JPS59141877A - Detecting circuit for sound multiplex discriminating signal - Google Patents
Detecting circuit for sound multiplex discriminating signalInfo
- Publication number
- JPS59141877A JPS59141877A JP58016470A JP1647083A JPS59141877A JP S59141877 A JPS59141877 A JP S59141877A JP 58016470 A JP58016470 A JP 58016470A JP 1647083 A JP1647083 A JP 1647083A JP S59141877 A JPS59141877 A JP S59141877A
- Authority
- JP
- Japan
- Prior art keywords
- signal
- wave detection
- resistance
- diode
- capacitor
- 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
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N5/00—Details of television systems
- H04N5/44—Receiver circuitry for the reception of television signals according to analogue transmission standards
- H04N5/60—Receiver circuitry for the reception of television signals according to analogue transmission standards for the sound signals
Landscapes
- Engineering & Computer Science (AREA)
- Multimedia (AREA)
- Signal Processing (AREA)
- Television Receiver Circuits (AREA)
Abstract
Description
【発明の詳細な説明】
産業上の利用分野
本発明は、テレビジョン音声多重信号復調器に用いられ
る音声多重信号検波回路に関するものである。DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an audio multiplex signal detection circuit used in a television audio multiplex signal demodulator.
従来例の構成とその問題点
従来のテレビジョン音声多重信号復調回路における音声
多重判別信号の検波回路の一例を第１図に示す。Configuration of a conventional example and its problems An example of a detection circuit for an audio multiplex discrimination signal in a conventional television audio multiplex signal demodulation circuit is shown in FIG.
図において、トランジスターＴ ｒ １． Ｔ ｒ ２
のベースに音声多重信号が加わり増幅される。トラ
ンジスターＴ ｒ ２ のコレクター負荷はコイルＬ
１ とコンデンサＣ４の共振回路で増幅度が太きい。In the figure, transistors T r 1. T r 2
An audio multiplex signal is added to the base of the signal and amplified. The collector load of the transistor T r 2 is the coil L
1 and the resonant circuit of capacitor C4, the amplification is high.
こｔＤ 信号ヲコンデンサＣ２で直流カットし、又直流
クランプ用ダイオードＤ１ を用いてクランプして、
ダイオードＤ２及びコンデンサＣ２と抵抗Ｒ２で整流検
波する。その検波信号が音声多重判別回路に加えられる
。The DC signal is cut off with the capacitor C2, and clamped with the DC clamping diode D1.
Rectification detection is performed using a diode D2, a capacitor C2, and a resistor R2. The detected signal is applied to the audio multiplex discrimination circuit.
次に、この回路の動作を説明する。トランジスターＴｒ
とＴ ｒ ２のベースにはキャリアが５５、１２５
ｋＨｚで、変調周波数がステレオ放送時に９８２．５
Ｈｚ、二重放送時に９２２．５Ｈｚの音声多重判別信号
信号が加えられ、トランジスター’ｒ ｒ １とＴ ｒ
２と負荷のコイルＬ とコンデンサＣ１が５５．１２５
ｋＴｏに共振する様に定数が決められているので太きな
増幅度で増幅される。Next, the operation of this circuit will be explained. Transistor Tr
And the base of T r 2 has carriers of 55 and 125
kHz, the modulation frequency is 982.5 during stereo broadcasting.
Hz, a 922.5Hz audio multiplex discrimination signal is added during dual broadcasting, and the transistors 'r r 1 and T r
2, load coil L and capacitor C1 are 55.125
Since the constant is determined so that it resonates with kTo, it is amplified with a large amplification degree.
その増幅された信号はダイオードＤ２とコンデンサＣ３
、抵抗Ｒ２でＡＭ検波される。ところが、入力信号が内
きすぎるとトランジスターＴ ｒ ２ のコレクター
で波形が歪んでＡＭ検波されるが波形が歪んでしまって
、後の判別回路が不安定となる。The amplified signal is passed through diode D2 and capacitor C3.
, AM detection is performed by resistor R2. However, if the input signal is too low, the waveform will be distorted in the collector of the transistor T r 2 and AM detection will be performed, but the waveform will be distorted and the subsequent discrimination circuit will become unstable.
発明の目的
本発明は、上記のような従来の欠点を除去し、入力信号
が内き過ぎても影響を受けない音声多重パ判別信号検波
回路を提供することを目的とする。OBJECTS OF THE INVENTION It is an object of the present invention to provide an audio multiplexer discriminating signal detection circuit which eliminates the above-mentioned conventional drawbacks and is not affected even if the input signal is too deep.
発明の構成
本発明においてｔは、音声多重判別信号を直接ダイオー
ドで検波し、検波用フィルターに加えるとともに、この
コンデンサーと抵抗と並列にツェナーダイオードと抵抗
の直列接続回路を接跣するもので、大き過ぎる信号が入
力された場合にはこのツェナーダイオードが導通して直
列に設けられている抵抗が４福度を下げるようになり、
大入力信号にも安定した検波信号が得られるものである
。Structure of the Invention In the present invention, t directly detects the audio multiplex discrimination signal with a diode, adds it to the detection filter, and connects a series connection circuit of a Zener diode and a resistor in parallel with this capacitor and resistor. When too much signal is input, this Zener diode becomes conductive and the resistor installed in series lowers the 4 degrees of fortune.
A stable detection signal can be obtained even with a large input signal.
実施例の説明
以下、本発明の一実施例について図面を参照して説明す
る。DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.
第２図において、入力信号（Ａ）は５５．１２５のキャ
リア（ＡＭ変調波）で、トランジスターＴ ｒ １及び
Ｔ ｒ ２の差動アンプに加わり、トランジスターＴ
ｒ ２のコレクターには５５．１’２５市に共振するコ
イルＬ１ とコンテンサーＣ１があり、大きく増幅さ
れて、その信号はダイオードＤ２及びコンテンサＣ３そ
して抵抗Ｒ２で整流されＡＭ検波される。In Fig. 2, the input signal (A) is a 55.125 carrier (AM modulated wave), which is applied to the differential amplifier of transistors T r 1 and T r 2, and is applied to the differential amplifier of transistors T
The collector of r2 has a coil L1 that resonates at 55.1'25 and a capacitor C1, and is greatly amplified, and the signal is rectified by a diode D2, a capacitor C3, and a resistor R2, and then subjected to AM detection.
その検波された信号電圧がコンデンサーｃ３と、抵抗Ｒ
２と並列に接続されたツェナーダイオードＤ３のツェナ
ー電圧よりも高くなると、ツェナーダイオードＤ３が導
通し、これと直列に挿入された抵抗Ｈ３か抵抗Ｒ２と並
列接続された状態となる。The detected signal voltage is applied to capacitor c3 and resistor R
When the Zener voltage becomes higher than the Zener voltage of the Zener diode D3 connected in parallel with the Zener diode D3, the Zener diode D3 becomes conductive and becomes connected in parallel with the resistor H3 or the resistor R2 inserted in series.
ここで、抵抗Ｒ２は非常に抵抗値の大きいもので検波ダ
イオードＤ２が導通しても共振回路（Ｌｌ １０１ ）
には影響しない。しかし、抵抗ｌ（３は抵抗値を抵
抗Ｒ２よりも小さく選んでおき、共振回路（Ｌｌ ＋
０１ ） と並列になったときに共振回路のダンピン
グ抗邸として働くようにする。すると、大きな入力信号
に対し増幅度を小さくし、トランジスターＴ ｒ ２
のコレクターでダイナミノクレンン以上の信号増幅を
行なわない。そうすれば常に信号（Ｂ）゛ の様な信号
状態で増巾され次の判別回路にはきれいな９８２．５＋
ｋＨｚ又は９２２．５ｋ）Ｉｔの信号が入力され、安定
した判別が行なわれる。Here, the resistor R2 has a very large resistance value, so even if the detection diode D2 is conductive, the resonant circuit (Ll 101 )
does not affect. However, the resistance value of the resistor l (3) is selected to be smaller than that of the resistor R2, and the resonant circuit (Ll +
01) so that it acts as a damping barrier for the resonant circuit when connected in parallel with. Then, the amplification degree is reduced for a large input signal, and the transistor T r 2
The collector does not amplify the signal beyond that of Dynamino Clean. In this way, the signal state like signal (B) will always be amplified, and the next discrimination circuit will receive a clean 982.5+ signal.
A signal of kHz or 922.5k)It is input, and stable discrimination is performed.
発りＪの効果
以上のように、本発明によれは、入力信号が大きくなっ
た場合でも歪のない増［ＩＪされた音声多重判別信号を
得ることができ、次段の判別回路にて常に安犀した動作
が行なわれる。As described above, according to the present invention, even when the input signal becomes large, it is possible to obtain an increased [IJ] audio multiplexed discrimination signal without distortion, and the next stage discrimination circuit always uses A calm movement is carried out.
第１図は従来例」における音声多重判別信号検波回路の
回路図、第２図は本発明の一実施例における音声多重判
別信号検波回路の回路図である。
Ｔｒ、Ｔｒ −・−・・トランジスタ、Ｌ ・・・・
コイル、１ ２
１Ｃ１，Ｃ２，Ｃ３・・・コンテンサー、Ｒ，、Ｒ
２・・・抵抗、Ｄ、Ｄ ・・・ダイオード、Ｄ３ツェ
ナー１ ２
ダイオード。
代」」人の氏名 弁理士 中 尾 緻 男 ほか１名第
１図
第２図FIG. 1 is a circuit diagram of a conventional audio multiplex discrimination signal detection circuit, and FIG. 2 is a circuit diagram of an audio multiplex discrimination signal detection circuit according to an embodiment of the present invention. Tr, Tr -...Transistor, L...
Coil, 1 2
1C1, C2, C3...condenser, R,,R
2...Resistor, D, D...Diode, D3 Zener 1 2 diode. Person's name: Patent attorney Takuo Nakao and one other person Figure 1 Figure 2
Claims (1)
デンサとでピーク検波し、その検波出力ラインと電源丑
たはアースラインとの間にツェナーダイオードと抵抗を
直列にして接欣した音声多重判別信号検波回路。Audio multiplex discrimination signal detection in which the peak of the audio multiplex discrimination signal in a television signal is detected using a rectifier and a capacitor, and a Zener diode and a resistor are connected in series between the detection output line and the power supply or ground line. circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP58016470A JPS59141877A (en) | 1983-02-02 | 1983-02-02 | Detecting circuit for sound multiplex discriminating signal |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP58016470A JPS59141877A (en) | 1983-02-02 | 1983-02-02 | Detecting circuit for sound multiplex discriminating signal |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS59141877A true JPS59141877A (en) | 1984-08-14 |
Family
ID=11917143
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP58016470A Pending JPS59141877A (en) | 1983-02-02 | 1983-02-02 | Detecting circuit for sound multiplex discriminating signal |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS59141877A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS625776U (en) * | 1985-06-27 | 1987-01-14 |
-
1983
- 1983-02-02 JP JP58016470A patent/JPS59141877A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS625776U (en) * | 1985-06-27 | 1987-01-14 |
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