JPS6233402Y2 - - Google Patents
Info
- Publication number
- JPS6233402Y2 JPS6233402Y2 JP17856581U JP17856581U JPS6233402Y2 JP S6233402 Y2 JPS6233402 Y2 JP S6233402Y2 JP 17856581 U JP17856581 U JP 17856581U JP 17856581 U JP17856581 U JP 17856581U JP S6233402 Y2 JPS6233402 Y2 JP S6233402Y2
- Authority
- JP
- Japan
- Prior art keywords
- antenna
- circuit
- variable
- capacitor
- frequency
- 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
- 239000003990 capacitor Substances 0.000 description 19
- 238000006243 chemical reaction Methods 0.000 description 6
- 230000010355 oscillation Effects 0.000 description 4
- 238000010586 diagram Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
Landscapes
- Channel Selection Circuits, Automatic Tuning Circuits (AREA)
- Input Circuits Of Receivers And Coupling Of Receivers And Audio Equipment (AREA)
Description
【考案の詳細な説明】
本考案はAM−FMラジオ受信機のアンテナ回
路に関するものである。[Detailed Description of the Invention] The present invention relates to an antenna circuit for an AM-FM radio receiver.
この種のAM−FMラジオ受信機においては、
AM受信回路にはアンテナ同調回路が設けられて
いるが、安価に製造させるためFM受信回路には
アンテナ同調回路は設けず、FMアンテナ回路は
非同調となつている。しかしながらFM信号の受
信帯域を制限して選択度を改着したい場合、FM
受信回路にもアンテナ同調回路を設ける必要があ
る。 In this type of AM-FM radio receiver,
Although the AM receiving circuit is equipped with an antenna tuning circuit, the FM receiving circuit is not equipped with an antenna tuning circuit in order to be manufactured at low cost, and the FM antenna circuit is non-tuned. However, if you want to modify the selectivity by limiting the reception band of the FM signal,
It is also necessary to provide an antenna tuning circuit in the receiving circuit.
本考案はかかる点に鑑み提案されたもので、
AMアンテナ同調回路の可変容量素子がFMアン
テナ同調回路の可変容量素子を兼用させることに
より、簡単な改良で安価にFMのアンテナ同調回
路を付加するAM−FMラジオ受信機のアンテナ
回路を提供するものである。 This invention was proposed in view of these points,
To provide an antenna circuit for an AM-FM radio receiver in which an FM antenna tuning circuit is added at low cost through simple improvement by allowing the variable capacitance element of the AM antenna tuning circuit to also serve as the variable capacitance element of the FM antenna tuning circuit. It is.
以下本考案を図面に従つて説明する。１はFM
受信用アンテナ、２は高周波増幅器、３はFM用
の周波数変換回路、４はAM用の周波数変換回
路、L1はFMアンテナの１次側コイル、L2はAM
アンテナの１次側コルをそれぞれ示している。 The present invention will be explained below with reference to the drawings. 1 is FM
Receiving antenna, 2 is a high frequency amplifier, 3 is a frequency conversion circuit for FM, 4 is a frequency conversion circuit for AM, L1 is the primary coil of the FM antenna, L2 is AM
The primary side coils of the antenna are shown respectively.
SWはバンド切換スイツチで開放状態において
AM受信回路に作動電圧を与え、接続状態におい
てFM受信回路に作動電圧を与えるようになつて
いる。また１０はAMアンテナ同調用可変コンデ
ンサ、１１はAMアンテナのトラツキング用半固
定コンデンサである。そして１２は高周波コイル
（トランス）T3の同調用可変コンデンサ、１３は
FMトラツキング用半固定コンデンサである。２
１は周波数変換回路３内の局部発振周波数を設定
する可変コンデンサ２０は周波数変換回路４内の
局部発振周波数を設定する可変コンデンサであ
る。尚上述４つの可変コンデンサ（可変容量ダイ
オードでもよい）は同時に連動して操作される。 SW is in the open state with the band selection switch.
An operating voltage is applied to the AM receiving circuit, and an operating voltage is applied to the FM receiving circuit in the connected state. Further, 10 is a variable capacitor for tuning the AM antenna, and 11 is a semi-fixed capacitor for tracking the AM antenna. 12 is a variable capacitor for tuning the high frequency coil (transformer) T3 , and 13 is
This is a semi-fixed capacitor for FM tracking. 2
Reference numeral 1 designates a variable capacitor 20 that sets the local oscillation frequency within the frequency conversion circuit 3. Reference numeral 1 designates a variable capacitor 20 that sets the local oscillation frequency within the frequency conversion circuit 4. Note that the four variable capacitors (variable capacitance diodes may also be used) mentioned above are operated in conjunction at the same time.
次に動作について説明する。図示の如くスイツ
チSWが開放されているときにはAM受信回路が
働く。可変コンデンサ１０はAMアンテナ（バー
アンテナ）L2とともに可変のアンテナ同調回路
を形成している。そして、可変コンデンサの容量
（例、可変範囲5PF〜335PF）を調整すると周波
数変換回路４内の局部発振周波数設定用の可変コ
ンデンサ２０も連動して容量が調整され、所望の
AM放送の中間周波信号が端子６に取出される。 Next, the operation will be explained. As shown in the figure, when the switch SW is open, the AM receiving circuit operates. The variable capacitor 10 forms a variable antenna tuning circuit together with the AM antenna (bar antenna) L2 . Then, when the capacitance of the variable capacitor (for example, variable range 5PF to 335PF) is adjusted, the capacitance of the variable capacitor 20 for setting the local oscillation frequency in the frequency conversion circuit 4 is also adjusted, and the capacitance is adjusted to the desired value.
An intermediate frequency signal of AM broadcasting is taken out to terminal 6.
次にスイツチSWを閉鎖するとFM受信回路が
働く。このとき上述の可変コンデンサ１０はコン
デンサC1と接続されコイルL1とともにFMのアン
テナ同調回路を構成する。一方AMアンテナの１
次側コイルL2はFM放送信号の周波数（例えば国
内ではAM放送の周波数範囲は531〜1602KHz、
FM放送の周波数範囲は76MHz〜91MHz）ではイ
ンピーダンスが大きくなり影響は無視できるよう
に選択されている。また可変コンデンサ１０は高
周波コイルT3の同調用コンデンサ１２と周波数
変換回路３内の局部発振周波数設定用可変コンデ
ンサ２１の両コンデンサと連動する。そのため可
変コンデンサ１０（例、可変範囲、Ｃ１×Ｖｃ／Ｃ１＋
Ｖｃ＝
4PF〜19PF…C1＝20PF、可変コンデンサ１０の
容量Vc＝5PF〜335PF）を調整すれば、所望の
FM放送の中間周波信号が端子５に取出される。
したがつて上記のFM−AM受信機ではFM放送の
受信に際して、AMアンテナ同調コンデンサが
FMアンテナ同調コンデンサとして働くためFM
放送信号に対する選択度が改善される。 Next, when the switch SW is closed, the FM receiving circuit is activated. At this time, the above-mentioned variable capacitor 10 is connected to the capacitor C 1 and together with the coil L 1 constitutes an FM antenna tuning circuit. On the other hand, AM antenna 1
The next coil L 2 is connected to the frequency of the FM broadcast signal (for example, in Japan, the frequency range of AM broadcast is 531 to 1602 KHz,
The impedance is large in the frequency range of FM broadcasting (76MHz to 91MHz), and the frequency is selected so that the effect can be ignored. Further, the variable capacitor 10 is interlocked with both the tuning capacitor 12 of the high frequency coil T 3 and the variable capacitor 21 for setting the local oscillation frequency in the frequency conversion circuit 3. Therefore, the variable capacitor 10 (e.g., variable range, C 1 ×Vc/C 1 +
By adjusting Vc = 4PF to 19PF...C 1 = 20PF, capacitance of variable capacitor 10 (Vc = 5PF to 335PF), the desired value can be obtained.
An intermediate frequency signal of FM broadcasting is taken out to terminal 5.
Therefore, in the above FM-AM receiver, when receiving FM broadcasts, the AM antenna tuning capacitor is
FM to act as FM antenna tuning capacitor
Selectivity to broadcast signals is improved.
このように本考案によれば、AMアンテナ同調
用の可変容量素子がFMアンテナ同調用の可変容
量素子を兼用するためFM放送の受信に際して
FM信号の受信帯域を制限でき、したがつてFM
信号の選択度が改善される。 As described above, according to the present invention, the variable capacitance element for AM antenna tuning also serves as the variable capacitance element for FM antenna tuning.
The reception band of the FM signal can be limited, therefore the FM
Signal selectivity is improved.
第１図は本考案の１実施例を示す回路図であ
る。
１……FMアンテナ、L1……FMアンテナコイ
ル、SW……AM−FM切換スイツチ、１０……可
変容量素子。
FIG. 1 is a circuit diagram showing one embodiment of the present invention. 1...FM antenna, L1 ...FM antenna coil, SW...AM-FM changeover switch, 10...variable capacitance element.
Claims (1)
において、 AM放送受信時には前記AMアンテナ同調回路
内の可変容量素子とFMアンテナコイルとを切離
しFM放送受信時には前記可変容量素子とFMア
ンテナコイルとを接続するAM−FM切換スイツ
チとを有し、前記FMアンテナコイルは前記可変
容量素子と接続されたときFMアンテナ同調回路
を形成することを特徴とするAM−FMラジオ受
信機のアンテナ回路。[Claims for Utility Model Registration] In an AM-FM receiver having an AM antenna tuning circuit, when receiving AM broadcasting, the variable capacitance element in the AM antenna tuning circuit and the FM antenna coil are separated, and when receiving FM broadcasting, the variable capacitance element is separated from the FM antenna coil. and an AM-FM selector switch for connecting the FM antenna coil and the FM antenna coil, the FM antenna coil forming an FM antenna tuning circuit when connected to the variable capacitance element. antenna circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP17856581U JPS5883845U (en) | 1981-11-30 | 1981-11-30 | AM-FM radio receiver antenna circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP17856581U JPS5883845U (en) | 1981-11-30 | 1981-11-30 | AM-FM radio receiver antenna circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5883845U JPS5883845U (en) | 1983-06-07 |
| JPS6233402Y2 true JPS6233402Y2 (en) | 1987-08-26 |
Family
ID=29973478
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP17856581U Granted JPS5883845U (en) | 1981-11-30 | 1981-11-30 | AM-FM radio receiver antenna circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5883845U (en) |
-
1981
- 1981-11-30 JP JP17856581U patent/JPS5883845U/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5883845U (en) | 1983-06-07 |
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