 10() sinsinNjnH eh nn 1010sinsincoscosNnNnh nntgh nn 1100sincoscossin0NNnnh nnh nn 10sin0Nnh nn( ) ( )(1)01h nh NnnN 12N 10sin0Nnh nn0( ) ( )(1)01h

2、nh NnnN 12N0/2 1100( )( )(1)NNnnnnH zh n zh Nn z 1(1)0( )NNmmh m z (1)1()NzH z 1mNn 令( )(1)01h nh NnnN 由1(1)0( )NNmmzh m z (1)11 ( )( )()2NH zH zzH z得11(1)001( )( )2NNnNnnnh n zzh n z1(1)01( )2NnNnnh nzzz11122120( )2NNnnNNnzzzh n (1)1 ()NH zzH z 由11221cos 221sin 2jNNnnz eNnzzNjn 11122120( )2NNnnNNnz

3、zH zzh n112011201( )cos2()( )1( )sin2jNNjnjz eNNjnNeh nnH eH zNjeh nn cos2jxjxeex( )(1)h nh Nn 11201()( )( )cos2jNNjjz enNH eH zeh nn12N1( )2N ( )(1)h nh Nn 11201()( )( )sin2jNNjjz enNH eH zjeh nn12N112201( )sin2NNjjnNeh nn0/21( )22N 11cos(1)cos22NNNnn 11cos22NNn对呈偶对称101( )( )cos2NnNHh nn1cos2Nn-320

4、11( )2 ( )cos22NnNNHhh nn121112cos()22NmNNhhmm12Nnm令120( )( )cos()NnHa nn1(0)2Nah11,.,2Nn1( )22Na nhn120( )( )cos()NnHa nn1(0)2Nah11,.,2Nn1( )22Na nhn( )0, , 2 H对呈偶对称cos()0, 2 n对，呈偶对称120( )( )cos()NnHa nn适合设计各种选频滤波器12012 ( )cos2NnNh nn101( )( )cos2NnNHh nn2112cos22NmNhmm2Nnm令/211( )( )cos2NnHb nn( )

5、22Nb nhn1,.,2Nn 1201( )2 ( )cos2NnNHh nn/211( )( )cos2NnHb nn( )22Nb nhn1,.,2Nn ( )H对呈奇对称( )01Hz 则是零点1 cos02n时1z 为零点( )0, 2H对呈偶对称/211( )( )cos2NnHb nn11sin(1)sin22NNNnn 11sin22NNn对呈奇对称101( )( )sin2NnNHh nn幅度函数：1sin2Nn -3201( )2 ( )sin2NnNHh nn12112sin()2NmNhmm12Nnm令121( )( )sin()NnHc nn1( )22Nc nhn1

6、1,.,2Nn其中：1( )02Nh nNh奇对称且 为奇数121( )( )sin()NnHc nn1( )22Nc nhn11,.,2Nn其中：( )0, 2H故对， 呈奇对称( )01Hz 则是零点0, , 2 sin()0n时121( )( )sin()NnHc nnsin()0, 2 n因对，呈奇对称不能设计101( )( )sin2NnNHh nn幅度函数：12012 ( )sin2NnNh nn1201( )2 ( )sin2NnNHh nn2112sin22NmNhmm2Nnm令/211( )( )sin2NnHd nn( )22Nd nhn1,.,2Nn /211( )( )

7、sin2NnHd nn( )22Nd nhn1,.,2Nn ( )01Hz 则是零点10, 2 sin02n时( )0, 2H对呈奇对称( )H对呈偶对称/211( )( )sin2NnHd nn( )0iH z*, 1/iizz即 也是零点(1)1( )()NH zzH z (1)1()( )0NiiiH zzH z 11( )(1)(1)iijjiiiH zrezrez111111iijjiiezezrr1222112 cosiiiirzr zr2122 cosiiirrzz1522NN10ijiiiizrer 或1）11iiiijjjjiiiirereeerr零点：12221( )12 cosiiiiiH zrzr zr2122 cosiiirrzz11( )11iijjiH zezez1212 cosirzz 1312NN10ijiiiizrer 或2） ，即零点在单位圆上iijjee零点：111( )11iiiH zrzzr1211iirzzr