JPS6242402B2 - - Google Patents
Info
- Publication number
- JPS6242402B2 JPS6242402B2 JP55121448A JP12144880A JPS6242402B2 JP S6242402 B2 JPS6242402 B2 JP S6242402B2 JP 55121448 A JP55121448 A JP 55121448A JP 12144880 A JP12144880 A JP 12144880A JP S6242402 B2 JPS6242402 B2 JP S6242402B2
- Authority
- JP
- Japan
- Prior art keywords
- circuit
- oscillation
- frequency
- uhf
- transistor
- 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
- 230000010355 oscillation Effects 0.000 claims description 21
- 239000003990 capacitor Substances 0.000 claims description 6
- 238000010586 diagram Methods 0.000 description 9
- 238000013016 damping Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 230000005236 sound signal Effects 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03B—GENERATION OF OSCILLATIONS, DIRECTLY OR BY FREQUENCY-CHANGING, BY CIRCUITS EMPLOYING ACTIVE ELEMENTS WHICH OPERATE IN A NON-SWITCHING MANNER; GENERATION OF NOISE BY SUCH CIRCUITS
- H03B5/00—Generation of oscillations using amplifier with regenerative feedback from output to input
- H03B5/18—Generation of oscillations using amplifier with regenerative feedback from output to input with frequency-determining element comprising distributed inductance and capacitance
- H03B5/1841—Generation of oscillations using amplifier with regenerative feedback from output to input with frequency-determining element comprising distributed inductance and capacitance the frequency-determining element being a strip line resonator
- H03B5/1847—Generation of oscillations using amplifier with regenerative feedback from output to input with frequency-determining element comprising distributed inductance and capacitance the frequency-determining element being a strip line resonator the active element in the amplifier being a semiconductor device
Landscapes
- Inductance-Capacitance Distribution Constants And Capacitance-Resistance Oscillators (AREA)
Description
【発明の詳細な説明】
本発明は、UHF発振回路に関するものであ
る。一般に、UHFチユーナ回路には、λ／２共
振回路とλ／４共振回路とがあるが、それぞれに
一長一短がある。すなわち、部品点数では、両者
共同等であるが、λ／４共振回路は、部品ばらつ
きに対する安定度、筐体サイズ、調整などの点で
λ／２共振回回よりすぐれており、λ／２共振回
路は高周波回路部分の設計、温度による周波数ド
リフトなどの点でλ／４共振回路よりすぐれてい
る。しかるに、現在のUHFチユーナ回路では、
ほとんどλ／４共振回路を採用しているが、これ
は設計の困難さはあつても、前述のように部品ば
らつきに対する安定度、筐体サイズ、調整の容易
さ等で充分メリツトがあるからである。しかし、
このλ／４共振回路は前述の温度による周波数ド
リフトが致命的であり、特に可変範囲の広い場合
（例えば米国及びCCIRチヤンネル）にこの傾向
が強く、したがつて発振回路のみλ／２共振回路
とし、他はλ／４共振回路とする方式等が用いら
れている。また、UHF発振回路にはλ／２、
λ／４に拘らず発振回路と同調回路のトラツキン
グずれを起こす引込み現象があり、設計を困難な
ものとしている。例えば第１図に示すような従来
の回路によれば、第２図に示すような発振回路と
同調回路のトラツキングずれをおこす引込み現象
があり、そのため、第３図のように高周波増幅部
の周波数特性において特定のチヤンネルの映像信
号と音声信号とに大きなレベル差が生じ、したが
つて回路設計を極めて困難にしていた。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a UHF oscillation circuit. Generally, UHF tuner circuits include λ/2 resonant circuits and λ/4 resonant circuits, each of which has advantages and disadvantages. In other words, although the number of parts is the same for both, the λ/4 resonant circuit is superior to the λ/2 resonant circuit in terms of stability against component variations, housing size, adjustment, etc. The λ/4 resonant circuit is superior to the λ/4 resonant circuit in terms of high-frequency circuit design and temperature-induced frequency drift. However, in the current UHF tuner circuit,
Most of the circuits use a λ/4 resonant circuit, and although it is difficult to design, it has sufficient advantages in terms of stability against component variations, housing size, ease of adjustment, etc., as mentioned above. be. but,
This λ/4 resonant circuit is fatally affected by the aforementioned temperature-induced frequency drift, and this tendency is particularly strong when the variable range is wide (for example, the US and CCIR channels). , and others use a λ/4 resonant circuit. In addition, the UHF oscillation circuit has λ/2,
Regardless of λ/4, there is a pull-in phenomenon that causes tracking deviation between the oscillation circuit and the tuning circuit, making design difficult. For example, in the conventional circuit shown in Fig. 1, there is a pull-in phenomenon that causes tracking deviation between the oscillation circuit and the tuning circuit as shown in Fig. 2. In terms of characteristics, a large level difference occurs between the video signal and audio signal of a specific channel, making circuit design extremely difficult.
本発明は、UHF発振回路において、温度変化
による周波数ドリフトと発振回路のトラツキング
ずれを改善することを目的としてなされたもので
発振素子であるトランジスタのエミツタとアース
間に抵抗とコンデンサの直列回路を挿入してなる
ものである。 The present invention was made with the aim of improving frequency drift due to temperature changes and tracking deviation of the oscillation circuit in a UHF oscillation circuit.A series circuit of a resistor and a capacitor is inserted between the emitter of a transistor, which is an oscillation element, and the ground. This is what happens.
以下、本発明の一実施例を図面について説明す
る。 An embodiment of the present invention will be described below with reference to the drawings.
第４図において、１は発振素子であるトランジ
スタ、２，３，４，５，６，７は抵抗、８，９，
１０，１１，１２はコンデンサ、１３，１４はコ
イル、１５は可変容量ダイオード、＋Ｂは電源端
子、Tuは同調電圧端子である。そして、特にこ
の回路において、前記発振用トランジスタ１のエ
ミツタとアース間に抵抗６とコンデンサ９の直列
回路を挿入した点を特徴としている。 In Fig. 4, 1 is a transistor which is an oscillation element, 2, 3, 4, 5, 6, 7 are resistors, 8, 9,
10, 11 and 12 are capacitors, 13 and 14 are coils, 15 is a variable capacitance diode, +B is a power supply terminal, and Tu is a tuning voltage terminal. This circuit is particularly characterized in that a series circuit of a resistor 6 and a capacitor 9 is inserted between the emitter of the oscillating transistor 1 and the ground.
つぎに本発明の現論的考察を行なう。 Next, a practical discussion of the present invention will be made.
損失のない（Ｑ＝∞）共振回路の共振角周波数
（ω０）は
で与えられるが、損失のある共振回路の共振角周
波数（ω0′）は、ω０より必ず低く、その相対誤
差は次式で与えられる。 The resonant angular frequency (ω 0 ) of a lossless (Q=∞) resonant circuit is However, the resonant angular frequency (ω 0 ') of a lossy resonant circuit is always lower than ω 0 , and its relative error is given by the following equation.
ω０−ω０′／ω０＝１／８Ｑ２
この損失の影響は、Ｑが低く周波数の高い
UHFでは無視することができない。例えばf0＝
930MHzをとるとつぎのようになる。0
′（Ｑ＝100）＝929.9884、△′＝11.6（KHz）0
″（Ｑ＝20）＝929.709、△″＝291（KHz）０
（Ｑ＝10）＝928.84、△＝1.16
（MHz）
一般に、UHF回路のＱは10程度であり、周波
数変化、温度変化によりＱが変化すれば、トラツ
キング、周波数ドリフトに影響を与えることが判
明した。 ω 0 - ω 0 ′/ω 0 = 1/8Q 2 The effect of this loss is low Q and high frequency.
It cannot be ignored in UHF. For example, f 0 =
Taking 930MHz results in the following. 0 ′ (Q=100) = 929.9884, △′ = 11.6 (KHz) 0 ″ (Q = 20) = 929.709, △″ = 291 (KHz) 0 (Q = 10) = 928.84, △ = 1.16
(MHz) Generally, the Q of a UHF circuit is about 10, and it has been found that if the Q changes due to frequency changes or temperature changes, it will affect tracking and frequency drift.
UHF発振回路のＱを決定する重要な要素とし
て、可変容量素子のRsと、発振トランジスタの
入出力インピーダンスがあるが、UHF発振回用
としても一般的なトランジスタである2SC288A
のｙパラメータのyibが第５図に示されている。
この第７図にはさらに、エミツタ抵抗、容量（漂
遊容量を1pFと仮定）を含めた入力アドミツタン
スを、従来例をyib′、本発明をyib″で併記した。 The important factors that determine the Q of a UHF oscillation circuit are the variable capacitance element Rs and the input/output impedance of the oscillation transistor, but the 2SC288A is a common transistor for UHF oscillation circuits.
The y parameter yib of is shown in FIG.
In FIG. 7, the input admittance including the emitter resistance and capacitance (assuming the stray capacitance is 1 pF) is also shown as yib' for the conventional example and yib'' for the present invention.
なお、コレクタ電流（Ic）は５ｍＡ、クレク
タ・ベース間電圧（ＶCB）は10Vとする。 Note that the collector current (Ic) is 5 mA, and the collector-base voltage (V CB ) is 10 V.
この第５図から明らかなように、従来例の
yib′のコンダクタンス分gib′はトランジスタ単体
のgibで略決定するのに対し、本考案のyib″のコ
ンダクタンス分gib″は抵抗のダンピング効果によ
り、gibで決定される比率は小さい。 As is clear from Fig. 5, the conventional example
The conductance gib' of yib' is approximately determined by the gib of a single transistor, whereas the ratio of the conductance gib'' of yib'' of the present invention determined by gib is small due to the damping effect of the resistor.
コンダクタンスgibの温度による変化が発振回
路のＱにどのように影響し、結果として発振周波
数にどのような影響が出るのかを明確に解析する
ことは困難であるが、実験結果は、gibの変化を
ダンピングにより補償することによりトラツキン
グずれ、温度変化による周波数ドリフトが改善さ
れることを示している。 Although it is difficult to clearly analyze how changes in conductance gib due to temperature affect the Q of the oscillation circuit and, as a result, the oscillation frequency, experimental results indicate that changes in gib It is shown that tracking deviation and frequency drift due to temperature changes can be improved by compensating with damping.
なお、抵抗６の抵抗値と、コンデンサ９の容量
値の関係は、抵抗値がコンダクタンス分の補正量
を決定してトラツキングずれ、周波数ドリフトを
改善し、また容量値がコンダクタンス分、サセプ
タンス分の補正量の周波数特性を支配して発振条
件を決定する。UHFチユーナにおける抵抗値お
よび容量値の最適値は周波数可変範囲、発振素子
の選定および動作点により異なるが、略つぎの値
である。 The relationship between the resistance value of the resistor 6 and the capacitance value of the capacitor 9 is that the resistance value determines the amount of correction for conductance and improves tracking deviation and frequency drift, and the capacitance value determines the amount of correction for conductance and susceptance. The oscillation conditions are determined by controlling the frequency characteristics of the quantity. The optimal values for the resistance and capacitance values in a UHF tuner vary depending on the frequency variable range, the selection of the oscillation element, and the operating point, but are approximately the following values.
Ｒ＝56〜100Ω
Ｃ＝３〜5pF
本発明は上述のように構成したので、周波数ド
リフトおよびトラツキングが大幅に改善されるも
のである。ちなみにトラツキング、温度変化によ
る周波数ドリフトが第６図および第７図に示すよ
うに、従来例に比較し、大幅に改善されているこ
とは明白である。R=56-100Ω C=3-5pF Since the present invention is constructed as described above, frequency drift and tracking are significantly improved. Incidentally, as shown in FIGS. 6 and 7, it is clear that tracking and frequency drift due to temperature changes are significantly improved compared to the conventional example.
なお、周波数ドリフトに関し、従来は510〜
650MHzのドリフト幅を温度係数で改善すること
は不可能であつたが、本発明では温度係数により
さらに改善することができる。 Regarding frequency drift, conventionally 510~
Although it has been impossible to improve the drift width at 650 MHz using a temperature coefficient, the present invention can further improve the drift width using a temperature coefficient.
第１図は従来のUHF発振回路図、第２図は従
来の発振回路と同調回路との同調電圧に対する周
波数特性図、第３図は従来回路における各チヤン
ネル毎のトラツキング特性図、第４図は本発明に
よるUHF発振回路の一実施例を示す電気回路
図、第５図は入力アドミツタンスの特性図、第６
図は本発明の回路における各チヤンネル毎のトラ
ツキング特性図、第７図は温度による周波数ドリ
フトの説明図である。
１……トランジスタ、６……抵抗、９……コン
デンサ。
Figure 1 is a conventional UHF oscillation circuit diagram, Figure 2 is a frequency characteristic diagram of the conventional oscillation circuit and tuning circuit with respect to tuning voltage, Figure 3 is a tracking characteristic diagram for each channel in the conventional circuit, and Figure 4 is a diagram of the tracking characteristics for each channel in the conventional circuit. An electric circuit diagram showing an embodiment of the UHF oscillation circuit according to the present invention, FIG. 5 is a characteristic diagram of input admittance, and FIG. 6 is a characteristic diagram of input admittance.
The figure is a tracking characteristic diagram for each channel in the circuit of the present invention, and FIG. 7 is an explanatory diagram of frequency drift due to temperature. 1...Transistor, 6...Resistor, 9...Capacitor.
Claims (1)
ジスタをベース接地とし、共振回路のＬとＣで設
定された周波数で発振するUHF発振回路におい
て、前記発振用トランジスタのエミツタとアース
間に、副共振の減衰用として低抵抗値の抵抗とコ
ンデンサの直列回路を挿入し、前記共振回路に可
変容量ダイオードを結合し、同調電圧によりこの
可変容量ダイオードの容量を可変して周波数を切
換えるようにしたことを特徴とするUHF発振回
路。1. In a UHF oscillation circuit that uses a transistor as an oscillation element, this transistor is grounded as a base, and oscillates at a frequency set by L and C of the resonant circuit. A series circuit of a low-resistance resistor and a capacitor is inserted, a variable capacitance diode is coupled to the resonant circuit, and the frequency is switched by varying the capacitance of the variable capacitance diode using a tuning voltage. UHF oscillation circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP12144880A JPS5745704A (en) | 1980-09-02 | 1980-09-02 | Uhf oscillating circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP12144880A JPS5745704A (en) | 1980-09-02 | 1980-09-02 | Uhf oscillating circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5745704A JPS5745704A (en) | 1982-03-15 |
| JPS6242402B2 true JPS6242402B2 (en) | 1987-09-08 |
Family
ID=14811380
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP12144880A Granted JPS5745704A (en) | 1980-09-02 | 1980-09-02 | Uhf oscillating circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5745704A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS59138103A (en) * | 1983-01-28 | 1984-08-08 | Nec Home Electronics Ltd | Transistor oscillating circuit |
| JPS6057241U (en) * | 1983-09-27 | 1985-04-22 | シャープ株式会社 | Local oscillator circuit of electronically tuned tuner |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS49127552A (en) * | 1973-04-05 | 1974-12-06 | ||
| JPS51144553A (en) * | 1975-05-27 | 1976-12-11 | Sperry Rand Corp | Variable frequency sine wave generator |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS52135035U (en) * | 1976-04-07 | 1977-10-14 |
-
1980
- 1980-09-02 JP JP12144880A patent/JPS5745704A/en active Granted
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS49127552A (en) * | 1973-04-05 | 1974-12-06 | ||
| JPS51144553A (en) * | 1975-05-27 | 1976-12-11 | Sperry Rand Corp | Variable frequency sine wave generator |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5745704A (en) | 1982-03-15 |
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