JPS5912841Y2 - stereo receiver - Google Patents
stereo receiverInfo
- Publication number
- JPS5912841Y2 JPS5912841Y2 JP1951778U JP1951778U JPS5912841Y2 JP S5912841 Y2 JPS5912841 Y2 JP S5912841Y2 JP 1951778 U JP1951778 U JP 1951778U JP 1951778 U JP1951778 U JP 1951778U JP S5912841 Y2 JPS5912841 Y2 JP S5912841Y2
- Authority
- JP
- Japan
- Prior art keywords
- separation
- stereo
- degree
- filter
- beat
- 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
- Noise Elimination (AREA)
- Stereo-Broadcasting Methods (AREA)
Description
【考案の詳細な説明】
本考案は、FMステレオ受信機に関するもので、特に該
受信機における低周波2チヤンネル出力間の分離度の改
善にかかる。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an FM stereo receiver, and particularly to improving the degree of separation between outputs of two low frequency channels in the receiver.
FM放送の多局化の際、受1信機側の大きな問題として
隣接妨害波に対する混信排除熊力が挙げられる。When FM broadcasting becomes multi-channel, a major problem on the receiver side is the ability to eliminate interference from adjacent interference waves.
特にその最悪の状況として隣接200 KHzの妨害が
あり、現在の受信機では、この状況でステレオ受信時に
は大幅なS/N比低下を生じる。Particularly, the worst situation is interference from adjacent 200 KHz, and in current receivers, this situation causes a significant drop in the S/N ratio during stereo reception.
この原因について次のことが確かめられている。The following has been confirmed as the cause of this.
まず、希望波、妨害波間の差であるビート周波数200
KHzがFM検波器の出力に混在して出てくることで
ある。First, the beat frequency 200 is the difference between the desired wave and the interference wave.
KHz appears mixed in the output of the FM detector.
そして、ステレオ動作時には、スイッチング方式のステ
レオ復調器が動作するが、このスイッチング周波数38
KHzの第5次高調波周波数190 KHzと、上記ビ
ート周波数200KHzが10KHzのビートを発生し
、このビート成分が受信機における低周波出力のS/N
比低下をもたらす主要因となっている。During stereo operation, a switching type stereo demodulator operates, and this switching frequency is 38.
The fifth harmonic frequency of 190 KHz and the above beat frequency of 200 KHz generate a 10 KHz beat, and this beat component is the S/N of the low frequency output at the receiver.
This is the main factor causing the ratio to decline.
もちろん、実際には希望波、妨害波とも変調されている
ので、この10KHzのビートは低周波帯域全体に広が
る。Of course, since both the desired wave and the interference wave are actually modulated, this 10 KHz beat spreads over the entire low frequency band.
ここで、この10KHzのビートを除去するための公知
の手段として、FM検波器の直後に200KHzのビー
トを十分減衰させるための低域通過フィルタ、あるいは
200KHz付近に減衰極を持つノツチフィルタを接続
することによって、復調出力のS/N比の改善に十分効
果があることが確かめられている。Here, as a known means for removing this 10 KHz beat, a low-pass filter or a notch filter having an attenuation pole near 200 KHz is connected immediately after the FM detector to sufficiently attenuate the 200 KHz beat. It has been confirmed that this is sufficiently effective in improving the S/N ratio of the demodulated output.
しかしながら、このフィルタの振幅および位相特性によ
ってステレオ復調信号の分離度が低下するという欠点が
ある。However, the amplitude and phase characteristics of this filter reduce the degree of separation of the stereo demodulated signals.
一般に振幅特性の影響については、合成信号中の主・副
チヤンネル間の利得差が1dBで15 dB程度の分離
度低下があり、また位相特性についても両チャンネル間
の位相差が1°で5dB程度の悪化を生じる。In general, regarding the influence of amplitude characteristics, if the gain difference between the main and sub channels in the composite signal is 1 dB, the degree of separation will decrease by about 15 dB, and regarding the phase characteristics, if the phase difference between both channels is 1 degree, the degree of separation will be reduced by about 5 dB. resulting in deterioration of
したがってフィルタの構成による程度差はあっても、分
離度の低下はまぬがれないものであった。Therefore, although there are differences in degree depending on the configuration of the filter, a decrease in the degree of separation is unavoidable.
そこで本考案は、フィルタを挿入してもその時点で再び
低廟波段における分離度調整を行なえば分離度がほぼも
との状態まで復帰することに着目し、上記フィルタの使
用時とフィルタ非使用時とにおいてそれぞれ分離度の最
適化を得る調整量を設定し、前記フィルタのオン・オフ
動作に連動して、上記輯定量を切換えることにより、い
ずれの場合にも良好なステレオ再生出力が得られるよう
にしたものである。Therefore, the present invention focuses on the fact that even if a filter is inserted, if the separation degree is adjusted again at the low wave stage at that point, the separation degree will return to almost its original state. By setting the adjustment amount to optimize the degree of separation at each time, and switching the adjustment amount in conjunction with the on/off operation of the filter, good stereo reproduction output can be obtained in any case. This is how it was done.
以下本考案をその一実施例を示す添付図面に基づいて説
明する。The present invention will be explained below based on the accompanying drawings showing one embodiment thereof.
第1図において、1はFM検波器、2は200 KHz
のビート除去用フィルタ、3はステレオ復調器、4は分
離度調整回路で、たとえば第2図に示すようなりロスト
ークキャンセル方式を用いた回路を使用する。In Figure 1, 1 is an FM detector, 2 is a 200 KHz
3 is a stereo demodulator, and 4 is a separation adjustment circuit. For example, a circuit using a losstalk cancellation method as shown in FIG. 2 is used.
ここで先に第2図について説明すると、41.42はク
ロストークキャンセル用トランジスタで、おのおのベー
スにステレオ復調器7からの左チャンネル信号Lin、
右チャンネル信号Rinが印加される。First, referring to FIG. 2, 41 and 42 are crosstalk canceling transistors, each of which has a left channel signal Lin from the stereo demodulator 7 at its base,
A right channel signal Rin is applied.
43は分離調整量設定用可変抵抗器で、これを調節する
ことによりおのおのコレクタ出力より純粋な左チヤンネ
ル出力信号Lout、右チャンネル信号Routを得る
。Reference numeral 43 denotes a variable resistor for setting a separation adjustment amount, and by adjusting this, a left channel output signal Lout and a right channel signal Rout which are pure from the respective collector outputs can be obtained.
また第1図において、5はフィルタ2のオン・オフ切換
スイッチ、6は前記切換スイッチ5に連動する調整量切
換スイッチで、フィルタ2のオン・オフにともなって、
可変抵抗器43とフィルタ2のオン時使用する可変抵抗
器44を切換える。Further, in FIG. 1, 5 is an on/off switch for the filter 2, and 6 is an adjustment amount switch that is linked to the changeover switch 5.
The variable resistor 43 and the variable resistor 44 used when the filter 2 is turned on are switched.
なお、7はフィルタ2のオン・オフ切換命令装置で、上
記切換スイッチ5,6はこの出力でもって切換わる。Note that 7 is an on/off switching command device for the filter 2, and the changeover switches 5 and 6 are switched by this output.
したがって上記構成において、ビート妨害のないときに
は切換スイッチ5,6を図示する状態と逆に切換えて、
FM検波器1とステレオ復調器3を直接接続するととも
に、分離度調整回路4の可変抵抗器としては可変抵抗器
43を用いる。Therefore, in the above configuration, when there is no beat disturbance, the changeover switches 5 and 6 are switched to the opposite state from that shown in the figure.
The FM detector 1 and the stereo demodulator 3 are directly connected, and a variable resistor 43 is used as the variable resistor of the separation degree adjustment circuit 4.
そしてビート妨害が生じるときには切換スイッチ5,6
を図示する状態に切換えてFM検波器1とステレオ復調
器3との間にフィルタ2を挿入するとともに、可変抵抗
京劇を用いる。When beat disturbance occurs, selector switches 5 and 6 are
is switched to the state shown in the figure, a filter 2 is inserted between the FM detector 1 and the stereo demodulator 3, and a variable resistance Peking Opera is used.
一般にフィルタ2の挿入により、合成液の主副チャンネ
ル間にゲイン差が生じた場合には、第3図にbで示すよ
うに正常な状態aからbのように帯域全体にわたってほ
ぼ同量の分離度悪化となるため、分離度調整回路4にお
ける再調整によってbからCへとほぼaまで復帰せしめ
る。Generally, when a gain difference occurs between the main and subchannels of the synthetic liquid due to the insertion of filter 2, the separation will be approximately the same amount over the entire band as shown in the normal state a to b, as shown by b in Figure 3. Since the degree of separation deteriorates, the degree of separation is readjusted in the degree of separation adjustment circuit 4 to return from b to C and almost to a.
また、位相による分離度悪化の場合には、第4図のaか
らdのように周波数によって異った量の悪化を示すが、
使用者が聴取の際には中域の分離度に対して敏感である
ため、中域で最も改善されるようにdからeへと調整す
れば効果的である。In addition, when the degree of separation deteriorates due to phase, the amount of deterioration varies depending on the frequency, as shown in a to d in Fig. 4.
Since the user is sensitive to the degree of separation in the midrange when listening, it is effective to adjust from d to e so that the midrange is improved the most.
以上説明したように本考案によればフィルタの使用・非
使用に応じて2通りの調整量を切換えできる分離度調整
回路を設けることにより、ビート妨害時のS/N比の向
上をはかることができるとともにステレオの分離度の悪
化を防止することができる。As explained above, according to the present invention, it is possible to improve the S/N ratio during beat disturbance by providing a separation adjustment circuit that can switch between two adjustment amounts depending on whether the filter is used or not. At the same time, deterioration of stereo separation can be prevented.
また、FM検波後にビート除去フィルタで妨害信号を除
去することによりフィルタ特性の自由度が大きくなり、
ステレオ複合信号の主・副チヤンネル間の振幅差の発生
を許容して位相差の発生を最小限にとどめる二とができ
、ステレオ復調時の分離度調整でほぼフィルタの無い場
合の分離度まで改善することができる。In addition, by removing interference signals with a beat removal filter after FM detection, the degree of freedom in filter characteristics is increased.
It is possible to minimize the phase difference by allowing the amplitude difference between the main and sub-channels of the stereo composite signal, and by adjusting the degree of separation during stereo demodulation, the degree of separation can be improved to almost the level without a filter. can do.
なお、分離度調整回路としては第2図に限定されるもの
ではない。Note that the degree of separation adjustment circuit is not limited to that shown in FIG.
第1図は本考案の一実施例におけるステレオ受信機のブ
ロック図、第2図は同受信機における分離度調整回路の
基本結線図、第3図、第4図は同受信機の作用を説明す
るための特性図である。
1・・・・・・FM検波器、2・・・・・・ビート除去
用フィルタ、3・・・・・・ステレオ復調器、4・・・
・・・分離度調整回路、5,6・・・・・・切換スイッ
チ、43.44・・・・・・分離度調整量設定用可変抵
抗器。Fig. 1 is a block diagram of a stereo receiver according to an embodiment of the present invention, Fig. 2 is a basic wiring diagram of a separation adjustment circuit in the receiver, and Figs. 3 and 4 explain the operation of the receiver. FIG. 1...FM detector, 2...Beat removal filter, 3...Stereo demodulator, 4...
... Separation adjustment circuit, 5, 6 ... Changeover switch, 43.44 ... Variable resistor for setting separation degree adjustment amount.
Claims (1)
除去用フィルタと、検波信号を前記ステレオ信号復調器
に直接接続するか、あるいは前記フィルタを通して前記
復調器に接続するかを定める切換手段と、この切換手段
に連動して動作し、2通りの調整量を切換えできるステ
レオ復調信号の分離調整回路とを有するステレオ受信機
。a beat removal filter installed between a detector and a stereo signal demodulator; and a switching means for determining whether to connect the detected signal directly to the stereo signal demodulator or to connect the detected signal to the demodulator through the filter. and a stereo demodulated signal separation and adjustment circuit that operates in conjunction with the switching means and can switch between two adjustment amounts.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP1951778U JPS5912841Y2 (en) | 1978-02-15 | 1978-02-15 | stereo receiver |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP1951778U JPS5912841Y2 (en) | 1978-02-15 | 1978-02-15 | stereo receiver |
Publications (2)
Publication Number | Publication Date |
---|---|
JPS54122712U JPS54122712U (en) | 1979-08-28 |
JPS5912841Y2 true JPS5912841Y2 (en) | 1984-04-17 |
Family
ID=28848767
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP1951778U Expired JPS5912841Y2 (en) | 1978-02-15 | 1978-02-15 | stereo receiver |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPS5912841Y2 (en) |
-
1978
- 1978-02-15 JP JP1951778U patent/JPS5912841Y2/en not_active Expired
Also Published As
Publication number | Publication date |
---|---|
JPS54122712U (en) | 1979-08-28 |
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