JPH0363857B2 - - Google Patents
Info
- Publication number
- JPH0363857B2 JPH0363857B2 JP12734183A JP12734183A JPH0363857B2 JP H0363857 B2 JPH0363857 B2 JP H0363857B2 JP 12734183 A JP12734183 A JP 12734183A JP 12734183 A JP12734183 A JP 12734183A JP H0363857 B2 JPH0363857 B2 JP H0363857B2
- Authority
- JP
- Japan
- Prior art keywords
- output
- signal
- sub
- matrix
- lch
- 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
Classifications
-
- 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
-
- 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
-
- 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
Landscapes
- Engineering & Computer Science (AREA)
- Signal Processing (AREA)
- Computer Networks & Wireless Communication (AREA)
- Stereo-Broadcasting Methods (AREA)
Description
【発明の詳細な説明】
この発明は、チユーナーにおけるノイズ低減回
路に関するものである。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a noise reduction circuit in a tuner.
従来この種の回路として、第１図に示すものが
あつた。これはハイブレンドと呼ばれる回路で、
図において１はステレオ復調器であり、Lch出力
２及びRch出力３との間には、スイツチＳとコン
デンサＣとの直列回路が接続されている。 A conventional circuit of this type is shown in FIG. This is a circuit called high blend,
In the figure, 1 is a stereo demodulator, and a series circuit of a switch S and a capacitor C is connected between an Lch output 2 and an Rch output 3.
かかる回路にあつては、チユーナーで入力電波
の小さいステレオ放送等を聞いた時に気になるノ
イズを軽減するもので、LchとRchの間に接続さ
れているスイツチＳをオンすることにより、Lch
とRchとがコンデンサＣで結合されたことにな
り、周波数の高い成分ほど混合量が多くなり、
Lch，Rchそれぞれの出力に含まれる逆相のノイ
ズ成分は混合され、各出力２，３にはノイズが軽
減された出力が得られる。 This circuit reduces the noise that becomes noticeable when listening to stereo broadcasts with small input radio waves using a tuner.By turning on the switch S connected between the Lch and Rch, the Lch
and Rch are combined by capacitor C, and the higher the frequency of the component, the greater the mixing amount.
The anti-phase noise components included in each of the Lch and Rch outputs are mixed, and outputs with reduced noise are obtained for each output 2 and 3.
従来の回路は以上のように構成されているの
で、高い周波数ほどLchとRchの混合比が大きく
なり、セパレーシヨン（分離度）が劣化するとい
う欠点があつた。 Since the conventional circuit is configured as described above, it has the disadvantage that the higher the frequency, the greater the mixing ratio of Lch and Rch, and the separation deteriorates.
この発明は上記のような従来のものの欠点を除
去するために成されたもので、出力電圧が大きい
ときだけサブ信号（Ｌ−Ｒ）の高い周波数成分を
通し、それ以外のときはサブ信号の高い周波数成
分をカツトし、かつ遅延信号を加えることによ
り、ノイズを軽減し、かつ聴感上広がり感を出す
ことのできる回路を提供することを目的としてい
る。 This invention was made in order to eliminate the drawbacks of the conventional ones as described above, and passes the high frequency component of the sub-signal (L-R) only when the output voltage is large, and passes the high frequency component of the sub-signal (L-R) at other times. The object of the present invention is to provide a circuit that can reduce noise and create a sense of audible spaciousness by cutting out high frequency components and adding a delayed signal.
以下、この発明の一実施例を図に基づいて説明
する。 Hereinafter, one embodiment of the present invention will be described based on the drawings.
第２図において、ステレオ復調器１のLch出力
２及びRch出力３はマトリツクス４に接続され、
マトリツクス４の出力にはメイン信号（Ｌ＋Ｒ）
とサブ信号（Ｌ−Ｒ）の信号が得られ、このうち
メイン信号はマトリツクス９の入力と遅延器５の
入力へ接続されている。また、サブ信号は電圧制
御フイルタ（以下VCFという）６の入力と検出
器７の入力へ接続されている。検出器７の出力
は、微分器１３の入力に接続され、その出力は
VCF６のコントロール端子へ接続されている。 In FIG. 2, Lch output 2 and Rch output 3 of stereo demodulator 1 are connected to matrix 4,
The output of matrix 4 is the main signal (L+R)
and sub-signals (LR) are obtained, of which the main signal is connected to the input of the matrix 9 and the input of the delay device 5. Further, the sub-signal is connected to the input of a voltage control filter (hereinafter referred to as VCF) 6 and the input of a detector 7. The output of the detector 7 is connected to the input of the differentiator 13, whose output is
Connected to the control terminal of VCF6.
また、遅延器５とVCF６の出力は混合器８に
よつて混合され、マトリツクス９の入力に接続さ
れている。また、マトリツクス９からは合成Lch
出力１０および合成Rch出力１１が出力されてい
る。 Further, the outputs of the delay device 5 and the VCF 6 are mixed by a mixer 8 and connected to the input of a matrix 9. Also, from matrix 9, synthetic Lch
Output 10 and composite Rch output 11 are output.
マトリツクス４及び９の構成は、第３図に示す
ように、各入力を加算器１５及び減算器１６に入
力することにより、入力の和及び差を出力してい
る。 As shown in FIG. 3, the structures of the matrices 4 and 9 output the sum and difference of the inputs by inputting each input to an adder 15 and a subtracter 16.
次に、この発明の動作について説明する。 Next, the operation of this invention will be explained.
まず、ステレオ復調器１から得られるLch出力
２、Rch出力３からマトリツクス回路４によりメ
イン信号（Ｌ＋Ｒ）、サブ信号（Ｌ−Ｒ）を得て
いる。 First, a main signal (L+R) and a sub signal (LR) are obtained from the Lch output 2 and Rch output 3 obtained from the stereo demodulator 1 by the matrix circuit 4.
このサブ信号のエンベローブを検出器７によつ
て検出し、微分器１３によつて微分することによ
りサブ信号のリーデイングエツジ（立ち上がり検
出）を行つている。この微分器１３の出力によつ
てサブ信号の立ち上がりが鋭い時は、VCF６の
カツトオフ周波数cを高く、それ以外の時はcを
低くするように、VCF６をコントロールする。 The envelope of this sub-signal is detected by a detector 7 and differentiated by a differentiator 13 to detect the leading edge of the sub-signal. When the rise of the sub-signal is sharp due to the output of the differentiator 13, the VCF 6 is controlled so that the cut-off frequency c of the VCF 6 is made high, and at other times, the cut-off frequency c is made low.
即ち、ノイズ成分が多いときには、サブ信号の
立上りは比較的緩やかであるから、カツトオフ周
波数cが低くなり、サブ信号の高い周波数成分は
VCF６から出力されないようにし、ノイズ成分
の少ないときはサブ信号の立上りが鋭くなり、c
を高くして、高い周波数成分を出力し、方向感や
定位を出している。 In other words, when there are many noise components, the rise of the sub-signal is relatively slow, so the cutoff frequency c becomes low, and the high frequency components of the sub-signal become
By preventing it from being output from VCF6, the rise of the sub signal becomes sharp when there are few noise components, and c
is raised to output high frequency components, providing a sense of direction and localization.
これにより聴感上ノイズは低減される。また、
メイン信号を遅延器５を通して所定時間遅延させ
た信号と、VCF６の出力とを混合器８で混合し、
この混合器８の出力と遅延させないメイン信号と
をマトリツクス９に入力して、加え合わせている
ので、上記のcが高いとき即ち、ノイズ成分の少
ないときには、遅延器５の出力よりVCF６の出
力レベルが大となり、混合器８の出力はほとんど
サブ信号が支配的となつて、マトリツクス９の出
力はステレオ復調器１のLch出力２及びRch出力
３とほぼ同じ信号が出力される。 This reduces audible noise. Also,
A signal obtained by delaying the main signal by a predetermined time through a delay device 5 and the output of the VCF 6 are mixed in a mixer 8,
The output of the mixer 8 and the main signal that is not delayed are input to the matrix 9 and added together, so when the above c is high, that is, when there are few noise components, the output level of the VCF 6 is higher than the output of the delay unit 5. becomes large, the output of the mixer 8 is almost dominated by the sub signal, and the output of the matrix 9 is almost the same signal as the Lch output 2 and the Rch output 3 of the stereo demodulator 1.
一方、cが低いとき、即ちノイズ成分が多いと
きには遅延器５の出力がVCF６の出力より大と
なつて、混合器８の出力は遅延器５の出力が支配
的となり、第３図に示すマトリツクスの構成から
明らかなように、マトリツクス９のLch及びRch
出力１０，１１にはこの遅延信号は逆相で現われ
ることになり、疑似的な広がり感を得ることがで
きる。従つて、VCF６で失なわれた広がり感を
補正することができる。 On the other hand, when c is low, that is, when there are many noise components, the output of delay device 5 becomes larger than the output of VCF 6, and the output of mixer 8 becomes dominated by the output of delay device 5, resulting in the matrix shown in FIG. As is clear from the configuration of matrix 9, Lch and Rch
These delayed signals appear in opposite phases at the outputs 10 and 11, giving a pseudo sense of spaciousness. Therefore, the sense of spaciousness lost in VCF6 can be corrected.
なお、上記実施例では遅延回路５の出力は常に
出力されるようになつていたが、これをVCF６
のカツトオフ周波数cが高い時には遅延回路５の
出力を小さくするようにすることで立ち上がりが
鋭い時に定位を出す効果を妨げないようにするこ
とができる。 Note that in the above embodiment, the output of the delay circuit 5 was always outputted, but this
By reducing the output of the delay circuit 5 when the cutoff frequency c is high, it is possible to avoid disturbing the localization effect when the rise is sharp.
第４図はかかる構成の実施例を示し、遅延回路
５の出力を電圧制御減衰器（VCA）１２を通し
て混合器８に入力し、微分器１３の出力を反転器
１４で反転した出力によりVCA１２の増幅をコ
ントロールする。ノイズ成分が少ないときには微
分器１３の出力が大となり、反転器１４の出力が
小となるからVCA１２の減衰度が大きくなり、
遅延回路５の出力を充分に減衰させて、VCF６
からのサブ信号出力をより支配的としている。 FIG. 4 shows an embodiment of such a configuration, in which the output of the delay circuit 5 is inputted to the mixer 8 through the voltage controlled attenuator (VCA) 12, and the output of the differentiator 13 is inverted by the inverter 14, and the output of the VCA 12 is inverted. Control amplification. When the noise component is small, the output of the differentiator 13 becomes large, and the output of the inverter 14 becomes small, so the attenuation degree of the VCA 12 becomes large,
After sufficiently attenuating the output of delay circuit 5, VCF6
The sub-signal output from is more dominant.
以上のようにこの発明によれば、サブ信号の高
い周波数成分を出力電圧が小さいときにはカツト
し、かつ遅延器により広がり感を出すようにした
ので、ステレオ感を保ちつつノイズ低減ができ
る。 As described above, according to the present invention, the high frequency components of the sub-signal are cut out when the output voltage is low, and the delay device is used to create a sense of spaciousness, so that noise can be reduced while maintaining the stereo effect.
第１図は従来のハイブレンドの回路を示す図、
第２図はこの発明の一実施例を示す図、第３図は
第２図、第４図におけるマトリツクス回路の構成
を示す図、第４図はこの発明の他の実施例を示す
図である。
１……ステレオ復調器、２……Lch出力、３…
…Rch出力、４，９……マトリツクス、５……遅
延器、６……VCF、７……レベル検出器、８…
…混合器、１０……合成Lch出力、１１……合成
Rch出力、１２……VCA、１３……微分器、１
４……反転器。
Figure 1 is a diagram showing the conventional high blend circuit.
FIG. 2 is a diagram showing one embodiment of the invention, FIG. 3 is a diagram showing the structure of the matrix circuit in FIGS. 2 and 4, and FIG. 4 is a diagram showing another embodiment of the invention. . 1...Stereo demodulator, 2...Lch output, 3...
...Rch output, 4,9...matrix, 5...delay device, 6...VCF, 7...level detector, 8...
...Mixer, 10...Synthesis Lch output, 11...Synthesis
Rch output, 12...VCA, 13...differentiator, 1
4...Inverter.
Claims (1)
と、サブ信号のエンベロープを微分して立上りの
鋭さを検出する検出手段と、前記検出手段の出力
によつて前記サブ信号のカツトオフ周波数を前記
サブ信号の立上りが鋭いとき高く、立上りが鋭く
ないとき低く制御するサブ信号制御手段と、前記
遅延手段の出力と前記サブ信号制御手段の出力と
を混合する混合手段と、前記混合手段の出力と前
記メイン信号とを合成し、左右の信号を出力する
マトリツクス手段とを備えたことを特徴とするノ
イズ低減回路。1. Delay means for delaying the main signal by a predetermined time; detection means for differentiating the envelope of the sub-signal to detect the sharpness of the rise; and a cutoff frequency of the sub-signal based on the output of the detection means. sub-signal control means for controlling the signal to be high when the rise is sharp and low when the rise is not sharp; mixing means for mixing the output of the delay means and the output of the sub-signal control means; and the output of the mixing means and the main signal and matrix means for synthesizing left and right signals and outputting left and right signals.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP12734183A JPS6019336A (en) | 1983-07-13 | 1983-07-13 | Noise reduction circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP12734183A JPS6019336A (en) | 1983-07-13 | 1983-07-13 | Noise reduction circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6019336A JPS6019336A (en) | 1985-01-31 |
| JPH0363857B2 true JPH0363857B2 (en) | 1991-10-02 |
Family
ID=14957521
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP12734183A Granted JPS6019336A (en) | 1983-07-13 | 1983-07-13 | Noise reduction circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6019336A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH03101057U (en) * | 1990-01-31 | 1991-10-22 | ||
| JP3837008B2 (en) * | 2000-03-31 | 2006-10-25 | パイオニア株式会社 | FM multiplex demodulator |
-
1983
- 1983-07-13 JP JP12734183A patent/JPS6019336A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6019336A (en) | 1985-01-31 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US5638452A (en) | Expandable multi-dimensional sound circuit | |
| JPS6221461B2 (en) | ||
| US3573382A (en) | A stereophonic receiver muting means with substitution of a dc circuit for an ac circuit | |
| JP4327087B2 (en) | Stereo signal processor | |
| CA2100154A1 (en) | Switched Signal Processing Circuit | |
| US7542748B2 (en) | Signal processing circuit comprising an attenuating unit, a detecting unit, and an attenuation rate setting unit | |
| US4737991A (en) | Audio multiplex television tuner | |
| JPS6019336A (en) | Noise reduction circuit | |
| US7035413B1 (en) | Dynamic spectral matrix surround system | |
| JP2711152B2 (en) | Multi-channel audio signal playback device | |
| EP0279422A2 (en) | FM/FMX Stereophonic receiver | |
| JPH0126575B2 (en) | ||
| JPS589615B2 (en) | FM Stereo Fukuchiyouhoushiki | |
| JPS6141177B2 (en) | ||
| JPH06224866A (en) | Signal processing circuit for band division due to fm stereo | |
| JPH0419864Y2 (en) | ||
| JPH0331294B2 (en) | ||
| JPH0787390B2 (en) | Noise reduction device for FM stereo tuner | |
| JPH0787391B2 (en) | Noise reduction device for FM stereo tuner | |
| JPH0342760Y2 (en) | ||
| JP2957598B2 (en) | FM stereo receiver | |
| JPS6110373Y2 (en) | ||
| JP2928041B2 (en) | FM receiver | |
| JPS59154832A (en) | Stereo demodulating circuit | |
| JPH04298200A (en) | Automatic sound volume adjustment device in surround circuit |