JPS6138289Y2

JPS6138289Y2 -

Info

Publication number: JPS6138289Y2
Application number: JP12983479U
Authority: JP
Priority date: 1979-09-19
Filing date: 1979-09-19
Publication date: 1986-11-05
Also published as: JPS5646313U

Description

【考案の詳細な説明】この考案は、たとえば中波と短波の両方を受信
できるラジオ受信機の中波と短波に共用の局部発
振回路に用いる発振回路に関する。DETAILED DESCRIPTION OF THE INVENTION This invention relates to an oscillation circuit used in a local oscillation circuit shared by medium waves and short waves, for example, in a radio receiver capable of receiving both medium waves and short waves.

従来、中波と短波に共用の局部発振回路は種々
考えられているが、スイツチの数が多く構成が複
雑になつたり、中波のときと短波のときで発振強
度が違つたりする不都合があつた。 Conventionally, various local oscillation circuits that can be used for both medium and short waves have been considered, but they have the disadvantages of having a large number of switches, making the configuration complicated, and having different oscillation strengths for medium and short waves. It was hot.

この考案は、このような不都合をなくしたもの
である。 This invention eliminates such inconvenience.

第１図は、この考案の発振回路の一例で、１は
発振用トランジスタ、２は発振用トランス、３は
中波と短波の切り換え用スイツチ、４は「短波
１」，「短波２」，「短波３」の切り換え用スイツチ
である。 Figure 1 shows an example of the oscillation circuit of this invention, where 1 is an oscillation transistor, 2 is an oscillation transformer, 3 is a switch for switching between medium wave and short wave, and 4 is "short wave 1", "short wave 2", " This is a switch for selecting "Shortwave 3".

そして、トランジスタ１のベースが第１及び第
２のコンデンサC₁及びC₂の直列回路を介して接
地されるとともに第３のコンデンサC₃の一端に
接続される。トランジスタ１のエミツタが第１及
び第２のコンデンサC₁及びC₂の接続点に接続さ
れるとともに第１の抵抗R₁を介してトランス２
の１次側の中間タツプに接続される。トランス２
の１次側の一端は接地される。また、トランス２
の１次側と並列に同調用バリコン５とトリマコン
デンサ６が接続される。トランス２の２次側の一
端は第４のコンデンサC₄を介して接地される。
そして、スイツチ３が中波側接点Ｍに切り換えら
れるときは、第３のコンデンサC₃の他端とトラ
ンス２の１次側の他端との間に第５のコンデンサ
C₅と第２の抵抗R₂の直列回路が接続される。ま
た、スイツチ３が短波側接点Ｓに切り換えられる
ときは、第３のコンデンサC₃の他端とトランス
２の２次側及び第４のコンデンサC₄の接続点と
の間に、スイツチ４が「短波１」，「短波２」，「短
波３」に対応する接点S1，S2，S3のいずれに切
り換えられるかに応じて、水晶振動子X1，X2あ
るいはX3が接続される。そして、トランス２の
２次側の他端が出力とされてミキサに接続され
る。 The base of the transistor 1 is grounded through a series circuit of the first and second capacitors C ₁ and C ₂ and is also connected to one end of the third capacitor C ₃ . The emitter of the transistor 1 is connected to the connection point of the first and second capacitors _C1 and _C2 , and is connected to the transformer ₂ through the first resistor R1.
Connected to the intermediate tap on the primary side of the transformer 2
One end of the primary side of is grounded. Also, transformer 2
A tuning variable capacitor 5 and a trimmer capacitor 6 are connected in parallel with the primary side of. One end of the secondary side of the transformer 2 is grounded via a fourth capacitor _C4 .
When the switch 3 is switched to the medium wave side contact M, a fifth capacitor is connected between the other end of the third capacitor _C3 and the other end of the primary side of the transformer 2.
A series circuit of C ₅ and a second resistor R ₂ is connected. When the switch 3 is switched to the short wave side contact S, the switch ₄ is connected between the other end of the third capacitor _C3 and the connection point of the secondary side of the transformer 2 and the fourth capacitor C4. Depending on which of the contacts S1, S2, and S3 corresponding to "short wave 1", "short wave 2", and "short wave 3" is switched, the crystal oscillators X1, X2, or X3 are connected. The other end of the secondary side of the transformer 2 is output and connected to the mixer.

なお、トランジスタ１のベースが抵抗R₃を介
してコレクタに接続され、コレクタが抵抗R₄を
介して正の電源電圧が得られる電源端子に接続さ
れるとともにコンデンサC₆を介して接地され
る。 Note that the base of the transistor 1 is connected to the collector via a resistor _R3 , and the collector is connected via a resistor _R4 to a power supply terminal from which a positive power supply voltage is obtained, and is grounded via a capacitor _C6 .

この場合、たとえば、トランス２の１次側の一
端から中間タツプまでは３ターン、中間タツプか
ら他端までは80〜90ターン、２次側は６ターンに
される。また、たとえば、 C₁＝150pF C₂＝100pF C₃＝27pF C₄＝390pF C₅＝15pF R₁＝470Ω R₂＝330Ω にされる。 In this case, for example, there are 3 turns from one end of the primary side of the transformer 2 to the intermediate tap, 80 to 90 turns from the intermediate tap to the other end, and 6 turns on the secondary side. Further, for example, C ₁ =150 pF C ₂ =100 pF C ₃ =27 pF C ₄ =390 pF C ₅ =15 pF R ₁ =470 Ω R ₂ =330 Ω.

この回路によると、中波の場合には、第１及び
第２のコンデンサC₁及びC₂が中波に対しては無
視できるので、第２図に示すようにハートレー発
振回路を構成し、バリコン５の操作により発振周
波数が変えられ、中波を受信できる。 According to this circuit, in the case of medium waves, the first and second capacitors C ₁ and C ₂ can be ignored for medium waves, so a Hartley oscillation circuit is configured as shown in Figure 2, and a variable capacitor is used. The oscillation frequency can be changed by the operation in step 5, and medium waves can be received.

一方、短波の場合には、トランス２の１次側の
一端から中間タツプまでが短波に対しては無視で
き、またトランス２の２次側も短波に対しては無
視できるので、第３図に示すようにコルビツツ発
振回路を構成し、スイツチ４の切り換えにより水
晶振動子X1，X2，X3のいずれかが選択され、
「短波１」，「短波２」あるいは「短波３」を受信
できる。 On the other hand, in the case of short waves, the area from one end of the primary side of transformer 2 to the intermediate tap can be ignored for short waves, and the secondary side of transformer 2 can also be ignored for short waves. A Kolbitz oscillator circuit is configured as shown, and one of crystal oscillators X1, X2, and X3 is selected by switching switch 4.
It can receive "shortwave 1", "shortwave 2" or "shortwave 3".

この考案によれば、中波と短波の切り換え用ス
イツチは１個でよく、構成がきわめて簡単にな
る。しかも、中波のときも短波のときも充分な発
振強度が得られる。 According to this invention, only one switch is required for switching between medium waves and short waves, making the configuration extremely simple. Furthermore, sufficient oscillation strength can be obtained for both medium and short waves.

[Brief explanation of drawings]

第１図はこの考案の発振回路の一例の接続図、
第２図及び第３図はそれぞれ各場合の等価回路図
である。１は発振用トランジスタ、２は発振用トラン
ス、３はスイツチ、C₁〜C₅は第１〜第５のコン
デンサ、R₁及びR₂は第１及び第２の抵抗、５は
同調用バリコンである。 Figure 1 is a connection diagram of an example of the oscillation circuit of this invention.
FIGS. 2 and 3 are equivalent circuit diagrams in each case. 1 is an oscillation transistor, 2 is an oscillation transformer, 3 is a switch, C ₁ to C ₅ are first to fifth capacitors, R ₁ and R ₂ are first and second resistors, and 5 is a tuning variable capacitor. be.

Claims

[Scope of utility model registration request]

It has an oscillation transistor, an oscillation transformer, and a switch, and the base of the transistor is connected to a reference potential point through a series circuit of first and second capacitors, and is also connected to one end of a third capacitor. The emitter of the transistor is connected to the connection point of the first and second capacitors, and is also connected to the intermediate tap on the primary side of the transformer via a first resistor, and one end of the primary side of the transformer is connected to the connection point of the first and second capacitors. It is connected to the reference potential point, and a tuning variable capacitor is connected in parallel with the primary side of the transformer.
One end of the secondary side of the transformer is connected to the reference potential point via a fourth capacitor, and when the switch is in one switching state, the other end of the third capacitor and the other end of the primary side of the transformer are connected. 5th between the ends
A series circuit of a capacitor and a second resistor is connected, and when the switch is in another switching state, the third
A crystal resonator is connected between the other end of the capacitor and a connection point between the secondary side of the transformer and the fourth capacitor, and the other end of the secondary side of the transformer is an output.