JPS6028315A - Input filter - Google Patents
Input filterInfo
- Publication number
- JPS6028315A JPS6028315A JP13585783A JP13585783A JPS6028315A JP S6028315 A JPS6028315 A JP S6028315A JP 13585783 A JP13585783 A JP 13585783A JP 13585783 A JP13585783 A JP 13585783A JP S6028315 A JPS6028315 A JP S6028315A
- Authority
- JP
- Japan
- Prior art keywords
- circuit
- trap
- filter
- input
- input 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.)
- Pending
Links
Classifications
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H7/00—Multiple-port networks comprising only passive electrical elements as network components
- H03H7/01—Frequency selective two-port networks
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H7/00—Multiple-port networks comprising only passive electrical elements as network components
- H03H7/01—Frequency selective two-port networks
- H03H7/17—Structural details of sub-circuits of frequency selective networks
- H03H7/1741—Comprising typical LC combinations, irrespective of presence and location of additional resistors
- H03H7/1758—Series LC in shunt or branch path
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H7/00—Multiple-port networks comprising only passive electrical elements as network components
- H03H7/01—Frequency selective two-port networks
- H03H7/17—Structural details of sub-circuits of frequency selective networks
- H03H7/1741—Comprising typical LC combinations, irrespective of presence and location of additional resistors
- H03H7/1791—Combined LC in shunt or branch path
Abstract
Description
【発明の詳細な説明】
〔発明の利用分野〕
本発明は、ケーブルテレビ用コンバータｆ−−すの入力
回路に設けた入力フィルタに関するものである。DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to an input filter provided in an input circuit of a cable television converter f--.
かかる入力フィルタとしての従来の広帯域入力バンドバ
スフィルタは、ｆユーナ入力端子に到達した信号（ｆヤ
ンネル）全数を、減衰させることなく、該フィルタに接
続されたＲＦ増幅器、或すは、周波数変換器に供給する
ため、前記ＲＦ増幅器、或いは周波数変換器において、
多波人力による相互変調歪と混変調妨害特性の劣化を生
ずるという欠点があった。A conventional wide-band input bandpass filter as such an input filter is capable of transmitting the entire signal (f channel) that reaches the f yun input terminal without attenuating the RF amplifier or frequency converter connected to the filter. In the RF amplifier or frequency converter to supply
This method has the disadvantage of causing intermodulation distortion and deterioration of intermodulation interference characteristics due to multiwave manual input.
本発明の目的は、前記した従来技術の欠点をなくシ、相
互変調歪と混変調妨害の改善を可能にした入力フィルタ
を提供することにある。SUMMARY OF THE INVENTION It is an object of the present invention to provide an input filter that eliminates the drawbacks of the prior art described above and makes it possible to improve intermodulation distortion and intermodulation interference.
チューナの入力端に到達した信号は、入力フィルタを通
過し、非直線要素の高い周波数変換器、或いはＲＦ増幅
器に入力される。一般に、前記非直線回路は、種々の歪
を包含しておシ、入力信号数が、ｎ波の時には、２波入
力されたときに比して相互変調歪で１０Ａｏ１ｇ（ｎ−
１）ｄＢ 、混変調妨害で２０Ｌｏｇ（ｎ−１） ｄＢ
、歪成分が劣化する。従って、非直線回路へ入力され
る信号数を減少せしめれば。The signal reaching the input end of the tuner passes through an input filter and is input to a high frequency converter with a non-linear element or an RF amplifier. In general, the nonlinear circuit includes various types of distortion, and when the number of input signals is n waves, the intermodulation distortion is 10Ao1g (n-
1) dB, 20Log(n-1) dB with cross-modulation interference
, the distortion component deteriorates. Therefore, the number of signals input to the nonlinear circuit can be reduced.
相互変調歪、混変調妨害等の各種歪の改善が得られる。Various distortions such as intermodulation distortion and cross-modulation interference can be improved.
そこで、本発明によるフィルタは、広帯域バンドパスフ
ィルタ内の信号系路と接地端子間に、インダクタ４スと
容量とスイッチングダイオードの直列接続よシなる直列
共振回路を少くとも１個以上付加接続し、前記スイッチ
ングダイオードに電圧を印加してオン・オフ制御するこ
とによが、前記直列共振回路をトラップ回路として動作
可能にしたものである。Therefore, the filter according to the present invention additionally connects at least one series resonant circuit, such as a series connection of an inductor, a capacitor, and a switching diode, between the signal path and the ground terminal in the broadband bandpass filter, By applying a voltage to the switching diode and controlling it on and off, the series resonant circuit can be operated as a trap circuit.
以下、本発明の一実施例を第１図及び第２図によシ説明
する。An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.
第１図は本発明の一実施例を示す回路構成図である。同
図において１は本発明による入力フィルタを示し、２は
従来より用いられている広帯域バンドパスフィルタ、３
は周波数変換器等の非直線回路を示し、４は本発明の特
徴とするトラップ回路を示す。バンドパスフィルタ２に
、インダクタンスＬ＋ 、 Ｌ２ 、容量ｃ、 、 ｃ
２ 、スイッチングダイオードＤ、、Ｄ２がそれぞれ図
示の如く直列接続されたトラップ回路４を付加するもの
である。Ｒ１−Ｒ５はバイアス用抵抗、Ｃ３はバイパス
コンデンサを示す。FIG. 1 is a circuit configuration diagram showing an embodiment of the present invention. In the figure, 1 indicates an input filter according to the present invention, 2 indicates a conventional wideband bandpass filter, and 3 indicates an input filter according to the present invention.
4 shows a non-linear circuit such as a frequency converter, and 4 shows a trap circuit which is a feature of the present invention. In the band pass filter 2, inductance L+, L2, capacitance c, , c
2, a trap circuit 4 is added in which switching diodes D, , D2 are connected in series as shown in the figure. R1-R5 are bias resistors, and C3 is a bypass capacitor.
低域チャンネル受信時には、該トラップ回路４の端子ｖ
２に電圧を印加し、端子Ｖ１を開放或いは０ボルトとす
ると、ダイオードＤ２は導通、ダイオードＤ１は非導通
となシ、該トラップ回路の等価回路は第２図（ａ）に示
した回路となる。このときアドミッタンスｔ２は
（但し ω＝２πｆ）
で表わされ、広帯域フィルタ２とトラップ回路４を接続
したフィルタ１の伝送特性は、
ｆ’ｏ２＝ １／２π舊■−−−−（２）にトンラグ特
性を有する第３図（ａ）となる。When receiving a low frequency channel, the terminal v of the trap circuit 4
When a voltage is applied to the trap circuit 2 and the terminal V1 is opened or set to 0 volts, the diode D2 becomes conductive and the diode D1 becomes non-conductive, and the equivalent circuit of the trap circuit becomes the circuit shown in Fig. 2 (a). . At this time, the admittance t2 is expressed as (where ω=2πf), and the transmission characteristic of the filter 1, which connects the broadband filter 2 and the trap circuit 4, is f'o2= 1/2π舊■---(2) The result is shown in FIG. 3(a), which has a lag characteristic.
中域チャンネル受信時には、該トラップ回路の端子ｖＩ
＃ ｖ２に電圧を印加すると、ダイオードＤ、、Ｄ。When receiving a mid-range channel, the terminal vI of the trap circuit
# When voltage is applied to v2, diodes D,,D.
が導通状態となシ、等価回路は第２図（ｂ）と表わされ
、アドミッタンス：ｆｏは
となる。このときのフィルタ１の伝送特性は、ｆ ａ
＋ ＝＝ １ ／２ｙｒ ５可’ −−−−（４）ｆｏ
２： １／２πｄ７７ −＝−（５）（但し、ｆｇ １
＜ ｆ６２． ）
Ｋトンラグ特性を有する第３図（ｂ）となる。When is in a conductive state, the equivalent circuit is shown in FIG. 2(b), and the admittance fo becomes. The transmission characteristic of filter 1 at this time is f a
+ == 1 /2yr 5 possible' -----(4) fo
2: 1/2πd77 -=-(5) (However, fg 1
<f62. ) Figure 3(b) shows Kton lag characteristics.
高域チャンネル受信時には、端子Ｖ、に電圧を印加し、
端子ｖ２を開放或ｈ／／′ｉｏボルトとすると、等価回
路は第２図（Ｃ）、アドミッタンスｔ１はとな少、フィ
ルタ１）；ｊ
ｆ’ｏ、 ＝ １／２πＩＴ；回−−−−（７）如トラ
ップ特性を有する第３図（ｃ）となる。When receiving a high frequency channel, apply voltage to terminal V,
If terminal v2 is open or set to h//'io volts, the equivalent circuit is shown in Fig. 2 (C), the admittance t1 is very small, filter 1);j f'o, = 1/2πIT; times---- (7) As shown in FIG. 3(c), the trap characteristic is as shown in FIG.
このようにトラップ回路４を付加することによって、フ
ィルタ１の通過帯域幅を狭くすることが可能とな少、非
直１回路３への入力信号数を、受信信号に影響を与える
ことなく、少くでき、それに伴な−、多信号入力による
相互変調歪、混変調妨害等の妨害特性の改善が可能とな
る。By adding the trap circuit 4 in this way, it is possible to narrow the passband width of the filter 1 and reduce the number of input signals to the non-direct 1 circuit 3 without affecting the received signal. Accordingly, it becomes possible to improve interference characteristics such as intermodulation distortion and cross-modulation interference due to multi-signal input.
次釦本発明の他の実施例を第４図、第５図および第６図
によシ説明する。Next button Another embodiment of the present invention will be explained with reference to FIGS. 4, 5, and 6.
第４図は１本発明の他の実施例を示す回路構成図である
。同図において１は本発明によるフィルタを示し、２は
広帯域バンドパスフィルタ、３は周波数変換器等の非直
線回路、４はトラップ回路を示す。FIG. 4 is a circuit diagram showing another embodiment of the present invention. In the figure, 1 represents a filter according to the present invention, 2 represents a broadband bandpass filter, 3 represents a non-linear circuit such as a frequency converter, and 4 represents a trap circuit.
第５図は、該トラップ回路４のＢ、端子にバンド切換え
用電圧を印加しＢＨ端子を開放とした時のトラップ回路
部４の高周波等価回路を示す。ここでＣｄ２はダイオー
ドＤ２の逆バイアスによる等価容量である、ここで
によ）Ｃ１〜Ｃ２，Ｌ、〜Ｌ２の定数を選ぶことにょル
、第６図（ｂ）の実ａ８で示す特性となる。ここで。FIG. 5 shows a high frequency equivalent circuit of the trap circuit section 4 when a band switching voltage is applied to the B terminal of the trap circuit 4 and the BH terminal is left open. Here, Cd2 is the equivalent capacitance due to the reverse bias of the diode D2. By selecting the constants of C1 to C2, L, and ~L2, the characteristic is shown by a8 in Figure 6(b). . here.
（ＥＬ）は高域チャンネル受信時のフィルタ波坦で５は
、Ｌ２．Ｃ２の直列共振によるドラッグである。同様に
（ｂ）は低域チャンネル受信時のフィルタ波形で６はＬ
２．Ｃ２，Ｃｄ２によるトラップ、７はＬｌ、Ｃ，によ
るトラップである。(EL) is the filter waveform when receiving a high frequency channel, and 5 is the L2. This is the drag due to series resonance of C2. Similarly, (b) is the filter waveform when receiving the low frequency channel, and 6 is the L
2. A trap is caused by C2, Cd2, and 7 is a trap caused by Ll, C.
このようにトラップ回路４の定数を（６）式に設定する
ことによ多低域チャンネル受信時のトラップ減衰量を増
大させることができ、非直線回路３への入力信号レベル
を、受信信号に影響を与えることなく、小さくすること
ができた。By setting the constant of the trap circuit 4 according to equation (6) in this way, it is possible to increase the amount of trap attenuation when receiving multiple low-frequency channels, and the level of the input signal to the nonlinear circuit 3 can be changed to the received signal. I was able to make it smaller without any impact.
本発明によれば、非直線回路に入力される信号数を減ら
すことが可能となるので、多信号入力による相互変調歪
、混変調妨害等の妨害特性の改善の効果がある。According to the present invention, it is possible to reduce the number of signals input to a non-linear circuit, thereby improving interference characteristics such as intermodulation distortion and cross-modulation interference due to multi-signal input.
第１図は本発明の一実施例を示す回路図、第２図（ａ）
、（ｂ） ＋ （ｃ）は第１図の回路におけるトラッ
プ回路部の等価回路を示す回路図、第３図（ａ） 、
（ｂ） 。
（Ｑ）は第２図（ａ） 、 （ｂ） 、 （Ｑ）に対応
した本発明の一実施例の総合伝送特性を示す特性図、第
４図は本発明の他の実施例を示す回路図、第５図は第４
図の回路におけるトラップ回路部の等価回路を示す回路
図、−第６図（ａ）は第４図の回路において高域チャン
ネル受信時のフィルタ特性図、第６図（ｂ）は同じく低
域チャンネル受信時のフィルタ特性を示す特性図、であ
る。
符号説明
１・・・入力フィルタ、２・・・広帯域バンドパスフィ
ルタ、３・・・非直線回路、４・・・トラップ回路、５
〜８・・・トラップ波形
０１〜Ｃ２・・・低誘電率容量、Ｃ３・・・高誘電率容
量り、〜Ｌ、・・・インダクタンス％ ＤＩ〜Ｄ２・・
・スイッチングダイオード、Ｒ１〜Ｒｇ・・・抵抗ｓ
ＢＬｓＢＨ・・・バンド切換え用電圧端子
才１図
一才Ｚ図
（α） （ｂ） （す
’ｆ’３１７
第５圀Fig. 1 is a circuit diagram showing an embodiment of the present invention, Fig. 2(a)
, (b) + (c) is a circuit diagram showing an equivalent circuit of the trap circuit section in the circuit of Fig. 1, Fig. 3 (a),
(b). (Q) is a characteristic diagram showing the overall transmission characteristics of one embodiment of the present invention corresponding to FIGS. 2(a), (b), and (Q), and FIG. 4 is a circuit showing another embodiment of the present invention. Figure 5 is the 4th
A circuit diagram showing an equivalent circuit of the trap circuit section in the circuit shown in the figure. - Figure 6 (a) is a filter characteristic diagram when receiving a high frequency channel in the circuit of Figure 4, and Figure 6 (b) is a diagram showing the filter characteristics for the low frequency channel in the circuit shown in Figure 4. FIG. 3 is a characteristic diagram showing filter characteristics at the time of reception. Description of symbols 1...Input filter, 2...Broad band pass filter, 3...Non-linear circuit, 4...Trap circuit, 5
~8...Trap waveform 01~C2...Low dielectric constant capacitance, C3...High dielectric constant capacitance, ~L,...Inductance% DI~D2...
・Switching diode, R1 to Rg...resistance s
BLsBH・・・Voltage terminal for band switching
Claims (1)
設けた入力フィルタにおいて、入力信号の経路と接地端
子の間に、インダクタンスと容量とスイッチングダイオ
ードの直列接続よシなる直列共振回路を少なくも１組接
続し、前記ダイオードをオン・オフ制御することによル
前記直列共振回路をトラップ回路として動作可能にした
ことを特徴とする入力フィルタ。 ２、特許請求の範囲第１項に記載の入力フィルタにおい
て、前記直列共振回路を少くとも２組もち、かつ前記ス
イッチングダイオードにバンド切換え用電圧を印加した
ことによシ前記直列共振回路の一方を動作させトラップ
を形成させるととも釦、同時に他方のスイッチングダイ
オードに印加される逆方向電圧によ多生じた接合容量と
残シの直列共振回路とによシ前記トラップ周波数の近傍
に別のトラップを形成せしめ信号減衰量を増大させたこ
とを特徴とする入力フィルタ。[Claims] 1) In the input filter provided in the input circuit of the cable TV converter tuner, a series resonant circuit consisting of a series connection of an inductance, a capacitance, and a switching diode is provided between the input signal path and the ground terminal. An input filter characterized in that the series resonant circuit can operate as a trap circuit by connecting at least one set of diodes and controlling the on/off of the diodes. 2. In the input filter according to claim 1, the input filter has at least two sets of the series resonant circuits, and one of the series resonant circuits is switched by applying a band switching voltage to the switching diode. When the button is activated to form a trap, another trap is created in the vicinity of the trap frequency due to the junction capacitance generated by the reverse voltage applied to the other switching diode and the remaining series resonant circuit. An input filter characterized in that the amount of signal attenuation that is formed is increased.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP13585783A JPS6028315A (en) | 1983-07-27 | 1983-07-27 | Input filter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP13585783A JPS6028315A (en) | 1983-07-27 | 1983-07-27 | Input filter |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS6028315A true JPS6028315A (en) | 1985-02-13 |
Family
ID=15161392
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP13585783A Pending JPS6028315A (en) | 1983-07-27 | 1983-07-27 | Input filter |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6028315A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS63244913A (en) * | 1987-03-30 | 1988-10-12 | Sony Corp | Inductor switching circuit |
| JPH0565116U (en) * | 1992-02-05 | 1993-08-27 | デイエツクスアンテナ株式会社 | Amplifier for joint hearing facility with frequency characteristic correction circuit |
| JPH07321586A (en) * | 1994-05-20 | 1995-12-08 | Kokusai Electric Co Ltd | Variable frequency band filter |
| JP2009545240A (en) * | 2006-07-28 | 2009-12-17 | フリースケール セミコンダクター インコーポレイテッド | Reconfigurable impedance matching and harmonic filter system |
-
1983
- 1983-07-27 JP JP13585783A patent/JPS6028315A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS63244913A (en) * | 1987-03-30 | 1988-10-12 | Sony Corp | Inductor switching circuit |
| JPH0565116U (en) * | 1992-02-05 | 1993-08-27 | デイエツクスアンテナ株式会社 | Amplifier for joint hearing facility with frequency characteristic correction circuit |
| JPH07321586A (en) * | 1994-05-20 | 1995-12-08 | Kokusai Electric Co Ltd | Variable frequency band filter |
| JP2009545240A (en) * | 2006-07-28 | 2009-12-17 | フリースケール セミコンダクター インコーポレイテッド | Reconfigurable impedance matching and harmonic filter system |
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