JPS585053A - Muting circuit - Google Patents
Muting circuitInfo
- Publication number
- JPS585053A JPS585053A JP10222081A JP10222081A JPS585053A JP S585053 A JPS585053 A JP S585053A JP 10222081 A JP10222081 A JP 10222081A JP 10222081 A JP10222081 A JP 10222081A JP S585053 A JPS585053 A JP S585053A
- Authority
- JP
- Japan
- Prior art keywords
- signal
- circuit
- sub
- electric field
- reception
- 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.)
- Pending
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04H—BROADCAST COMMUNICATION
- H04H40/00—Arrangements specially adapted for receiving broadcast information
- H04H40/18—Arrangements characterised by circuits or components specially adapted for receiving
- H04H40/27—Arrangements characterised by circuits or components specially adapted for receiving specially adapted for broadcast systems covered by groups H04H20/53 - H04H20/95
- H04H40/36—Arrangements characterised by circuits or components specially adapted for receiving specially adapted for broadcast systems covered by groups H04H20/53 - H04H20/95 specially adapted for stereophonic broadcast receiving
- H04H40/45—Arrangements characterised by circuits or components specially adapted for receiving specially adapted for broadcast systems covered by groups H04H20/53 - H04H20/95 specially adapted for stereophonic broadcast receiving for FM stereophonic broadcast systems receiving
- H04H40/72—Arrangements characterised by circuits or components specially adapted for receiving specially adapted for broadcast systems covered by groups H04H20/53 - H04H20/95 specially adapted for stereophonic broadcast receiving for FM stereophonic broadcast systems receiving for noise suppression
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/06—Receivers
- H04B1/16—Circuits
- H04B1/1646—Circuits adapted for the reception of stereophonic signals
Landscapes
- Engineering & Computer Science (AREA)
- Signal Processing (AREA)
- Computer Networks & Wireless Communication (AREA)
- Stereo-Broadcasting Methods (AREA)
Abstract
Description
【発明の詳細な説明】
本発明はＦＭチニ−すまたはテレビジ日ン音声多重チニ
ーナの弱入力時のサブ信号を減衰させるミ、：Ｌ−ティ
ング回路に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an L-ting circuit for attenuating a sub-signal of an FM channel or television audio multiplex channel at the time of weak input.
従来、たとえばテレビジ翳ン音声多重チニ−すにおいて
、弱入力時にはパイロット信号検出回路の誤動作を避け
るために、一定の電界強度以下になると多重受信からモ
ノラル受信への切換え、またはミニ、−ティングによる
出力遮断を行なっている。Conventionally, in order to avoid malfunction of the pilot signal detection circuit when the input is weak, for example, in a TV screen audio multiplexing system, when the electric field strength falls below a certain level, multiplex reception is switched to monaural reception, or output by mini-tinging is used. I am doing a blockade.
上記の如き従来の方法によるときは受信電界強度が時間
とともに変化する様な場合、たとえば車載のＦＭチニ−
すまたはテレビジ■ン音声多重チ囁−すの場合において
、多重受信のモノラル受信の切換え、またはミューティ
ング回路が頻発して非常に不快な受信状態となる。When using the conventional method as described above, if the received field strength changes over time,
In the case of multi-channel audio or television broadcasting, the switching of multiplex reception to monaural reception or the muting circuit frequently occurs, resulting in a very unpleasant reception condition.
本発明は上記にかんがみなされたもので、上記の欠点を
解消したミューティング回路を綽することを目的とする
ものである。The present invention has been made in view of the above, and an object of the present invention is to provide a muting circuit that eliminates the above-mentioned drawbacks.
本発明は受信電界強度の大小に従ってサブ信号レベルを
変化させ、ステレオ放送受信時はステレオ受信からモノ
ラル受信への切換えを徐々に行なうことによりＳ／Ｎを
改善し、ステレオ受信とモノラル受信との切換えに伴な
う違和感を少なくし、また２か国語放送受信時にもサブ
信号のレベルが次第に絞って行くことによって、メイン
信号に切換るときの違和感を少なくすることを特徴とす
るものである。The present invention improves S/N by changing the sub-signal level according to the magnitude of the received electric field strength, and gradually switching from stereo reception to monaural reception when receiving stereo broadcasts, and switching between stereo reception and monaural reception. This system is characterized by reducing the sense of discomfort associated with switching to the main signal by gradually narrowing down the level of the sub signal even when receiving bilingual broadcasting.
以下、本発明を実施例により説明する。The present invention will be explained below with reference to Examples.
第１図は本発明の一実施例のブロック図であり、テレビ
ジーン音声多重チニ−すの場合の例を示している。第１
図において、１は受信アンテナを、２はフロントエンド
を、３は中間周波段およびＦＭ復調回路を示し、中間周
波段およびｕｌｉｌＷＪ路３の中間周波段における前段
において受信電界強度を検出し該電界強度に対応した出
方電圧が出方されるように構成しである。４は多重信号
復調回路を、５は多重信号復調回路４からのメイン信号
およびサブ信号を入力するマトリックス回路である。FIG. 1 is a block diagram of an embodiment of the present invention, and shows an example of a TV-generated audio multiplexing system. 1st
In the figure, 1 is a receiving antenna, 2 is a front end, and 3 is an intermediate frequency stage and an FM demodulation circuit, and the received electric field strength is detected at the intermediate frequency stage and at the front stage of the intermediate frequency stage of the ulil WJ path 3. The configuration is such that an output voltage corresponding to the output voltage is output. 4 is a multiple signal demodulation circuit, and 5 is a matrix circuit into which the main signal and sub signals from the multiple signal demodulation circuit 4 are input.
多重信号復調回路４からのサブ信号出方は、受信電界強
度に対応した中間周波段および復調回路３からの出力電
圧により減衰率が制御される電圧制御減衰器６を通して
マトリックス回路５に入力するように構成する。The sub-signal output from the multiplex signal demodulation circuit 4 is input to the matrix circuit 5 through an intermediate frequency stage corresponding to the received electric field strength and a voltage-controlled attenuator 6 whose attenuation rate is controlled by the output voltage from the demodulation circuit 3. Configure.
そこで、受信アンテナ１で受信された放送波はフロント
エンド２、中間周波段および復調回路３を経て多重信号
復調回路４に入力される。多重信号復調回路４で＊＊＊
されたメイン信号はそのままマトリックス回路５に入力
されるが、多重信号復調回路４で復調されたサブ信号は
、受信電界強度に対応した減衰比に制御されている電圧
制御減衰器６により、受信電界強度に応じた出方レベル
に制御されて、マトリックス回路５に入力される。Therefore, the broadcast wave received by the receiving antenna 1 is inputted to the multiplex signal demodulation circuit 4 via the front end 2, the intermediate frequency stage, and the demodulation circuit 3. With multiplex signal demodulation circuit 4***
The main signal thus obtained is input to the matrix circuit 5 as it is, but the sub-signal demodulated by the multiplex signal demodulation circuit 4 is processed by a voltage-controlled attenuator 6 whose attenuation ratio corresponds to the received electric field strength. The output level is controlled according to the intensity and input to the matrix circuit 5.
従つて、マトリックス回路５に入力されるサブ信号は受
信電界強度の減少に伴って減衰され、第２図において破
線に示す如く、パイロット信号検出が不能となる前に徐
々に減衰させられることになる。Therefore, the sub-signal input to the matrix circuit 5 is attenuated as the received field strength decreases, and as shown by the broken line in FIG. 2, it is gradually attenuated before pilot signal detection becomes impossible. .
なお、第２図において実線はメイン信号レベルを示しヤ
いる。Note that in FIG. 2, the solid line indicates the main signal level.
従って、ステレオ放送受信時は、ステレオ受信からモノ
ラル受信への切換ｉｔ徐々に行なわれ、ステレオ受信と
モノラル受信の切換えに伴なう違和感は減少し、また２
か国語放送受信時においてもサブ信号（外国語）のレベ
ルが次第に絞られて行くのでメイン信号（日本語）に切
換るときの違和感も減少する。Therefore, when receiving stereo broadcasts, the switch from stereo reception to monaural reception is carried out gradually, the discomfort caused by switching between stereo reception and monaural reception is reduced, and the
Even when receiving multilingual broadcasts, the level of the sub signal (foreign language) is gradually narrowed down, which reduces the discomfort when switching to the main signal (Japanese).
また、ステレオ受信からモノラル受信への切換えを徐々
に行なわれることにより、第３図において破線で示した
如＜Ｓ／Ｎが改善される。すなわち、第３図において曲
線Ａはステレオ受信に固定したときの電界強度に対する
Ｓ／Ｎを示す曲線であり、曲線Ｂはモノラル受信に固定
したときの電界強度に対するＳ／Ｎを示す曲線であって
、電界強度の低下に伴ってモノラル受信に徐々に切換え
るためＳ ／ Ｎ ｉｔ破線りに示す如くになり、弱電
界入力時にはＳ／Ｎはモノラル受信の場合のＳ／Ｎに近
づき、矢印間で示したＳ／Ｎの改善を得ることができる
。なお、曲線Ｃは分離度を示す曲線である。Further, by gradually switching from stereo reception to monaural reception, the S/N ratio is improved as shown by the broken line in FIG. That is, in FIG. 3, curve A is a curve showing the S/N with respect to electric field strength when fixed to stereo reception, and curve B is a curve showing S/N with respect to electric field strength when fixed to monaural reception. As the electric field strength decreases, the signal gradually switches to monaural reception, so the S/Nit becomes as shown by the broken line, and when a weak electric field is input, the S/N approaches the S/N for monaural reception, as shown between the arrows. It is possible to obtain an improvement in S/N. Note that the curve C is a curve showing the degree of separation.
つぎに本発明の他の実施例について説明する。Next, other embodiments of the present invention will be described.
第４図は本発明の他の実施例のブロック図゛であり、Ｆ
Ｍステレオチ１−すの場合の例を示している。FIG. 4 is a block diagram of another embodiment of the present invention.
An example in the case of M stereo channels is shown.
第４図において第１図に示した本発明の一実施例の構成
要素と同一構成要素には同一の符号を付して示しである
。In FIG. 4, the same components as those of the embodiment of the present invention shown in FIG. 1 are denoted by the same reference numerals.
７はマトリックス方式のＦＭステレオ復°調回路であっ
て、ローパスフィルタ８、バンドパスフィルタ９、同期
信号発生回路１１、サブ信号復調回路１０およびマトリ
ックス回路１２とからなっている。またサブ信号復調回
路１０とマトリックス回路１２ととの間には電界強度に
対応して出力される中間周波増幅段および復調回路３の
中間周波段からの出力電圧により減衰□比が制御される
電圧制御減衰器６が接続しである。Reference numeral 7 denotes a matrix-type FM stereo demodulation circuit, which includes a low-pass filter 8, a band-pass filter 9, a synchronization signal generation circuit 11, a sub-signal demodulation circuit 10, and a matrix circuit 12. Further, between the sub-signal demodulation circuit 10 and the matrix circuit 12, a voltage whose attenuation □ ratio is controlled by the output voltage from the intermediate frequency amplification stage and the intermediate frequency stage of the demodulation circuit 3 is connected in accordance with the electric field strength. A controlled attenuator 6 is connected.
上記の如く構成した本発明の他の実施例において、受信
アンテナ１で受信されたＦＭ放送波は、フロントエンド
２、中間周波段および復調回路３を経てマルチプレフク
ース方式のＦＭステレオ復調回路７に入力される。ＦＭ
ステレオ復調回路７においては従来のＦＭステレオ復調
回路の場合と同様にローパスフィルタ８によりコンポジ
ット信号からメイン信号が取り出されマトリックス回路
１２に入力される。またコンポジット信号からバンドパ
スフィルタ９によりサブ信号のＤＳＢ信号が取り出され
サブ信号復調回路１０に入力される。一方、同期信号発
生回路１１においてコンポジ、）信号中からバイロフト
信号（１９ＫＨｚ）が取り出され、逓倍されてた出力信
号（３８ＫＨｚ）が出力される。この同期信号発生回路
１１の出力信号がサブ信号復調回路１０に入力されてサ
ブ信号のＤＳＢ信号に注入される。そこでサブ信号復調
回路１０においてサブ信号の振幅変調波に復元のうえＡ
Ｍ検波されてサブ信号復調回路１０からサブ信号が出力
される。このサブ信号は電圧制御減衰器６により受信電
界強度に応じた出力レベルに制御されてマトリックス回
路１２に入力される。In another embodiment of the present invention configured as described above, the FM broadcast wave received by the receiving antenna 1 passes through the front end 2, the intermediate frequency stage, and the demodulation circuit 3, and then is sent to the FM stereo demodulation circuit 7 of the multi-preflux method. is input. FM
In the stereo demodulation circuit 7, the main signal is extracted from the composite signal by the low-pass filter 8 and input to the matrix circuit 12, as in the conventional FM stereo demodulation circuit. Further, a DSB signal of a sub signal is extracted from the composite signal by a band pass filter 9 and inputted to a sub signal demodulation circuit 10. On the other hand, in the synchronizing signal generating circuit 11, a biloft signal (19 KHz) is extracted from the composite signal, and a multiplied output signal (38 KHz) is output. The output signal of the synchronization signal generation circuit 11 is input to the sub-signal demodulation circuit 10 and injected into the DSB signal of the sub-signal. Therefore, the sub-signal demodulation circuit 10 restores the amplitude modulated wave of the sub-signal and then
After M detection, the sub signal is output from the sub signal demodulation circuit 10. This sub-signal is input to the matrix circuit 12 after being controlled by the voltage-controlled attenuator 6 to an output level corresponding to the received electric field strength.
従ってマトリックス回路１２に入力されるサブ信号は受
信電界強度の減少に伴って減衰され、前記した本発明の
一実施例の場合と同様、バイロフト信号出力が不能とな
る前において徐々減衰させられることになる。Therefore, the sub-signals input to the matrix circuit 12 are attenuated as the received electric field strength decreases, and as in the case of the embodiment of the present invention described above, the sub-signals input to the matrix circuit 12 are gradually attenuated before the biloft signal output becomes disabled. Become.
従って前記じた本発明の一実施例の場合と全く同様に、
ステレオ放送受信時において、ステレオ受信からモノラ
ル受信への切換えは徐々に行なわれ、ステレオ受信とモ
ノラル受信の切換えに伴なう違和感は減少し、また低電
界強度の場合におけるＳ／Ｎが改善される。Therefore, just as in the case of the embodiment of the present invention mentioned above,
When receiving stereo broadcasts, switching from stereo reception to monaural reception is performed gradually, reducing the discomfort caused by switching between stereo reception and monaural reception, and improving S/N in the case of low electric field strength. .
以上説明した如（本発明によれば、ステレオ放送受信時
に弱入力時Ｓ／Ｎが改善され、かつステレオ受信とモノ
ラル受信との切換えは徐々に行なわれて切換え時の違和
感は殆んどなくなる。As explained above (according to the present invention), the S/N ratio is improved during weak input during stereo broadcast reception, and the switching between stereo reception and monaural reception is performed gradually, so that there is almost no discomfort when switching.
また、電界強度が変動することが多い車載のＦＭチニ−
す、テレビジ■ン音声多重チニ−すに用いたとき効果を
発揮する。In addition, in-vehicle FM chinys, where the electric field strength often fluctuates,
This method is effective when used in television multiplexed audio channels.
第１図は本発明の一実施例のブロック図。
第２図および第３図は本発明の一実施例の作用の説明に
供する受信電界強度対出力特性および受信電界強度対Ｓ
／Ｎ特性。
第４図は本発明の他の実施例のブロック図。
２・・・フロントエンド、３・・・中間周波段および復
調回路、４・・・多重信号復調回路、５および１２・・
・マ［リックス回路、６・・・電圧制御減衰器、７・・
・マトリックス方式のＦＭステレオ復調回路、８・・・
ローパスフィルタ、９・・・バンドパスフィルタ、１０
・・・サブ信号復調回路、１１・・・同期信号発生回路
。FIG. 1 is a block diagram of an embodiment of the present invention. FIGS. 2 and 3 show received electric field strength vs. output characteristics and received electric field strength vs. S
/N characteristics. FIG. 4 is a block diagram of another embodiment of the present invention. 2...Front end, 3...Intermediate frequency stage and demodulation circuit, 4...Multiple signal demodulation circuit, 5 and 12...
・Matrix circuit, 6...Voltage controlled attenuator, 7...
・Matrix type FM stereo demodulation circuit, 8...
Low-pass filter, 9...Band-pass filter, 10
...Sub signal demodulation circuit, 11...Synchronization signal generation circuit.
Claims (1)
−すにおいて、受゛慢信電界強度に対応した電圧を出力
する受信電界強度検出手段と、該受信電界強度検出手段
の出力電圧により減衰比が制御される電圧制御減衰器と
を備え、前記電圧制御減衰−器により弱電界強度時にサ
ブ信号の出力レベルを一炭化させることを特徴とするミ
ニ−ティング回路。In an FM stereo channel or a television audio multiplex channel, a receiving field strength detecting means outputs a voltage corresponding to the receiving field strength, and an attenuation ratio is controlled by the output voltage of the receiving field strength detecting means. 1. A minting circuit comprising a voltage controlled attenuator, wherein the voltage controlled attenuator unifies the output level of a sub-signal at a weak electric field strength.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10222081A JPS585053A (en) | 1981-07-02 | 1981-07-02 | Muting circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10222081A JPS585053A (en) | 1981-07-02 | 1981-07-02 | Muting circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS585053A true JPS585053A (en) | 1983-01-12 |
Family
ID=14321575
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP10222081A Pending JPS585053A (en) | 1981-07-02 | 1981-07-02 | Muting circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS585053A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS604054U (en) * | 1983-06-20 | 1985-01-12 | 株式会社ケンウッド | stereo demodulator |
| EP0219113A2 (en) | 1985-10-15 | 1987-04-22 | Fuji Photo Film Co., Ltd. | Method of processing silver halide color photographic material |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS51115706A (en) * | 1975-03-13 | 1976-10-12 | Siemens Ag | Circuit device for adjusting continuously standard width in stereophonic decoder |
-
1981
- 1981-07-02 JP JP10222081A patent/JPS585053A/en active Pending
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS51115706A (en) * | 1975-03-13 | 1976-10-12 | Siemens Ag | Circuit device for adjusting continuously standard width in stereophonic decoder |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS604054U (en) * | 1983-06-20 | 1985-01-12 | 株式会社ケンウッド | stereo demodulator |
| EP0219113A2 (en) | 1985-10-15 | 1987-04-22 | Fuji Photo Film Co., Ltd. | Method of processing silver halide color photographic material |
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