JPS5846592Y2 - AM-FM radio receiver band switching circuit - Google Patents
AM-FM radio receiver band switching circuitInfo
- Publication number
- JPS5846592Y2 JPS5846592Y2 JP15581577U JP15581577U JPS5846592Y2 JP S5846592 Y2 JPS5846592 Y2 JP S5846592Y2 JP 15581577 U JP15581577 U JP 15581577U JP 15581577 U JP15581577 U JP 15581577U JP S5846592 Y2 JPS5846592 Y2 JP S5846592Y2
- Authority
- JP
- Japan
- Prior art keywords
- transistor
- radio receiver
- reception
- switching circuit
- emitter
- 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
Description
【考案の詳細な説明】
本考案はＦＭ受信時ＩＦ増幅用、ＡＭ受信時コンバータ
ー用として動作するトランジスタを有するＡＭ−ＦＭラ
ジオ受信機のバンド切換回路に関するものである。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a band switching circuit for an AM-FM radio receiver having a transistor that operates for IF amplification during FM reception and as a converter during AM reception.
第１図は斯種ラジオ受信機のバンド切換回路の従来例を
示す回路図で、第１図に於いて使用されている部品は下
記の通りである。FIG. 1 is a circuit diagram showing a conventional example of a band switching circuit of this type of radio receiver, and the components used in FIG. 1 are as follows.
Ｔ１はＦＭ用ＩＦＴ、’ｌ’２はＡＭ用ＩＦＴ、Ｔｒ、
はＦＭＩＦＭ幅とＡＭコンバーターを兼ねるトランジス
タ、ＣＦｌはＦＭＭセラミックフィルタ、ＬｌはＡＭ用
アンテナコイル、Ｌ２はＡＭ用発振コイル、Ｃ１はＦＭ
用テ゛カップリングコンテ゛ンサ、Ｃ２はＦＭ時Ｔｒ、
のベースバイパス用コンデンサ、Ｃ３はＡＭ注注入用コ
ンテアンサＣ４はトランジスタＴｒ、のエミッタバイパ
ス用コンデンサ、ＶＣ３はＡＭアンテナ側バリコン、■
Ｃ２はＡＭＭ振側バリコン、Ｒ１はＩ・ランジスタＴｒ
１のベースバイアス用抵抗、Ｒ２は１〜ランジスタＴｒ
、のエミッタバイアス用抵抗、Ｒ３はＡＭ時の大入力歪
、大入力笛音妨害殴書用抵抗、Ｒ４はＡＭＭ入電圧平滑
用抵抗、Ｒ５はｌ・ランジスタＴｒ１のコレクタバイア
ス、及びセラミックフィルタＣＦ、とのマツチング用抵
抗、Ｒ６はセラミックフィルタＣＦ。T1 is IFT for FM, 'l'2 is IFT for AM, Tr,
is the FMIFM width and the transistor that also serves as the AM converter, CFi is the FMM ceramic filter, Ll is the AM antenna coil, L2 is the AM oscillation coil, and C1 is the FM
Coupling capacitor for use, C2 is Tr at FM,
C3 is the capacitor for the base bypass of the AM injection capacitor, C4 is the capacitor for the emitter bypass of the transistor Tr, VC3 is the variable capacitor on the AM antenna side, ■
C2 is AMM swing side variable capacitor, R1 is I transistor Tr
1 base bias resistor, R2 is 1 to transistor Tr
, R3 is a resistor for large input distortion during AM, large input whistling noise interference, R4 is a resistor for smoothing AMM input voltage, R5 is collector bias of l transistor Tr1, and ceramic filter CF. The matching resistor R6 is a ceramic filter CF.
の出力側マツチング用及びＡＭ用ＩＦＴＴ２との結合用
抵抗、Ｓｌ、Ｓ２．Ｓ３はバンド切換スイッチである。Resistors for output side matching and coupling with AM IFTT2, Sl, S2. S3 is a band changeover switch.
第１図の回路では、
■ ＦＭ受信時に、ＡＭＭ入力信号がＡＭ用アンテナコ
イルＬ１の２次側巻線１１′を通してトランジスタＴｒ
１のベースに導かれ、ストレート検波によりＡＭ信号の
妨害が発生するのを防止する為に、バンド切換スイッチ
Ｓ２を使用してＡＭ用アンテナコイルＬ１の２次側巻線
ｌ 、／をアースする必要があった。In the circuit shown in Figure 1, ■ During FM reception, the AMM input signal passes through the secondary winding 11' of the AM antenna coil L1 to the transistor Tr.
In order to prevent AM signal interference caused by straight detection, it is necessary to ground the secondary windings l, / of the AM antenna coil L1 using the band selection switch S2. was there.
■ また、ＡＭ受受信人大入力信号対する歪、笛音妨害
を改善するためＴｒ、のエミッタバイパス用コンデンサ
Ｃ４に直列に小抵抗Ｒ３（１０〜４７Ω程度）を挿入す
る事から、ＦＭ受信時にはこのＲ３のショートシてＦＭ
ＩＦＭ得の低下を防止するためのバンド切換スイッチＳ
１が必要であった。■ Also, in order to improve distortion and whistling interference for AM receiver/receiver large input signals, a small resistor R3 (approximately 10 to 47 Ω) is inserted in series with the emitter bypass capacitor C4 of the Tr, so when receiving FM, this R3 short FM
Band selection switch S to prevent IFM gain from decreasing
1 was necessary.
尚、バンド切換スイッチＳ３はＴｒ、のコレクタ負荷の
ショーテイング用及びＦＭ用電源ライン切換用で゛ある
。The band changeover switch S3 is used for shorting the collector load of the Tr and for changing over the FM power line.
本考案は上述の２つの問題点を１回路のバンド切換スイ
ッチで解決せんとするもので、以下本考案の一実施例を
第２図に従い説明する。The present invention attempts to solve the above-mentioned two problems with a single circuit band changeover switch.An embodiment of the present invention will be described below with reference to FIG.
尚第２図に於いて、第１図と同一部品については第１図
と同一の図番を用いることにする。In FIG. 2, the same numbers as in FIG. 1 are used for the same parts as in FIG. 1.
第２図の回路では、バンド切換スイッチＳ１′のＦＭ側
固定端子には、ＦＭ受信時のトランジスタＴｒ、のエミ
ッタバイパス用とＡＭ受信時の発振電圧注入用を兼ねる
コンテ゛ンサＣ４′のアース側端子を接続するとともに
、抵抗Ｒ４を介してＡＭ用発振コイルＬ２の１次側巻線
１２を接続し、ＡＭ側固定端子にはＡＭ用アンテナコイ
ルＬ１の２次側巻線１１′のアース側を接続し、共通（
ＣＯＭＭＯＮ）端子にはアースＥを夫々接続したことを
特徴としている。In the circuit shown in Fig. 2, the FM side fixed terminal of the band changeover switch S1' is connected to the ground side terminal of a capacitor C4', which serves both for emitter bypass of the transistor Tr during FM reception and for injecting oscillation voltage during AM reception. At the same time, connect the primary winding 12 of the AM oscillation coil L2 via the resistor R4, and connect the ground side of the secondary winding 11' of the AM antenna coil L1 to the AM fixed terminal. ,common(
COMMON) terminals are connected to earth E, respectively.
尚第２図に於いて、０３′はＡＭ用アンテナコイルＬ１
の２次側巻線１１′とトランジスタＴｒ、のベース結合
用コンデンサである。In Fig. 2, 03' is the AM antenna coil L1.
This is a capacitor for coupling the base of the secondary winding 11' and the transistor Tr.
斯様に構成してなるＡＭ−ＦＭラジオ受信機に於いて、
ＦＭ受信時、ＡＭ用アンテナコイルＬ１にＡＭ大入力信
号が人ってきても、アンテナコイルＬ１の２次側巻線１
１′はアース側がバンド切換スイッチＳ１′によって切
断されているので、トランジスタＴｒ１にＡＭ信号が全
く導かれることなく、ＡＭの妨害信号は発生しない。In the AM-FM radio receiver configured in this way,
During FM reception, even if a large AM input signal comes to the AM antenna coil L1, the secondary winding 1 of the antenna coil L1
Since the ground side of transistor 1' is disconnected by band changeover switch S1', no AM signal is introduced to transistor Tr1, and no AM interference signal is generated.
又、トランジスタＴｒ工のエミッタバイパス用コンテ゛
ンサＣ４′はＳ１′によって直接アースされるので、利
得の低下も起こらない。Further, since the emitter bypass capacitor C4' of the transistor Tr is directly grounded by S1', no decrease in gain occurs.
更にこのときＡＭ用発振コイルＬ２からの発振注入電圧
はスイッチＳ１′を介してアースに側路される。Furthermore, at this time, the oscillation injection voltage from the AM oscillation coil L2 is bypassed to ground via the switch S1'.
ＡＭ受信時には、ＡＭ用アンテナコイルＬ１の２次側巻
線１１′のアース側はバンド切換スイッチＳｌ′によっ
てアースＥに接続され、アンテナコイル孔工に発生した
ＡＭ信号はトランジスタＴｒ１のベースに導かれる。During AM reception, the ground side of the secondary winding 11' of the AM antenna coil L1 is connected to the ground E by the band changeover switch Sl', and the AM signal generated in the antenna coil hole is guided to the base of the transistor Tr1. .
又トランジスタＴｒ１のエミッタにはＡＭ発振コイルＬ
２よりＲ４，Ｃ４′を通して発振注入電圧が導かれ、ト
ランジスタＴｒ１はＡＭコンバーター用として動作する
。Also, an AM oscillation coil L is connected to the emitter of the transistor Tr1.
The oscillation injection voltage is led from 2 through R4 and C4', and the transistor Tr1 operates as an AM converter.
大入力歪及び大人力笛音妨害に対しては、注入平滑用抵
抗Ｒ４を適切に選ぶ（１０〜１０１）ことにより改善す
ることができる。Large input distortion and adult power whistle disturbance can be improved by appropriately selecting the injection smoothing resistor R4 (10 to 101).
尚、注入コンデンサＣ４’の値は０．００１〜０ 、０
２２μＦ程度が通常であるので、ＦＭ受信時のバイパス
効果は充分である。In addition, the value of injection capacitor C4' is 0.001 to 0,0.
Since it is usually about 22 μF, the bypass effect during FM reception is sufficient.
以上の様に本考案に係るＡＭ−ＦＭラジオ受信機のバン
ド切換回路は、従来回路に比べ全く機能を損ねる事なく
、バンド切換回路数を１回路削減することが出来、コス
トの低減、機器の小型化に有効である。As described above, the band switching circuit of the AM-FM radio receiver according to the present invention can reduce the number of band switching circuits by one without impairing the function compared to conventional circuits, reducing costs and improving equipment efficiency. Effective for downsizing.
第１図は従来のＡＭ−ＦＭラジオ受信機のバンド切換回
路を示す回路図、第２図は本考案に係るＡＭ−ＦＭラジ
オ受信機のバンド切換回路を示す回路図である。
Ｔｒｌ・・・・・・トランジスタ、Ｃ４′・・・・・・
コンデンサ、Ｒ４・・・・・・抵抗、Ｌｌ・・・・・・
ＡＭ用アンテナコイル、１１′・・・・・・ＡＭ用アン
テナコイルの２次側巻線、Ｌ２・・・・・・ＡＭ用発振
コイル、Ｓ１′・・・・・・バンドの切換スイッチ。FIG. 1 is a circuit diagram showing a band switching circuit of a conventional AM-FM radio receiver, and FIG. 2 is a circuit diagram showing a band switching circuit of an AM-FM radio receiver according to the present invention. Trl...Transistor, C4'...
Capacitor, R4... Resistor, Ll...
AM antenna coil, 11'... Secondary winding of AM antenna coil, L2... AM oscillation coil, S1'... band changeover switch.
Claims (2)
ＩＦ増幅用、ＡＭ受信時コンバーター用として共用する
ようにしたＡＭ−ＦＭラジオ受信機に於いて、前記トラ
ンジスタのエミッタ側には、一端が前記トランジスタの
エミッタに接続されＦＭ受信時のエミッタバイパス用と
ＡＭ受信時の発振電圧注入用を兼ねるコンテ゛ンサと、
１回路のバンド切換スイッチとを設け、該スイッチのＦ
Ｍ側固定端子には前記コンデンサの他端を接続するとと
もに、抵抗を介してＡＭ用発振コイルを接続し、ＡＭ側
固定端子にはＡＭ用高周波同調コイルの２次側巻線のア
ース側を接続し、共通端子にはアースを夫々接続してな
るＡＭ−ＦＭラジオ受信機のバンド切換回路。(1) In an AM-FM radio receiver in which one emitter-grounded transistor is shared for IF amplification during FM reception and for converter during AM reception, one end of the transistor is connected to the emitter side of the transistor. a capacitor that is connected to the emitter of and serves both as an emitter bypass during FM reception and an oscillation voltage injection during AM reception;
A one-circuit band changeover switch is provided, and the F of the switch is provided.
Connect the other end of the capacitor to the M side fixed terminal, and connect the AM oscillation coil via a resistor, and connect the ground side of the secondary winding of the AM high frequency tuning coil to the AM side fixed terminal. A band switching circuit for an AM-FM radio receiver consists of a common terminal connected to the ground, respectively.
であることを特徴とする実用新案登録請求の範囲第１項
記載のＡＭ−ＦＭラジオ受信機のバンド切換回路。(2) The band switching circuit for an AM-FM radio receiver according to claim 1, wherein the AM high frequency tuning coil is an AM antenna coil.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15581577U JPS5846592Y2 (en) | 1977-11-17 | 1977-11-17 | AM-FM radio receiver band switching circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15581577U JPS5846592Y2 (en) | 1977-11-17 | 1977-11-17 | AM-FM radio receiver band switching circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5481213U JPS5481213U (en) | 1979-06-08 |
| JPS5846592Y2 true JPS5846592Y2 (en) | 1983-10-24 |
Family
ID=29145194
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP15581577U Expired JPS5846592Y2 (en) | 1977-11-17 | 1977-11-17 | AM-FM radio receiver band switching circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5846592Y2 (en) |
-
1977
- 1977-11-17 JP JP15581577U patent/JPS5846592Y2/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5481213U (en) | 1979-06-08 |
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