EEET0485 Digital Signal Processing

1
DSP 7Digital Filter Structures
???????????????????????
??.??. ?????? ????????????? ???????
??????????????????????
2
????????

• ?? ??????????????????????????????? ???
  ?????????????????
• ?? ????????????????????????????????
  ??????????????????????????????? (signal flow
  graph) ?????????????????? (transfer function)

3
Aircraft control
motor control
special effects
Digital Controller
????? ????????????
CD/ DAT
Digital Filters
?????????
????????
Mobile Receivers
X-rays
Bluetooth
Digital TV
ECG monitoring
3-D reconstruction
4
???????????????????????

• ??????????????????????????????????????????????????
  ??????????????????????????????????? ???/???? ???

???????? 1 ???????????????????? ??????
???????????????? ????????????????????????????????
???????????
?????????????? Digital Filter
??????????? ???????????
???????????
5
??????????????????????? (???)
???????? 2 ???????????????????
???????????????????????????? ????? (ECG)
???????????????????? ???????????????????? ??????
?????? ECG ???
?????????????? Digital Filter
?????? ECG ??? ?????? ECG ????
?????? ECG ????
6
ECG ???????????????????
7
ECG ???????????????? 50 Hz
8
ECG ????????????????? 50 Hz
9
GSM Downconverter Block Diagram
10
Spectral Mask
11
A cascaded integrated comb (CIC) decimation
filter
12
?????????????????????
????????????????????????????????????????????
???????? ??????????????????????????????
????????????? ??????????????? (Transfer function)
13
????????????????????? (???)
???????????????????? (Finite Impulse Response
FIR)
h(n)
??????????????????????? (Infinite Impulse
Response IIR)
h(n)

14
??????????????????????????

• ???????????? (Basic Elements)
• ??????
• ??????
• ????????????

A
???????? ???????????????????????????
??????????????????? 1
15
?????????????????????????????????
????????????????????????????????
????????
???
???????????????????
??????????????? z ??????????????????????? ????
??????????????
16
???????????????????
MATLAB code
w 00.01pi frequency points H
0.50.5exp(- i w) subplot(2,1,1)plot(w,
abs(H)) subplot(2,1,2)plot(w, angle(H))
?????? ?????????????? ??? ??????????????? (Low
pass filter)
dsp_7_1.eps
17
??????????????????????????

• FIR
• Direct form
• Cascade form
• Linear-phase form
• Frequency-sampling

• IIR
• Direct form I and II
• Cascade form
• Parallel form

18
FIR Direct Form
???????????????? FIR ???????????
?????????????????????????????????? ?????????????
???????????? q3
19
FIR Cascade Form
????????? ????????? ??????? ??????????????????????
? ????? ???
??????
????????????????? ?? ???????????
20
FIR Cascade Form (???)
???? M5
21
FIR Linear-phase Form
??????????????????????? ??????????????????????????
?????????????
1 ?????? (symmetric)
2.???????????????? (Anti-symmetric)
??? N ???? ?????? ??? h(n) ?????????? (1)
???????? ???? N6
0
1
2
3
4
5
22
????????????????????????????? 50 !!
23
FIR Linear-phase Form TYPE I (???? N ??????)
...
...
24
FIR Linear-phase Form TYPE II (???? N ??????)
...
...
25
FIR Frequency Sampling (1)
????????????????????????? ???????????? ??? DFT
??? DFT
26
FIR Frequency Sampling (2)
???????????? ??? cascade ??? ????????
????????????????????? ????? N ???
27
FIR Frequency Sampling (3)
28
IIR Direct Forms
?????????? IIR ?????????????????????
????????????????????????? (difference eq.)
??????? ?????????????? FIR ????????????? nominator
FIR
??????? ??????????????????? IIR ??????? Direct
form
29
IIR Direct Form I
30
???????????? ?????? ????
????
???
31
IIR Direct Form II
32
IIR Cascade
?????????????????????cascade ??? FIR ??????????
IIR ???
???????????????????????? 1 ?????? ???
??????????????? ??????
??????????????????????????????????????
33
IIR Cascade (???)
34
IIR Parallel Form
???????????? ?????????????????????????????????????
??????? Partial Fraction Expansion ????????
factor ???
????? ??? ???????????????
35
IIR Parallel Form (???)
???? N 4 ( Ns2)
36
????????????? FIR 1
????????????????????
???????????????????? FIR
-0.1
0.2
???????????????????????????? linear phase type II
37
????????????? FIR 1
???????? ? ????? node
-0.1
0.2
38
????????????? FIR 1
????????? ??? node
-0.1
0.2
39
????????????? FIR 1
?????????
-0.1
0.2
40
????????????? FIR 1
??? ???????????????????????????????
????DTFT ???????????? ????????????????
41
????????????? IIR 1
??? ??????????????????????? ?????????????????????
????? direct form I ??? direct form II
??????????????????
42
????????????? IIR 1
Direct form I
43
????????????? IIR 1
Direct form II
44
????????????? IIR 2
???? ??????????????? H(z) ??? ????????? direct
form II ???????????
45
(No Transcript)
46
(No Transcript)
47
??????????????????????
48
????

• ?????????????????????? ??? FIR ??? IIR
• ???????????????????????????????????????????????
  ??????? ????????????????
• ???? ?????????????????????????????????????? ???
  ???????????????? ????????????????????