JPH0110009Y2 - - Google Patents
Info
- Publication number
- JPH0110009Y2 JPH0110009Y2 JP7766580U JP7766580U JPH0110009Y2 JP H0110009 Y2 JPH0110009 Y2 JP H0110009Y2 JP 7766580 U JP7766580 U JP 7766580U JP 7766580 U JP7766580 U JP 7766580U JP H0110009 Y2 JPH0110009 Y2 JP H0110009Y2
- Authority
- JP
- Japan
- Prior art keywords
- circuit
- frequency
- high frequency
- switch
- gain
- 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
- Control Of Amplification And Gain Control (AREA)
- Noise Elimination (AREA)
- Circuits Of Receivers In General (AREA)
- Input Circuits Of Receivers And Coupling Of Receivers And Audio Equipment (AREA)
Description
【考案の詳細な説明】
本発明は受信周波数帯域の上限又は下限で他受
信周波数帯域の放送信号と混信が起ることがない
ようにした受信機の高周波利得自動切換装置に関
する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic high frequency gain switching device for a receiver that prevents interference with broadcast signals of other reception frequency bands at the upper or lower limits of a reception frequency band.
特にFM受信機において、FM放送を受信する
場合、受信周波数帯域の上限又は下限で他受信周
波数帯域の放送信号、例えばテレビ放送信号の妨
害を受けやすい。そのため高周波回路の選択度を
上げることが考えられるが、高周波回路の選択度
を上げても0.5MHzの範囲にある他受信周波数帯
域の放送信号を十分に減衰させることは難しい。 In particular, when an FM receiver receives FM broadcasts, it is susceptible to interference by broadcast signals in other reception frequency bands, such as television broadcast signals, at the upper or lower limits of the reception frequency band. Therefore, it is possible to increase the selectivity of the high frequency circuit, but even if the selectivity of the high frequency circuit is increased, it is difficult to sufficiently attenuate broadcast signals in other receiving frequency bands within the 0.5 MHz range.
そこで本考案は２放送信号の妨害排除は高周波
回路の利得を下げることによつても同様な効果が
あることに鑑みて、選局装置が受信周波数帯域の
上限又は下限まで変化されたとき、スイツチ等を
制御し高周波回路の利得を低下させることによつ
て他受信周波帯域の信号の妨害を受けることがな
いようにした受信機の高周波利得自動切換装置を
提供するもので、以下図面に従つて説明をする。 Therefore, the present invention has been developed based on the fact that the same effect can be achieved by reducing the gain of the high frequency circuit in eliminating interference with broadcast signals.When the channel selection device is changed to the upper or lower limit of the receiving frequency band, The present invention provides an automatic high-frequency gain switching device for a receiver, which prevents interference from signals in other receiving frequency bands by controlling the high-frequency circuit and reducing the gain of the high-frequency circuit. Give an explanation.
１はアンテナ、２は前記アンテナ１に接続され
た高周波回路、３は前記高周波回路の利得を切換
える切換回路で、スイツチ４及び該スイツチ４に
て制御されるトランジスタ５，６を有する。前記
スイツチ４は選局装置例えばバリコンの軸７と共
に回転するドラム８に設けられた可動接片９、及
びバリコンの軸７が受信周波数帯域の上限又は下
限まで回転されたときに、前記可動接片９が接触
されるように設けられた固定接片１０，１０を有
する。１１はIF増幅回路、１２は検波回路、１
３はAF増幅回路、１４はスピーカーである。 1 is an antenna, 2 is a high frequency circuit connected to the antenna 1, and 3 is a switching circuit for switching the gain of the high frequency circuit, which includes a switch 4 and transistors 5 and 6 controlled by the switch 4. The switch 4 is a movable contact piece 9 provided on a drum 8 that rotates together with a shaft 7 of a channel selection device, for example, a variable condenser, and when the shaft 7 of the variable condenser is rotated to the upper or lower limit of the reception frequency band, the movable contact piece 9 9 has fixed contact pieces 10, 10 provided so as to be in contact with each other. 11 is an IF amplifier circuit, 12 is a detection circuit, 1
3 is an AF amplifier circuit, and 14 is a speaker.
次に本考案の動作を説明する。今バリコンの軸
７を回転することによつて選局され、高周波回路
２が−FM放送信号の周波数に同調される。する
とアンテナ１に受信されたFM放送信号は高周波
回路２で増幅、周波数変換された後、IF増幅回
路１１に加えられ、さらに増幅され検波回路１２
でAF信号に検波される。そしてAF増幅回路１３
を通つてスピーカー１４に加わり、スピーカー１
４を駆動する。ところでバリコンの軸７をテレビ
放送信号の周波数帯域に近い上限の周波数帯域ま
で回転されると、可動接片９が固定接片１０に接
触しスイツチ４がオンされる。するとトランジス
タ５がオンされ、トランジスタ６がオフされる。
それによつて高周波回路２のバイアス電圧が減少
し、高周波回路２の利得が低下し、テレビ放送信
号の妨害が排除される。因みに高周波回路２の利
得を20dB下げると、AM排除比は20dB上がる。 Next, the operation of the present invention will be explained. Now, the channel is selected by rotating the shaft 7 of the variable capacitor, and the high frequency circuit 2 is tuned to the frequency of the -FM broadcast signal. Then, the FM broadcast signal received by the antenna 1 is amplified and frequency converted by the high frequency circuit 2, and then applied to the IF amplifier circuit 11, where it is further amplified and sent to the detection circuit 12.
detected by the AF signal. And AF amplifier circuit 13
through speaker 14, and speaker 1
Drive 4. By the way, when the shaft 7 of the variable capacitor is rotated to an upper limit frequency band close to the frequency band of a television broadcast signal, the movable contact piece 9 comes into contact with the fixed contact piece 10 and the switch 4 is turned on. Then, transistor 5 is turned on and transistor 6 is turned off.
Thereby, the bias voltage of the high frequency circuit 2 is reduced, the gain of the high frequency circuit 2 is reduced, and interference with the television broadcast signal is eliminated. Incidentally, if the gain of high frequency circuit 2 is lowered by 20 dB, the AM rejection ratio will increase by 20 dB.
本考案の受信機の高周波利得制御回路は上述し
た如く、選局装置が受信周波数帯域の上限又は下
限まで変化されたときに制御される制御素子を設
け、該制御素子によつて高周波回路の利得を低下
させるようにしたので、受信周波帯域の上限又は
下限で隣接周波数帯域の信号の妨害を排除でき
る。 As described above, the high frequency gain control circuit of the receiver of the present invention is provided with a control element that is controlled when the tuning device is changed to the upper or lower limit of the reception frequency band, and the control element controls the gain of the high frequency circuit. Since the frequency is lowered, interference with signals in adjacent frequency bands can be eliminated at the upper or lower limits of the receiving frequency band.
図は本考案の受信機の高周波利得自動切換装置
の回路図である。
２……高周波回路、３……切換回路、４……ス
イツチ、５，６……トランジスター。
The figure is a circuit diagram of an automatic high frequency gain switching device for a receiver according to the present invention. 2...High frequency circuit, 3...Switching circuit, 4...Switch, 5, 6...Transistor.
Claims (1)
び周波数変換する高周波回路と、前記選局を行な
う選択装置が受信周波数帯域の上限又は下限まで
選局されたときオン又はオフされるスイツチと、
該スイツチにて制御されるトランジスタとよりな
り、前記選局装置が受信周波帯域の上限又は下限
まで選局されたときに、前記スイツチをオン又は
オフさせることにより、トランジスタをオン又は
オフさせ、高周波回路の利得を低下させることを
特徴とする受信機の高周波利得自動切換装置。 a high frequency circuit that tunes, amplifies, and converts the frequency of a broadcast signal received by an antenna; a switch that is turned on or off when the selection device that performs tuning is tuned to the upper or lower limit of the receiving frequency band;
The transistor is controlled by the switch, and when the channel selection device is tuned to the upper or lower limit of the receiving frequency band, turning the switch on or off turns the transistor on or off, and transmits high frequency signals. An automatic high-frequency gain switching device for a receiver, characterized by reducing the gain of a circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7766580U JPH0110009Y2 (en) | 1980-06-03 | 1980-06-03 |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7766580U JPH0110009Y2 (en) | 1980-06-03 | 1980-06-03 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS572721U JPS572721U (en) | 1982-01-08 |
| JPH0110009Y2 true JPH0110009Y2 (en) | 1989-03-22 |
Family
ID=29440224
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP7766580U Expired JPH0110009Y2 (en) | 1980-06-03 | 1980-06-03 |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0110009Y2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS62189806A (en) * | 1986-02-17 | 1987-08-19 | Sanyo Electric Co Ltd | Rf agc circuit |
| JPS6414902U (en) * | 1987-07-16 | 1989-01-25 |
-
1980
- 1980-06-03 JP JP7766580U patent/JPH0110009Y2/ja not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| JPS572721U (en) | 1982-01-08 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US2174566A (en) | Automatic tuning arrangement | |
| GB455649A (en) | Improvements in or relating to radio receivers | |
| US4357712A (en) | Radio receiver | |
| JPS6218982Y2 (en) | ||
| JPS6318177Y2 (en) | ||
| JPS6134774Y2 (en) | ||
| JPH048675Y2 (en) | ||
| JPS584270Y2 (en) | radio receiver | |
| JPS6324670Y2 (en) | ||
| JPS6233402Y2 (en) | ||
| JPS6233404Y2 (en) | ||
| JPS5822330Y2 (en) | Jidouritokuseigiyosouchi | |
| JP2572471Y2 (en) | FM stereo receiver | |
| JPS6241467Y2 (en) | ||
| JPS5926666Y2 (en) | radio receiver | |
| JPS5931070Y2 (en) | Chuyuna | |
| JPS6041331A (en) | radio receiver | |
| JPS6324669Y2 (en) | ||
| JPS6318191Y2 (en) | ||
| JPS5941604B2 (en) | electronic tuning receiver | |
| JPS596013Y2 (en) | search | |
| JPS6311777Y2 (en) | ||
| JPS5840656Y2 (en) | automatic tuning receiver | |
| JPS5555618A (en) | Radio receiver | |
| JPS6324668Y2 (en) |