JPS60136410A - U-v switching circuit of electronic tuner - Google Patents

U-v switching circuit of electronic tuner

Info

Publication number
JPS60136410A
JPS60136410A JP24309283A JP24309283A JPS60136410A JP S60136410 A JPS60136410 A JP S60136410A JP 24309283 A JP24309283 A JP 24309283A JP 24309283 A JP24309283 A JP 24309283A JP S60136410 A JPS60136410 A JP S60136410A
Authority
JP
Japan
Prior art keywords
vhf
uhf
reception
circuit
mixing stage
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
Application number
JP24309283A
Other languages
Japanese (ja)
Inventor
Akira Nakai
中井　晃
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Panasonic Holdings Corp
Original Assignee
Matsushita Electric Industrial Co Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Matsushita Electric Industrial Co Ltd filed Critical Matsushita Electric Industrial Co Ltd
Priority to JP24309283A priority Critical patent/JPS60136410A/en
Publication of JPS60136410A publication Critical patent/JPS60136410A/en
Pending legal-status Critical Current

Links

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

  • Superheterodyne Receivers (AREA)
  • Channel Selection Circuits, Automatic Tuning Circuits (AREA)

Abstract

PURPOSE:To set an optimum bias for UHF reception and that for VHF reception by inserting a resistance between the cathode of a switching diode for switching between UHF and VHF bands and the base of a transistor (TR) in a mixing stage. CONSTITUTION:The operating bias voltage of a TR10 in the mixing stage is so set that it is optimum at a VHF reception time. When the UHF band is received, a bus BU is turned on to give a prescribed voltage +B, and an IF signal obtained in a UHF circuit mixing stage 4 passes an IF tuning circuit 6, a resistance attenuator 21, and a switching diode 13, which is made conductive by the voltage of the bus BU, and is supplied to the TR10 of the VHF mixing stage. The base bias voltage of the TR10 is made higher than that for VHF reception by a resistance R simultaneously with conduction of the switching diode 13, and the TR10 is operated with an emitter current higher than that for VHF reception. The resistance value R is so set that this emitter current is an optimum value for VHF and UHF reception. Thus, optimum bias conditions are set easily.

Description

【発明の詳細な説明】 （産業上の利用分野） 本発明は、プリント基板上に所要電子部品を組込んだ形
式のチューナに関するもので、とくにそのＵ−Ｖ切換回
路に関するものである。DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a tuner in which necessary electronic components are incorporated on a printed circuit board, and particularly to its UV switching circuit.

（従来例の構成とその問題点） 第１図は、従来例としてのＵＨＦ−■Ｆコンビネーショ
ン型電子チューナの基本回路構成を示すものである。ま
た第２図は、そのＵＨＦ　−ＶＨＦ切換回路とその周辺
回路の詳細回路図である。(Constitution of Conventional Example and Its Problems) FIG. 1 shows the basic circuit configuration of a UHF-■F combination type electronic tuner as a conventional example. FIG. 2 is a detailed circuit diagram of the UHF-VHF switching circuit and its peripheral circuits.

従来例における欠点は、■Ｆバンド受信時とＵＩ（Ｆバ
ンド受信時の混合段トランジスタの最適動作条件が、一
致しないととにある。その具体例として、ＶＨＦバンド
とＵＨＦバンド各条件下における混合段トランジスタの
エミッタ電流をパラメータにしたときの利得、及び上側
隣接チャンネルによるビート妨害の特性を第３図および
第４図に示す。The drawback of the conventional example is that the optimal operating conditions of the mixing stage transistor during F-band reception and UI (F-band reception) do not match.As a specific example, the mixing stage transistor under each condition of VHF band and UHF band FIGS. 3 and 4 show the gain when the emitter current of the stage transistor is used as a parameter, and the characteristics of beat disturbance due to the upper adjacent channel.

第３図の実線に示した曲線はＶＨＦバンド受信時の、特
性であシこの場合、エミッタ電流は１．５〜２、０　ｍ
Ａで利得最大となシ、破線で示したＵＨＦバンドもほぼ
最大利得が得られ、この場合はＵＨＦ−ＶＩ（Ｆ両バン
ドに共通な動作電流がめられる。しかし第４図に示す上
側隣接チャンネルビート妨害特性においては実線で示し
たＶＨＦバンドと破線で示したＵＨＦバンドの特性が大
きく異なシ、両バンドに共通な混合段］・ランジスタバ
イアス電圧が得られない。この原因は、ＶＨＦバンド受
信時とＵＨＦバンド受信時に、　ＶＨＦ混合段トランジ
スタの機能が異なっていることに起因している。即ち、
■Ｆバンド受信時には、混合段として動作しＵＨＦバン
ド受信時には、単なる増幅段として動作するためである
と考えられる。このことは、現状のＵＨＦ−■Ｆコンビ
ネーション型電子チューナの回路構成から、避けること
のできないものである。The curve shown by the solid line in Figure 3 is the characteristic when receiving VHF band. In this case, the emitter current is 1.5 to 2.0 m
When the gain is maximum at A, almost the maximum gain is also obtained in the UHF band shown by the broken line, and in this case, a common operating current is observed for both UHF-VI (F bands. However, the upper adjacent channel beat shown in Fig. 4 Regarding the disturbance characteristics, the characteristics of the VHF band shown by the solid line and the UHF band shown by the broken line are very different. This is due to the different functions of the VHF mixing stage transistors when receiving the UHF band.
(2) This is thought to be because it operates as a mixing stage during F-band reception, and operates as a mere amplification stage during UHF-band reception. This cannot be avoided due to the circuit configuration of the current UHF-F combination type electronic tuner.

（発明の目的） 本発明は、上記従来例における欠点を改良し極めて簡単
な方法で、ＵＨＦ　、■Ｆ両バンドに最も適した■Ｆ混
合段トランジスタの動作条件を得ることを目的とするも
のである。(Objective of the Invention) The object of the present invention is to improve the drawbacks of the above-mentioned conventional example and to obtain operating conditions of a F mixed-stage transistor most suitable for both UHF and F bands using an extremely simple method. be.

（発明の構成） 本発明の骨子は、ＵＨＦバンド受信時に前記従来例の欠
点を改良するために、ＵＨＦ受信時とＶＨＦ受信時に、
■Ｆ混合段トランジスタの動作バイアス電圧を切換える
ことにあシ、かつその手段も、従来例に対し、抵抗を１
点追加するだけの極めて簡単な構成となっている。即ち
、ＩＪＨＦ　、！：　ＶＨＦ　（７）バンド切換えを行
なうスイッチングダイオードのカソード端子と混合段ト
ランジスタとの間に抵抗を接続して、ＵＨＦ受信時とＶ
ＨＦ受信時に混合段トランジスタのバイアス電圧を切換
えるようにしたことを特徴とするものである。(Structure of the Invention) The gist of the present invention is to improve the drawbacks of the conventional example when receiving the UHF band.
■It is necessary to switch the operating bias voltage of the F mixed-stage transistor, and the means for doing so is different from the conventional example by reducing the resistance by 1.
It has an extremely simple configuration, just adding points. That is, IJHF,! : VHF (7) Connect a resistor between the cathode terminal of the switching diode that performs band switching and the mixed stage transistor, and
This device is characterized in that the bias voltage of the mixed stage transistor is switched during HF reception.

（実施例の説明） 第５図は本発明の一実施例の回路図である。第２図の従
来例の回路と異なる点はスイッチングダイオード１３の
カソードとＶＨＦ混合段トランジスタ１０のベースの間
に抵抗Ｒが接続されていることである。(Description of Embodiment) FIG. 5 is a circuit diagram of an embodiment of the present invention. The difference from the conventional circuit shown in FIG. 2 is that a resistor R is connected between the cathode of the switching diode 13 and the base of the VHF mixed stage transistor 10.

第５図の回路において、混合段トランジスタ１０の動作
バイアス電圧はＶＨＦバンド受信時に最適となるように
設定されているものとする。ＵＨＦバンド受信時は％　
ＢＵがＯＮとなシ所定の十Ｂ電圧が与えられ、ＵＨＦ回
路混合段４で得られたＩＦ倍信号、■Ｆ同調回路６、抵
抗減衰器２１を経て、ＢＵ電圧によって導通状態となっ
ているスイッチングダイオード１３を通過し■Ｆ混合段
トランジスタ１０に供給される。本実施例によれば、ス
イッチングダイオード１３が導通すると同時に抵抗Ｒに
よって次段のＶＨＦ混合段トランジスタ１０のベースバ
イアス電圧が、　ＶＨＦバンド受信時に比べて高い電圧
値に変化し、ＶＨＦバンド受信時よシも高い値のエミッ
タ電流で動作する。このエミッタ電流値を、■Ｆ受信時
、ＵＨＦ受信時それぞれの場合に、最適な値が得られる
よう抵抗値を設定することによって前記の、従来例にお
ける欠点を改良できるものである。In the circuit shown in FIG. 5, it is assumed that the operating bias voltage of the mixed stage transistor 10 is set to be optimal during VHF band reception. % when receiving UHF band
When BU is ON, a predetermined 10B voltage is applied, and after passing through the IF multiplied signal obtained by the UHF circuit mixing stage 4, the F tuning circuit 6, and the resistor attenuator 21, it becomes conductive due to the BU voltage. The signal passes through the switching diode 13 and is supplied to the F mixed stage transistor 10. According to this embodiment, at the same time as the switching diode 13 becomes conductive, the base bias voltage of the VHF mixed stage transistor 10 in the next stage changes to a higher voltage value than when receiving the VHF band, and the voltage value becomes higher than that when receiving the VHF band. also operates with high values of emitter current. By setting the resistance value so as to obtain the optimum value of this emitter current value for both F reception and UHF reception, the above-mentioned drawbacks of the conventional example can be improved.

（発明の効果） 本発明は以上の構成によシ、ＵＨＦ　、■Ｆ両バンドで
異なる■Ｆ混合段トランジスタの最適動作バイアス条件
が、簡単に設定でき、利得、上側隣接チャンネルビート
妨害ともに秀れた特性を持つＶＨＦ混合段が得られる。(Effects of the Invention) With the above configuration, the present invention can easily set the optimal operating bias conditions of the F mixed stage transistor, which are different for both the UHF and F bands, and is excellent in both gain and upper adjacent channel beat interference. A VHF mixing stage with similar characteristics is obtained.

【図面の簡単な説明】[Brief explanation of the drawing]

第１図は従来例のＵＨＦ　−ＶＨＦコンビネーション型
電子チューナの基本構成のブロック図であシ、第２図は
そのＵＨＦ　−ＶＨＦ切換回路とその周辺回路の詳細回
路図である。 （５） 第３図はＶＨＦ混合トランジスタのエミッタ電流と利得
の関係を示す図、第４図は該エミッタ電流と上側隣接チ
ャンネルビ′−ト妨害との関係を示す図である。 第５図は本発明の一実施例の回路図である。 １・・・ＵＨＦ入力同調回路、２・・・ＵＩ（ＦＲＦ増
幅トランジスタ、３・・・ＵＨＦ″ＨＦ間調回路、４・
・・ＵＨＦ’混合トランジスタ、５・・・ＵＨＦ局部発
振器、６・・・ＵＨＦ−ＩＦ同調回路、７・・・ＶＨＦ
入力同調回路、８・・・ＶＨＦ　ＲＦ増幅トランジスタ
、９・・・ＶＨＦ段間同調回路、１０・・・ＶＨＦ混合
段トランジスタ、１１・・・ＩＦ同調回路、１２・・・
■Ｆ局部発振器、１３・・・ＵＨＦ　／　ＶＨＦ切換え
スイッチング回路、２１・・・抵抗減衰器、２２゜２３
．２４．２５・・・バイアス抵抗、Ｒ・・・抵抗。 （６） 第１図 第２図 第３図　第４図 第５図 ／１　．６　ウ１　Ｉフ　ｈFIG. 1 is a block diagram of the basic configuration of a conventional UHF-VHF combination type electronic tuner, and FIG. 2 is a detailed circuit diagram of the UHF-VHF switching circuit and its peripheral circuits. (5) FIG. 3 is a diagram showing the relationship between the emitter current and gain of a VHF mixed transistor, and FIG. 4 is a diagram showing the relationship between the emitter current and upper adjacent channel beat interference. FIG. 5 is a circuit diagram of an embodiment of the present invention. 1...UHF input tuning circuit, 2...UI (FRF amplification transistor, 3...UHF''HF intertone circuit, 4...
...UHF' mixed transistor, 5...UHF local oscillator, 6...UHF-IF tuning circuit, 7...VHF
Input tuning circuit, 8...VHF RF amplification transistor, 9...VHF interstage tuning circuit, 10...VHF mixed stage transistor, 11...IF tuning circuit, 12...
■F local oscillator, 13...UHF/VHF switching circuit, 21...resistance attenuator, 22゜23
．． 24.25...Bias resistance, R...Resistance. (6) Figure 1 Figure 2 Figure 3 Figure 4 Figure 5/1. 6 U1 I h

Claims (1)

【特許請求の範囲】[Claims] ＴＪＨＦ　十Ｂ電源の０Ｎ−ＯＦＦにより、スイッチン
グダイオードを開閉して、ＵＨＦ　、　ＶＨＦバンド切
換えを行なうＵＨＦ　／　ＶＨＦコンビネーション型電
子チューすにおいて、前記スイッチングダイオードのカ
ソード端子と混合段トランジスタのベース端子との間に
抵抗を接続してＵＨＦ受信時とＶＴ（Ｆ受信時に混合段
トランジスタのバイアス電圧を切換えるようにしたこと
を特徴とする電子チューナのＵ−■切換え回路。In a UHF/VHF combination type electronic tuner that switches between UHF and VHF bands by opening and closing a switching diode by turning the TJHF 1B power supply ON and OFF, the voltage between the cathode terminal of the switching diode and the base terminal of the mixed stage transistor is A U-■ switching circuit for an electronic tuner, characterized in that a resistor is connected to the circuit to switch the bias voltage of a mixed stage transistor when receiving UHF and when receiving VT (F).
JP24309283A 1983-12-24 1983-12-24 U-v switching circuit of electronic tuner Pending JPS60136410A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP24309283A JPS60136410A (en) 1983-12-24 1983-12-24 U-v switching circuit of electronic tuner

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP24309283A JPS60136410A (en) 1983-12-24 1983-12-24 U-v switching circuit of electronic tuner

Publications (1)

Publication Number Publication Date
JPS60136410A true JPS60136410A (en) 1985-07-19

Family

ID=17098665

Family Applications (1)

Application Number Title Priority Date Filing Date
JP24309283A Pending JPS60136410A (en) 1983-12-24 1983-12-24 U-v switching circuit of electronic tuner

Country Status (1)

Country Link
JP (1) JPS60136410A (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS63268316A (en) * 1987-02-05 1988-11-07 フィリップス　エレクトロニクス　ネムローゼ　フェンノートシャップ Rf tuner circuit
JPH01278113A (en) * 1988-04-30 1989-11-08 Matsushita Electric Ind Co Ltd Electronic tuner
KR100424691B1 (en) * 2000-11-29 2004-03-27 알프스 덴키 가부시키가이샤 Vhf band and uhf band television signal receiving tuner

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS63268316A (en) * 1987-02-05 1988-11-07 フィリップス　エレクトロニクス　ネムローゼ　フェンノートシャップ Rf tuner circuit
JPH01278113A (en) * 1988-04-30 1989-11-08 Matsushita Electric Ind Co Ltd Electronic tuner
KR100424691B1 (en) * 2000-11-29 2004-03-27 알프스 덴키 가부시키가이샤 Vhf band and uhf band television signal receiving tuner

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