JPH0518291B2 - - Google Patents
Info
- Publication number
- JPH0518291B2 JPH0518291B2 JP5725383A JP5725383A JPH0518291B2 JP H0518291 B2 JPH0518291 B2 JP H0518291B2 JP 5725383 A JP5725383 A JP 5725383A JP 5725383 A JP5725383 A JP 5725383A JP H0518291 B2 JPH0518291 B2 JP H0518291B2
- Authority
- JP
- Japan
- Prior art keywords
- point
- intermediate point
- corresponding point
- filter
- basic circuit
- 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 - Lifetime
Links
- 239000003990 capacitor Substances 0.000 claims description 12
- 238000010586 diagram Methods 0.000 description 10
- 238000006243 chemical reaction Methods 0.000 description 5
- 238000000034 method Methods 0.000 description 3
- 230000035945 sensitivity Effects 0.000 description 2
- 238000004088 simulation Methods 0.000 description 2
Classifications
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H11/00—Networks using active elements
- H03H11/02—Multiple-port networks
- H03H11/04—Frequency selective two-port networks
- H03H11/12—Frequency selective two-port networks using amplifiers with feedback
- H03H11/126—Frequency selective two-port networks using amplifiers with feedback using a single operational amplifier
Description
【発明の詳細な説明】
産業上の利用分野
本発明は、能動RCフイルタに関するものであ
る。DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an active RC filter.
従来技術
ビデオテープレコーダ等において制御用の基準
信号を取り出すために回路として各種のフイルタ
が使用されている。このような用途を有するフイ
ルタの一種としての抵抗両終端LCはしご形受動
フイルタの通過域における低素子感度性は良く知
られており、この低素子感度性を、能動RCフイ
ルタでも実現するために、LCシミユレーシヨン
法が多く研究されてきている。しかし、リープフ
ログ等のこの種の従来のシミユレーシヨン方法
は、元の回路と等価の特性を実現するのが必ずし
も容易でなく、また、比較的多くの演算増巾器が
必要となつてしまうなど必ずしも満足のいくもの
でなかつた。BACKGROUND OF THE INVENTION Various types of filters are used as circuits in video tape recorders and the like to extract reference signals for control. The low element sensitivity in the passband of resistor-double-terminated LC ladder-type passive filters, which are a type of filter with such uses, is well known, and in order to realize this low element sensitivity in the active RC filter, Much research has been done on LC simulation methods. However, with this type of conventional simulation method such as leapfrog, it is not always easy to realize characteristics equivalent to the original circuit, and it is not always satisfactory, such as requiring a relatively large number of operational amplifiers. It wasn't something I could do.
発明の目的
本発明の目的は、前述したような従来技術にか
んがみて、元の回路と等価の特性を有する能動
RCフイルタを、容易にしかも使用する演算増巾
器の数が比較的少数となるようにして、実現しう
るようにすることにある。Purpose of the Invention In view of the prior art as described above, the purpose of the present invention is to provide an active circuit with characteristics equivalent to the original circuit.
An object of the present invention is to easily realize an RC filter by using a relatively small number of operational amplifiers.
発明の構成
本発明によれば、入力対応点と、節点対応点
と、出力対応点と、第１中間点と、第２中間点
と、入力対応点と第１中間点との間に接続された
キヤパシタと、節点対応点と第１中間点との間に
接続された抵抗と、第１中間点と第２中間点との
間に接続された抵抗と、入力側を第２中間点、出
力側を出力対応点に接続するようにして第２中間
点と出力対応点との間に接続された演算増巾器
と、第１中間点と出力対応点との間に接続された
キヤパシタと、第１中間点とアースとの間に接続
された抵抗と、第２中間点とアースとの間に接続
されたキヤパシタとからなる基本回路の出力対応
点を他の基本回路の節点対応点のいずれかに接続
することにより、前記LC受動フイルタと等価の
特性を有した能動RCフイルタが構成される。Configuration of the Invention According to the present invention, an input corresponding point, a node corresponding point, an output corresponding point, a first intermediate point, a second intermediate point, and a connection between the input corresponding point and the first intermediate point are provided. a resistor connected between the node corresponding point and the first intermediate point; a resistor connected between the first intermediate point and the second intermediate point; an operational amplifier connected between the second intermediate point and the output corresponding point such that its side is connected to the output corresponding point, and a capacitor connected between the first intermediate point and the output corresponding point; The output corresponding point of a basic circuit consisting of a resistor connected between the first intermediate point and the ground, and a capacitor connected between the second intermediate point and the ground is connected to any node corresponding point of the other basic circuit. By connecting the two, an active RC filter having characteristics equivalent to the LC passive filter is constructed.
実施例
次に、添付図面に基づいて本発明の実施例につ
いて本発明をより詳細に説明する。Embodiments Next, the present invention will be described in more detail with reference to embodiments of the present invention based on the accompanying drawings.
本発明によつて、LC受動低域通過フイルタと
等価の特性を有する能動RCフイルタを構成する
場合について、一例を挙げて以下説明する。第１
図は、無限極３個、有限極ｎ個をもつ一般的な
（2n＋３）次のLC受動低域通過フイルタの回路を
示している。この回路の破線内のインダクタンス
を等価変換し、更に、各インピーダンスを１／ｓ
倍すると、第２図に示す回路が得られる。第２図
の変換後の回路の節点方程式は、次のようにな
る。 An example of configuring an active RC filter having characteristics equivalent to an LC passive low-pass filter according to the present invention will be described below. 1st
The figure shows a general (2n+3) order LC passive low-pass filter circuit with three infinite poles and n finite poles. Equivalently transform the inductance within the broken line of this circuit, and further convert each impedance to 1/s
When multiplied, the circuit shown in FIG. 2 is obtained. The nodal equations of the circuit after conversion in FIG. 2 are as follows.
（S2Ci＋SGi＋o+2
〓K=1
１／Li、ｋ）Vi＝SGi′Vi
＋ o+2
〓K=1 k≠1
（１／Li、ｋVk） ……(1)
（ｉ＝１，……，ｎ＋２）
ただし、Gi′は、ｉ＝１のときGi′＝Gi、ｉ≠１
のときGi′＝０である。(S 2 C i +SG i + o+2 〓 K=1 1/L i , k)V i =SG i ′V i + o+2 〓 K=1 k≠1 (1/L i , kV k ) ...(1) (i=1,...,n+ 2 ) However, when i=1, G i ′=G i , i≠1
When , G i '=0.
これら（ｎ＋２）個の節点方程式は、第３図に
示すような基本回路を用いて個々にシミユレート
できる。この基本回路は、入力電圧Vioの加えら
れる入力対応点、節点電圧V1，……Vkの現われ
る節点対応点と、出力電圧V0の現われる出力対
応点と、第１中間点J1と、第２中間点J2と、入力
対応点と第１中間点J1との間に接続されたキヤパ
シタCaと、節点対応点と第１中間点J1との間に
接続された抵抗G1，……Gkと、第１中間点J1と
第２中間点J2との間に接続された抵抗G2と、入
力側を第２中間点J2、出力側を出力対応点に接続
するようにして第２中間点J2と出力対応点との間
に接続された演算増巾器OAと、第１中間点J1と
出力対応点との間に接続されたキヤパシタCbと、
第１中間点J1とアースとの間に接続された抵抗Ｇ
と、第２中間点J2とアースとの間に接続されたキ
ヤパシタＣとからなつている。Ｋは、演算増巾器
OAの利得を示している。このような第３図の基
本回路の節点方程式は、次のように与えられる。 These (n+2) nodal equations can be individually simulated using a basic circuit as shown in FIG. This basic circuit consists of an input corresponding point where the input voltage V io is applied, a node corresponding point where the nodal voltages V 1 , . . . V k appear, an output corresponding point where the output voltage V 0 appears, and the first intermediate point J 1 . , a capacitor Ca connected between the second intermediate point J2 , the input corresponding point and the first intermediate point J1 , and a resistor G1 connected between the node corresponding point and the first intermediate point J1 . ,...G k , a resistor G 2 connected between the first intermediate point J 1 and the second intermediate point J 2 , and the input side connected to the second intermediate point J 2 and the output side connected to the output corresponding point. an operational amplifier OA connected between the second intermediate point J 2 and the output corresponding point, and a capacitor Cb connected between the first intermediate point J 1 and the output corresponding point,
A resistor G connected between the first intermediate point J 1 and ground
and a capacitor C connected between the second intermediate point J2 and ground. K is arithmetic amplifier
Shows OA gain. The nodal equations of the basic circuit shown in FIG. 3 are given as follows.
（S2C2／3G2＋SCa＋G2／３）V0
＝〓GkVk＋SCaVio ……(2)
（３〓Gk＝G2、２〓Ck＝Ｇ、Ca＋Cb＝Ｃ、Ｋ＝
３）
式(2)の各方程式の各項を、式(1)の各方程式の対応
する項と比較して、基本回路の抵抗、キヤパシタ
等の各素子の素子値を決定する。これによつてで
きる（ｎ＋２）個の基本回路を、同じ節点に対応
するもの同志で接続すれば、目的とする能動RC
フイルタが構成される。 (S 2 C 2 /3G 2 +SC a +G 2 /3)V 0 =〓G k V k +SC a V io ......(2) (3〓G k =G 2 , 2〓C k =G, C a +C b =C, K=
3) Compare each term of each equation in equation (2) with the corresponding term in each equation of equation (1) to determine the element value of each element such as the resistor and capacitor of the basic circuit. If you connect the (n+2) basic circuits created by this with those corresponding to the same node, you can achieve the desired active RC.
A filter is configured.
本発明のこのような構成方法に従つて、遮断周
波数が10KHz、通過域リツプル幅が0.1dB、12K
Hzで40dBの減衰をもつ７次低域通過フイルタを
構成してみた。極は無限に３個、有限に２個
（12.2KHzと14.8KHz）である。演算増巾器は
LF356を使用し、素子の精度は0.5パーセントで
ある。構成されたフイルタの周波数特性の測定値
と理論値とを第４図に示している。第４図のグラ
フにおいて、曲線Ｂは、周波数特性曲線の通過域
特性の部分Ａを拡大して示すものであり、その縦
軸の目盛は一目盛0.1dBとなつている。 According to this configuration method of the present invention, the cutoff frequency is 10KHz, the passband ripple width is 0.1dB, and the 12K
I constructed a 7th-order low-pass filter with an attenuation of 40 dB at Hz. There are infinitely three poles and finitely two poles (12.2KHz and 14.8KHz). The arithmetic amplifier is
LF356 is used and the element accuracy is 0.5%. FIG. 4 shows measured values and theoretical values of the frequency characteristics of the constructed filter. In the graph of FIG. 4, curve B shows an enlarged portion A of the passband characteristic of the frequency characteristic curve, and the scale of the vertical axis is 0.1 dB.
なお、第５図に、この７次低域通過フイルタの
原LCフイルタ回路図（第１図に対応）を示し、
第６図に、その変換回路図（第２図に対応、ただ
し、インピーダンスを１／ｓ倍する前）を示し、
第７図ａ，ｂ，ｃおよびｄに本発明の実施例の具
体的回路図を示している。第７図ａ，ｂ，ｃおよ
びｄの各回路は、第３図の基本回路に対応してお
り、それら各回路において、同一番号の節点同志
を結線し、Vio−OUTPUT端子間で入出力特性
を測定したものが、第４図に示した特性である。
第５図、第６図および第７図の各回路図において
は、各素子の数値を付記している。 In addition, Fig. 5 shows the original LC filter circuit diagram (corresponding to Fig. 1) of this 7th-order low-pass filter.
Figure 6 shows the conversion circuit diagram (corresponding to Figure 2, but before the impedance is multiplied by 1/s),
FIGS. 7a, b, c and d show specific circuit diagrams of embodiments of the present invention. The circuits in Figure 7 a, b, c, and d correspond to the basic circuit in Figure 3, and in each circuit, nodes with the same number are connected to each other, and input/output is performed between the V io and OUTPUT terminals. The measured characteristics are shown in FIG.
In each circuit diagram of FIG. 5, FIG. 6, and FIG. 7, numerical values of each element are added.
発明の効果
本発明による能動RCフイルタは、前述したよ
うにして構成されるので、比較的少数の演算増巾
器で元の回路と等価な特性をもつ有極形低域通過
フイルタを実現できる。Effects of the Invention Since the active RC filter according to the present invention is configured as described above, a polarized low-pass filter having characteristics equivalent to the original circuit can be realized with a relatively small number of operational amplifiers.
第１図はLC受動低域通過フイルタの一例を示
す回路図、第２図は第１図の変換回路を示す図、
第３図は第２図の変換回路の節点方程式をシユミ
レートする基本回路を示す図、第４図は本発明に
よる能動RCフイルタの一例の周波数特性の測定
値と理論値とを示す図、第５図は、第４図にその
特性を示した７次低域通過フイルタの原LCフイ
ルタ回路図、第６図は、第４図の原LCフイルタ
の変換回路図、第７図は、本発明の実施例の具体
的回路である。
Vio……入力電圧、V1，Vk……節点電圧、V0…
…出力電圧、J1……第１中間点、J2……第２中間
点、Ca……キヤパシタ、G1，Gk……抵抗、G2…
…抵抗、OA……演算増巾器、Cb……キヤパシ
タ、Ｇ……抵抗、Ｃ……キヤパシタ。
Fig. 1 is a circuit diagram showing an example of an LC passive low-pass filter, Fig. 2 is a diagram showing the conversion circuit of Fig. 1,
FIG. 3 is a diagram showing a basic circuit that simulates the nodal equations of the conversion circuit in FIG. The figure shows the original LC filter circuit diagram of the 7th order low-pass filter whose characteristics are shown in Figure 4, Figure 6 is the conversion circuit diagram of the original LC filter of Figure 4, and Figure 7 shows the circuit diagram of the original LC filter of the present invention. This is a specific circuit of an example. V io ...Input voltage, V 1 , V k ...Node voltage, V 0 ...
...output voltage, J 1 ...first intermediate point, J 2 ...second intermediate point, C a ...capacitor, G 1 , G k ...resistance, G 2 ...
...Resistor, OA...Arithmetic amplifier, C b ...Capacitor, G...Resistor, C...Capacitor.
Claims (1)
と、第１中間点と、第２中間点と、入力対応点と
第１中間点との間に接続されたキヤパシタと、節
点対応点と第１中間点との間に接続された抵抗
と、第１中間点と第２中間点との間に接続された
抵抗と、入力側を第２中間点、出力側を出力対応
点に接続するようにして第２中間点と出力対応点
との間に接続された演算増巾器と、第１中間点と
出力対応点との間に接続されたキヤパシタと、第
１中間点とアースとの間に接続された抵抗と、第
２中間点とアースとの間に接続されたキヤパシタ
とからなる基本回路の出力対応点を他の基本回路
の節点対応点のいずれかに接続することを特徴と
する能動RCフイルタ。 ２ 前記基本回路の前記各素子の素子値は、前記
基本回路にてLC受動フイルタの節点方程式を
個々に直接シミユレートし、前記LC受動フイル
タの節点方程式と対応する前記基本回路の節点方
程式の対応する項を比較することによつて決定さ
れる特許請求の範囲第１項記載の能動RCフイル
タ。[Claims] 1. An input corresponding point, a node corresponding point, an output corresponding point, a first intermediate point, a second intermediate point, and a capacitor connected between the input corresponding point and the first intermediate point. , a resistor connected between the node corresponding point and the first intermediate point, a resistor connected between the first intermediate point and the second intermediate point, the input side is the second intermediate point, and the output side is the resistor connected between the node corresponding point and the first intermediate point. an operational amplifier connected between the second intermediate point and the output corresponding point so as to be connected to the output corresponding point; a capacitor connected between the first intermediate point and the output corresponding point; Connect the output corresponding point of a basic circuit consisting of a resistor connected between the intermediate point and the ground, and a capacitor connected between the second intermediate point and the ground to one of the node corresponding points of the other basic circuit. An active RC filter characterized by connecting. 2. The element value of each element of the basic circuit is determined by directly simulating the nodal equations of the LC passive filter individually in the basic circuit, and calculating the element value of the nodal equation of the basic circuit corresponding to the nodal equation of the LC passive filter. The active RC filter according to claim 1, wherein the active RC filter is determined by comparing the terms.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5725383A JPS59183521A (en) | 1983-04-01 | 1983-04-01 | Active rc filter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5725383A JPS59183521A (en) | 1983-04-01 | 1983-04-01 | Active rc filter |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS59183521A JPS59183521A (en) | 1984-10-18 |
| JPH0518291B2 true JPH0518291B2 (en) | 1993-03-11 |
Family
ID=13050359
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP5725383A Granted JPS59183521A (en) | 1983-04-01 | 1983-04-01 | Active rc filter |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS59183521A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2909239A1 (en) | 2006-11-27 | 2008-05-30 | Thomson Licensing Sas | ACTIVE PASS FILTER |
-
1983
- 1983-04-01 JP JP5725383A patent/JPS59183521A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS59183521A (en) | 1984-10-18 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Soliman | Generation of current conveyor-based all-pass filters from op amp-based circuits | |
| JP2964149B2 (en) | Filter circuit | |
| JPS6236404B2 (en) | ||
| JP2906832B2 (en) | Fully differential analog circuit | |
| JPS6351571B2 (en) | ||
| US9837987B2 (en) | Floating immittance emulator | |
| US3936777A (en) | Arrangements for simulating inductance and filter networks incorporating such improvements | |
| Cox | A digitally programmable switched-capacitor universal active filter/oscillator | |
| JPH0518291B2 (en) | ||
| CN103973254A (en) | Transimpedance type integrated band-pass filter design method | |
| SE508697C2 (en) | Method and apparatus for time continuous filtration in digital CMOS process | |
| JP2666860B2 (en) | Negative impedance circuit | |
| US3990025A (en) | Network with a single amplifier for simulating an FDNR circuit | |
| US4245202A (en) | Floating gyrator having a current cancellation circuit | |
| CA1063193A (en) | Single amplifier network for simulating a super-inductor circuit | |
| RU2019023C1 (en) | Active rc filter | |
| JP3170796B2 (en) | Active filter circuit | |
| JPS623937Y2 (en) | ||
| JPS60675Y2 (en) | Signal addition circuit | |
| Bruton | A transistor realization of the generalized impedance converter | |
| US3471797A (en) | Frequency selective filters using passive impedances and two-terminal active networks | |
| CA1063192A (en) | Single amplifier network for simulating an fdnr circuit | |
| JPS6115633Y2 (en) | ||
| JPS628967B2 (en) | ||
| JPH0633703Y2 (en) | De-emphasis circuit |