JP3122322B2 - Active low-pass filter - Google Patents
Active low-pass filterInfo
- Publication number
- JP3122322B2 JP3122322B2 JP06333856A JP33385694A JP3122322B2 JP 3122322 B2 JP3122322 B2 JP 3122322B2 JP 06333856 A JP06333856 A JP 06333856A JP 33385694 A JP33385694 A JP 33385694A JP 3122322 B2 JP3122322 B2 JP 3122322B2
- Authority
- JP
- Japan
- Prior art keywords
- amplifier circuit
- grounded
- pass filter
- base
- active low
- 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
Links
Landscapes
- Networks Using Active Elements (AREA)
- Amplifiers (AREA)
Description
【０００１】[0001]
【産業上の利用分野】本発明は高周波信号処理回路（Ｏ
ＳＣ，ＭＩＸＥＲ，ＡＭＰ等）で発生する高調波を減衰
してスプリアス妨害を抑止する等の為に使用して好適で
あり、かつＩＣチップ上にも形成できる能動低域通過フ
ィルターに関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-frequency signal processing circuit (O
The present invention relates to an active low-pass filter which is suitable for use for attenuating harmonics generated in SC, MIXER, AMP, etc. to suppress spurious interference and can be formed on an IC chip.
【０００２】[0002]
【従来の技術】図３は，従来例の能動低域通過フイルタ
を示す回路図である。１は、増幅作用をする演算増幅器
である。２は、高周波信号の入力端子である。３は、高
周波信号の出力端子である。Ｒ１は、入力端子２からの
高周波信号を入力して、低域通過フィルタのカットオフ
周波数を設定する抵抗である。Ｃ１は、演算増幅器の出
力端子３と前記の抵抗Ｒ１との間に接続されて、抵抗Ｒ
１と共に、充放電による過渡応答を利用して、カットオ
フ周波数を設定する容量である。Ｒ２は、Ｒ１を介して
入力された高周波信号を演算増幅噐の非反転入力端子に
伝達する抵抗である。Ｃ２は、演算増幅器１の非反転入
力端子とグランド間に接続され、Ｒ２と共に、放電によ
る過渡応答を利用して、カットオフ周波数を設定する容
量である。Ｒａは、演算増幅器の反転入力端子とグラン
ド間に接続され、低域通過フィルタの通過域の利得を設
定する抵抗である。Ｒｂは、演算増幅器１の出力端子と
反転入力端子間に接続され、低域通過フィルタの通過域
の利得を設定する抵抗である。端子２より入力された高
周波信号はＲ１とＣ１およびＲ２とＣ２で設定されたカ
ットオフ点以下の周波数成分は減衰されずに出力端子３
より出力される。カットオフ点以上の周波数成分は、Ｒ
１とＣ１およびＲ２とＣ２による過渡応答の遅れにより
高域カットされて出力端子３より出力される。電圧利得
Ａは、抵抗Ｒａ、Ｒｂで決定され、以下の値となる。 Ａ＝１＋（Ｒｂ／Ｒａ） また、カットオフ周波数はＲ１，Ｃ１，Ｒ２，Ｃ２の値
で決まる。2. Description of the Related Art FIG. 3 is a circuit diagram showing a conventional active low-pass filter. Reference numeral 1 denotes an operational amplifier that performs an amplifying operation. 2 is an input terminal for a high-frequency signal. Reference numeral 3 denotes an output terminal for a high-frequency signal. R1 is a resistor that inputs a high-frequency signal from the input terminal 2 and sets a cutoff frequency of the low-pass filter. C1 is connected between the output terminal 3 of the operational amplifier and the resistor R1, and a resistor R1
Along with 1, it is a capacity for setting a cutoff frequency using a transient response due to charging and discharging. R2 is a resistor for transmitting the high-frequency signal input via R1 to the non-inverting input terminal of the operational amplifier. C2 is a capacitor that is connected between the non-inverting input terminal of the operational amplifier 1 and the ground, and that sets a cutoff frequency using a transient response due to discharge together with R2. Ra is a resistor connected between the inverting input terminal of the operational amplifier and the ground and setting the gain in the pass band of the low-pass filter. Rb is a resistor connected between the output terminal and the inverting input terminal of the operational amplifier 1 and for setting the gain in the pass band of the low-pass filter. In the high-frequency signal input from the terminal 2, the frequency components below the cut-off point set by R1 and C1 and R2 and C2 are not attenuated and are output to the output terminal 3
Output. The frequency component above the cutoff point is R
High frequencies are cut off due to delays in the transient response due to R1 and C1 and R2 and C2, and output from the output terminal 3. The voltage gain A is determined by the resistors Ra and Rb and has the following value. A = 1 + (Rb / Ra) The cutoff frequency is determined by the values of R1, C1, R2, and C2.
【０００３】[0003]
【発明が解決しようとする課題】しかしながら、従来の
能動低域通過フィルタは以下のような問題があった。す
なわち、従来の能動低域通過フィルタは、演算増幅器１
を使用して構成されているが、演算増幅器１は、極めて
高い利得を有する為、高域周波数で発振しやすく安定に
動作できる周波数は０〜１０ＭＨｚ程度が限界であり、
それより高い周波数にカットオフ周波数を設定出来ない
という問題があった。本発明の目的は、以上の問題を解
決し、従来どうりＩＣチップ上に構成できる能動低域通
過フィルタを提供することにある。However, the conventional active low-pass filter has the following problems. That is, the conventional active low-pass filter includes the operational amplifier 1
However, since the operational amplifier 1 has an extremely high gain, the frequency at which it can easily oscillate at a high frequency and stably operate is limited to about 0 to 10 MHz.
There is a problem that the cutoff frequency cannot be set to a higher frequency. SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems and to provide an active low-pass filter that can be conventionally formed on an IC chip.
【０００４】[0004]
【問題を解決するための手段】請求項１に記載の発明に
よる能動低域通過フィルタは、エミッタ接地増幅回路
と、該エミッタ接地増幅回路の後段に接続されるベ−ス
接地増幅回路と、前記エミッタ接地増幅回路と前記ベー
ス接地増幅回路の接続点とグランド間に接続される容量
と、前記ベース接地増幅回路の出力端より前記エミッタ
接地増幅回路の入力端に接続される帰還用抵抗と、前記
ベ−ス接地増幅回路の入力端に信号経路と直列に接続さ
れる抵抗を有することを特徴とする。請求項２に記載の
発明による能動低域通過フィルタは、エミッタ接地増幅
回路と、該エミッタ接地増幅回路の後段に、複数段にわ
たって、縦続接続されるベ−ス接地増幅回路と前記エミ
ッタ接地増幅回路及び前記複数段のベ−ス接地増幅回路
の複数の接続点とグランド間に接続される容量と、前記
複数段のベ−ス接地増幅回路のうち、最後段のベ−ス接
地増幅回路の出力端より、前記エミッタ接地増幅回路の
入力端に接続される帰還用抵抗とを有することを特徴と
する。請求項３に記載の発明による能動低域通過フィル
タは、請求項２に記載の能動低域通過フィルタであって
前記ベ−ス接地増幅回路の入力端には、信号経路に直列
に抵抗が備えられていることを特徴とする。According to the present invention, there is provided an active low-pass filter according to the present invention, comprising: a common-emitter amplifier; a common-base amplifier connected downstream of the common-emitter amplifier; A capacitor connected between the connection point between the common-emitter amplifier circuit and the common-base amplifier circuit and the ground, a feedback resistor connected from an output terminal of the common-base amplifier circuit to an input terminal of the common-emitter amplifier circuit ,
Connected in series with the signal path to the input terminal of the base grounded amplifier circuit
It is characterized by having a resistance . An active low-pass filter according to a second aspect of the present invention is a grounded-amplifier circuit, and a grounded-base amplifier circuit and a grounded-amplifier circuit cascade-connected in a plurality of stages subsequent to the grounded-amplifier circuit. And a capacitance connected between a plurality of connection points of the plurality of stages of the grounded ground amplifiers and the ground, and an output of the last one of the plurality of stages of the grounded grounded amplifiers. And a feedback resistor connected to an input terminal of the common-emitter amplifier circuit. An active low-pass filter according to a third aspect of the present invention is the active low-pass filter according to the second aspect, wherein an input terminal of the grounded base amplifier circuit is connected in series with a signal path. wherein the resistor is provided in the.
【０００５】[0005]
【作用】請求項１に記載の能動低域通過フイルタによれ
ば、エミッタ接地増幅回路とベ−ス接地増幅回路の２段
で構成している事により、演算増幅器と異なり利得が低
く、高域周波数まで増幅させても発振しない。また、群
遅延は、トランジスタの内部容量のみに依存し、その群
遅延は、高域まで線形性を保っているので、カットオフ
周波数を容易に、数百ＭＨｚと、高く設定できる。ベー
ス接地増幅回路は出力インピーダンスが高く、入出力逆
方向アイソレーション特性が良好な為、負荷インピーダ
ンスの値に影響されずにエミッタ接地増幅回路とベース
接地増幅回路の接続点とグランド間に接続する容量の値
を決定することが出来るので、前記各増幅回路の接続点
とグランド間に、高域をカットする容量を設ける事によ
って、入出力に接続される回路のインピ−ダンスによ
る、カットオフ周波数の変動が少ない。初段に設けられ
たエミッタ接地増幅回路は、信号の位相を反転させ前記
ベース接地増幅回路の出力端より前記エミッタ接地増幅
回路の入力端に抵抗を接続して、負帰還させているの
で、安定に、通過帯域の利得をフラットにできる。ま
た、ベ−ス接地増幅回路のエミッタに直列に抵抗を接続
する事により、前段増幅回路の負荷線を変更する事がで
き、低い電流でも、歪を低下できる。請求項２に記載の
能動低域通過フイルタによれば、エミッタ接地増幅回路
の後段に、複数段のべース接地増幅回路を縦続接続する
ことによって、フィルタの段数を増やし、ベース接地と
する事によって、利得は、急峻な減衰特性を得る。請求
項３に記載の能動低域通過フイルタによれば、ベ−ス接
地増幅回路の入力インピ−ダンスは、数１０Ωと低い
為、前段増幅回路の電流波形が歪易く、電流を増やす必
要があった。ベース接地増幅回路を複数段にわたって縦
続接続した場合においても、ベ−ス接地増幅回路のエミ
ッタに直列に抵抗を接続する事により、前段増幅回路の
負荷線を変更する事ができ、低い電流でも、歪を低下で
きる。According to the active low-pass filter according to the first aspect, since the active low-pass filter is constituted by two stages of the common emitter amplifier circuit and the common base amplifier circuit, the gain is low unlike the operational amplifier, and It does not oscillate even when amplified up to the frequency. Further, the group delay depends only on the internal capacitance of the transistor, and since the group delay maintains linearity up to a high frequency range, the cutoff frequency can be easily set as high as several hundred MHz. The grounded base amplifier has high output impedance and good input / output reverse isolation characteristics, so it is not affected by the value of the load impedance and the capacitance connected between the connection point between the grounded emitter amplifier and the grounded base amplifier and the ground By providing a capacitor that cuts high frequencies between the connection point of each amplifier circuit and the ground, the cutoff frequency of the cut-off frequency due to the impedance of the circuit connected to the input and output can be determined. Little fluctuation. The common-emitter amplifier circuit provided in the first stage inverts the phase of the signal, connects a resistor from the output terminal of the common-base amplifier circuit to the input terminal of the common-emitter amplifier circuit, and performs negative feedback. , The gain of the pass band can be made flat. Ma
Also, connect a resistor in series to the emitter of the base grounded amplifier circuit
By doing so, it is possible to change the load line of the preamplifier circuit.
Thus, distortion can be reduced even at a low current. According to the active low-pass filter described in claim 2, a plurality of base grounded amplifier circuits are cascaded after the common emitter amplifier circuit, thereby increasing the number of filter stages and grounding the base. As a result, the gain obtains a steep attenuation characteristic. According to the active low-pass filter of the third aspect, since the input impedance of the base-grounded amplifier circuit is as low as several tens of ohms, the current waveform of the front-stage amplifier circuit is easily distorted, and it is necessary to increase the current. Was. Vertical multi-stage grounded amplifier circuit
Even in the case where the connection is made in series, by connecting a resistor in series to the emitter of the base-grounded amplifier circuit, the load line of the preceding-stage amplifier circuit can be changed, and the distortion can be reduced even with a low current.
【０００６】[0006]
【実施例】図１はこの発明の一実施例である能動低域フ
イルタを示す回路図である。端子１より入力した高周波
信号は、結合容量Ｃ１を経て、トランジスタＱ１で増幅
され、容量Ｃ３で高域カットされ、抵抗Ｒ２を経て、ト
ランジスタＱ２で増幅され容量Ｃ６で高域カットされ、
抵抗Ｒ３を経て、トランジスタＱ３で増幅され、結合容
量Ｃ５を経て端子２より出力される。Ｃ３及びＣ４の容
量値を選ぶ事によって、カットオフ周波数を設定するこ
とができる。図６に、Ｃ３，Ｃ４の容量値と特性の変化
を示す。トランジスタＱ１のベース端子とグランド間、
トランジスタＱ３のコレクタ端子とグランド間に接続さ
れる容量Ｃ２、Ｃ５は、入出力インピーダンス整合用容
量である。抵抗Ｒ４は、出力負荷抵抗である。容量Ｃ
８，Ｃ９は、トランジスタＱ２，Ｑ３のベース接地容量
である。抵抗Ｒ１，Ｒ７，Ｒ８，Ｒ９はトランジスタの
ベースバイアス用抵抗である。抵抗Ｒ５は、信号通過帯
域の利得を平坦化ならしめる為の負帰還用抵抗である。
図４に負帰還用抵抗Ｒ５の抵抗値と通過域の得性の変化
を示す。初段増幅回路に、エミッタ接地を用いるのは、
高周波入力信号を位相反転して出力し、負帰還動作を可
能ならしめる為である。エミッタ接地増幅回路の後段に
ベース接地増幅回路を用いるのは、入力位相を同相で出
力する為と、ベース接地増幅回路の高周波特性が良好な
為である。またベース接地増幅回路は出力インピーダン
スが高く、入出力逆方向アイソレーション特性が良好な
為、負荷インピーダンスの値に影響されずにエミッタ接
地増幅回路とベース接地増幅回路の接続点とグランド間
に接続する容量の値を決定することが出来るので、カッ
トオフ点の設定が容易となる。ベ−ス接地増幅回路の入
力に接続される抵抗Ｒ２，Ｒ３は、ベ−ス接地増幅回路
の入力インピ−ダンスは、数１０Ωと低い為、前段に接
続される増幅回路の電流波形が歪易く、前段に接続され
る増幅回路の負荷線を変更して、歪を低下する為の抵抗
である。FIG. 1 is a circuit diagram showing an active low-pass filter according to an embodiment of the present invention. The high-frequency signal input from the terminal 1 is amplified by the transistor Q1 via the coupling capacitor C1, cut by the capacitor C3, cut through the resistor R2, amplified by the transistor Q2 and cut by the capacitor C6,
The signal is amplified by the transistor Q3 via the resistor R3, and output from the terminal 2 via the coupling capacitor C5. The cutoff frequency can be set by selecting the capacitance values of C3 and C4. FIG. 6 shows the change in the capacitance values and characteristics of C3 and C4. Between the base terminal of transistor Q1 and ground,
Capacitors C2 and C5 connected between the collector terminal of the transistor Q3 and the ground are input / output impedance matching capacitors. The resistance R4 is an output load resistance. Capacity C
8, C9 are grounded base capacitances of the transistors Q2, Q3. The resistors R1, R7, R8, R9 are base bias resistors of the transistor. The resistor R5 is a negative feedback resistor for flattening the gain of the signal pass band.
FIG. 4 shows the change in the resistance value of the negative feedback resistor R5 and the passband gain. The reason why the grounded emitter is used for the first-stage amplifier circuit is that
This is because the phase of the high frequency input signal is inverted and output to enable a negative feedback operation. The reason why the common-base amplifier circuit is used after the common-emitter amplifier circuit is that the input phase is output in the same phase and that the high-frequency characteristics of the common-base amplifier circuit are good. The grounded base amplifier circuit has a high output impedance and good input / output reverse isolation characteristics, so it is connected between the ground point of the grounded emitter amplifier circuit and the grounded base amplifier circuit and the ground without being affected by the value of the load impedance. Since the value of the capacitance can be determined, it is easy to set the cutoff point. Since the input impedance of the resistors R2 and R3 connected to the input of the base grounded amplifier circuit is as low as several tens of ohms, the current waveform of the amplifier circuit connected to the preceding stage is easily distorted. Are resistors for changing the load line of the amplifier circuit connected to the preceding stage to reduce distortion.
【０００７】図２は、図１に示す能動低域通過フィルタ
を平衡回路化したものであり、動作は単に図１に示す不
平衡回路の能動低域通過フィルタが、平衡回路の低域通
過フィルタとなったものであり、図１と対応する部分に
は同一の番号を附し、図２の説明を省略する。尚、前記
本発明の一実施例に示す能動低域通過フィルタは、バイ
ポーラトランジスタを使用して構成しているが、ＦＥＴ
に置き換えても使用出来ることはいうまでもない。FIG. 2 shows a circuit in which the active low-pass filter shown in FIG. 1 is formed into a balanced circuit. The operation is simply that the active low-pass filter of the unbalanced circuit shown in FIG. The parts corresponding to those in FIG. 1 are denoted by the same reference numerals, and the description of FIG. 2 is omitted. The active low-pass filter according to the embodiment of the present invention is configured using a bipolar transistor.
It goes without saying that it can be used even if it is replaced with.
【０００８】[0008]
【発明の効果】請求項１に記載の発明によれば、エミッ
タ接地増幅回路とベ−ス接地増幅回路の２段で構成して
いる事により、演算増幅器と異なり利得が低く、高域周
波数まで増幅させても発振しない、また、群遅延は、ト
ランジスタの内部容量のみに依存し、その群遅延特性
は、高域まで線形性を保っているので、容易にカットオ
フ周波数が高くできる。またベース接地増幅回路は出力
インピーダンスが高く、入出力逆方向アイソレーション
特性が良好な為、負荷インピーダンスの値に影響されず
にエミッタ接地増幅回路とベース接地増幅回路の接続点
とグランド間に接続する容量の値を決定することが出来
るので、カットオフ点の設定が容易となり、通過帯域の
遅延特性の直線性が良好な能動低域通過フィルタを実現
出来る。また、ベ−ス接地増幅回路のエミッタに直列に
抵抗を接続する事により、前段増幅回路の負荷線を変更
する事ができ、歪を少なくできる。また請求項２に記載
の発明によれば、複数段のベース接地増幅回路を縦続接
続する事によって、フィルタの段数を増やし、急峻な減
衰特性を得る。また請求項３に記載の発明によれば、ベ
−ス接地増幅回路の入力インピ−ダンスは、数１０Ωと
低い為、前段増幅回路の電流波形が歪易く、ベ−ス接地
増幅回路のエミッタに直列に抵抗を接続する事により、
前段増幅回路の負荷線を変更する事ができ、歪を少なく
できる。更に、同じ減衰量でもベ−ス接地増幅回路の入
力に接続されたコンデンサの容量値を小さくでき、より
ＩＣチップ上に形成しやすくなる。According to the first aspect of the present invention, unlike the operational amplifier, the gain is low and the high frequency range is different from that of the operational amplifier because the amplifier is constituted by two stages of the common emitter amplifier circuit and the common base amplifier circuit. Even if it is amplified, it does not oscillate, and the group delay depends only on the internal capacitance of the transistor, and its group delay characteristics maintain linearity up to a high frequency range, so that the cutoff frequency can be easily increased. The grounded base amplifier circuit has a high output impedance and good input / output reverse isolation characteristics, so it is connected between the ground point of the grounded emitter amplifier circuit and the grounded base amplifier circuit and the ground without being affected by the value of the load impedance. Since the value of the capacitance can be determined, the cut-off point can be easily set, and an active low-pass filter having good linearity of the pass band delay characteristic can be realized. Also, it is connected in series with the emitter of the base grounded amplifier circuit.
Change the load line of the preamplifier circuit by connecting a resistor
And distortion can be reduced. According to the second aspect of the present invention, a cascade connection of a plurality of stages of grounded base amplification circuits increases the number of filter stages and obtains a steep attenuation characteristic. According to the third aspect of the present invention, since the input impedance of the grounded-base amplifier circuit is as low as several tens of ohms, the current waveform of the preceding-stage amplifier circuit is easily distorted, and the input impedance of the base-grounded amplifier circuit is reduced. By connecting a resistor in series,
The load line of the preamplifier circuit can be changed, and distortion can be reduced. Further, even with the same amount of attenuation, the capacitance value of the capacitor connected to the input of the base grounding amplifier circuit can be reduced, so that the capacitor can be easily formed on an IC chip.
【０００９】[0009]
【図１】この発明による能動低域通過フイルタの１実施
例である。FIG. 1 is an embodiment of an active low-pass filter according to the present invention.
【図２】この発明による能動低域通過フイルタの他の実
施例である。FIG. 2 is another embodiment of the active low-pass filter according to the present invention.
【図３】従来の能動低域通過フィルタである。FIG. 3 is a conventional active low-pass filter.
【図４】この発明による能動低域通過フイルタの特性で
ある。FIG. 4 shows the characteristics of an active low-pass filter according to the present invention.
【図５】この発明による能動低域通過フイルタのベース
接地増幅回路の段数を変化した時の特性FIG. 5 shows characteristics of the active low-pass filter according to the present invention when the number of stages of the grounded base amplifier circuit is changed.
【図６】この発明による能動低域通過フイルタのＣ３，
Ｃ４を変化した時の特性である。FIG. 6 shows C3 of the active low-pass filter according to the present invention.
This is a characteristic when C4 is changed.
１ 入力端子 ２ 出力端子 Ｑ１〜Ｑ３ トランジスタ Ｃ１〜Ｃ１０容量 Ｒ１，Ｒ６〜Ｒ９ バイアス給電用抵抗 Ｒ２，Ｒ３ ベ−ス接地入力インピ−ダンス設定抵抗 Ｒ４ 負荷抵抗 Ｒ５ 負帰還抵抗 Ｖｃｃ 電源 1 Input terminal 2 Output terminal Q1 to Q3 Transistor C1 to C10 Capacitance R1, R6 to R9 Bias supply resistance R2, R3 Base ground input impedance setting resistance R4 Load resistance R5 Negative feedback resistance Vcc power supply
フロントページの続き (58)調査した分野(Int.Cl.7，ＤＢ名) H03H 11/12 H03F 1/34 H03H 11/04 Continuation of the front page (58) Field surveyed (Int.Cl. 7 , DB name) H03H 11/12 H03F 1/34 H03H 11/04
Claims (3)
接地増幅回路の後段に接続されるベ−ス接地増幅回路
と、前記エミッタ接地増幅回路と前記ベース接地増幅回
路の接続点とグランド間に接続される容量と、前記ベー
ス接地増幅回路の出力端より前記エミッタ接地増幅回路
の入力端に接続される帰還用抵抗と、前記ベ−ス接地増
幅回路の入力端に信号経路と直列に接続される抵抗とを
有する能動低域通過フィルタ。1. A the emitter grounded amplifier circuit, base is connected downstream of the emitter grounded amplifier circuit - a scan grounded amplifier circuit is connected between the connection point and the ground of the said emitter amplifier circuit based amplifier circuit that capacitance and a feedback resistor connected to the input terminal of the emitter grounded amplifier circuit from the output terminal of the base-grounded amplifier circuit, wherein the base - scan the ground up
An active low-pass filter having a resistor connected in series with the signal path at an input of the width circuit .
地増幅回路の後段に、複数段にわたって、縦続接続され
るベ−ス接地増幅回路と前記エミッタ接地増幅回路及び
前記複数段のベ−ス接地増幅回路の複数の接続点とグラ
ンド間に接続される容量と、前記複数段のベ−ス接地増
幅回路のうち、最後段のベ−ス接地増幅回路の出力端よ
り、前記エミッタ接地増幅回路の入力端に接続される帰
還用抵抗とを有する能動低域通過フィルタ。2. A grounded-amplifier circuit, a grounded-amplifier circuit cascaded over a plurality of stages subsequent to the grounded-amplifier circuit, a grounded-amplifier circuit, and the grounded-amplifier circuit of the plurality of stages. A capacitor connected between a plurality of connection points of the circuit and ground, and an input terminal of the grounded emitter amplifier circuit from an output terminal of the last grounded ground amplifier circuit of the plurality of stages of grounded ground amplifier circuits. An active low-pass filter having a feedback resistor connected to the end.
信号経路に直列に抵抗が備えられている請求項２に記載
の能動低域通過フィルタ。3. An input terminal of the grounded base amplifier circuit,
3. The active low-pass filter according to claim 2 , wherein a resistor is provided in series with the signal path.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP06333856A JP3122322B2 (en) | 1994-12-16 | 1994-12-16 | Active low-pass filter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP06333856A JP3122322B2 (en) | 1994-12-16 | 1994-12-16 | Active low-pass filter |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH08172340A JPH08172340A (en) | 1996-07-02 |
| JP3122322B2 true JP3122322B2 (en) | 2001-01-09 |
Family
ID=18270713
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP06333856A Expired - Fee Related JP3122322B2 (en) | 1994-12-16 | 1994-12-16 | Active low-pass filter |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3122322B2 (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3556469B2 (en) | 1998-05-27 | 2004-08-18 | アルプス電気株式会社 | Active low-pass filter |
| JP2007259409A (en) * | 2006-02-27 | 2007-10-04 | Mitsubishi Electric Corp | Variable gain amplifier |
| JP5512040B2 (en) * | 2011-04-04 | 2014-06-04 | 三菱電機株式会社 | Bandwidth variable amplifier |
| JP2016054452A (en) * | 2014-09-04 | 2016-04-14 | 住友電気工業株式会社 | Optical modulator driving circuit |
-
1994
- 1994-12-16 JP JP06333856A patent/JP3122322B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH08172340A (en) | 1996-07-02 |
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