JPS6326568B2 - - Google Patents
Info
- Publication number
- JPS6326568B2 JPS6326568B2 JP15659383A JP15659383A JPS6326568B2 JP S6326568 B2 JPS6326568 B2 JP S6326568B2 JP 15659383 A JP15659383 A JP 15659383A JP 15659383 A JP15659383 A JP 15659383A JP S6326568 B2 JPS6326568 B2 JP S6326568B2
- Authority
- JP
- Japan
- Prior art keywords
- reactance element
- diode
- circuit
- frequency
- input
- 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
Links
- 230000001939 inductive effect Effects 0.000 claims description 5
- 239000003990 capacitor Substances 0.000 description 9
- 230000003321 amplification Effects 0.000 description 6
- 238000003199 nucleic acid amplification method Methods 0.000 description 6
- 238000010586 diagram Methods 0.000 description 4
- 230000006866 deterioration Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 230000000903 blocking effect Effects 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03J—TUNING RESONANT CIRCUITS; SELECTING RESONANT CIRCUITS
- H03J5/00—Discontinuous tuning; Selecting predetermined frequencies; Selecting frequency bands with or without continuous tuning in one or more of the bands, e.g. push-button tuning, turret tuner
- H03J5/24—Discontinuous tuning; Selecting predetermined frequencies; Selecting frequency bands with or without continuous tuning in one or more of the bands, e.g. push-button tuning, turret tuner with a number of separate pretuned tuning circuits or separate tuning elements selectively brought into circuit, e.g. for waveband selection or for television channel selection
- H03J5/242—Discontinuous tuning; Selecting predetermined frequencies; Selecting frequency bands with or without continuous tuning in one or more of the bands, e.g. push-button tuning, turret tuner with a number of separate pretuned tuning circuits or separate tuning elements selectively brought into circuit, e.g. for waveband selection or for television channel selection used exclusively for band selection
- H03J5/244—Discontinuous tuning; Selecting predetermined frequencies; Selecting frequency bands with or without continuous tuning in one or more of the bands, e.g. push-button tuning, turret tuner with a number of separate pretuned tuning circuits or separate tuning elements selectively brought into circuit, e.g. for waveband selection or for television channel selection used exclusively for band selection using electronic means
Landscapes
- Channel Selection Circuits, Automatic Tuning Circuits (AREA)
- Noise Elimination (AREA)
Description
【発明の詳細な説明】
産業上の利用分野
本発明は不要信号による妨害排除能力を向上さ
せた電子同調チユーナに関するものである。DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an electronically tuned tuner with improved ability to eliminate interference caused by unnecessary signals.
従来例の構成とその問題点
アメリカを中心とするケーブルテレビの普及増
に伴ない、テレビジヨン受像機またはビデオテー
プレコーダ用電子同調チユーナにおいても、ケー
ブルテレビ受信可能な電子同調チユーナが増加し
てきている。Conventional configurations and their problems With the increasing popularity of cable television, especially in the United States, the number of electronic tuning tuners that can receive cable television is increasing, even in electronic tuning tuners for television receivers or video tape recorders. .
しかしながら、ケーブルテレビ受信チヤンネル
数の増加に伴ない、テレビチユーナで発生する非
直線歪みによる混変調、ビート防害が従来以上に
増加することになる。 However, as the number of cable television reception channels increases, cross-modulation and beat prevention due to non-linear distortion generated in television tuners will increase more than ever.
第１図は、従来からの電子同調チユーナの入力
回路構成を示すものである。第１図において
HPFは電子同調チユーナの中間周波数減衰用の
低域遮断フイルタであり、IF妨害対策用フイル
タである。L1，L2は同調用インダクタンス、L3，
L4は入力整合用インダクタンス、C3，C5，C7，
C8，C9，C10は高周波接地用コンデンサ、C1，
C2，C4，C6は直流阻止用コンデンサ、Q1は高周
波増幅用素子、DTは同調用可変容量ダイオード、
DS1は高バンド及び低バンド切換用スイツチング
ダイオードである。R1，R2，R3，R4，R5，R6は
ダイオード及び高周波増幅素子への直流バイアス
用抵抗、AGCは高周波増幅用素子Q1への利得制
御電圧供給端子、BSは低バンド、高バンド切換
用のバンドスイツチ端子、BTは同調用可変容量
ダイオードへの電圧供給端子、B+は高周波増幅
用素子Q1の駆動用電源端子である。 FIG. 1 shows the input circuit configuration of a conventional electronically tuned tuner. In Figure 1
The HPF is a low-frequency cutoff filter for attenuating the intermediate frequency of an electronically tuned tuner, and is a filter for preventing IF interference. L 1 , L 2 are tuning inductances, L 3 ,
L 4 is the input matching inductance, C 3 , C 5 , C 7 ,
C 8 , C 9 , C 10 are high frequency grounding capacitors, C 1 ,
C 2 , C 4 , C 6 are DC blocking capacitors, Q 1 is a high frequency amplification element, D T is a tuning variable capacitance diode,
D S1 is a switching diode for high band and low band switching. R 1 , R 2 , R 3 , R 4 , R 5 , R 6 are DC bias resistors for the diode and high frequency amplification element, AGC is a gain control voltage supply terminal for high frequency amplification element Q 1 , and B S is a low B T is a voltage supply terminal for the tuning variable capacitance diode, and B + is a power supply terminal for driving the high frequency amplification element Q 1 .
以上のような回路構成においては、例えば
CATVのような受信チヤンネルの多いチヤンネ
ルかつ受信周波数レンジの広いチヤンネルを同調
しようとすると、同調回路の負荷Ｑは従来のチユ
ーナより更に低くおさえられる。この場合、同調
回路のＱが低くなるため、帯域外選択度特性の悪
化をまねく。これは、入力同調回路のみならず、
高周波増幅用素子Q1の出力側に接続される同調
回路についても同様であり、チユーナ総合での帯
域外選択度特性としても充分とはいえない。
CATV受信の場合、受信チヤンネルの増加に伴
ない、増幅用素子及び混合用素子で発生する非直
線歪みによる混変調、ビート妨害が無視できな
く、帯域外選択度の悪化は、更にこの不要信号に
対する妨害を増加することになる。特にCATV
受信の場合は、低バンド受信の場合の受信チヤン
ネルより上の周波数による妨害を、特に考慮する
必要がある。 In the above circuit configuration, for example,
When attempting to tune a channel with many reception channels and a wide reception frequency range, such as CATV, the load Q of the tuning circuit can be kept lower than that of a conventional tuner. In this case, the Q of the tuning circuit becomes low, leading to deterioration of out-of-band selectivity characteristics. This applies not only to the input tuning circuit, but also to
The same applies to the tuning circuit connected to the output side of the high-frequency amplification element Q1 , and the out-of-band selectivity characteristics of the overall tuner cannot be said to be sufficient.
In the case of CATV reception, as the number of reception channels increases, cross-modulation and beat interference due to non-linear distortion generated in amplification elements and mixing elements cannot be ignored, and the deterioration of out-of-band selectivity further increases the This will increase interference. Especially CATV
In the case of reception, special consideration must be given to interference from frequencies above the reception channel in the case of low-band reception.
発明の目的
本発明はこのような従来の欠点を解決するもの
で、帯域外選択度特性を改善することにより、不
要信号に対する妨害を低減させることを目的とす
るものである。OBJECTS OF THE INVENTION The present invention solves these conventional drawbacks, and aims to reduce interference with unnecessary signals by improving out-of-band selectivity characteristics.
発明の構成
この目的を達成するために本発明は、入力端子
と入力同調回路の間に直列に誘導性リアクタンス
素子を挿入接続し、その誘導性リアクタンス素子
の一方または両方の端子に容量性リアクタンス素
子と高周波スイツチング用ダイオードの直列回路
の一端を接続するとともに、他端を接地し、かつ
容量性リアクタンス素子と高周波スイツチング用
ダイオードの中点を直流電圧駆動用バイアス抵抗
素子を介してバンドスイツチ端子に接続したもの
である。Structure of the Invention In order to achieve this object, the present invention connects an inductive reactance element in series between an input terminal and an input tuning circuit, and connects a capacitive reactance element to one or both terminals of the inductive reactance element. Connect one end of the series circuit of the high-frequency switching diode and the high-frequency switching diode, and ground the other end, and connect the midpoint of the capacitive reactance element and the high-frequency switching diode to the band switch terminal via the DC voltage drive bias resistance element. This is what I did.
実施例の説明
第２図に本発明の一実施例による電子同調チユ
ーナの回路構成を示す。アンテナ入力端子または
低域遮断フイルタHPFと入力同調回路の間に、
直列にインダクタンスL5を挿入接続し、入力同
調回路とインダクタンスL5の接続点からコンデ
ンサC11と高周波スイツチング用ダイオードDS2を
直列接続し、ダイオードDS2の他端を接地し、コ
ンデンサC11とダイオードDS2の中点より抵抗R7
を介して、バンドスイツチ端子BSに接続されて
いる。ダイオードDS2は、低バンド受信において、
バンドスイツチ端子BSからの直流電源によりオ
ン状態となり、高バンドにおいては、オフ状態に
なるようバンドスイツチ端子BCと常に連動され
るよう配慮されている。低バンド受信時は、ダイ
オードDS2はオンとなり、入力回路は、インダク
タンスL5とコンデンサC11よりなる低域波フイ
ルターを構成し、高域周波数領域の減衰特性を改
善することに寄与する。なお、この場合のインダ
クタンスL5とコンデンサC11の定数は、低バンド
受信チヤンネルより、やや高い周波数にカツトオ
フ周波数を決めるよう決定される。また、高バン
ド受信時は、ダイオードDS2はオフとなり、入力
同調回路は、インダクタンスL5のみが直列に入
り、インダクタンスL5は整合用コイルの一部と
して動作し、かつ誘導性リアクタンス素子の直列
接続により、受信周波数より高い周波数領域での
インピーダンス増加に伴ない、高域減衰特性を改
善することができる。DESCRIPTION OF EMBODIMENTS FIG. 2 shows a circuit configuration of an electronic tuning tuner according to an embodiment of the present invention. Between the antenna input terminal or low-frequency cutoff filter HPF and the input tuning circuit,
Insert and connect inductance L5 in series, connect capacitor C11 and high frequency switching diode D S2 in series from the connection point of input tuning circuit and inductance L5 , ground the other end of diode D S2 , and connect capacitor C11 and Resistor R 7 from the midpoint of diode D S2
is connected to the band switch terminal B S via. Diode D S2 is used for low band reception.
It is turned on by DC power from the band switch terminal B S , and is always linked to the band switch terminal B C so that it is turned off in high bands. During low band reception, diode D S2 is turned on, and the input circuit forms a low frequency filter consisting of inductance L 5 and capacitor C 11 , contributing to improving the attenuation characteristics in the high frequency region. Note that the constants of the inductance L 5 and the capacitor C 11 in this case are determined so as to set the cutoff frequency at a slightly higher frequency than the low band reception channel. Furthermore, during high band reception, the diode D S2 is turned off, and the input tuning circuit has only the inductance L5 connected in series.The inductance L5 operates as a part of the matching coil, and the inductive reactance element is connected in series. Through this connection, high-frequency attenuation characteristics can be improved as the impedance increases in a frequency region higher than the receiving frequency.
以上のように比較的簡単な回路構成により、高
域選択度特性を改善することができる。 As described above, the high frequency selectivity characteristics can be improved with a relatively simple circuit configuration.
また、第３図のようにインダクタンスL5の両
方の端子にコンデンサC11，C12の一端をそれぞれ
接続し、他端を共通接続してダイオードDS2のカ
ソードに接続することにより、更に高域選択度特
性を改善することができる。 In addition, as shown in Figure 3, by connecting one end of capacitors C 11 and C 12 to both terminals of inductance L 5 , and connecting the other ends in common to the cathode of diode D S2 , even higher frequencies can be achieved. Selectivity characteristics can be improved.
また、コンデンサC11，C12の代りに、可変容量
ダイオードを用いてもよい。 Furthermore, variable capacitance diodes may be used instead of the capacitors C 11 and C 12 .
発明の効果
以上のように本発明の電子同調チユーナによれ
ば、高域減衰特性を改善することができ、これに
より不要信号に対する妨害を低減させることがで
きるという効果が得られる。Effects of the Invention As described above, according to the electronically tuned tuner of the present invention, it is possible to improve the high-frequency attenuation characteristics, thereby achieving the effect that interference with unnecessary signals can be reduced.
第１図は従来の電子同調チユーナの入力回路を
示す回路図、第２図は本発明の一実施例による電
子同調チユーナの入力回路を示す回路図、第３図
は本発明の他の実施例による電子同調チユーナの
入力回路の要部の回路図である。
L5……インダクタンス、C11，C12……コンデン
サ、DS2……ダイオード、R7……抵抗、BS……バ
ンドスイツチ端子。
FIG. 1 is a circuit diagram showing an input circuit of a conventional electronically tuned tuner, FIG. 2 is a circuit diagram showing an input circuit of an electronically tuned tuner according to an embodiment of the present invention, and FIG. 3 is a circuit diagram showing an input circuit of an electronically tuned tuner according to an embodiment of the present invention. 1 is a circuit diagram of a main part of an input circuit of an electronically tuned tuner according to JP, Ltd.; FIG. L 5 ... Inductance, C 11 , C 12 ... Capacitor, D S2 ... Diode, R 7 ... Resistor, B S ... Band switch terminal.
Claims (1)
リアクタンス素子を挿入接続し、その誘導性リア
クタンス素子の一方または両方の端子に容量性リ
アクタンス素子と高周波スイツチング用ダイオー
ドの直列回路の一端を接続するとともに、他端を
接地し、かつ容量性リアクタンス素子と高周波ス
イツチング用ダイオードの中点を直流電圧駆動用
バイアス抵抗素子を介してバンドスイツチ端子に
接続したことを特徴とする電子同調チユーナ。 ２ 容量性リアクタンス素子として、可変容量ダ
イオードを使用したことを特徴とする特許請求の
範囲第１項に記載の電子同調チユーナ。[Claims] 1. An inductive reactance element is inserted and connected in series between an input terminal and an input tuning circuit, and a capacitive reactance element and a high frequency switching diode are connected in series to one or both terminals of the inductive reactance element. An electronic device characterized in that one end of the circuit is connected, the other end is grounded, and the midpoint between the capacitive reactance element and the high-frequency switching diode is connected to a band switch terminal via a DC voltage drive bias resistance element. I agree with you. 2. The electronic tuning tuner according to claim 1, wherein a variable capacitance diode is used as the capacitive reactance element.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP58156593A JPS6047520A (en) | 1983-08-26 | 1983-08-26 | Electronic tuner |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP58156593A JPS6047520A (en) | 1983-08-26 | 1983-08-26 | Electronic tuner |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6047520A JPS6047520A (en) | 1985-03-14 |
| JPS6326568B2 true JPS6326568B2 (en) | 1988-05-30 |
Family
ID=15631148
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP58156593A Granted JPS6047520A (en) | 1983-08-26 | 1983-08-26 | Electronic tuner |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6047520A (en) |
-
1983
- 1983-08-26 JP JP58156593A patent/JPS6047520A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6047520A (en) | 1985-03-14 |
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