JPH0744420B2 - Active filter circuit - Google Patents

Active filter circuit

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Publication number
JPH0744420B2
JPH0744420B2 JP1002519A JP251989A JPH0744420B2 JP H0744420 B2 JPH0744420 B2 JP H0744420B2 JP 1002519 A JP1002519 A JP 1002519A JP 251989 A JP251989 A JP 251989A JP H0744420 B2 JPH0744420 B2 JP H0744420B2
Authority
JP
Japan
Prior art keywords
resistor
operational amplifier
capacitor
filter circuit
pass filter
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Fee Related
Application number
JP1002519A
Other languages
Japanese (ja)
Other versions
JPH02183612A (en
Inventor
直人 吉岡
昭一 藤田
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Murata Manufacturing Co Ltd
Original Assignee
Murata Manufacturing Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Murata Manufacturing Co Ltd filed Critical Murata Manufacturing Co Ltd
Priority to JP1002519A priority Critical patent/JPH0744420B2/en
Publication of JPH02183612A publication Critical patent/JPH02183612A/en
Publication of JPH0744420B2 publication Critical patent/JPH0744420B2/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

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Description

【発明の詳細な説明】 （産業上の利用分野） 本発明は、１次ローパスフィルタおよび２次ローパスフ
ィルタからなる３次ローパスフィルタと２次ローパスフ
ィルタとの両フィルタ特性を合わせ持つアクティブフィ
ルタ回路に関する。The present invention relates to an active filter circuit having both filter characteristics of a third-order low-pass filter composed of a first-order low-pass filter and a second-order low-pass filter and a second-order low-pass filter. .

（従来の技術） この種の従来例のアクティブフィルタ回路は、第２図に
示すように３次ローパスフィルタ２と、２次ローパスフ
ィルタ４とで構成されており、いずれのフィルタ2,4も
演算増幅器6,8を具備していた。(Prior Art) An active filter circuit of a conventional example of this type is composed of a third-order low-pass filter 2 and a second-order low-pass filter 4 as shown in FIG. It was equipped with amplifiers 6 and 8.

（発明が解決しようとする問題点） しかしながら、このようにそれぞれのフィルタ2,4が演
算増幅器6,8を具備しているために、その演算増幅器6,8
そのもののがコスト的に高くつくのみならず、そこでの
電力消費も大きく、しかも構成も複雑化しているととも
に、回路基板などに組み込む場合に小型化には適してい
ないなどの不具合があった。(Problems to be Solved by the Invention) However, since the respective filters 2 and 4 are provided with the operational amplifiers 6 and 8 as described above, the operational amplifiers 6 and 8 are not provided.
Not only is it expensive in terms of cost, but it also consumes a large amount of power and has a complicated structure, and it is not suitable for miniaturization when incorporated into a circuit board or the like.

そこで、本発明は１つの演算増幅器を用いたもので３次
ローパスフィルタと２次ローパスフィルタとの両フィル
タ特性を備えさせることで、コスト的に安く電力消費も
少なくて済み、しかも簡単かつ小型化可能な構成を有す
るアクティブフィルタ回路を提供することを目的として
いる。Therefore, the present invention uses one operational amplifier and is provided with both filter characteristics of a third-order low-pass filter and a second-order low-pass filter, so that the cost is low, the power consumption is low, and the size is simple and compact. It is an object to provide an active filter circuit having a possible configuration.

（実施例） 以下、本発明の実施例を図面を参照して詳細に説明す
る。第１図は本発明の実施例に係るアクティブフィルタ
回路の回路図である。(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings. FIG. 1 is a circuit diagram of an active filter circuit according to an embodiment of the present invention.

まず、３次ローパスフィルタと２次ローパスフィルタと
からなるアクティブフィルタ回路の合成伝達関数Ｔ
（Ｓ）はそれに対する入力電圧をVi、出力電圧をVoとし
た場合、 ただし、 X1＝ω0＋ω1/Q1＋ω2/Q2、 X2＝ω1 2＋ω2 2＋ω1ω0/Q1＋ω2ω0/Q2＋ω1ω2/Q
1Q2、 X3＝（ω0＋ω2/Q2）ω1 2＋（ω0＋ω1/Q1）ω2 2＋ω0
ω1ω2/Q1Q2 X4＝ω0ω1ω2（ω2/Q1＋ω1/Q2）＋ω1 2ω2 2 X5＝ω0ω1 2ω2 2であり、 また、Ｈはフィルタの通過域利得、Ｓはｊωであらわさ
れる角周波数、Q1,Q2は２次ローパスフィルタの尖鋭
度、ω0は１次ローパスフィルタのカットオフ角周波
数、ω1，ω2は２次ローパスフィルタのカットオフ角周
波数、でそれぞれあらわされる。First, a composite transfer function T of an active filter circuit including a third-order low-pass filter and a second-order low-pass filter.
(S) is when the input voltage is Vi and the output voltage is Vo, However, X 1 = ω 0 + ω 1 / Q 1 + ω 2 / Q 2 , X 2 = ω 1 2 + ω 2 2 + ω 1 ω 0 / Q 1 + ω 2 ω 0 / Q 2 + ω 1 ω 2 / Q
1 Q 2 , X 3 = (ω 0 + ω 2 / Q 2 ) ω 1 2 + (ω 0 + ω 1 / Q 1 ) ω 2 2 + ω 0
ω 1 ω 2 / Q 1 Q 2 X 4 = ω 0 ω 1 ω 2 (ω 2 / Q 1 + ω 1 / Q 2 ) + ω 1 2 ω 2 2 X 5 = ω 0 ω 1 2 ω 2 2 Further, H is the pass band gain of the filter, S is the angular frequency represented by jω, Q 1 and Q 2 are the sharpness of the secondary low-pass filter, ω 0 is the cutoff angular frequency of the primary low-pass filter, and ω 1 and ω 2 is the cutoff angular frequency of the second-order low-pass filter.

つぎに、本実施例のアクティブフィルタ回路10は、利得
ＫがＨ＝Ｋの演算増幅器12を用い、入力端14から演算増
幅器12の入力部16までの間に第１、第２、第３、第４お
よび第５の抵抗R1ないしR5をこの順序で直列接続し、第
１抵抗R1および第２抵抗R2の接続部18とアース20との間
に第１コンデンサC1、第２抵抗R2および第３抵抗R3の接
続部22と演算増幅器の出力部24との間に第２コンデンサ
C2、第３抵抗R3および第４抵抗R4の接続部26とアース18
との間に第３コンデンサC3、第４抵抗R4および第５抵抗
R5の接続部28と演算増幅器12の出力部24との間に第４コ
ンデンサC4、第５抵抗R5および演算増幅器12の入力部16
の接続部30とアース18との間に第５コンデンサC5を接続
してなり、第１ないし第５コンデンサC1ないしC5の容量
をそれぞれC1〜C5とし、前記第１抵抗ないし第５抵抗R1
ないしR5の抵抗値をそれぞれr1〜r5とおいた場合、当該
アクティブフィルタ回路の伝達関数Vo/Viは次式であら
わされる。Next, the active filter circuit 10 of this embodiment uses the operational amplifier 12 having a gain K of H = K, and the first, second, third, and third sections are provided between the input terminal 14 and the input section 16 of the operational amplifier 12. The fourth and fifth resistors R 1 to R 5 are serially connected in this order, and the first capacitor C 1 and the second capacitor R 1 are connected between the connection 18 of the first resistor R 1 and the second resistor R 2 and the ground 20. A second capacitor is provided between the connecting portion 22 of the resistor R 2 and the third resistor R 3 and the output portion 24 of the operational amplifier.
Connection between C 2 , third resistor R 3 and fourth resistor R 4 26 and ground 18
Between the third capacitor C 3 , the fourth resistor R 4 and the fifth resistor
The fourth capacitor C 4 , the fifth resistor R 5, and the input section 16 of the operational amplifier 12 are provided between the connection section 28 of R 5 and the output section 24 of the operational amplifier 12.
A fifth capacitor C 5 is connected between the connection portion 30 of the above and the ground 18, and the capacities of the first to fifth capacitors C 1 to C 5 are C 1 to C 5 , respectively, and the first resistor to the first resistor 5 resistance R 1
If the resistance values of R 5 to R 5 are r 1 to r 5 , respectively, the transfer function Vo / Vi of the active filter circuit is expressed by the following equation.

ただし、 Ａ＝A1/P、Ｂ＝B1/P、Ｃ＝C1/P、Ｄ＝D1/P、Ｅ＝1/P
で、かつ、 A1＝r1r2r3r4{(1-K)C1C2C3C4+C1C2C3C5}+r1r2r3r5{C1C2
C3C5+C1C2C4C5}+r1r2r4r5{C1C2C4C5+C1C3C4C5}+r1r3r4r
5{C1C3C4C5+C2C3C4C5}+r2r3r4r5C2C3C4C5、 B1＝〔r1r2r3{C1C2C3+(1-K)C1C2C4+C1C2C5}+r1r2r4{C1C
2C5+(1-K)C1C2C4+(1-K)C1C3C4+C1C3C5}+r1r2r5{C1C3C5+
C1C4C5+C1C2C5}+r1r3r4{(1-K)C1C3C4+C1C3C5+(1-K)C2C3
C4+C2C3C5}+r1r3r5{C1C3C5+C1C4C5+C2C3C5+C2C4C5}+r1r
4r5{C1C4C5+C2C4C5+C3C4C5}+r2r3r4{(1-K)C2C3C4+C2C3C
5}+r2r3r5{C2C3C5+C2C4C5}+r2r4r5{C2C4C5+C3C4C5}+r3r
4r5C3C4C5〕 C1＝[r1r2{(1-K)C1C2+C1C3+(1-K)C1C4+C1C5}+r1r3{C1C3
+(1-K)C1C4+C1C5+C2C3+(1-K)C2C4+C2C5}+r1r4{(1-K)C1C
4+C1C5+(1-K)C2C4+C2C5+(1-K)C3C4+C3C5}+r1r5{C1C5+C2
C5+C3C5+C4C5}+r2r3{C2C3+(1-K)C2C4+C2C5}+r2r4{(1-K)
C2C4+C2C5+(1-K)C3C4+C3C5}+r2r5{C2C5+C3C5+C4C5}+r3r
4{(1-K)C3C4+C3C5}+r3r5{C3C5+C4C5}+r4r5C4C5] D1＝r1{C1+(1-K)C2+C3+(1-K)C4+C5}+r2{(1-K)C2+C3+(1-
K)C4+C5}+r3{C3+(1-K)C4+C5}+r4{(1-K)C4+C5}+r5C5 Ｐ＝C1C2C3C4C5r1r2r3r4r5 したがって、前記（１）（２）式の分母におけるＳの係
数がそれぞれ等しくなるように各コンデンサの容量と抵
抗の抵抗値とを選定することにより、実施例のアクティ
ブフィルタ回路は、１個の演算増幅器12でもって前記所
望の合成特性を得ることができることになる。 However, A = A 1 / P, B = B 1 / P, C = C 1 / P, D = D 1 / P, E = 1 / P
And A 1 = r 1 r 2 r 3 r 4 {(1-K) C 1 C 2 C 3 C 4 + C 1 C 2 C 3 C 5 } + r 1 r 2 r 3 r 5 {C 1 C 2
C 3 C 5 + C 1 C 2 C 4 C 5 } + r 1 r 2 r 4 r 5 {C 1 C 2 C 4 C 5 + C 1 C 3 C 4 C 5 } + r 1 r 3 r 4 r
5 {C 1 C 3 C 4 C 5 + C 2 C 3 C 4 C 5 } + r 2 r 3 r 4 r 5 C 2 C 3 C 4 C 5 , B 1 = (r 1 r 2 r 3 {C 1 C 2 C 3 + (1-K) C 1 C 2 C 4 + C 1 C 2 C 5 } + r 1 r 2 r 4 {C 1 C
2 C 5 + (1-K) C 1 C 2 C 4 + (1-K) C 1 C 3 C 4 + C 1 C 3 C 5 } + r 1 r 2 r 5 {C 1 C 3 C 5 +
C 1 C 4 C 5 + C 1 C 2 C 5 } + r 1 r 3 r 4 {(1-K) C 1 C 3 C 4 + C 1 C 3 C 5 + (1-K) C 2 C 3
C 4 + C 2 C 3 C 5 } + r 1 r 3 r 5 {C 1 C 3 C 5 + C 1 C 4 C 5 + C 2 C 3 C 5 + C 2 C 4 C 5 } + r 1 r
4 r 5 {C 1 C 4 C 5 + C 2 C 4 C 5 + C 3 C 4 C 5 } + r 2 r 3 r 4 {(1-K) C 2 C 3 C 4 + C 2 C 3 C
5 } + r 2 r 3 r 5 {C 2 C 3 C 5 + C 2 C 4 C 5 } + r 2 r 4 r 5 {C 2 C 4 C 5 + C 3 C 4 C 5 } + r 3 r
4 r 5 C 3 C 4 C 5 ] C 1 = [r 1 r 2 {(1-K) C 1 C 2 + C 1 C 3 + (1-K) C 1 C 4 + C 1 C 5 } + r 1 r 3 {C 1 C 3
+ (1-K) C 1 C 4 + C 1 C 5 + C 2 C 3 + (1-K) C 2 C 4 + C 2 C 5 } + r 1 r 4 {(1-K) C 1 C
4 + C 1 C 5 + (1-K) C 2 C 4 + C 2 C 5 + (1-K) C 3 C 4 + C 3 C 5 } + r 1 r 5 {C 1 C 5 + C 2
C 5 + C 3 C 5 + C 4 C 5 } + r 2 r 3 {C 2 C 3 + (1-K) C 2 C 4 + C 2 C 5 } + r 2 r 4 {(1-K)
C 2 C 4 + C 2 C 5 + (1-K) C 3 C 4 + C 3 C 5 } + r 2 r 5 {C 2 C 5 + C 3 C 5 + C 4 C 5 } + r 3 r
4 {(1-K) C 3 C 4 + C 3 C 5 } + r 3 r 5 {C 3 C 5 + C 4 C 5 } + r 4 r 5 C 4 C 5 ] D 1 = r 1 {C 1 + (1-K) C 2 + C 3 + (1-K) C 4 + C 5 } + r 2 {(1-K) C 2 + C 3 + (1-
K) C 4 + C 5 } + r 3 {C 3 + (1-K) C 4 + C 5 } + r 4 {(1-K) C 4 + C 5 } + r 5 C 5 P = C 1 C 2 C 3 C 4 C 5 r 1 r 2 r 3 r 4 r 5 Therefore, in order to make the coefficients of S in the denominators of the above equations (1) and (2) equal, By selecting, the active filter circuit of the embodiment can obtain the desired combined characteristic with only one operational amplifier 12.

なお、この実施例では上記（１）（２）の分子における
Ｓの係数も等しくなるようにしている。もっとも、この
分子間の関係は所望の合成特性をその形を変えずに上下
に平行移動させる、すなわち利得を全体的に変えるのに
関係するだけであるため、必ずしもこの例のように両係
数を一致させなくてもよい。In this embodiment, the coefficients of S in the numerator of (1) and (2) are made equal. However, since the relationship between the molecules is only related to the translation of desired synthetic characteristics up and down without changing its shape, that is, to the overall change of gain, both coefficients are not necessarily changed as in this example. It does not have to match.

（効果） 以上説明したことから明らかなように本発明によれば、
１個の演算増幅器でもって３次ローパスフィルタの特性
と２次ローパスフィルタの特性との合成特性が得られる
ことから、コスト的に安く電力消費も少なくて済み、し
かも簡単かつ小型化可能な構成を有するアクティブフィ
ルタ回路を提供することができる。(Effect) As is apparent from the above description, according to the present invention,
A single operational amplifier can provide a combined characteristic of the characteristics of the third-order low-pass filter and the characteristics of the second-order low-pass filter, so that the cost is low, the power consumption is low, and the configuration is simple and compact. An active filter circuit having the same can be provided.

【図面の簡単な説明】[Brief description of drawings]

第１図は本発明の一実施例に係るアクティブフィルタ回
路の回路図、第２図は従来例のアクティブフィルタ回路
の回路図である。 12……演算増幅器、14……入力端、16……演算増幅器の
入力部、24……演算増幅器の出力部、C1ないしC5……コ
ンデンサ、R1ないしR5……抵抗。FIG. 1 is a circuit diagram of an active filter circuit according to an embodiment of the present invention, and FIG. 2 is a circuit diagram of a conventional active filter circuit. 12 ...... operational amplifier, 14 ...... inputs, 16 inputs of ...... operational amplifier, the output of 24 ...... operational amplifier, C 1 to C 5 ...... capacitor, to no R 1 R 5 ...... resistance.

Claims (1)

【特許請求の範囲】[Claims] 【請求項１】入力電圧をVi、出力電圧をVoとした場合、
伝達関数Vo/Viが、 ただし、 X1＝ω0＋ω1/Q1＋ω2/Q2、 X2＝ω1 2＋ω2 2＋ω1ω0/Q1＋ω2ω0/Q2＋ω1ω2/Q
1Q2、 X3＝（ω0＋ω2/Q2）ω1 2＋（ω0＋ω1/Q1）ω2 2＋ω0
ω1ω2/Q1Q2 X4＝ω0ω1ω2（ω2/Q1＋ω1/Q2）＋ω1 2ω2 2 X5＝ω0ω1 2ω2 2であり、 また、Ｈはフィルタの通過域利得、Ｓはｊωであらわさ
れる角周波数、Q1,Q2は２次ローパスフィルタの尖鋭
度、ω0は１次ローパスフィルタのカットオフ角周波
数、ω1，ω2は２次ローパスフィルタのカットオフ角周
波数、でそれぞれあらわされる特性を実現するアクティ
ブフィルタ回路であって、 利得ＫがＨ＝Ｋの演算増幅器を用い、入力端から演算増
幅器の入力部までの間に第１、第２、第３、第４および
第５の抵抗をこの順序で直列接続し、第１抵抗および第
２抵抗の接続部とアースとの間に第１コンデンサ、第２
抵抗および第３抵抗の接続部と演算増幅器の出力部との
間に第２コンデンサ、第３抵抗および第４抵抗の接続部
とアースとの間に第３コンデンサ、第４抵抗および第５
抵抗の接続部と演算増幅器の出力部との間に第４コンデ
ンサ、第５抵抗および演算増幅器の入力部の接続部とア
ースとの間に第５コンデンサを接続してなり、 前記第１ないし第５コンデンサの容量をそれぞれC1〜C5
とし、前記第１抵抗ないし第５抵抗の抵抗値をそれぞれ
r1〜r5とおいた場合、当該アクティブフィルタ回路の伝
達関数Vo/Viは次式であらわされ、 ただし、 Ａ＝A1/P、Ｂ＝B1/P、Ｃ＝C1/P、Ｄ＝D1/P、Ｅ＝1/P
で、かつ、 A1＝r1r2r3r4{(1-K)C1C2C3C4+C1C2C3C5}+r1r2r3r5{C1C2
C3C5+C1C2C4C5}+r1r2r4r5{C1C2C4C5+C1C3C4C5}+r1r3r4r
5{C1C3C4C5+C2C3C4C5}+r2r3r4r5C2C3C4C5、 B1＝〔r1r2r3{C1C2C3+(1-K)C1C2C4+C1C2C5}+r1r2r4{C1C
2C5+(1-K)C1C2C4+(1-K)C1C3C4+C1C3C5}+r1r2r5{C1C3C5+
C1C4C5+C1C2C5}+r1r3r4{(1-K)C1C3C4+C1C3C5+(1-K)C2C3
C4+C2C3C5}+r1r3r5{C1C3C5+C1C4C5+C2C3C5+C2C4C5}+r1r
4r5{C1C4C5+C2C4C5+C3C4C5}+r2r3r4{(1-K)C2C3C4+C2C3C
5}+r2r3r5{C2C3C5+C2C4C5}+r2r4r5{C2C4C5+C3C4C5}+r3r
4r5C3C4C5〕 C1＝[r1r2{(1-K)C1C2+C1C3+(1-K)C1C4+C1C5}+r1r3{C1C3
+(1-K)C1C4+C1C5+C2C3+(1-K)C2C4+C2C5}+r1r4{(1-K)C1C
4+C1C5+(1-K)C2C4+C2C5+(1-K)C3C4+C3C5}+r1r5{C1C5+C2
C5+C3C5+C4C5}+r2r3{C2C3+(1-K)C2C4+C2C5}+r2r4{(1-K)
C2C4+C2C5+(1-K)C3C4+C3C5}+r2r5{C2C5+C3C5+C4C5}+r3r
4{(1-K)C3C4+C3C5}+r3r5{C3C5+C4C5}+r4r5C4C5] D1＝r1{C1+(1-K)C2+C3+(1-K)C4+C5}+r2{(1-K)C2+(1-K)C
4+C5}+r3{C3+(1-K)C4+C5}+r4{(1-K)C4+C5}+r5C5 Ｐ＝C1C2C3C4C5r1r2r3r4r5 そして、前記両式（１）（２）の少なくとも分母におけ
るＳの係数を満足するように前記容量および抵抗値を選
定していることを特徴とするアクティブフィルタ回路。1. When the input voltage is Vi and the output voltage is Vo,
Transfer function Vo / Vi is However, X 1 = ω 0 + ω 1 / Q 1 + ω 2 / Q 2 , X 2 = ω 1 2 + ω 2 2 + ω 1 ω 0 / Q 1 + ω 2 ω 0 / Q 2 + ω 1 ω 2 / Q
1 Q 2 , X 3 = (ω 0 + ω 2 / Q 2 ) ω 1 2 + (ω 0 + ω 1 / Q 1 ) ω 2 2 + ω 0
ω 1 ω 2 / Q 1 Q 2 X 4 = ω 0 ω 1 ω 2 (ω 2 / Q 1 + ω 1 / Q 2 ) + ω 1 2 ω 2 2 X 5 = ω 0 ω 1 2 ω 2 2 Further, H is the pass band gain of the filter, S is the angular frequency represented by jω, Q 1 and Q 2 are the sharpness of the secondary low-pass filter, ω 0 is the cutoff angular frequency of the primary low-pass filter, and ω 1 and ω 2 is an active filter circuit that realizes the characteristics expressed by the cut-off angular frequency of the second-order low-pass filter, using an operational amplifier with a gain K of H = K, and between the input end and the input part of the operational amplifier. First, second, third, fourth, and fifth resistors are connected in series in this order, and the first capacitor and the second resistor are connected between the connection portion of the first resistor and the second resistor and the ground.
The second capacitor is provided between the connecting portion of the resistor and the third resistor and the output portion of the operational amplifier, and the third capacitor, the fourth resistor and the fifth portion are provided between the connecting portion of the third resistor and the fourth resistor and the ground.
A fourth capacitor is connected between the connection part of the resistor and the output part of the operational amplifier, and a fifth capacitor is connected between the connection part of the fifth resistance and the input part of the operational amplifier and the ground. Set the capacity of 5 capacitors to C 1 to C 5 respectively.
And the resistance values of the first resistor to the fifth resistor are respectively
When r 1 to r 5 are set, the transfer function Vo / Vi of the active filter circuit is expressed by the following equation, However, A = A 1 / P, B = B 1 / P, C = C 1 / P, D = D 1 / P, E = 1 / P
And A 1 = r 1 r 2 r 3 r 4 {(1-K) C 1 C 2 C 3 C 4 + C 1 C 2 C 3 C 5 } + r 1 r 2 r 3 r 5 {C 1 C 2
C 3 C 5 + C 1 C 2 C 4 C 5 } + r 1 r 2 r 4 r 5 {C 1 C 2 C 4 C 5 + C 1 C 3 C 4 C 5 } + r 1 r 3 r 4 r
5 {C 1 C 3 C 4 C 5 + C 2 C 3 C 4 C 5 } + r 2 r 3 r 4 r 5 C 2 C 3 C 4 C 5 , B 1 = (r 1 r 2 r 3 {C 1 C 2 C 3 + (1-K) C 1 C 2 C 4 + C 1 C 2 C 5 } + r 1 r 2 r 4 {C 1 C
2 C 5 + (1-K) C 1 C 2 C 4 + (1-K) C 1 C 3 C 4 + C 1 C 3 C 5 } + r 1 r 2 r 5 {C 1 C 3 C 5 +
C 1 C 4 C 5 + C 1 C 2 C 5 } + r 1 r 3 r 4 {(1-K) C 1 C 3 C 4 + C 1 C 3 C 5 + (1-K) C 2 C 3
C 4 + C 2 C 3 C 5 } + r 1 r 3 r 5 {C 1 C 3 C 5 + C 1 C 4 C 5 + C 2 C 3 C 5 + C 2 C 4 C 5 } + r 1 r
4 r 5 {C 1 C 4 C 5 + C 2 C 4 C 5 + C 3 C 4 C 5 } + r 2 r 3 r 4 {(1-K) C 2 C 3 C 4 + C 2 C 3 C
5 } + r 2 r 3 r 5 {C 2 C 3 C 5 + C 2 C 4 C 5 } + r 2 r 4 r 5 {C 2 C 4 C 5 + C 3 C 4 C 5 } + r 3 r
4 r 5 C 3 C 4 C 5 ] C 1 = [r 1 r 2 {(1-K) C 1 C 2 + C 1 C 3 + (1-K) C 1 C 4 + C 1 C 5 } + r 1 r 3 {C 1 C 3
+ (1-K) C 1 C 4 + C 1 C 5 + C 2 C 3 + (1-K) C 2 C 4 + C 2 C 5 } + r 1 r 4 {(1-K) C 1 C
4 + C 1 C 5 + (1-K) C 2 C 4 + C 2 C 5 + (1-K) C 3 C 4 + C 3 C 5 } + r 1 r 5 {C 1 C 5 + C 2
C 5 + C 3 C 5 + C 4 C 5 } + r 2 r 3 {C 2 C 3 + (1-K) C 2 C 4 + C 2 C 5 } + r 2 r 4 {(1-K)
C 2 C 4 + C 2 C 5 + (1-K) C 3 C 4 + C 3 C 5 } + r 2 r 5 {C 2 C 5 + C 3 C 5 + C 4 C 5 } + r 3 r
4 {(1-K) C 3 C 4 + C 3 C 5 } + r 3 r 5 {C 3 C 5 + C 4 C 5 } + r 4 r 5 C 4 C 5 ] D 1 = r 1 {C 1 + (1-K) C 2 + C 3 + (1-K) C 4 + C 5 } + r 2 {(1-K) C 2 + (1-K) C
4 + C 5 } + r 3 {C 3 + (1-K) C 4 + C 5 } + r 4 {(1-K) C 4 + C 5 } + r 5 C 5 P = C 1 C 2 C 3 C 4 C 5 r 1 r 2 r 3 r 4 r 5 and that the capacitance and resistance values are selected so as to satisfy at least the coefficient of S in the denominator of both equations (1) and (2) Characteristic active filter circuit.
JP1002519A 1989-01-09 1989-01-09 Active filter circuit Expired - Fee Related JPH0744420B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP1002519A JPH0744420B2 (en) 1989-01-09 1989-01-09 Active filter circuit

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP1002519A JPH0744420B2 (en) 1989-01-09 1989-01-09 Active filter circuit

Publications (2)

Publication Number Publication Date
JPH02183612A JPH02183612A (en) 1990-07-18
JPH0744420B2 true JPH0744420B2 (en) 1995-05-15

Family

ID=11531620

Family Applications (1)

Application Number Title Priority Date Filing Date
JP1002519A Expired - Fee Related JPH0744420B2 (en) 1989-01-09 1989-01-09 Active filter circuit

Country Status (1)

Country Link
JP (1) JPH0744420B2 (en)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107911097A (en) * 2018-01-04 2018-04-13 成都威邦科技有限公司 A kind of bandpass filter
CN110518902A (en) * 2019-08-22 2019-11-29 广州金升阳科技有限公司 A kind of pulse width signal isolation and transmission circuit

Also Published As

Publication number Publication date
JPH02183612A (en) 1990-07-18

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