JPS6115632B2 - - Google Patents
Info
- Publication number
- JPS6115632B2 JPS6115632B2 JP53150222A JP15022278A JPS6115632B2 JP S6115632 B2 JPS6115632 B2 JP S6115632B2 JP 53150222 A JP53150222 A JP 53150222A JP 15022278 A JP15022278 A JP 15022278A JP S6115632 B2 JPS6115632 B2 JP S6115632B2
- Authority
- JP
- Japan
- Prior art keywords
- circuit
- luminance signal
- color
- signal
- diode
- 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
- 230000003321 amplification Effects 0.000 claims description 20
- 238000003199 nucleic acid amplification method Methods 0.000 claims description 20
- 230000001629 suppression Effects 0.000 claims description 2
- 238000001514 detection method Methods 0.000 description 5
- 238000010586 diagram Methods 0.000 description 3
- 239000002131 composite material Substances 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 1
- 238000000034 method Methods 0.000 description 1
Landscapes
- Processing Of Color Television Signals (AREA)
Description
【発明の詳細な説明】
本発明は、カラーテレビジヨン受像機等におい
て色ノイズが目立たないように信号処理を行なう
ようにした装置に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device that performs signal processing in a color television receiver or the like so that color noise is not noticeable.
カラーテレビジヨン受像機等においては入力信
号中に雑音信号が多く含まれている場合に色ノイ
ズが発生するが、この色ノイズは画面中の明るい
部分ではあまり目立たず、暗い部分においてよく
目立ち、画質をはなはだしく低下せしめるという
不都合がある。 In color television receivers, etc., color noise occurs when the input signal contains a lot of noise signals, but this color noise is less noticeable in bright areas of the screen and more noticeable in dark areas, which affects image quality. This has the disadvantage of significantly reducing the
そこで本発明は、かかる色ノイズ特に暗い部分
での色ノイズが目立たないようにして画質を向上
することができるようにカラーテレビジヨン信号
を処理できる装置を最も簡単な構成で安価に提供
することを目的とし、そのために、輝度信号のレ
ベルが所定レベルよりも黒レベル側になつたとき
すなわち画面上で暗くなつたときに、帯域増幅回
路の搬送色信号の増幅度を小さくするように制御
して、その暗い部分における色ノイズを抑圧する
ようにしたことを特徴としている。 SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an apparatus capable of processing a color television signal with the simplest configuration and at a low cost so that the color noise, particularly in dark areas, can be made inconspicuous and the image quality can be improved. For this purpose, the amplification degree of the carrier chrominance signal of the band amplification circuit is controlled to be reduced when the level of the luminance signal becomes closer to the black level than a predetermined level, that is, when the screen becomes dark. , is characterized by suppressing color noise in dark areas.
特に、本発明においては、映像検波回路と映像
増幅回路と帯域増幅回路と色飽和度調整用の可変
抵抗器とを備えたカラーテレビ受信機において、
その色飽和度調整用の可変抵抗器と並列に定電圧
ダイオードを接続し、それらの並列回路の一端を
抵抗を介して接地し、またダイオードを介して映
像増幅回路中の輝度信号のあらわれる点に接続
し、さらにこの並列回路の他端を他の抵抗を介し
て電源に接続するようにした点に特徴がある。そ
して、かかる簡単な回路構成により、輝度信号が
所定レベルよりも黒レベル側になつている時、そ
のレベルに応じて、色飽和度を下げて色ノイズを
減少させることができる。 In particular, in the present invention, in a color television receiver equipped with a video detection circuit, a video amplification circuit, a band amplification circuit, and a variable resistor for color saturation adjustment,
A constant voltage diode is connected in parallel with the variable resistor for color saturation adjustment, one end of the parallel circuit is grounded via a resistor, and the diode is connected to the point where the luminance signal appears in the video amplification circuit. The feature is that the other end of this parallel circuit is connected to a power supply via another resistor. With such a simple circuit configuration, when the luminance signal is closer to the black level than the predetermined level, the color saturation can be lowered in accordance with the level to reduce color noise.
特に、かかる構成により、１個の定電圧ツエナ
ーダイオード、２個の抵抗器および１個のダイオ
ードを追加することにより実現でき、回路定数を
設定すれば、少い追加部品点数で最も簡単に、コ
ストの安い部品でかつ組立も簡単で少い工数で低
コストにでき、輝度レベルの暗い部分の色ノイズ
を減少させて見やすいカラー画像が得られるとい
う作用効果を奏する。 In particular, with this configuration, it can be realized by adding one constant voltage Zener diode, two resistors, and one diode, and if the circuit constants are set, it is the simplest and cost effective method with a small number of additional components. The present invention is made of inexpensive parts, is easy to assemble, requires few man-hours, and can be made at low cost, and has the effect of reducing color noise in dark areas of brightness levels to provide an easy-to-read color image.
以下、本発明につき、その一実施例を示す図面
を参照して詳細に説明する。 EMBODIMENT OF THE INVENTION Hereinafter, the present invention will be described in detail with reference to the drawings showing one embodiment thereof.
まず、第１図はその回路構成を示し、ここで、
１は映像検波回路、２は映像増幅回路、３は帯域
増幅回路であり、これらの回路そのものは従来の
カラーテレビジヨン受像機におけるそれらと全く
同様のものである。すなわち、映像検波回路１は
VIF信号の入力トランス４と検波用ダイオード５
と低域ろ波回路６を有し、映像増幅回路２は輝度
信号増幅用のトランジスタ７，８と遅延線９を有
し、帯域増幅回路３は搬送色信号増幅用の複合差
動増幅回路構成に接続されたトランジスタ１０〜
１５を有している。この帯域増幅回路３の複合差
動増幅回路はトランジスタ１０のベースに加えら
れる搬送色信号を増幅するものであるが、トラン
ジスタ１２，１５のベースに色飽和度調整用の可
変抵抗器１６から加えられる色飽和度制御用の制
御電圧によつてその増幅度が制御される。図示の
場合には、制御電圧が大きくなるほど増幅度が増
大するように制御される。 First, Figure 1 shows its circuit configuration, where:
1 is a video detection circuit, 2 is a video amplification circuit, and 3 is a band amplification circuit, and these circuits themselves are exactly the same as those in a conventional color television receiver. That is, the video detection circuit 1 is
VIF signal input transformer 4 and detection diode 5
and a low-pass filter circuit 6, the video amplification circuit 2 has transistors 7 and 8 for luminance signal amplification, and a delay line 9, and the band amplification circuit 3 has a composite differential amplification circuit configuration for amplifying carrier color signals. Transistor 10 connected to
It has 15. The composite differential amplifier circuit of the band amplifier circuit 3 amplifies the carrier color signal applied to the base of the transistor 10, and the carrier color signal is applied to the bases of the transistors 12 and 15 from a variable resistor 16 for color saturation adjustment. The degree of amplification is controlled by a control voltage for color saturation control. In the illustrated case, the amplification degree is controlled to increase as the control voltage increases.
このような一般的な回路に加えて、本装置にお
いては、可変抵抗器１６と並列に定電圧ダイオー
ド１７を接続し、それらの並列回路の一端を抵抗
１８を介して接地しまたダイオード１９を介して
映像増幅回路２中の輝度信号のあらわれる点ここ
ではトランジスタ８のエミツタに接続し、さらに
この並列回路の他端を抵抗２０を介して電源Ｖcc
に接続するようにしている。 In addition to such a general circuit, in this device, a constant voltage diode 17 is connected in parallel with the variable resistor 16, and one end of the parallel circuit is grounded through a resistor 18 and connected through a diode 19. The point at which the luminance signal appears in the video amplifier circuit 2 is connected to the emitter of the transistor 8, and the other end of this parallel circuit is connected to the power supply V cc via a resistor 20.
I am trying to connect to.
次に、このような構成における動作について第
２図の波形図を参照して説明する。まず、映像増
幅回路２中のトランジスタ８のエミツタに第２図
Ａのような波形の輝度信号があらわれるとする。
そして、図中の破線で示した所定レベルよりも黒
レベル側になるような画面中の暗い部分において
色ノイズが目立つていたものとする。そこでこの
回路では、輝度信号がこの所定レベルよりも黒レ
ベル側になつたときにダイオード１９が導通する
ように、抵抗１６，１８，２０を選定して抵抗１
６，１８の相互接続点Ｃの電圧を設定する。この
ようにすると、Ｃ点における電圧波形は、第２図
Ｃのように、輝度信号が所定レベルよりも黒レベ
ル側になつているときにはダイオード１９が導通
することによつてその輝度信号のレベルとほぼ同
じ電圧まで輝度信号に従つて低下し、（ａの範
囲）、輝度信号が所定レベルよりも白レベル側に
なつているときにはダイオード１９が遮断するの
で一定のレベルになる（ｂの範囲）。このとき、
抵抗１６，２０の相互接続点Ｂにおける電圧波形
は、定電圧ダイオード１７が存在することによ
り、常にＣ点の電圧よりもこの定電圧ダイオード
１７の他端電圧分Ｅだけ高くなつて、第２図Ｂの
ようになる。すなわち、可変抵抗器１６の両端に
かかる電圧差は常にＥで一定であつて、接地点に
対する電圧だけが範囲ａにおいて低下するように
なる。 Next, the operation in such a configuration will be explained with reference to the waveform diagram of FIG. 2. First, it is assumed that a luminance signal having a waveform as shown in FIG. 2A appears at the emitter of the transistor 8 in the video amplifier circuit 2.
Assume that color noise is noticeable in a dark part of the screen where the black level is higher than the predetermined level indicated by the broken line in the figure. Therefore, in this circuit, the resistors 16, 18, and 20 are selected so that the diode 19 becomes conductive when the luminance signal becomes closer to the black level than this predetermined level.
Set the voltage at the interconnection point C of 6 and 18. In this way, when the luminance signal is closer to the black level than the predetermined level as shown in FIG. The voltage decreases to approximately the same voltage according to the luminance signal (range a), and when the luminance signal is closer to the white level than the predetermined level, the diode 19 shuts off, resulting in a constant level (range b). At this time,
Due to the presence of the constant voltage diode 17, the voltage waveform at the interconnection point B of the resistors 16 and 20 is always higher than the voltage at point C by the voltage E at the other end of the constant voltage diode 17, as shown in FIG. It will look like B. That is, the voltage difference across the variable resistor 16 is always constant at E, and only the voltage relative to the ground point decreases in range a.
そこで、この可変抵抗器１６の摺動端子により
その他端電圧を分圧して増幅度制御用の制御電圧
を作成すると、第２図中に一点鎖線で示したＤの
ような制御電圧が得られる。すなわち、輝度信号
が所定レベルよりも白レベル側であつて画面上の
明るい部分では搬送色信号の増幅度が従来と同様
に一定に保たれるが、輝度信号が一旦所定レベル
よりも黒レベル側になつて色ノイズが目立つよう
な画面上での暗い部分になると搬送色信号の増幅
度が自動的に減小せしめられ、色ノイズを発生す
るような色信号が抑圧されて色ノイズの発生が抑
圧されることになる。これにより、画面上での暗
い部分でも色ノイズが目立つことがなくなつて画
質の良好なカラーテレビジヨン画像が映出される
ものである。 Therefore, when the voltage at the other end is divided by the sliding terminal of the variable resistor 16 to create a control voltage for controlling the amplification degree, a control voltage such as D shown by a chain line in FIG. 2 is obtained. In other words, in bright areas on the screen where the luminance signal is closer to the white level than a predetermined level, the amplification degree of the carrier color signal is kept constant as before, but once the luminance signal is closer to the black level than the predetermined level. When it becomes a dark area on the screen where color noise is noticeable, the amplification degree of the carrier color signal is automatically reduced, suppressing the color signal that causes color noise and preventing the generation of color noise. It will be oppressed. As a result, color noise is not noticeable even in dark areas on the screen, and a color television image with good image quality is displayed.
このように、本回路を用いることによつて、従
来画面上の暗い部分で目立つていた色ノイズを抑
圧することができる。 In this way, by using this circuit, it is possible to suppress the color noise that was conventionally noticeable in dark areas on the screen.
以上詳述した通り、本発明においては輝度信号
のレベルを検出し、その輝度信号が所定レベルよ
りも黒レベル側になつたときに帯域増幅回路にお
ける搬送色信号の増幅度を減少せしめるようにし
たので、画面上の暗い部分における色ノイズの発
生を抑圧することができ、良好な画質のカラーテ
レビジヨン画像を映出することのできる装置を得
ることができるものである。 As detailed above, in the present invention, the level of the luminance signal is detected, and when the luminance signal becomes closer to the black level than a predetermined level, the amplification degree of the carrier color signal in the band amplifier circuit is reduced. Therefore, it is possible to obtain an apparatus that can suppress the occurrence of color noise in dark areas on the screen and can display color television images of good quality.
特に、本発明によれば、定電圧ツエナー１個、
抵抗器２個、ダイオード１個を追加するだけで実
現出来る最もコストの安い合理的な回路構成を提
供することができる。 In particular, according to the invention, one constant voltage Zener;
By simply adding two resistors and one diode, it is possible to provide the lowest cost and most rational circuit configuration.
第１図は本発明の一実施例における色ノイズ抑
圧装置の回路図、第２図は同装置の動作を説明す
るための波形図である。
１……映像検波回路、２……映像増幅回路、３
……帯域増幅回路、１６……可変抵抗器、１７…
…定電圧ダイオード、１８……抵抗、１９……ダ
イオード、２０……抵抗。
FIG. 1 is a circuit diagram of a color noise suppression device according to an embodiment of the present invention, and FIG. 2 is a waveform diagram for explaining the operation of the device. 1...Video detection circuit, 2...Video amplification circuit, 3
...bandwidth amplifier circuit, 16...variable resistor, 17...
... Constant voltage diode, 18 ... Resistor, 19 ... Diode, 20 ... Resistor.
Claims (1)
所定レベルよりも黒レベル側にあつたときに帯域
増幅回路における搬送色信号の増幅度を低下させ
るようにするとともに、上記帯域増幅回路におけ
る搬送色信号の増幅度を制御するための制御電圧
を発生する可変抵抗器に並列に定電圧ダイオード
を接続し、上記可変抵抗器と定電圧ダイオードド
との並列回路の一端を抵抗を介して接地するとと
もに輝度信号が所定レベルよりも黒レベルになつ
たときに導通するダイオードを介して映像増幅回
路中の上記輝度信号があらわれる点に接続し、上
記並列回路の他端を別の抵抗を介して電源に接続
したことを特徴とする色ノイズ抑圧装置。1 The level of the luminance signal is detected, and when the luminance signal is closer to the black level than a predetermined level, the amplification degree of the carrier color signal in the band amplifier circuit is lowered, and the carrier color signal in the band amplifier circuit is lowered. A constant voltage diode is connected in parallel to a variable resistor that generates a control voltage for controlling the degree of amplification of the signal, and one end of the parallel circuit of the variable resistor and the constant voltage diode is grounded via the resistor. Connect to the point where the luminance signal appears in the video amplifier circuit through a diode that becomes conductive when the luminance signal becomes blacker than a predetermined level, and connect the other end of the parallel circuit to the power supply via another resistor. A color noise suppression device characterized in that:
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15022278A JPS5575388A (en) | 1978-12-04 | 1978-12-04 | Color noise suppression device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15022278A JPS5575388A (en) | 1978-12-04 | 1978-12-04 | Color noise suppression device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5575388A JPS5575388A (en) | 1980-06-06 |
| JPS6115632B2 true JPS6115632B2 (en) | 1986-04-25 |
Family
ID=15492196
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP15022278A Granted JPS5575388A (en) | 1978-12-04 | 1978-12-04 | Color noise suppression device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5575388A (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5744385A (en) * | 1980-08-29 | 1982-03-12 | Hitachi Ltd | Signal processing circuit of color video camera |
| JPS601989A (en) * | 1983-06-17 | 1985-01-08 | Canon Inc | Image pickup device |
| JPS6030290A (en) * | 1983-07-29 | 1985-02-15 | Hitachi Ltd | Signal processing circuit of color video camera |
| JPS6462995A (en) * | 1987-09-02 | 1989-03-09 | Mitsubishi Electric Corp | Color saturation control circuit |
| JPH02235494A (en) * | 1989-03-09 | 1990-09-18 | Nippon Hoso Kyokai <Nhk> | Low brightness level correction system for reception color television signal |
-
1978
- 1978-12-04 JP JP15022278A patent/JPS5575388A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5575388A (en) | 1980-06-06 |
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