JPS61192138A - Stereo modulation circuit - Google Patents
Stereo modulation circuitInfo
- Publication number
- JPS61192138A JPS61192138A JP3196885A JP3196885A JPS61192138A JP S61192138 A JPS61192138 A JP S61192138A JP 3196885 A JP3196885 A JP 3196885A JP 3196885 A JP3196885 A JP 3196885A JP S61192138 A JPS61192138 A JP S61192138A
- Authority
- JP
- Japan
- Prior art keywords
- signal
- channel
- attenuator
- analog switch
- audio signal
- 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.)
- Granted
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04H—BROADCAST COMMUNICATION
- H04H20/00—Arrangements for broadcast or for distribution combined with broadcast
- H04H20/86—Arrangements characterised by the broadcast information itself
- H04H20/88—Stereophonic broadcast systems
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04H—BROADCAST COMMUNICATION
- H04H20/00—Arrangements for broadcast or for distribution combined with broadcast
- H04H20/44—Arrangements characterised by circuits or components specially adapted for broadcast
- H04H20/46—Arrangements characterised by circuits or components specially adapted for broadcast specially adapted for broadcast systems covered by groups H04H20/53-H04H20/95
- H04H20/47—Arrangements characterised by circuits or components specially adapted for broadcast specially adapted for broadcast systems covered by groups H04H20/53-H04H20/95 specially adapted for stereophonic broadcast systems
- H04H20/48—Arrangements characterised by circuits or components specially adapted for broadcast specially adapted for broadcast systems covered by groups H04H20/53-H04H20/95 specially adapted for stereophonic broadcast systems for FM stereophonic broadcast systems
Landscapes
- Engineering & Computer Science (AREA)
- Signal Processing (AREA)
- Stereo-Broadcasting Methods (AREA)
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は、不要スペクトラムの低減を図ったＦＭステレ
オ放送のマルチブレックス変調回路（以下、ＭＰＸ′Ｒ
調回路という）Ｋ関するものである。[Detailed Description of the Invention] [Industrial Application Field] The present invention is directed to an FM stereo broadcast multiplex modulation circuit (hereinafter referred to as MPX'R) which aims to reduce unnecessary spectrum.
This is related to K (referred to as the control circuit).
従来からに″Ｍ放送用ＭＰＸｉ調回路には、マトリクス
形とスイッチング形の変調回路が用いられているＯ
ＦＭステレオ放送信号を第２図で説明する。左右の音声
信号（Ｌ、几）の和信号（Ｌ＋ａ）３ｔが、主信号とし
て５０Ｈｚ〜１５ ｋＨｚを占有し、差信号（Ｌ−几）
が３８ｋＨｚの搬送波で搬送波抑圧変調された副信号３
２として、３３ｋＨｚ±１５ ｋＨｚ 、すなわち、２
３ｋＨｚ〜５３ｋＨｚの帯域を占有している。復調時に
搬送波を再生するのに必要なパイロ。Conventionally, matrix type and switching type modulation circuits have been used in MPXi modulation circuits for ``M broadcasting.'' Figure 2 explains the OFM stereo broadcast signal.The sum of left and right audio signals (L, 几) The signal (L+a) 3t occupies 50Hz to 15 kHz as the main signal, and the difference signal (L-几)
Sub signal 3 is carrier suppression modulated using a 38 kHz carrier wave.
2, 33kHz±15kHz, i.e. 2
It occupies a band of 3kHz to 53kHz. Pyro required to regenerate the carrier wave during demodulation.
ト信号３３は３８ｋＨｚの搬送波の１／２０周波数であ
る１ ｇ ｋＨｚで位相も同期している。The phase of the digital signal 33 is also synchronized at 1 g kHz, which is 1/20 frequency of the 38 kHz carrier wave.
マトリ、ジス形のＭＰＸ変調回路は、左音声信号と、右
音声信号の２つのステレオ音声信号を和信号と差信号の
２つの信号に置き換えて、このうち差信号を３８ｋＨｚ
の搬送波で、搬送波抑圧振幅変調し、和信号と合成して
コンポジ、ト信号を得るものである。また、時分割合成
することで、コンポジ、ト信号を得る方法もあり、これ
をスイ、テング形のＭＰＸ変調回路という０
〔発明が解決しようとする問題点〕
従来のＭＰＸｉｇ１１回路では、搬送波抑圧Ｄｉ幅変調
・を行なう際５０チのデー−ティー比の方形波を搬送波
に用いる為、方形波の高調波によっても搬送波抑圧振幅
変調されて不要スペクトラムが多電に発生する。このた
め、ｒ２−ハス・フィルター（以下ＬＰＦ）を用いて除
去する必要がある。The matrix-type MPX modulation circuit replaces two stereo audio signals, a left audio signal and a right audio signal, with two signals, a sum signal and a difference signal, and converts the difference signal into a 38kHz signal.
The carrier wave is subjected to carrier wave suppression amplitude modulation and combined with the sum signal to obtain a composite signal. There is also a method of obtaining a composite signal by time-division synthesis, which is called a switch-type MPX modulation circuit. When width modulation is performed, a square wave with a duty ratio of 50 inches is used as a carrier wave, so harmonics of the square wave are also subjected to carrier wave suppression amplitude modulation, resulting in multiple unnecessary spectrums. Therefore, it is necessary to remove it using an r2-Has filter (hereinafter referred to as LPF).
例えば、搬送波の第３次高調波による影響は、レベルに
おいては、基本変調波の１中−１０ｄＢである０周波数
においては、搬送波３ ｆ３ ｋＨｚの３倍の１１４１
４ｈで、これに音声変調がかかるため、１１４ｋＨｚ
±１５ ｋＨｚすなわち、９９ ｋＨｚ 〜１２９ ｋ
Ｈｚの範囲に影響がでる。このよりに、搬送波の第３次
高調波による占有帯域の下限はすでに示した基本波の占
有帯域の上限５３ｋＨｚからみて、０．９ オクターブ
程度しか離れていない。この為、不要スペクトラムを一
４０ｄＢＣ上）以下にするには、 ３０ｄＢ１０ｃｔ
以上の急峻な力、トオ７特性を持つＬＰＦを使用する必
要がある。For example, the influence of the third harmonic of the carrier wave is, in terms of level, at the 0 frequency, which is -10 dB in 1 of the fundamental modulation wave, the level is 1141, which is three times the carrier wave 3 f3 kHz.
4h, and audio modulation is applied to this, so the frequency is 114kHz.
±15 kHz or 99 kHz to 129 kHz
The Hz range is affected. As a result, the lower limit of the occupied band by the third harmonic of the carrier wave is only about 0.9 octave apart from the upper limit of 53 kHz of the occupied band of the fundamental wave, which has already been shown. Therefore, to reduce the unnecessary spectrum to -40dBC above) or less, 30dB10ct
It is necessary to use an LPF with the above steep force and To7 characteristics.
通常、このような急峻な特性のＬＰＦとして、７次ない
し１１次のテエビテエ７形ＬＰＦが、使われるが、ＬＰ
Ｆの位相特性が大変悪く、コンポジット信号とパイロ、
ト信号との位相差が生じ易い０その上、通過帯域内にも
、す、プルが出易く、更に５０ｋＨｚ 近辺の側帯波
も若干除かれてしまい、和信号と差信号の変調反とのレ
ベル差が生じる０このため、５６Ｈｚ〜１５ ｋＨｚの
全音声入力帯域、特に高域で高セパレーションを確保す
るのは、極めて困難であるＯ
又、ＬＰＦ自身、温度変化や湿気に弱く、経時変化を生
じ易く信頼性を悪化させる欠点がある。Normally, a 7th to 11th order Tevitae 7 type LPF is used as an LPF with such a steep characteristic.
The phase characteristics of F are very poor, and composite signals and pyro,
In addition, a pull is likely to occur within the passband, and sideband waves around 50kHz are also slightly removed, causing a difference in the level of the modulation signal between the sum signal and the difference signal. Therefore, it is extremely difficult to ensure high separation in the entire audio input band from 56 Hz to 15 kHz, especially in the high range.In addition, the LPF itself is sensitive to temperature changes and humidity, and changes over time. There is a drawback that reliability is easily deteriorated.
なお、マトリ、ジス形のＭＰＸ変調回路の場合。In addition, in the case of Matri-type and Jis-type MPX modulation circuits.
アナログ掛算器を用いて、適正量の３８ｋＨｚ の正弦
波で、搬送波抑圧振幅変調を行えば、（これを非飽和式
マトリクス形という）高調波を発生しないが信号系路が
和信号と、差信号で異なるため遅延時間差やレベル差が
生じ易い。更に搬送波のレベル変動が、直接差信号の変
調波のレベル変動になり、温度や電源電圧の変化による
アナログ掛算器の伝達関数の変化も直接、差信号の変調
波のレベル変動につながる。このような差信号の変調波
のレベル変動は、すなわち、和信号と差信号との利得差
になシ、やはシ分離度を悪化させる。たとえば、和信号
と差信号との間に、０．１ｄＢの利得差があるだけで、
分Ｎ１寂は、４０ｄＢ程腿しか確保できなくなる。If carrier suppression amplitude modulation is performed using an appropriate amount of 38kHz sine wave using an analog multiplier, harmonics will not be generated (this is called a non-saturated matrix type), but the signal path will be able to combine the sum signal and the difference signal. Because of this difference, delay time differences and level differences are likely to occur. Further, level fluctuations in the carrier wave directly lead to level fluctuations in the modulated wave of the difference signal, and changes in the transfer function of the analog multiplier due to changes in temperature or power supply voltage also directly lead to level fluctuations in the modulated wave of the difference signal. Such level fluctuations of the modulated wave of the difference signal deteriorate the gain difference between the sum signal and the difference signal, or the degree of separation. For example, if there is only a 0.1 dB gain difference between the sum signal and the difference signal,
At N1 Jaku, only the thighs can be secured by about 40 dB.
本発明の目的は、急峻な特性を持つＬＰＦや、アナログ
掛算器を用いずに、高信頼性と高性能を両立したＭＰＸ
変調回路を提供することである。The purpose of the present invention is to provide an MPX that achieves both high reliability and high performance without using an LPF with steep characteristics or an analog multiplier.
An object of the present invention is to provide a modulation circuit.
本発明によれば、左音声信号を入力する第１０入力端子
と、この左音声信号を多段階に分圧する第１のアッテネ
ターと、この第１のアッテネターの出力を入力する第１
の多チヤンネル入力アナログスイッチと、可変アッテネ
ターと右音声信号を入力する第２の入力端子と、この右
音声信号を入力し、右音声信号を多段階に分圧する第２
のアッテネターと、この第２のアッテネターの出力を入
力する第２の多チャンネルアナログスイッチと、第１お
よび第２の多チヤンネル入力アナログスイッチの各出力
を合成する合成回路と、と金有し、第１および第２の多
チヤンネル入力アナログスイッチに３８ｋＨｚの周期で
疑似正弦波状に伝達特性が変化するようなタイピング信
号を供給したＭＰＸＫｒＡ回路を得る。According to the present invention, there is provided a tenth input terminal into which the left audio signal is input, a first attenuator which divides the voltage of the left audio signal into multiple stages, and a first attenuator into which the output of the first attenuator is input.
a multi-channel input analog switch, a variable attenuator, a second input terminal for inputting the right audio signal, and a second input terminal for inputting the right audio signal and dividing the right audio signal into multiple stages.
attenuator, a second multi-channel analog switch inputting the output of the second attenuator, and a synthesis circuit synthesizing each output of the first and second multi-channel input analog switches; An MPXKrA circuit is obtained in which the first and second multi-channel input analog switches are supplied with a typing signal whose transfer characteristics change in a quasi-sinusoidal manner at a period of 38 kHz.
次に１図面を参照して本発明を説明する。 The invention will now be described with reference to one drawing.
まず、第１図を用いて本発明の詳細な説明する。First, the present invention will be explained in detail using FIG.
入力端子ｌに左音声信号を受け、これを抵抗アクテネタ
−３を介して多チャンネルアナログスイッチ５に加え、
さらにバ、７アーアング７を介して、抵抗９の一端に与
える０同様に、右音声信号を入力端子２に加え、抵抗ア
ッテネタ−４を介して多チャンネルアナログスイッチ６
に供給し、さらにバ、７アーアング８を介して、抵抗ｌ
Ｏの一端に与える。抵抗９と１０の他方端同志を共通に
接続し、その接続点よｆｉＬＰＦｌｌを介して７エ、イ
ズ・シフター１２に与え、その出力を出力端１３に供給
する。更に、多チャンネルアナログスイッチ５．７にタ
イミング信号を与えるタイミングデコーダー１４を有し
ている。Receives the left audio signal at the input terminal l, applies it to the multi-channel analog switch 5 via the resistor actuator 3,
Further, the right audio signal is applied to the input terminal 2 through the resistor attenuator 4, and the right audio signal is applied to one end of the resistor 9 through the resistor attenuator 4.
is supplied to the resistor l through the
Apply to one end of O. The other ends of the resistors 9 and 10 are connected in common, and the connection point is applied to the shifter 12 via fiLPFll, and its output is supplied to the output terminal 13. Furthermore, it has a timing decoder 14 which provides timing signals to the multi-channel analog switch 5.7.
次に動作の説明を行なう。Next, the operation will be explained.
入力端子ｌに左の音声信号を入力する。入力された音声
信号は抵抗アッテネター３に入るが、抵抗アッテネター
３は多チャンネルアナログスイッチ５と組み合わせて、
可変減衰量のアッテネターを構成している。抵抗値を適
切な値とし、タイミングデコーダー１４よシアナログス
イッテのチャンネルを順次切シ換えられるように信号を
与えることによシ、（ｌ）式に示す伝達関数ｆＬ（ｔ）
ｉｃ伝達特性を近似できる疑似正弦波の伝Ｓ特性を持つ
アナログ掛算器を構成し、変調された音声信号は、バッ
ファー７を介し、抵抗９に与えられて左音声の変調信号
を得る。Input the left audio signal to input terminal l. The input audio signal enters the resistor attenuator 3, and the resistor attenuator 3 is combined with the multi-channel analog switch 5.
It constitutes an attenuator with variable attenuation. By setting the resistance value to an appropriate value and applying a signal to the timing decoder 14 to sequentially switch the channels of the analog switch, the transfer function fL(t) shown in equation (l) can be obtained.
An analog multiplier having a pseudo sine wave transmission characteristic that can approximate the IC transmission characteristic is configured, and the modulated audio signal is applied to a resistor 9 via a buffer 7 to obtain a left audio modulation signal.
ｆＬ（ｔ）” ｉ（１＋ ｃｏｓｗｔ ） （ｗ＝２ｒ
ｆ 、 ｆ ＝３８ｋＨｚ）・・・・・・（１）
同様に入力端子２に加えられた右音声信号は抵抗アッテ
ネター４と、多チャンネルアナログスイッチ６とタイミ
ングデコーダー１４によシ（２）弐に示す伝達関数ｆｎ
（幻とに近似される伝達関数をもつアナログ掛算器を構
成しバッファー８と、抵抗１ｏに与えて右音声の変調信
号を得る。fL(t)”i(1+coswt)(w=2r
f, f = 38kHz) (1) Similarly, the right audio signal applied to input terminal 2 is sent to resistor attenuator 4, multi-channel analog switch 6, and timing decoder 14 (2) Transfer function fn
(An analog multiplier with a transfer function approximated by phantom is constructed and applied to the buffer 8 and the resistor 1o to obtain the modulation signal of the right audio.
！
ｆｉｌ（ｔ）−Ｈ（１−ｃｏｓｗｔ ） （ｗ＝２ｇｆ
、 ｆ ＝３８ｊｃＨｚ ）・・・・・・（２）
このように合成された左と右の音声変調信号は、抵抗９
と１０との直列回路で加算される。その後。! fil(t)-H(1-coswt) (w=2gf
, f = 38jcHz) (2) The left and right audio modulation signals synthesized in this way are connected to the resistor 9.
and 10 are added in a series circuit. after that.
ＬＰＦＩＩで疑似正弦波のわずかな高調波を除去し７エ
イズ・シフター１２で、ＬＰＦの位相回転の補正を行な
い出力端１３ヘコンポジ、ト信号を出力するＯ
このようにすることによシ変調時に生じる高調波成分は
、等制約に疑似正弦波で乗算したものになる為、非常に
減少し、残った高調波も高次のものくなるので簡単に除
去できる。The LPF II removes slight harmonics of the pseudo sine wave, and the 7 aids shifter 12 corrects the phase rotation of the LPF and outputs a composite signal to the output terminal 13. Since the harmonic components are equal constraints multiplied by a pseudo sine wave, they are greatly reduced, and the remaining harmonics are also of high order, so they can be easily removed.
この方式は、ＬＰＰが簡素化でき、アナログスイ、テの
ＯＮ抵抗も無視でき抵抗アッテネターの相対値でほとん
ど精度が決まシ、抵抗の温度係数も相殺されるので安定
性ＫｉＥれ再現性も高い。In this method, the LPP can be simplified, the ON resistance of the analog switch and switch can be ignored, and the accuracy is almost determined by the relative value of the resistance attenuator.The temperature coefficient of the resistance is also canceled out, so the stability, KiE, and reproducibility are high.
こうした結果、従来のスイッチング形や、非＆ｌＨマ）
＋７クス式で生じた問題が解消できる。As a result, conventional switching type and non-&lH type
The problems that occurred with the +7 system can be resolved.
まず、従来のスイッチング形と比べると、ＬＰＦが簡単
なもので済むのでＬＰＦによる差信号の変調帯域の位相
回転や減衰がほとんどなく又、その補正も容易であるの
で、５０Ｈｚ〜１５ｋＨｚの音声全帯域にわたり分ＸＩ
度が非常に良く、シかも温度変化。First, compared to the conventional switching type, the LPF is simple, so there is almost no phase rotation or attenuation in the modulation band of the difference signal caused by the LPF, and the correction is easy, so the entire audio band from 50Hz to 15kHz can be used. over minutes XI
The temperature is very good, and the temperature changes easily.
湿度、撮動１Ｍ時変化といったものに対し、はとんど影
響を受けず組み立て後の調整も容易である。It is hardly affected by things such as humidity and changes over 1M of photography, and adjustments after assembly are easy.
父、非飽和形マトリクス形と比べると、和信号と差信号
の変調波は四−経路を通っているので独立した経路を通
ることによる和信号と差信号の変調波との利得差や遅延
時間差は起こらず、アナログ掛算器を用いないため搬送
波レベルや温度や電源電圧の変化によプ、差信号の変調
レベルが変化し分離度を悪化させることは全くない。Compared to the non-saturated matrix type, the modulated waves of the sum signal and difference signal pass through four paths, so the gain difference and delay time difference between the modulated waves of the sum signal and difference signal due to passing through independent paths. Since no analog multiplier is used, the modulation level of the difference signal will not change due to changes in the carrier wave level, temperature, or power supply voltage, and the degree of separation will not deteriorate at all.
このように本発明はマトリクス回路やアナログ掛算器の
不要なスイッチング形の置所とＬＰＦの悪影響を受けな
い非飽和形のマトリクス形の長所を兼ねそなえている。As described above, the present invention has both the advantages of a switching type circuit that does not require a matrix circuit or an analog multiplier, and the advantages of a non-saturated matrix type circuit that is not affected by the adverse effects of an LPF.
次に第３図を用いて不発明をＦＭ放送用ステレオＭＰＸ
変調回路に適用した一笑施例を説明する。尚、第１図と
対応する部分には同じ参照符号を付した。Next, using Fig. 3, we will explain the invention using the stereo MPX for FM broadcasting.
An example applied to a modulation circuit will be described. Note that parts corresponding to those in FIG. 1 are given the same reference numerals.
左チャンネルの入力端子ｌでは左音声信号を受は右チャ
ンネルの入力端子２では右音声信号を受ける。The left channel input terminal 1 receives the left audio signal, and the right channel input terminal 2 receives the right audio signal.
抵抗γツテネータ３．４はそれぞれ１６の出方を有して
いる。従って多チヤンネル入力のアナログマルテグレク
＋ｊ５．６はそれぞれ１６の入力を持っている。タイミ
ングデコーダー１４では１２１６ｋＨｚの原発振信号を
分周したｔｉ０８ｊｃＨｚ（Ｑｌ ）、 ３０４ ｋＨ
ｚ（Ｑ２）、１５２ｋＨｚ（Ｑ３）、７６ｋＨｚ（Ｑ４
）の各タイミング信号の極性を、ａｓｋｎｚ（Ｑｓ）の
タイミング信号の極性によシ反転させるようにしたもの
を、それぞれ１６チヤンネルアナログスイツテ５．６に
制−信号として入力している。これにより、アナログス
イッチ５．６はＩｌ、 Ｉ、 、 Ｉ３．・・−Ｉｌｌ
、Ｉｎ、Ｉｆ・。The resistor gamma testeners 3.4 each have 16 openings. Therefore, the analog malteglek + J5.6 of the multi -yannel input has 16 input. The timing decoder 14 divides the original oscillation signal of 1216 kHz to ti08jcHz (Ql), 304 kHz.
z (Q2), 152kHz (Q3), 76kHz (Q4
) is inverted according to the polarity of the asknz (Qs) timing signal and is input as a control signal to the 16-channel analog switch 5.6. This causes the analog switches 5.6 to switch Il, I, , I3 . ...-Ill
,In,If・.
ＩＩ ％ −”’＊ ｂ ｅ Ｉｔ ｅ Ｉｆ ＠ Ｉ
２ ＋ ”’ という具合に入力接点を３３ｋＨｚの
周期で切シ換えて音声信号を受はル。ツレぞれの抵抗Ｒ
ｎ （ｎ ＝ｌ 、 ２ 、−、 Ｎ−１゜ＮＵＮはア
ナログスイッチのチャンネル数）をΣＲＮ１８０１
Ｒｎ ＝−（１−（ｏｓ （Ｔ（ｎ］）））−Σ偕−（
几。＝０とする）・・・・・・（３）とし、バッファー
アンプ７．８の利得を１１１とすれば、入力端子１から
パワファーアングアｔでの伝達特性は第４図のようにな
る０第４図（ａ）が伝達特性を示し、同図（ｂ）が３８
ｋＨｚのクロック君号を示しており、これら相互の位
相関係を示している０入力端子２とのバッファーアンプ
８の出力までの伝達時性は第４図図示のものとは逆相の
ものとなる０第４図図示の伝達ｔＷＪ性の場合、第３１
次未満の高調波は存在せず、その帯域は１１６３ｋＨｚ
以上とな９、基本次変調波の上限５３ ｋＨｚからみて
４オクタ一ブ強離れており、高調波レベルも約−３０ｄ
Ｂであシ、−６ｄｎ／ ｏｃｔのＣＲ，１段のＬＰＦで
も容易に高調波レベルを一４０ｄＢ以下に抑えることが
できるＯこのように、バッファーアンプ７．８の出力は
、それぞれ抵抗９，１ｏを通り合成されて出方され、Ｌ
ＰＦＩＩで、３１次以上の高調波を除去し、７エイズシ
ツクー１２で位相補正を行ない、出力端１３へ出力され
る。II % -”'* b e It e If @ I
The input contact is switched at a frequency of 33kHz as follows: 2 + "' to receive the audio signal.Resistance R on each side
n (n = l, 2, -, N-1゜NUN is the number of channels of the analog switch) as ΣRN1801 Rn = -(1-(os (T(n)))) -Σ偕-(
几. = 0) (3), and if the gain of buffer amplifier 7.8 is 111, the transfer characteristic from input terminal 1 to power amplifier t will be as shown in Figure 4. 0 Figure 4(a) shows the transfer characteristics, and Figure 4(b) shows the 38
It shows the clock code of kHz, and shows their mutual phase relationship.The transmission time between the 0 input terminal 2 and the output of the buffer amplifier 8 is in reverse phase from that shown in Fig. 4. 0 In the case of the transmission tWJ property shown in Fig. 4, the 31st
There are no harmonics below the following, and the band is 1163kHz.
From the above 9, it is a little over 4 octaves away from the upper limit of the fundamental modulation wave, 53 kHz, and the harmonic level is also about -30 d.
With B, the harmonic level can be easily suppressed to less than -40 dB even with a CR of -6 dn/oct and a single stage LPF. In this way, the output of buffer amplifier 7.8 is connected to resistors 9 and 1 oct, respectively. , synthesized and output, L
The PFII removes harmonics of the 31st order and higher, the phase is corrected by the 7-ray filter 12, and the signal is output to the output terminal 13.
この実施例の場合、ＬＰＦＩＩが抵抗とコンデンサとの
フィルター１段によって構成しているため。In the case of this embodiment, the LPFII is constituted by one stage of filter consisting of a resistor and a capacitor.
位相回転は７エイズシフター１２で完全に補正可能であ
る。パイロット信号は入力端子１５よシ入力する０
なお、上記実施例ではパイロット信号の作成法について
はふれていないが、パイロ、ト信号も疑似正弦波をもと
に発生させるす法を利用すればやはり。The phase rotation can be completely corrected by the 7 aids shifter 12. The pilot signal is input through the input terminal 15.Although the method for creating the pilot signal is not mentioned in the above embodiment, the pilot signal can also be generated by generating it based on a pseudo sine wave. .
ＬＰＦによる悪影響からのがれることができる。It is possible to escape from the negative effects of LPF.
このように、本発明によれば扁性能と高信頼性を両立し
た）゛Ｍ放送用ＭＰＸステレオ放送用変調器を提供でき
る。As described above, according to the present invention, it is possible to provide a modulator for MPX stereo broadcasting for M broadcasting that has both low performance and high reliability.
ｌＸ１図は本発明の原理を示す回路ブロック図であり、
第２図はステレオコンポジ、ト信号の周波数スペクトラ
ムを示す図であり、第３図は本発明の一実施例による回
路図であシ、第４図は左音声信号用変調部の疑似正弦波
状の伝達特性を示すもので、同図（ａ）はバ、７アアン
グの出力波形、同図１ｂ）は３８ｋＨｚのクロ、り信号
を示すものである。
１・・・・・・左音声信号用入力端子、２・・・・・・
右音声信号用入力端子、３・・・・・・左音声信号用抵
抗アッテネター、４・・・・・・右音声信号用抵抗アッ
テネター、５・・・・・・左音声信号用多チャンネル入
力アナログスイ、テ、６・・・・・・右音声信号用多チ
ャンネル入力アナログスイッチ。
７・・・・・左音声信号用バッファーアンプ、８・・・
・・・石音声信号用バ、７アーアング、９・・・・・・
抵抗、１０・・・・・・ｍ抗、１１・・・・・・ローパ
スフィルター、１２・・・・・・７エイズ・シフター、
１３・・・・・・出力端子、１４・・・・・・タイミン
グデコーダー、１５・・・・・・パイロ、ト信号入力端
子、３１・・・・・・和信号（Ｌ＋）Ｌ）のスペクトラ
ム、３２・・・・・差信号（Ｌ−几）を搬送波抑圧振幅
変調し第１図
第２図Figure lX1 is a circuit block diagram showing the principle of the present invention,
FIG. 2 is a diagram showing the frequency spectrum of a stereo composite signal, FIG. 3 is a circuit diagram according to an embodiment of the present invention, and FIG. The transfer characteristics are shown in Figure 1(a) showing the output waveforms of 7A and 7A, and 1B) of the same figure showing the 38kHz black signal. 1... Left audio signal input terminal, 2...
Input terminal for right audio signal, 3...Resistance attenuator for left audio signal, 4...Resistance attenuator for right audio signal, 5...Multi-channel input analog for left audio signal Sui, Te, 6...Multi-channel input analog switch for right audio signal. 7...Buffer amplifier for left audio signal, 8...
...Stone audio signal bar, 7 aang, 9...
Resistor, 10...m resistance, 11...Low pass filter, 12...7 aids shifter,
13...Output terminal, 14...Timing decoder, 15...Pyro signal input terminal, 31...Spectrum of sum signal (L+)L) , 32... The difference signal (L-几) is subjected to carrier wave suppression amplitude modulation in Figs. 1 and 2.
Claims (1)
端子からの前記左音声信号を、多段階に分圧する第１の
アッテネターと、該第１のアッテネターからの出力を選
択的に受ける第１の多チャンネル入力アナログスイッチ
と、該第１の多チャンネル入力アナログスイッチの出力
を受ける第１の合成用抵抗と、右音声信号を入力する第
２の入力端子と、該第２の入力端子からの右音声信号を
多段階に分圧する第２のアッテネターと、該第２のアッ
テネターからの出力を選択的に受ける第２の多チャンネ
ルアナログスイッチと、該第２の多チャンネルアナログ
スイッチからの出力を受ける第２の合成用抵抗とを有し
、前記第１および第２の多チャンネル入力アナログスイ
ッチにはタイミングデコーダより３８ｋＨｚの周期で疑
似正弦波状に伝達特性が変化するようなタイミング信号
を供給することを特徴とするステレオ変調回路。a first input terminal into which a left audio signal is input; a first attenuator that voltage-divides the left audio signal from the first input terminal into multiple stages; and a first attenuator that selectively controls the output from the first attenuator. a first multi-channel input analog switch that receives the output, a first synthesis resistor that receives the output of the first multi-channel input analog switch, a second input terminal that receives the right audio signal, and a second input terminal that receives the output of the first multi-channel input analog switch; a second attenuator that divides the right audio signal from the terminal into multiple stages; a second multi-channel analog switch that selectively receives the output from the second attenuator; and a second combining resistor that receives the output, and supplies a timing signal whose transfer characteristic changes in a pseudo-sinusoidal manner with a period of 38 kHz from a timing decoder to the first and second multi-channel input analog switches. A stereo modulation circuit characterized by:
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3196885A JPS61192138A (en) | 1985-02-20 | 1985-02-20 | Stereo modulation circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3196885A JPS61192138A (en) | 1985-02-20 | 1985-02-20 | Stereo modulation circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS61192138A true JPS61192138A (en) | 1986-08-26 |
| JPH0416970B2 JPH0416970B2 (en) | 1992-03-25 |
Family
ID=12345750
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3196885A Granted JPS61192138A (en) | 1985-02-20 | 1985-02-20 | Stereo modulation circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS61192138A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2007040095A1 (en) * | 2005-09-30 | 2007-04-12 | Thine Electronics, Inc. | Stereo modulator and fm stereo modulator using the same |
-
1985
- 1985-02-20 JP JP3196885A patent/JPS61192138A/en active Granted
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2007040095A1 (en) * | 2005-09-30 | 2007-04-12 | Thine Electronics, Inc. | Stereo modulator and fm stereo modulator using the same |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0416970B2 (en) | 1992-03-25 |
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