JPS5834830Y2 - AFT device - Google Patents
AFT deviceInfo
- Publication number
- JPS5834830Y2 JPS5834830Y2 JP1977143593U JP14359377U JPS5834830Y2 JP S5834830 Y2 JPS5834830 Y2 JP S5834830Y2 JP 1977143593 U JP1977143593 U JP 1977143593U JP 14359377 U JP14359377 U JP 14359377U JP S5834830 Y2 JPS5834830 Y2 JP S5834830Y2
- Authority
- JP
- Japan
- Prior art keywords
- aft
- tuning
- tuning coil
- local oscillation
- varicap diode
- 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
Landscapes
- Channel Selection Circuits, Automatic Tuning Circuits (AREA)
- Superheterodyne Receivers (AREA)
Description
【考案の詳細な説明】
本考案はターレット式ＶＨＦチューナに於て、チャンネ
ル切替時にＡＦＴを切る装置に関するものである。[Detailed Description of the Invention] The present invention relates to a device for turning off the AFT when switching channels in a turret type VHF tuner.
一般に、■ＨＦチューナに於ける微調は手動と自動があ
り、この自動はチューナからの中間周波信号の段階で行
われ、ＡＦＴ装置が用いられている。In general, there are two types of fine adjustment in an HF tuner: manual and automatic.This automatic adjustment is performed at the intermediate frequency signal stage from the tuner, and an AFT device is used.
このＡＦＴ装置は、従来では第１図に示すような回路構
成を有していた。This AFT device conventionally had a circuit configuration as shown in FIG.
つまり、チューナの局部発振回路に挿入したバリキャッ
プダイオードＤにＡＦＴ信号を抵抗を介して印加する構
成である。In other words, the configuration is such that the AFT signal is applied via a resistor to the varicap diode D inserted in the local oscillation circuit of the tuner.
また、第１図のＬはチャンネル毎の同調コイルで、この
同調コイルＬと、バリキャップダイオードＤとでもって
同調回路が形成される。Further, L in FIG. 1 is a tuning coil for each channel, and this tuning coil L and a varicap diode D form a tuning circuit.
ところで、同調コイルＬはチャンネル切替毎にインダク
タンスが急変するが、その時、ＡＦＴ信号を切ることが
望ましい。By the way, the inductance of the tuning coil L changes suddenly every time the channel is switched, and it is desirable to turn off the AFT signal at that time.
匙ち、ＡＦＴ電圧がある許容範囲を逸脱した場合、これ
が直接にバリキャップダイオードＤに入ると回路動作不
能になる可能性が強くなる。However, if the AFT voltage deviates from a certain allowable range and directly enters the varicap diode D, there is a strong possibility that the circuit will become inoperable.
またチャンネル切替時に誤動作の可能性も大きくなる。Furthermore, there is a greater possibility of malfunction when switching channels.
そこで本考案はチャンネル切替時にＡＦＴ信号を切るこ
とを主目的に、第２°図に示すようなＡＦＴ装置を提供
する。Therefore, the present invention provides an AFT device as shown in FIG. 2, the main purpose of which is to cut off the AFT signal when switching channels.
即ち、本考案は同調コイルＬの一端にＡＦＴ信号を印加
する回路構成で、ＡＦＴ信号は同調コイルＬを通してバ
リキャップダイオードＤに印加される。That is, the present invention has a circuit configuration in which an AFT signal is applied to one end of a tuning coil L, and the AFT signal is applied to a varicap diode D through the tuning coil L.
また、このようにすれは、チャンネル切替で同調コイル
Ｌの端子１゜１が離れることにより、ＡＦＴ信号は完全
に切られる。Furthermore, in this case, the AFT signal is completely cut off when the terminal 1.1 of the tuning coil L is separated by channel switching.
尚、第２図のＲは抵抗、Ｃはコンデンサ、Ｔはトランジ
スタで、これらは公知構成でよい。In FIG. 2, R is a resistor, C is a capacitor, and T is a transistor, and these may be of known construction.
ところで、ターレット式ＶＨＦｆｌユーナの同調コイル
Ｌは、第３図に示すように回転円板２の周上に等間隔で
配夕１ルた同調軸３に取付けられ、そして、同調コイル
Ｌの端子１は同調軸３から突出させたコンタクト板４に
接続されている。By the way, the tuning coil L of the turret type VHF fl Yuna is attached to the tuning shaft 3 arranged at equal intervals on the circumference of the rotating disk 2, as shown in FIG. is connected to a contact plate 4 protruding from the tuning shaft 3.
またＡＦＴ回路側の端子はステーターバー５のスプリン
グコンタクト６に接続され、このスプリングコンタクト
６とコンタクト板４との接触の有無で同調コイルＬの切
替えがなされる。Further, the terminal on the AFT circuit side is connected to a spring contact 6 of the stator bar 5, and the tuning coil L is switched depending on whether or not the spring contact 6 is in contact with the contact plate 4.
従って、チャンネル切替時にＡＦＴ信号を確実に切るた
めには、スプリングコンタクト６からコンタクト板４が
完全に離れることが必要である。Therefore, in order to reliably turn off the AFT signal when switching channels, it is necessary that the contact plate 4 separate completely from the spring contact 6.
上記必要性の対策としては、例えば同調軸３の間隔を十
分に大きくとり、コンタクト板４がスプリングコンタク
ト６に同時に２個が接触しないようにするとか、またコ
ンタクト板４の突出高を低くするとか、コンタクト板４
を第５図に示すように三角形状に尖らせるとかが可能で
ある。Countermeasures for the above-mentioned necessity include, for example, making the interval between the tuning shafts 3 sufficiently large so that two contact plates 4 do not contact the spring contacts 6 at the same time, and lowering the protruding height of the contact plate 4. , contact plate 4
It is possible to sharpen it into a triangular shape as shown in FIG.
以上説明したように、本考案はターレット式ＶＨＦチュ
ーナに挿入したバリキャップダイオードに、ＡＦＴ信号
を同調コイルを介して印加するようになしたから、チャ
ンネル切替時にＡＦＴが完全に切られ、従って、ＡＦＴ
バンドをかなり広くとることが可能となった。As explained above, in the present invention, the AFT signal is applied to the varicap diode inserted in the turret type VHF tuner via the tuning coil, so that the AFT is completely turned off when switching channels.
It became possible to make the band considerably wider.
また正規の同調周波数に対するＡＦＴ範囲としての引込
範囲逸脱による誤動作の防止が可能となる。Furthermore, it is possible to prevent malfunctions due to deviation from the pull-in range as the AFT range with respect to the normal tuning frequency.
第１図は従来のＡＦＴ装置の回路図、第２図は本考案に
係るＡＦＴ装置の実施例を示す回路図、第３図は同調コ
イルに於ける接点説明図、第４図は第３図の電気的説明
図、第５図は同調コイルの接点応用図である。
Ｄ・・・・・・バリキャップダイオード、Ｌ・・・・・
・同調コイル。Fig. 1 is a circuit diagram of a conventional AFT device, Fig. 2 is a circuit diagram showing an embodiment of an AFT device according to the present invention, Fig. 3 is an explanatory diagram of contacts in a tuning coil, and Fig. 4 is a diagram illustrating contacts in a tuning coil. FIG. 5 is an electrical diagram showing the contact points of the tuning coil. D...Varicap diode, L...
- Tuning coil.
Claims (1)
ルの局部発振回路を形成するターレット式ＶＨＦチュー
ナにおいて、前記局部発振回路はその同調回路にＡＦＴ
端子からＡＦＴ信号が印加されるバリキャップダイオー
ドを具備し、前記ＡＦＴ信号を前記局部発振回路に接続
された同調コイルを経て前記バリキャップタイオードに
供給して選択チャンネルでのＡＦＴ動作を可能とすると
共に、チャンネル切替時には前記同調コイルを前記局部
発振回路から切離して前記ＡＦＴ信号の前記バリキャッ
プダイオードへの供給を切断することを特徴とするＡＦ
Ｔ装置。In a turret-type VHF tuner that switches a tuning coil for each channel to form a local oscillation circuit for the selected channel, the local oscillation circuit has an AFT in its tuning circuit.
A varicap diode is provided to which an AFT signal is applied from a terminal, and the AFT signal is supplied to the varicap diode via a tuning coil connected to the local oscillation circuit to enable AFT operation on a selected channel. Additionally, when switching channels, the tuning coil is disconnected from the local oscillation circuit to cut off the supply of the AFT signal to the varicap diode.
T device.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1977143593U JPS5834830Y2 (en) | 1977-10-25 | 1977-10-25 | AFT device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1977143593U JPS5834830Y2 (en) | 1977-10-25 | 1977-10-25 | AFT device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5468523U JPS5468523U (en) | 1979-05-15 |
| JPS5834830Y2 true JPS5834830Y2 (en) | 1983-08-05 |
Family
ID=29121416
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1977143593U Expired JPS5834830Y2 (en) | 1977-10-25 | 1977-10-25 | AFT device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5834830Y2 (en) |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS4935522U (en) * | 1972-06-26 | 1974-03-29 | ||
| JPS4946483A (en) * | 1972-09-05 | 1974-05-04 | ||
| JPS505684U (en) * | 1973-05-11 | 1975-01-21 |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5177015U (en) * | 1974-12-12 | 1976-06-17 |
-
1977
- 1977-10-25 JP JP1977143593U patent/JPS5834830Y2/en not_active Expired
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS4935522U (en) * | 1972-06-26 | 1974-03-29 | ||
| JPS4946483A (en) * | 1972-09-05 | 1974-05-04 | ||
| JPS505684U (en) * | 1973-05-11 | 1975-01-21 |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5468523U (en) | 1979-05-15 |
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