JPH0349468Y2 - - Google Patents
Info
- Publication number
- JPH0349468Y2 JPH0349468Y2 JP1984191611U JP19161184U JPH0349468Y2 JP H0349468 Y2 JPH0349468 Y2 JP H0349468Y2 JP 1984191611 U JP1984191611 U JP 1984191611U JP 19161184 U JP19161184 U JP 19161184U JP H0349468 Y2 JPH0349468 Y2 JP H0349468Y2
- Authority
- JP
- Japan
- Prior art keywords
- circuit
- resistor
- low
- series
- 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
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Description
【考案の詳細な説明】
（産業上の利用分野）
この考案はローパスフイルタ回路に関し、特に
たとえばLCシミユレーシヨン法によるFDNR回
路を用いたローパスフイルタ回路に関する。[Detailed Description of the Invention] (Industrial Field of Application) This invention relates to a low-pass filter circuit, and particularly relates to a low-pass filter circuit using, for example, an FDNR circuit based on the LC simulation method.
（従来技術）
第４図に示すようなLC素子で実現されたｎ次
のローパスフイルタは、FDNR回路を用いて、
第５図に示すようなローパスフイルタ回路として
構成できることが、たとえば特開昭56−119521号
公報などでよく知られている。なお、第５図にお
いて、出力側の終端コンデンサCnに並列接続さ
れた抵抗R0はたとえば実開昭56−104232号公報
などで知られる低域伝達特性の劣化を補正するた
めのものである。(Prior art) An n-order low-pass filter realized with an LC element as shown in Fig. 4 uses an FDNR circuit.
It is well known, for example, from Japanese Patent Application Laid-Open No. 119521/1983 that it can be configured as a low-pass filter circuit as shown in FIG. In FIG. 5, the resistor R 0 connected in parallel to the output-side terminating capacitor Cn is for correcting the deterioration of the low-frequency transfer characteristic known from, for example, Japanese Utility Model Application Laid-Open No. 56-104232.
（考案が解決しようとする問題点）
第５図に示すような従来のFDNR回路を用い
たローパスフイルタにおいては、たとえば、各回
路素子の特性あるいはそのばらつきの影響によつ
て、通過帯周波数特性が、第３図の点線で示すよ
うに設計特性から外れる現象が起きる。そして、
このような特性のずれは、従来では、一度設計し
た後ではFDNR回路内を調整しないと補正する
ことができないものであつた。(Problems to be solved by the invention) In a low-pass filter using a conventional FDNR circuit as shown in Fig. 5, for example, the passband frequency characteristics are affected by the characteristics of each circuit element or their variations. , a phenomenon that deviates from the design characteristics occurs as shown by the dotted line in FIG. and,
Conventionally, such deviations in characteristics could not be corrected without adjusting the FDNR circuit once it was designed.
それゆえに、この考案の主たる目的は、簡単な
構成によつて、特に遮断周波数付近における周波
数特性の劣化を補正できる、ローパスフイルタ回
路を提供することである。 Therefore, the main purpose of this invention is to provide a low-pass filter circuit that can correct deterioration in frequency characteristics, especially near the cut-off frequency, with a simple configuration.
（問題点を解決するための手段）
この考案は、出力側の終端コンデンサに抵抗を
並列接続した並列回路と直列に終端抵抗を接続し
た、FDNR回路を用いたローパスフイルタ回路
である。(Means for solving the problem) This idea is a low-pass filter circuit using an FDNR circuit, which has a parallel circuit in which a resistor is connected in parallel to a terminating capacitor on the output side, and a terminating resistor is connected in series.
（作用）
終端抵抗が遮断周波数付近における周波数特性
を持ち上げ、肩落ちした特性を第３図の実線で示
すような理想的な特性に補正する。(Function) The terminating resistor raises the frequency characteristics near the cutoff frequency and corrects the sagging characteristics to ideal characteristics as shown by the solid line in FIG. 3.
（考案の効果）
この考案によれば、終端コンデンサに抵抗を並
列接続した並列回路と直列に終端抵抗を接続する
だけの簡単な構成によつて、通過帯周波数特性、
特に遮断周波数付近での周波数特性の劣化を補正
することができる。(Effects of the invention) According to this invention, the passband frequency characteristics can be
In particular, deterioration of frequency characteristics near the cutoff frequency can be corrected.
この考案の上述の目的、その他の目的、特徴お
よび利点は、図面を参照して行なう以下の実施例
の詳細な説明から一層明らかとなろう。 The above objects, other objects, features and advantages of the present invention will become more apparent from the following detailed description of embodiments with reference to the drawings.
（実施例）
第１図はこの考案の一実施例を示す回路図であ
る。この実施例は、LCシミユレーシヨン法によ
る有極形ローパスフイルタを示す。(Embodiment) FIG. 1 is a circuit diagram showing an embodiment of this invention. This example shows a polarized low-pass filter based on the LC simulation method.
入力端子INと出力端子OUTとの間に並列アー
ムが形成される。詳しく説明すると、入力端子
INと出力端子OUTとの間に複数の直列抵抗R2，
R4……，Roが接続され、入力側の直列抵抗R2と
入力端子INとの間には入力側の終端コンデンサ
C3と入力抵抗Riとの並列回路が接続される。出力
側の直列抵抗Roと出力端子OUTとの接続点に
は、アースとの間に、互いに並列接続された出力
側の終端抵抗Coと出力抵抗R0とが接続される。
この出力抵抗R0は先に引用した実開昭56−
104232号の低域側の補正用抵抗と同じである。 A parallel arm is formed between the input terminal IN and the output terminal OUT. To explain in detail, the input terminal
Multiple series resistors R 2 between IN and output terminal OUT,
R 4 ..., R o is connected, and a terminating capacitor on the input side is connected between the series resistor R 2 on the input side and the input terminal IN.
A parallel circuit of C 3 and input resistor R i is connected. At the connection point between the output-side series resistor R o and the output terminal OUT, an output-side terminating resistor C o and an output resistor R 0 , which are connected in parallel with each other, are connected between the ground and the connection point.
This output resistance R 0 is
It is the same as the low frequency correction resistor in No. 104232.
なお、直列抵抗の各直列接続点とアースとの間
には、それぞれ、抵抗R3とFDNR回路Z1との直
列接続、R5とFDNR回路Z2との直列接続、……
が接続される。そして、このようなFDNR回路
Z1，Z2，……の回路構成はたとえば第２図に示さ
れる。このようなFDNR回路は、よく知られて
いるように、第４図に示すようなLC素子を演算
子ｓ（ｓ＝jω，ω＝2πf）で割つて、その素子を
置換したものである。 In addition, between each series connection point of the series resistor and the ground, there is a series connection between resistor R 3 and FDNR circuit Z 1 , a series connection between R 5 and FDNR circuit Z 2 , etc.
is connected. And a FDNR circuit like this
The circuit configuration of Z 1 , Z 2 , . . . is shown in FIG. 2, for example. As is well known, such an FDNR circuit is obtained by dividing an LC element as shown in FIG. 4 by an operator s (s=jω, ω=2πf) and replacing the element.
そして、特徴的に、終端コンデンサCoと出力
抵抗R0との並列接続点と出力側の直列抵抗Roお
よび出力端子OUTの接続点との間に終端抵抗Rz
が接続されている。 Characteristically, a terminating resistor R z is connected between the parallel connection point of the terminating capacitor C o and the output resistor R 0 and the connection point of the output side series resistor R o and the output terminal OUT.
is connected.
新らたに付加された終端抵抗Rzの抵抗値は、
実験によれば、直列抵抗R2，R4，……，Roの総
和すなわちΣR2，R4，……，Roの10〜20％程度
の値に選べばよい。そして、このような終端抵抗
Rzを挿入することにより、その周波数特性が、
第３図の実線で示すように遮断周波数付近で補正
される。 The resistance value of the newly added terminating resistor R z is
According to experiments, the value should be selected to be about 10 to 20% of the sum of the series resistances R 2 , R 4 , . . . , Ro , that is, ΣR 2 , R 4 , . . . , Ro . And a terminating resistor like this
By inserting R z , the frequency characteristic becomes
As shown by the solid line in FIG. 3, the correction is made near the cut-off frequency.
実験によれば、終端コンデンサCoの容量を
1500pFとし、直列抵抗の総和が14.8kΩである場
合、終端抵抗Rzを2.2kΩとすれば、その遮断周波
数で0.3dBの減衰の補正が実現できた。 According to experiments, the capacitance of the termination capacitor C o is
When the resistance is 1500 pF and the total series resistance is 14.8 kΩ, if the terminating resistor R z is set to 2.2 kΩ, an attenuation correction of 0.3 dB can be realized at that cut-off frequency.
第１図はこの考案の一実施例を示す回路図であ
る。第２図は第１図実施例に用いられるFDNR
回路の一例を示す回路図である。第３図は周波数
特性を示すグラフであり、点線は従来技術におい
て劣化した特性を示し、実線は第１図実施例の特
性を示す。第４図はLC素子を用いたｎ次のロー
パスフイルタ回路の一例を示す回路図である。第
５図は第４図回路をFDNR回路を用いて実現し
た回路図である。
図において、R2，R4，……，Roは直列抵抗、
Z1，Z2，……はFDNR回路、C3は入力側終端コ
ンデンサ、Coは出力終端コンデンサ、Rzは終端
抵抗を示す。
FIG. 1 is a circuit diagram showing an embodiment of this invention. Figure 2 shows the FDNR used in the example shown in Figure 1.
FIG. 2 is a circuit diagram showing an example of a circuit. FIG. 3 is a graph showing frequency characteristics, where the dotted line shows the deteriorated characteristics in the prior art, and the solid line shows the characteristics in the embodiment of FIG. 1. FIG. 4 is a circuit diagram showing an example of an n-th order low-pass filter circuit using LC elements. FIG. 5 is a circuit diagram in which the circuit shown in FIG. 4 is realized using an FDNR circuit. In the figure, R 2 , R 4 , ..., Ro are series resistances,
Z 1 , Z 2 , ... are the FDNR circuits, C 3 is the input-side termination capacitor, Co is the output termination capacitor, and R z is the termination resistance.
Claims (1)
ンデンサ間に縦続接続された複数のFDNR回路
および複数の直列抵抗とを含むローパスフイルタ
回路において、 前記出力側の終端コンデンサと抵抗との並列回
路と直列に、前記複数の直列抵抗の抵抗値の総和
の10ないし20％の抵抗値を有する終端抵抗を接続
したことを特徴とする、ローパスフイルタ回路。[Claims for Utility Model Registration] In a low-pass filter circuit including input and output termination capacitors, a plurality of FDNR circuits and a plurality of series resistors connected in cascade between the termination capacitors, the output side termination capacitor and the resistor, A low-pass filter circuit, characterized in that a terminating resistor having a resistance value of 10 to 20% of the total resistance value of the plurality of series resistors is connected in series with the parallel circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1984191611U JPH0349468Y2 (en) | 1984-12-17 | 1984-12-17 |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1984191611U JPH0349468Y2 (en) | 1984-12-17 | 1984-12-17 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS61107224U JPS61107224U (en) | 1986-07-08 |
| JPH0349468Y2 true JPH0349468Y2 (en) | 1991-10-22 |
Family
ID=30749050
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1984191611U Expired JPH0349468Y2 (en) | 1984-12-17 | 1984-12-17 |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0349468Y2 (en) |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS60247314A (en) * | 1984-04-27 | 1985-12-07 | Toko Inc | Fdnr type low pass filter |
-
1984
- 1984-12-17 JP JP1984191611U patent/JPH0349468Y2/ja not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| JPS61107224U (en) | 1986-07-08 |
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