JPH0161254B2 - - Google Patents
Info
- Publication number
- JPH0161254B2 JPH0161254B2 JP545782A JP545782A JPH0161254B2 JP H0161254 B2 JPH0161254 B2 JP H0161254B2 JP 545782 A JP545782 A JP 545782A JP 545782 A JP545782 A JP 545782A JP H0161254 B2 JPH0161254 B2 JP H0161254B2
- Authority
- JP
- Japan
- Prior art keywords
- voltage
- tuning
- intermediate tap
- sliding contact
- circuit
- 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
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
Landscapes
- Channel Selection Circuits, Automatic Tuning Circuits (AREA)
Description
【発明の詳細な説明】
本発明は、テレビ受像機等の受信機における同
調電圧発生回路に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a tuning voltage generation circuit in a receiver such as a television receiver.
テレビ受像機の電子チユーナは、同調用可変素
子としてバラクタ・ダイオードが使用されるが、
１個のバラクタ・ダイオードでチヤンネル１〜62
全てをカバーすることはできないので、VHFロ
ーチヤンネルVL（１〜３）、VHFハイチヤンネル
VH（４〜12）、UHF全チヤンネル（13〜62）の３
バンドに分けて、各バンド毎に同調回路のコイ
ル、VHF、UHFチユーナのＢ電圧その他を切換
えている。 Electronic tuners in television receivers use varactor diodes as variable tuning elements.
Channels 1 to 62 with one varactor diode
Since it is not possible to cover everything, VHF Low Channel Channel V L (1 to 3), VHF Haiti Channel Channel
V H (4-12), 3 of all UHF channels (13-62)
It is divided into bands, and the tuning circuit coil, VHF, UHF tuner B voltage, etc. are switched for each band.
そして、プリセツト時には、可変抵抗器により
プリセツト電圧を発生させ、そのプリセツト電圧
に応じて、他の回路により各バンドの同調電圧を
発生させて、プリセツトが行なわれるようになつ
ている。すなわち、第１図ａに示すように、選局
チヤンネルに対して可変抵抗で変化するプリセツ
ト電圧を設定して、そのプリセツト電圧に応じて
バンドを割当てて、第１図ｂに示すように各バン
ド毎に同様な範囲で変化する同調電圧が得られる
ようにし、１個の同調回路に２個以上のバラク
タ・ダイオードが必要ないようになつている。 At the time of presetting, a variable resistor generates a preset voltage, and in accordance with the preset voltage, another circuit generates a tuning voltage for each band, thereby performing presetting. That is, as shown in Fig. 1a, a preset voltage that changes with a variable resistor is set for the selected channel, and bands are assigned according to the preset voltage, and each band is set as shown in Fig. 1b. This allows a tuning voltage that varies in a similar range for each tuning circuit to avoid the need for more than one varactor diode in one tuning circuit.
しかしながら、従来では、可変抵抗で一旦得た
プリセツト電圧を更に処理して各バンドの同調電
圧を発生させる方式であるため、回路が複雑化す
ると共にコスト高となるという問題があつた。 However, in the conventional method, a preset voltage once obtained by a variable resistor is further processed to generate a tuning voltage for each band, which has resulted in problems of complicated circuits and high costs.
本発明は斯る点に鑑みて成されたものであり、
その目的は、可変抵抗によつて直接複数のバンド
の同調電圧が得られるようにして、極めて簡単で
コスト的にも有利となる同調電圧発生回路を提供
することである。 The present invention has been made in view of these points,
The purpose is to provide a tuning voltage generation circuit which is extremely simple and cost-effective by directly obtaining tuning voltages of a plurality of bands using a variable resistor.
以下、本発明を実施例によつて説明する。第２
図はその原理を示す図であり、摺動接点１ａを有
する可変抵抗器１の一端１ｂに電圧V0を与え、
他端１ｃを電圧Ｅ（＜V0）（例えば零ボルト）と
し、中間タツプ１ｄを設けて、この中間タツプ１
ｄと一端１ｂとの間にスイツチ２を、また他端１
ｃとの間にスイツチ３を接続したものである。 Hereinafter, the present invention will be explained with reference to Examples. Second
The figure shows the principle, in which a voltage V 0 is applied to one end 1b of a variable resistor 1 having a sliding contact 1a,
The other end 1c is set to a voltage E (<V 0 ) (for example, zero volts), and an intermediate tap 1d is provided.
d and one end 1b, and the other end 1
A switch 3 is connected between the switch and c.
この回路においては、スイツチ２，３共にオフ
となつている場合には、可変抵抗器１の摺動接点
１ａを摺動させるとそこから得られる電圧Vaは、
第３図ａに示すようにＥとV0の間を変化するよ
うになる。一方、スイツチ２のみをオンすれば中
間タツプ１ｄの電圧がV0となるので、その中間
タツプ１ｄと他端１ｃの間Ａを摺動接点１ａを摺
動させれば第３図ｂのＡに示すようにやはりＥと
V0の間を変化する電圧が得られ、またスイツチ
３のみをオンにすれば中間タツプ１ｄの電圧がＥ
となるので、その中間タツプ１ｄと一端１ｂの間
(B)を摺動接点１ａを摺動させれば第３図ｂのＢに
示すようにやはりＥとV0の間を変化する電圧が
得られる。すなわち、摺動接点１ａが中間タツプ
１ｄから一端１ｂ側にあるか、他端１ｃ側にある
かによつてスイツチ２，３をオン・オフすれば、
第３図ｂに示す特性の電圧が得られる。 In this circuit, when both switches 2 and 3 are off, the voltage Va obtained by sliding the sliding contact 1a of the variable resistor 1 is
As shown in FIG. 3a, it changes between E and V 0 . On the other hand, if only the switch 2 is turned on, the voltage at the intermediate tap 1d becomes V0 , so if the sliding contact 1a is slid between the intermediate tap 1d and the other end 1c, the voltage becomes A in Fig. 3b. As shown, E and
A voltage that changes between V and 0 can be obtained, and if only switch 3 is turned on, the voltage at intermediate tap 1d becomes E
Therefore, between the middle tap 1d and one end 1b
By sliding the sliding contact 1a (B), a voltage varying between E and V 0 can be obtained as shown in B of FIG. 3B. That is, if the switches 2 and 3 are turned on and off depending on whether the sliding contact 1a is on the one end 1b side or the other end 1c side from the intermediate tap 1d,
A voltage having the characteristics shown in FIG. 3b is obtained.
従つて、スイツチ２，３が共にオフの場合を
UHF、スイツチ２のみがオンの場合をVL、スイ
ツチ３のみがオンの場合をVHのバンドとした同
調電圧Vaを摺動接点１ａから得ることができ、
第３図ｃに示すようにこの同調電圧Vaはいずれ
もＥとV0の間を変化する。 Therefore, if both switches 2 and 3 are off,
UHF, a tuning voltage Va can be obtained from the sliding contact 1a, with the band being V L when only switch 2 is on, and V H when only switch 3 is on.
As shown in FIG. 3c, this tuning voltage Va varies between E and V0 .
第４図は具体的実施例であり、可変抵抗器１の
中間タツプ１ｄを抵抗Ｒを介してオペアンプ４の
出力端子４ａに接続すると共に、その中間タツプ
１ｄをそのオペアンプ４の非反転入力端子（＋）
４ｂに、摺動接点１ａを反転入力端子（−）４ｃ
に接続し、電圧V0、Ｅをそのオペアンプ４の電
源としたものである。 FIG. 4 shows a specific embodiment in which the intermediate tap 1d of the variable resistor 1 is connected to the output terminal 4a of the operational amplifier 4 via the resistor R, and the intermediate tap 1d is connected to the non-inverting input terminal ( +)
4b, the sliding contact 1a is connected to the inverting input terminal (-) 4c
, and the voltages V 0 and E are used as power sources for the operational amplifier 4.
この例においては、摺動接点１ａが中間タツプ
１ｄよりも他端１ｃ側にある場合には、摺動接点
１ａで得られる電圧Vaは中間タツプ１ｄで得ら
れる電圧Vdより低く、Va＜Vdであるので、オ
ペアンプ４の出力端子４ａにはハイレベルの電圧
（＝V0）が現われ、この電圧が抵抗Ｒを介して正
帰還されると共に中間タツプ１ｄに加わる。よつ
て中間タツプ１ｄはV0より若干低い電圧となり、
摺動接点１ａが中間タツプ１ｄと他端１ｃとの間
Ａを摺動することにより、電圧VaはV0より若干
低い電圧とＥとの間で変化する。すなわち、この
場合は中間タツプ１ｄと一端１ｂの間が短絡され
たと等価になる。 In this example, when the sliding contact 1a is closer to the other end 1c than the intermediate tap 1d, the voltage Va obtained at the sliding contact 1a is lower than the voltage Vd obtained at the intermediate tap 1d, and Va<Vd. Therefore, a high level voltage (=V 0 ) appears at the output terminal 4a of the operational amplifier 4, and this voltage is positively fed back via the resistor R and is applied to the intermediate tap 1d. Therefore, the intermediate tap 1d has a voltage slightly lower than V 0 ,
By sliding the sliding contact 1a between the intermediate tap 1d and the other end 1c, the voltage Va changes between a voltage slightly lower than V0 and E. That is, in this case, it is equivalent to a short circuit between the intermediate tap 1d and the one end 1b.
一方、摺動接点１ａが中間タツプ１ｄよりも一
端１ｂ側にある場合には、摺動接点１ａで得られ
る電圧Vaは中間タツプ１ｄで得られる電圧Vdよ
りも高く、Va＞Vdであるので、オペアンプ４の
出力端子４ａにはローレベルの電圧（＝Ｅ）が現
われ、この電圧が抵抗Ｒを介して正帰還されると
共に中間タツプ１ｄに加わる。よつて中間タツプ
１ｄはＥより若干高い電圧となり、摺動接点１ａ
が中間タツプ１ｄと一端１ｂとの間Ｂを摺動する
ことにより、電圧VaはV0とＥより若干高い電圧
との間で変化する。すなわち、この場合は中間タ
ツプ１ｄと一端１ｃの間が短絡されたと等価にな
る。なお、抵抗ＲはＥ＜Vd＜V0とするためのも
のである。すなわち、Vd＝Ｅ、Vd＝V0となる
と、電圧Vaが電圧Vdより大又は小とならず、オ
ペアンプ４の反転復帰動作ができなくなるので、
これを防止するためである。 On the other hand, when the sliding contact 1a is located closer to one end 1b than the intermediate tap 1d, the voltage Va obtained at the sliding contact 1a is higher than the voltage Vd obtained at the intermediate tap 1d, and Va>Vd. A low level voltage (=E) appears at the output terminal 4a of the operational amplifier 4, and this voltage is positively fed back via the resistor R and is applied to the intermediate tap 1d. Therefore, the intermediate tap 1d has a voltage slightly higher than E, and the sliding contact 1a
By sliding B between the intermediate tap 1d and one end 1b, the voltage Va changes between V0 and a voltage slightly higher than E. That is, in this case, it is equivalent to a short circuit between the intermediate tap 1d and the one end 1c. Note that the resistor R is provided to satisfy E<Vd< V0 . In other words, when Vd=E and Vd= V0 , the voltage Va will not become larger or smaller than the voltage Vd, and the operational amplifier 4 will not be able to perform an inversion return operation.
This is to prevent this.
以上のように、第４図に示した回路では、摺動
接点１ａが中間タツプ１ｄから一端１ｂ側にある
か他端１ｃ側にあるかによつて、その中間タツプ
１ｄの電圧が自動的に、一端１ｂの電圧V0、又
は他端１ｃの電圧Ｅに近い電圧に切換わるので、
２個のバンド（VL・VH）の同調電圧をその摺動
接点１ａから得ることができる。この場合、オペ
アンプ４の出力端子４ａの電圧（V0、Ｅ）を、
２個のバンドのバンド切換信号として利用するこ
とができる。 As described above, in the circuit shown in FIG. 4, depending on whether the sliding contact 1a is on the one end 1b side or the other end 1c side from the intermediate tap 1d, the voltage at the intermediate tap 1d is automatically adjusted. , the voltage is switched to a voltage close to the voltage V 0 at one end 1b or the voltage E at the other end 1c,
Tuning voltages of two bands (V L and V H ) can be obtained from the sliding contact 1a. In this case, the voltage (V 0 , E) at the output terminal 4a of the operational amplifier 4 is
It can be used as a band switching signal for two bands.
なお、３バンド（VL、VH、UHF）の同調電圧
を得ることができるようにするためには、更に中
間タツプ１ｄと抵抗Ｒの間にスイツチを介在させ
て、UHFバンド選択の時にそのスイツチをオフ
にすれば良い。 In addition, in order to be able to obtain tuning voltages for three bands (V L , V H , UHF), a switch is further interposed between the intermediate tap 1d and the resistor R, and when selecting the UHF band, a switch is inserted between the intermediate tap 1d and the resistor R. Just turn off the switch.
以上のように本発明によれば、可変抵抗器によ
つて直接複数バンドの同調電圧を得ることがで
き、従来のようにプリセツト電圧を複数バンドの
同調電圧に変換する必要がないので、回路が簡単
となり、コスト的に極めて有利となるという特徴
がある。 As described above, according to the present invention, it is possible to directly obtain tuning voltages for multiple bands using a variable resistor, and there is no need to convert preset voltages into tuning voltages for multiple bands as in the conventional case. It is characterized by being simple and extremely advantageous in terms of cost.
第１図ａは従来のテレビ受像機のチユーナの選
局チヤンネルとプリセツト電圧の特性図、ｂはプ
リセツト電圧と同調電圧の特性図、第２図は本発
明の原理説明用の回路図、第３図ａは第２図のス
イツチ２，３オフの時の摺動接点電圧の特性図、
ｂはスイツチ２，３をオンオフさせた場合の同特
性図、ｃは同調電圧特性図、第４図は本発明の一
実施例の回路図である。
Fig. 1a is a characteristic diagram of the tuning channel and preset voltage of a tuner of a conventional television receiver, b is a characteristic diagram of the preset voltage and tuning voltage, Fig. 2 is a circuit diagram for explaining the principle of the present invention, and Fig. 3 Figure a is a characteristic diagram of the sliding contact voltage when switches 2 and 3 in Figure 2 are off,
b is the same characteristic diagram when switches 2 and 3 are turned on and off, c is a tuning voltage characteristic diagram, and FIG. 4 is a circuit diagram of an embodiment of the present invention.
Claims (1)
調電圧を発生する回路において、摺動接点および
中間タツプを有する可変抵抗器と、該可変抵抗器
の両端に印加される電圧と同一電圧を電源電圧と
して印加され、且つ上記中間タツプの電圧と上記
摺動接点の電圧を入力してそれらの間の大小関係
に応じて出力端子の電位を反転するオペアンプと
を具備し、上記摺動接点の電圧を上記同調電圧と
し、上記オペアンプの出力電圧をバンド切換電圧
とすると共に上記中間タツプに抵抗を介して印加
したことを特徴とする同調電圧発生回路。1 In a circuit that generates a tuning voltage to be applied to a varactor diode of a tuning circuit, a variable resistor having a sliding contact and an intermediate tap, and the same voltage as the voltage applied across the variable resistor is applied as a power supply voltage. and an operational amplifier that inputs the voltage of the intermediate tap and the voltage of the sliding contact and inverts the potential of the output terminal according to the magnitude relationship between them, and converts the voltage of the sliding contact into the tuning voltage. A tuning voltage generation circuit characterized in that the output voltage of the operational amplifier is used as a band switching voltage and is applied to the intermediate tap via a resistor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP545782A JPS58123222A (en) | 1982-01-19 | 1982-01-19 | Tuning voltage generating circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP545782A JPS58123222A (en) | 1982-01-19 | 1982-01-19 | Tuning voltage generating circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS58123222A JPS58123222A (en) | 1983-07-22 |
| JPH0161254B2 true JPH0161254B2 (en) | 1989-12-27 |
Family
ID=11611747
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP545782A Granted JPS58123222A (en) | 1982-01-19 | 1982-01-19 | Tuning voltage generating circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS58123222A (en) |
-
1982
- 1982-01-19 JP JP545782A patent/JPS58123222A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS58123222A (en) | 1983-07-22 |
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