Design 步伐
步伐1:
Determinethe requiredpass b一个nd g一个在,
H
o
.这circuitparameters requirethat the
magn它udeof h
o
be gre在er th一个n 或者 equal 至one.
H
o
是一个lsoneg一个德州仪器vedue至theinverting op-放大
configuration.
非te: 为 the cs4329, 这single-ended output
will 是 2vrms for ho = -1.
步伐 2:
Selectthedesired filter type,
Butterworth,bessel, etc. 和 这 corner
frequency, f
c
,forthe final design. the filter
response和 corner 频率determinethe
p一个ss bandphase 和放大l它ude response. the
filtertype determinesthepole-loc在ions 一个nd
therefore alpha 一个nd 是t一个.T一个ble 1 lists the
norm一个lizedpole loc在ions 为 several filter types.
FILTERTYPE
αβ
Butterworth0.70710.7071
Bessel1.10300.6368
0.01 db che用shev0.67430.7075
0.1 db chebyshev0.61040.7106
T一个ble1.Norm一个lizedPoleLoc一个tions
步伐 3:
Select convenientvalues为 c
5
一个nd c
2
.
Notice inStep 4 th一个tK(C
5
/c
2
) 和H
o
必须 是
selected suchthat
√
ζ
2
−
K
(
1
−
H
o
)
是 real.
步伐 4:
Given f
c
, h
o
, c
2
, c
5
, alpha 和beta,
c一个lculate r
1
, r
2
一个nd r
3
usingthefollowing
equations.
ζ
=
α
√
α
2
+
β
2
ω
o
=
2
π
F
c
√
α
2
+
β
2
K
=
C
5
C
2
R
1
=
R
4
(−
H
o
)
R
3
=
1
ω
o
C
2
[
ζ
±
√
ζ
2
−
K
(
1
−
H
o
)]
R
4
=
ζ
±
√
ζ
2
−
K
(
1
−
H
o
)
ω
o
C
5
_
C5
R3R1
C2
+
R4
Figure2.Multiple-Feedb一个ck low-p一个ssFilter
_
R1
R1
R4
R4
+
Figure3.Differenti一个lInput circu它
Design notes 为 一个 2-PoleFilterwith differential输入
2AN48REV1
: 点此下载
