JPH0413885B2 - - Google Patents
Info
- Publication number
- JPH0413885B2 JPH0413885B2 JP13313581A JP13313581A JPH0413885B2 JP H0413885 B2 JPH0413885 B2 JP H0413885B2 JP 13313581 A JP13313581 A JP 13313581A JP 13313581 A JP13313581 A JP 13313581A JP H0413885 B2 JPH0413885 B2 JP H0413885B2
- Authority
- JP
- Japan
- Prior art keywords
- variable capacitance
- tuning
- resistor
- capacitance diodes
- tuning voltage
- 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
- 230000001747 exhibiting effect Effects 0.000 claims description 2
- 230000010355 oscillation Effects 0.000 description 20
- 230000000694 effects Effects 0.000 description 5
- 238000010586 diagram Methods 0.000 description 4
- 230000003321 amplification Effects 0.000 description 2
- 239000003990 capacitor Substances 0.000 description 2
- 238000003199 nucleic acid amplification method Methods 0.000 description 2
Classifications
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03J—TUNING RESONANT CIRCUITS; SELECTING RESONANT CIRCUITS
- H03J3/00—Continuous tuning
- H03J3/02—Details
- H03J3/16—Tuning without displacement of reactive element, e.g. by varying permeability
- H03J3/18—Tuning without displacement of reactive element, e.g. by varying permeability by discharge tube or semiconductor device simulating variable reactance
- H03J3/185—Tuning without displacement of reactive element, e.g. by varying permeability by discharge tube or semiconductor device simulating variable reactance with varactors, i.e. voltage variable reactive diodes
Landscapes
- Superheterodyne Receivers (AREA)
Description
【発明の詳細な説明】
(イ) 産業上の利用分野
本発明は可変容量ダイオードを同調素子として
用いたチユーナ装置に関するものである。DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a tuner device using a variable capacitance diode as a tuning element.
(ロ) 従来の技術
斯種チユーナ装置は第１図に示すように入力端
子１に接続された入力同調回路２と、RF増幅器
３及びその出力側に設けられた段間同調回路４と
からなるRF増幅段５と、局部発振回路６と、前
記RF増幅段５からの入力信号と局部発振回路６
からの局部発振信号との周波数差のIF（中間周波
数）信号を出力端子８に出力するミキサ７とから
構成されており、チユーニング電圧源としての選
局装置９からチユーニング電圧が、それぞれの回
路の可変容量ダイオードD1，D2，D3，D4に抵抗
R1，R2，R3，R4を通して与えられる。(b) Prior art As shown in FIG. 1, this type of tuner device consists of an input tuning circuit 2 connected to an input terminal 1, an RF amplifier 3, and an interstage tuning circuit 4 provided on the output side thereof. RF amplification stage 5, local oscillation circuit 6, input signal from the RF amplification stage 5 and local oscillation circuit 6
The mixer 7 outputs an IF (intermediate frequency) signal with a frequency difference from the local oscillation signal from the output terminal 8 to the output terminal 8, and the tuning voltage is supplied from the tuning device 9 as a tuning voltage source to each circuit. Resistance to variable capacitance diodes D 1 , D 2 , D 3 , D 4
It is given through R 1 , R 2 , R 3 , R 4 .
ここで、以下の説明においては特に段間同調回
路４と局部発振回路６の関係が重要であるので、
可変容量ダイオードとチユーニング電圧供給路の
抵抗のうち段間同調回路４のものをそれぞれ第１
可変容量ダイオード、第１抵抗と呼び、局部発振
回路６のそれらをそれぞれ第２可変容量ダイオー
ド及び第２抵抗と呼ぶことにする。尚、段間同調
回路４については、図示の場合複同調回路となつ
ているが、単同調回路であつてもよい。 Here, in the following explanation, the relationship between the interstage tuning circuit 4 and the local oscillation circuit 6 is particularly important, so
Among the variable capacitance diodes and the resistances of the tuning voltage supply path, those of the interstage tuning circuit 4 are
The variable capacitance diode and the first resistor will be referred to as a variable capacitance diode, and those of the local oscillation circuit 6 will be referred to as a second variable capacitance diode and a second resistor, respectively. Note that although the inter-stage tuning circuit 4 is a double-tuned circuit in the illustrated case, it may be a single-tuned circuit.
さて、従来のチユーナでは抵抗R1、第１抵抗
R2，R3、第２抵抗R4はトラツキング調整のため
に抵抗値が同程度の大きさのものを使用してい
る。そして、使用される抵抗は一般にその値が数
十kΩ〜100kΩの範囲のものを使用していた。 Now, in the conventional tuner, the resistance R 1 and the first resistance
R 2 , R 3 and the second resistor R 4 have similar resistance values for tracking adjustment. The resistors used generally have values in the range of several tens of kΩ to 100 kΩ.
また、選局装置の出力インピーダンスは当然、
機種毎に異なるが、通常10kΩ〜100kΩの範囲内
に収まる。 Also, the output impedance of the channel selection device is naturally
Although it varies depending on the model, it usually falls within the range of 10kΩ to 100kΩ.
しかし、以下に述べる如き不都合が生じてい
た。即ち、RF増幅器３で増幅された信号が大き
い場合には第１可変容量ダイオードD2，D3と、
DCカツト用コンデンサC1，C2の接続点ａに比較
的大きな整流電圧が発生し、この電圧がチユーニ
ング電圧の共通ライン１０から第２抵抗R4を介
して第２可変容量ダイオードD4に印加され、こ
の可変容量ダイオードの逆方向電流を変化せし
め、局部発振周波数のドリフトを招くのである。
尚、前記接続点ａに整流電圧が生じるのは、接続
点ａにおける入力信号の振幅が大きくなると、そ
の入力信号の負の半サイクルでは第１可変容量ダ
イオードD2，D3が導通し、正の半サイクルでは
オフ状態で、その容量が充電されるためである。
また、大きな入力信号が接続点ａに現れる場合と
しては、チヤンネル切換え時やプリセツト時など
が挙げられる。これらの場合にはRF増幅器３に
AGC電圧がかからないか、又は極めて小さくな
るためRF増幅器３が最大ゲインで動作し、大き
な出力を生じるのである。而して、接続点ａの電
位が高くなつて、しかもチユーニング電圧共通ラ
イン１０のチユーニング電圧よりも高くなると上
述したように局部発振回路６の第２可変容量ダイ
オードD4のバイアスを変えるように作用して局
部発振周波数を所期の値よりも高い方へドリフト
させることになる。この場合、選局装置の出力イ
ンピーダンスR5の値が0Ωであれば前記共通ライ
ン１０の電圧上昇はなくなり、局部発振周波数の
ドリフトも生じないが、選局装置９は、当然、出
力インピーダンスR5を備えている。 However, the following inconveniences occurred. That is, when the signal amplified by the RF amplifier 3 is large, the first variable capacitance diodes D2 , D3 ,
A relatively large rectified voltage is generated at the connection point a of the DC cut capacitors C 1 and C 2 , and this voltage is applied from the common line 10 of the tuning voltage to the second variable capacitance diode D 4 via the second resistor R 4 This changes the reverse current of this variable capacitance diode, causing a drift in the local oscillation frequency.
The rectified voltage is generated at the connection point a because when the amplitude of the input signal at the connection point a increases, the first variable capacitance diodes D 2 and D 3 conduct during the negative half cycle of the input signal, and the positive voltage increases. This is because the capacitor is in the off state during the half cycle, and its capacity is charged.
Further, cases where a large input signal appears at the connection point a include times such as channel switching and presetting. In these cases, RF amplifier 3
Since the AGC voltage is not applied or becomes extremely small, the RF amplifier 3 operates at maximum gain and produces a large output. As a result, when the potential at the connection point a becomes higher and moreover becomes higher than the tuning voltage of the tuning voltage common line 10, it acts to change the bias of the second variable capacitance diode D4 of the local oscillation circuit 6, as described above. This causes the local oscillation frequency to drift higher than the intended value. In this case, if the value of the output impedance R 5 of the tuning device 9 is 0Ω, there will be no voltage rise on the common line 10 and no drift in the local oscillation frequency will occur . It is equipped with
横軸に周波数、縦軸に局部発振周波数の変化量
をとり、出力インピーダンスR5が100kΩ、47kΩ、
22kΩ、10kΩの選局装置の局部発振周波数の変化
量を第２図に示す。 The horizontal axis shows the frequency, and the vertical axis shows the amount of change in local oscillation frequency.The output impedance R5 is 100kΩ, 47kΩ,
Figure 2 shows the amount of change in local oscillation frequency of the 22kΩ and 10kΩ channel selection devices.
この第２図から分かるように、出力インピーダ
ンスR5が小さい選局装置を採用しても、局部発
振周波数の変化量あまり小さくならず効果が薄い
ことが分かる。 As can be seen from FIG. 2, even if a channel selection device with a small output impedance R5 is employed, the amount of change in the local oscillation frequency is not so small and the effect is weak.
又、選局装置（チユーニング電圧源）の出力イ
ンピーダンスR5を小さくすることなしに上述の
不都合を解消するためには、選局装置の出力イン
ピーダンスを小さくせずに、共通ラインの電圧上
昇を小さくするには、第１抵抗R2，R3の値を従
来に比べて大きく選定してやればよい。 In addition, in order to eliminate the above-mentioned disadvantage without reducing the output impedance R5 of the tuning device (tuning voltage source), it is necessary to reduce the voltage rise on the common line without reducing the output impedance of the tuning device. In order to do this, the values of the first resistors R 2 and R 3 should be selected to be larger than the conventional values.
この第１抵抗R2，R3の値を大きくすれば、当
然、トラツキング調整のため、第２抵抗R4の値
も、この第１抵抗R2，R3の値と同じく大きくす
るのが好ましいが、このように、第１抵抗R2，
R3、第２抵抗R4の値を大きくすると、周知の如
く次の問題が発生する。 If the values of the first resistors R 2 and R 3 are increased, the value of the second resistor R 4 is also preferably increased to the same value as the first resistors R 2 and R 3 for tracking adjustment. However, in this way, the first resistance R 2 ,
As is well known, when the values of R 3 and second resistor R 4 are increased, the following problem occurs.
可変容量ダイオードの逆方向電流（漏れ電流）
は温度によつて変動するので、この第１抵抗R2，
R3、第２抵抗R4の値が大きいと、この第１抵抗
R2，R3、第２抵抗R4での電圧降下も温度変動に
より大きくなり、動作の安定したチユーナが提供
できない。 Reverse current (leakage current) of variable capacitance diode
varies depending on the temperature, so this first resistance R 2 ,
If the values of R 3 and second resistor R 4 are large, this first resistor
The voltage drop across R 2 , R 3 and the second resistor R 4 also increases due to temperature fluctuations, making it impossible to provide a tuner with stable operation.
(ハ) 発明が解決しようとする課題
本発明では、必要とされる局部発振周波数の精
度に比べて、同調回路に必要とされる周波数特性
の精度が、それ程高くないことを利用して、上記
の問題を解決するものである。(c) Problems to be Solved by the Invention In the present invention, the above-mentioned problem can be solved by taking advantage of the fact that the accuracy of the frequency characteristics required for a tuning circuit is not so high compared to the accuracy of the local oscillation frequency required. It solves the problem of
(ニ) 課題を解決するための手段
本発明は、RF増幅器３の出力側同調回路４の
第１可変容量ダイオードD2，D3に第１抵抗R2，
R3を介して、一方局部発振回路６に設けられた
第２可変容量ダイオードD4に第２抵抗R4を介し
てそれぞれ共通のチユーニング電圧源９からのチ
ユーニング電圧を印加するようにしたチユーナ装
置において、
前記第１可変容量ダイオードD2，D3による入
力信号整流電圧に対しては前記チユーニング電圧
源９出力インピーダンスR5より高く且つ前期第
２抵抗R4の値より高いインピーダンスを呈する
が、前記可変容量ダイオードD2，D3の逆方向電
流に対しては低インピーダンスを呈する手段１
１，１２を前記第１可変容量ダイオードD2，D3
へのチユーニング電圧供給路に前記第１抵抗R2，
R3と直列に設けたことを特徴とするチユーナ装
置である。(d) Means for Solving the Problems The present invention provides the first variable capacitance diodes D 2 , D 3 of the output side tuning circuit 4 of the RF amplifier 3 with a first resistor R 2 ,
A tuner device in which a tuning voltage from a common tuning voltage source 9 is applied via a second resistor R 4 to a second variable capacitance diode D 4 provided in the local oscillation circuit 6 via R 3 . In this case, the input signal rectified voltage by the first variable capacitance diodes D 2 and D 3 exhibits an impedance higher than the output impedance R 5 of the tuning voltage source 9 and higher than the value of the second resistor R 4 , but the Means 1 exhibiting low impedance for reverse current of variable capacitance diodes D 2 and D 3
1 and 12 are the first variable capacitance diodes D 2 and D 3
The first resistor R 2 is connected to the tuning voltage supply path to the tuning voltage supply path.
This is a tuner device characterized by being installed in series with R3 .
(ホ) 作用
本発明は上述の如く構成されているため、r2
（＋R2）、r3（＋R3）とR5との分圧比が大きくな
り、その分共通ライン１０に対する接続点ａの電
位の影響が軽減される。これによつて、局部発振
周波数のドリフトを殆ど招かないようにできる。(E) Effect Since the present invention is configured as described above, r 2
(+R 2 ), r 3 (+R 3 ) and R 5 become larger, and the influence of the potential at the connection point a on the common line 10 is reduced accordingly. Thereby, it is possible to almost avoid causing a drift in the local oscillation frequency.
即ち、接続点ａに生じる入力信号整流電圧の局
部発振回路６への影響は好適に阻止されると共に
第１可変容量ダイオードD2，D3の逆方向電流に
よるチユーニング電圧の電圧効果は小さくするこ
とができる。 That is, the influence of the input signal rectified voltage generated at the connection point a on the local oscillation circuit 6 is preferably prevented, and the voltage effect of the tuning voltage due to the reverse current of the first variable capacitance diodes D 2 and D 3 is reduced. I can do it.
(ヘ) 実施例 本発明の一実施例を第４図に示す。(f) Examples An embodiment of the present invention is shown in FIG.
第１抵抗R2，R3と直列に、接続点ａに現れる
入力信号電圧に対しては高インピーダンスを呈す
るが、第１可変容量ダイオードD2，D3の逆方向
電流に対しては低インピーダンスを呈する手段１
１，１２をそれぞれ接続する。この手段１１，１
２は高抵抗r2，r3とスイツチングダイオードD5，
D6をそれぞれ並列に接続したものである。 In series with the first resistors R 2 and R 3 , it presents a high impedance to the input signal voltage appearing at the connection point a, but has a low impedance to the reverse current of the first variable capacitance diodes D 2 and D 3 . Means 1 for presenting
Connect 1 and 12 respectively. This means 11,1
2 is high resistance r 2 , r 3 and switching diode D 5 ,
D 6 are connected in parallel.
斯る実施例では、正常時において、チユーニン
グ電圧はそれぞれダイオードD5，D6を介した後
に第１抵抗R2，R3を介して可変容量ダイオード
D2，D3に印加される。このため、チユーニング
電圧がこの高抵抗r2，r3により電圧降下すること
はない。又、接続点ａの電圧はそれぞれ第１抵抗
R2，R3だけなく、高抵抗r2，r3をも介して、共通
ライン１０に印加される。 In this embodiment, during normal operation, the tuning voltage is applied to the variable capacitance diode via the first resistors R 2 and R 3 after passing through the diodes D 5 and D 6 respectively.
Applied to D 2 and D 3 . Therefore, the tuning voltage will not drop due to these high resistances r 2 and r 3 . Also, the voltage at the connection point a is the first resistor.
It is applied to the common line 10 not only through R 2 , R 3 but also through high resistances r 2 , r 3 .
第３図は第２図と同様のグラフにおいて、高抵
抗（＋第１抵抗）の値を27kΩから220kΩ、
330kΩ、470kΩ、820kΩと順次変えた場合の特性
を示しており、局部発振周波数の変化を簡単に小
さくできることが分かる。 Figure 3 shows the same graph as Figure 2, but the value of high resistance (+1st resistance) is changed from 27kΩ to 220kΩ.
It shows the characteristics when changing the resistance to 330kΩ, 470kΩ, and 820kΩ in sequence, and it can be seen that the change in the local oscillation frequency can be easily reduced.
尚、前述の如く、第２抵抗R4の値は一般に数
＋kΩ〜100kΩの範囲内であるので、高抵抗r2，r3
は200kΩ以上の高い値とすればよいが、第１可変
容量ダイオードD2，D3の逆方向電流による電圧
降下をあまり大きくしないために上限は1MΩ程
度にとどめておくことが好ましい。この時、第１
抵抗R2，R3の値は数kΩ程度の低抵抗でもよい。 As mentioned above, the value of the second resistor R 4 is generally within the range of several + kΩ to 100 kΩ, so the high resistance r 2 , r 3
may be set to a high value of 200 kΩ or more, but it is preferable to keep the upper limit at about 1 MΩ in order to prevent the voltage drop due to the reverse current of the first variable capacitance diodes D 2 and D 3 from becoming too large. At this time, the first
The values of the resistors R 2 and R 3 may be as low as several kΩ.
(ト) 発明の効果
上述の如く本発明によればRF増幅器３が大き
なゲインで作動したような場合に、その出力側の
同調回路４の可変容量ダイオードD2，D3により
入力信号が整流されて可変容量ダイオードD2，
D3のカソード側に生じる高電圧がチユーニング
電圧供給路１０を通して局部発振回路６側に作用
して局部発振周波数を正規の値よりも変化せしめ
るという不都合を好適に払拭できると共に、可変
容量ダイオードの逆方向電流による電圧降下は小
さくすることができ、温度変動によりチユーナの
動作が不安定になるという不都合も払拭できると
いう効果があり、極めて有用である。(G) Effects of the Invention As described above, according to the present invention, when the RF amplifier 3 operates with a large gain, the input signal is rectified by the variable capacitance diodes D 2 and D 3 of the tuning circuit 4 on the output side. variable capacitance diode D 2 ,
The inconvenience that the high voltage generated on the cathode side of D 3 acts on the local oscillation circuit 6 side through the tuning voltage supply path 10 and changes the local oscillation frequency beyond the normal value can be suitably eliminated, and the inconvenience of the reverse of the variable capacitance diode can be eliminated. The voltage drop due to the directional current can be reduced, and the disadvantage that the operation of the tuner becomes unstable due to temperature fluctuation can be eliminated, which is extremely useful.
第１図はチユーナ装置の一般的構成を示す回路
図である。第２図はチユーナ装置の入力信号レベ
ルに対する局部発振周波数の変化量を選局装置の
出力インピーダンスの値ごとに示す特性図であ
る。第３図は本発明の効果を説明するための特性
図でる。第４図は本発明の１つの実施例を示すチ
ユーナ装置の要部回路図である。
３……RF増幅器、４……段間同調回路、D2，
D3……第１可変容量ダイオード、R2，R3……第
１抵抗、D4……第２可変容量ダイオード、R4…
…第２抵抗、９……選局装置、１１，１２……手
段、D5，D6……スイツチングダイオード。
FIG. 1 is a circuit diagram showing the general configuration of a tuner device. FIG. 2 is a characteristic diagram showing the amount of change in the local oscillation frequency with respect to the input signal level of the tuner device for each value of the output impedance of the tuning device. FIG. 3 is a characteristic diagram for explaining the effects of the present invention. FIG. 4 is a circuit diagram of a main part of a tuner device showing one embodiment of the present invention. 3...RF amplifier, 4...Interstage tuning circuit, D 2 ,
D3 ...First variable capacitance diode, R2 , R3 ...First resistor, D4 ...Second variable capacitance diode, R4 ...
...Second resistor, 9...Tuning selection device, 11, 12...Means, D5 , D6 ...Switching diode.
Claims (1)
容量ダイオードD2，D3に第１抵抗R2，R3を介し
て、一方局部発振回路６に設けられた第２可変容
量ダイオードD4に第２抵抗R4を介してそれぞれ
共通のチユーニング電圧源９からのチユーニング
電圧を印加するようにしたチユーナ装置におい
て、 前記第１可変容量ダイオードD2，D3による入
力信号整流電圧に対しては前記チユーニング電圧
源９出力インピーダンスR5より高く且つ前期第
２抵抗R4の値より高いインピーダンスを呈する
が、前記可変容量ダイオードD2，D3の逆方向電
流に対しては低インピーダンスを呈する手段１
１，１２を前記第１可変容量ダイオードD2，D3
へのチユーニング電圧供給路に前記第１抵抗R2，
R3と直列に設けたことを特徴とするチユーナ装
置。 ２ 前記手段１１，１２は高抵抗r2，r3と、前記
逆方向電流に対しては導通する向きで前記高抵抗
r2，r3に並列に接続されたスイツチングダイオー
ドD5，D6とから形成されていることを特徴とす
る特許請求の範囲第１項記載のチユーナ装置。[Claims] 1. The first variable capacitance diodes D 2 , D 3 of the output side tuning circuit 4 of the RF amplifier 3 are connected via the first resistors R 2 , R 3 , and the first variable capacitance diodes D 2 , D 3 of the output side tuning circuit 4 of the RF amplifier 3 are connected to In a tuner device in which a tuning voltage from a common tuning voltage source 9 is applied to two variable capacitance diodes D4 via a second resistor R4 , the input signal from the first variable capacitance diodes D2 and D3 is For the rectified voltage, it exhibits an impedance higher than the output impedance R5 of the tuning voltage source 9 and higher than the value of the second resistor R4 , but for the reverse current of the variable capacitance diodes D2 and D3, Means 1 exhibiting low impedance
1 and 12 are the first variable capacitance diodes D 2 and D 3
The first resistor R 2 is connected to the tuning voltage supply path to the tuning voltage supply path.
A tuner device characterized by being installed in series with R3 . 2 The means 11 and 12 have high resistances r 2 and r 3 , and the high resistances are oriented in a direction that conducts with respect to the reverse direction current.
The tuner device according to claim 1 , characterized in that it is formed of switching diodes D5 and D6 connected in parallel to r2 and r3 .
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP13313581A JPS5834631A (en) | 1981-08-24 | 1981-08-24 | Tuner |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP13313581A JPS5834631A (en) | 1981-08-24 | 1981-08-24 | Tuner |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5834631A JPS5834631A (en) | 1983-03-01 |
| JPH0413885B2 true JPH0413885B2 (en) | 1992-03-11 |
Family
ID=15097581
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP13313581A Granted JPS5834631A (en) | 1981-08-24 | 1981-08-24 | Tuner |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5834631A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6925291B2 (en) * | 2002-09-27 | 2005-08-02 | Thomson Licensing S.A. | Electronic alignment system for a television signal tuner |
-
1981
- 1981-08-24 JP JP13313581A patent/JPS5834631A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5834631A (en) | 1983-03-01 |
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