JPS59101987A - Picture quality adjusting circuit - Google Patents
Picture quality adjusting circuitInfo
- Publication number
- JPS59101987A JPS59101987A JP57212417A JP21241782A JPS59101987A JP S59101987 A JPS59101987 A JP S59101987A JP 57212417 A JP57212417 A JP 57212417A JP 21241782 A JP21241782 A JP 21241782A JP S59101987 A JPS59101987 A JP S59101987A
- Authority
- JP
- Japan
- Prior art keywords
- circuit
- resonance
- image quality
- picture quality
- quality adjusting
- 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
- H04N5/76—Television signal recording
- H04N5/91—Television signal processing therefor
- H04N5/93—Regeneration of the television signal or of selected parts thereof
- H04N5/931—Regeneration of the television signal or of selected parts thereof for restoring the level of the reproduced signal
- H04N5/9315—Regeneration of the television signal or of selected parts thereof for restoring the level of the reproduced signal the level control being frequency dependent
Landscapes
- Engineering & Computer Science (AREA)
- Multimedia (AREA)
- Signal Processing (AREA)
- Television Signal Processing For Recording (AREA)
Abstract
Description
【発明の詳細な説明】
この発明は、画質調整回路に関し、特にたとえば画像信
号を再生ずる装置に用いられるｉｉ！］質調整回路の改
良に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an image quality adjustment circuit, and particularly to an ii! used in a device for reproducing image signals, for example. ]Regarding improvement of quality adjustment circuit.
第１図は画質調整回路を含む従来の映像信号再生装置を
示すブロック図である。図において、たとえば磁気テー
プ（図示せず）などから読取られた映像信号はヘッドア
ンプ１に与えられ増幅される。なお、第１図の装置は、
２ヘッドアジマス方式であるため、２つのヘッドから読
取られた信号を混合するための混合増幅回路１ａが設け
られている。ヘッドアンプ１の出力はイコライザ回路（
等価器）２に与えられる。このイコライザ回路２は、磁
気テープから読取られた映像信号の周波数特性を揃える
ためのものであり、複数の共振手段（共振回路または共
振素子）などを含む。イコライザ回路２の出力はリミッ
タ４を介してＦＭ検波回路５に与えられ、ＦＭ検波され
る。ＦＭ検波回路５の出力はローパスフィルタ６に与え
られ、包絡線検波される。ローパスフィルタ６の出力は
ディエンファシス回路７に与えられる。通常、ビデオテ
ープレコーダなどにおいては、磁気テープに映像信号を
記録する場合Ｓ／Ｎ比を稼ぐために高域を持上げるエン
ファシスを行なう。そのため、再生時においては、その
逆特性を持ったディエンファシス回路７によって高域を
元のレベルに戻している。ディエンファシス回路７の出
力は画質調整回路８に与えられる。この画質調整回路８
は、たとえば表示画面上において視覚的に最も目立つ周
波数の利得を変化することによって画質を調整するため
のものである。すなわち、視覚的に最も目立つ周波数の
利得を上げれば画像がシャープに見えるし、逆にその部
分の利得を下げれば画像がソフトに見える。このような
利得調整のために、画質調整回路８には、利得調整用の
可変抵抗器８ａが設けられる。画質調整回路８の出力は
たとえばＣＲＴディスプレイなどの表示装置に与えられ
る。FIG. 1 is a block diagram showing a conventional video signal reproducing device including an image quality adjustment circuit. In the figure, a video signal read from, for example, a magnetic tape (not shown) is supplied to a head amplifier 1 and amplified. The device shown in Figure 1 is
Since it is a two-head azimuth system, a mixing amplification circuit 1a is provided to mix signals read from the two heads. The output of head amplifier 1 is an equalizer circuit (
Equalizer) is given to 2. The equalizer circuit 2 is for equalizing the frequency characteristics of video signals read from the magnetic tape, and includes a plurality of resonance means (resonance circuits or resonance elements). The output of the equalizer circuit 2 is given to the FM detection circuit 5 via the limiter 4 and subjected to FM detection. The output of the FM detection circuit 5 is given to a low-pass filter 6 and subjected to envelope detection. The output of the low-pass filter 6 is given to a de-emphasis circuit 7. Usually, in a video tape recorder or the like, when recording a video signal on a magnetic tape, emphasis is applied to increase the high frequency range in order to increase the S/N ratio. Therefore, during reproduction, the high frequency range is returned to its original level by a de-emphasis circuit 7 having the opposite characteristics. The output of the de-emphasis circuit 7 is given to an image quality adjustment circuit 8. This image quality adjustment circuit 8
is for adjusting the image quality by changing the gain of the visually most noticeable frequency on the display screen, for example. In other words, if you increase the gain of the most visually noticeable frequency, the image will appear sharper, and conversely, if you decrease the gain of that part, the image will appear softer. For such gain adjustment, the image quality adjustment circuit 8 is provided with a variable resistor 8a for gain adjustment. The output of the image quality adjustment circuit 8 is given to a display device such as a CRT display.
ところで、上述の画質調整回路８は、周波数特性を変化
させるために必要ケ共振素子をいくつか使用し、また後
段の回路とのインピーダンス整合のためにバッファ素子
（たとえばエミッタフォロワ）を使用している。そのた
め、回路のコストが高いという欠点があった。By the way, the above-mentioned image quality adjustment circuit 8 uses several resonant elements necessary for changing the frequency characteristics, and also uses a buffer element (for example, an emitter follower) for impedance matching with the subsequent circuit. . Therefore, there was a drawback that the circuit cost was high.
それゆえに、この発明の主たる目的は、従来の画質調整
回路に比べて安価な画質調整回路を提供することである
。Therefore, a main object of the present invention is to provide an image quality adjustment circuit that is cheaper than conventional image quality adjustment circuits.
この発明は、要約すれば、イコライザ回路に含まれる共
振手段を画質！ｔｉＩ！回路の共振手段として共用する
ことによって、部品点数の削減を図り安価な画質調整回
路を得るようにしたものである。In summary, this invention improves image quality by improving the resonance means included in the equalizer circuit! TiI! By sharing the circuit as a resonance means, the number of parts can be reduced and an inexpensive image quality adjustment circuit can be obtained.
この発明の上述の目的およびその他の目的と特徴は、図
面を参照して以下の詳細な説明から一層明らかとなろう
。The above objects and other objects and features of the invention will become more apparent from the following detailed description in conjunction with the drawings.
第２図はこの発明の一実施例を示すブロック図である。FIG. 2 is a block diagram showing an embodiment of the present invention.
図において、第１図と同様のヘッドアンプ１から出力さ
れる映像信号（ＦＭ変調されている）は、トラップ回路
１０により色信号が除去された後イコライザ回路１１に
与えられる。このイコライザ回路１１は、２つの共振素
子１１ａおよび１１ｂを含む。そして、共振素子１１ｂ
の出力端と接地との間には、可変抵抗器８０が接続され
ている。この可変抵抗器８０は、共振素子１１ｂと協働
して画質調整回路を構成する。すなわち、イコライザ回
路１１の共振素子１１ｂが画質調整回路の共振素子とし
て共用される。イコライザ回路１１の出力は、第１図と
同様のリミッタ４を介して後段のＦＭ検波回路などに与
えられる。In the figure, a video signal (FM modulated) output from a head amplifier 1 similar to that shown in FIG. 1 is applied to an equalizer circuit 11 after color signals are removed by a trap circuit 10. This equalizer circuit 11 includes two resonant elements 11a and 11b. And the resonant element 11b
A variable resistor 80 is connected between the output end and ground. This variable resistor 80 constitutes an image quality adjustment circuit in cooperation with the resonant element 11b. That is, the resonant element 11b of the equalizer circuit 11 is shared as a resonant element of the image quality adjustment circuit. The output of the equalizer circuit 11 is given to a subsequent FM detection circuit or the like via a limiter 4 similar to that shown in FIG.
上述のような装置では、可変抵抗器８０の抵抗値を変化
することによって、共振素子１１ｂの出力のレベルを変
化することができる。したがって、共振素子１１ｂの共
振周波数の利得を変化させることができ、画質の調整が
行なえる。In the device as described above, by changing the resistance value of the variable resistor 80, the output level of the resonant element 11b can be changed. Therefore, the gain of the resonance frequency of the resonance element 11b can be changed, and the image quality can be adjusted.
なお、第２図の実論例では、説明を簡単にするために２
つの共振素子を含むイコライザ回路を示したが、通常こ
のようなイコライザ回路はさらに多くの共振素子を含む
。したがって、画質調整のために必要な周波数（画面上
で視覚的に最も目立つ周波数）に最も近い共振周波数を
有する共振素子に可変抵抗器８０を接続することが好ま
しい。In addition, in the practical example shown in Figure 2, in order to simplify the explanation, 2
Although an equalizer circuit is shown that includes one resonant element, such equalizer circuits typically include many more resonant elements. Therefore, it is preferable to connect the variable resistor 80 to a resonant element having a resonant frequency closest to the frequency required for image quality adjustment (the most visually noticeable frequency on the screen).
なお、可変抵抗器８０は共振素子の出力に対して直列に
接続させることも可能である。Note that the variable resistor 80 can also be connected in series with the output of the resonant element.
以上のように、この発明によれば、イコライザ回路の共
振手段を画質調整回路の共振手段として共用するように
したので、部品点数の大幅な削減が図れ、安価な画質調
整回路を得ることができる。As described above, according to the present invention, since the resonance means of the equalizer circuit is shared as the resonance means of the image quality adjustment circuit, the number of parts can be significantly reduced, and an inexpensive image quality adjustment circuit can be obtained. .
また、通常イコライザ回路は多数の共振手段を含むため
、画質調整のために変化したい周波数を自由に選択する
ことができる。Further, since an equalizer circuit usually includes a large number of resonance means, it is possible to freely select a frequency to be changed for adjusting image quality.
第１図は従来の画質調整回路を用いた映像信号再生装置
を示すブロック図である。
第２図はこの発明の一実施例を示すブロック図である。
図において、１１はイコライザ回路、１１ａおよびｉｌ
ｌは共振素子、８０は可変抵抗器を示す。FIG. 1 is a block diagram showing a video signal reproducing apparatus using a conventional image quality adjustment circuit. FIG. 2 is a block diagram showing an embodiment of the present invention. In the figure, 11 is an equalizer circuit, 11a and il
1 represents a resonant element, and 80 represents a variable resistor.
Claims (3)
性を決定するために複数の共振手段を有して構成される
イコライザ回路を少なくとも含むような映像信号再生装
置において、 映像信号の所定の周波数における利得を変化することに
よって画質の調整を行なうような画質調整回路であって
、 前記複数の共振手段のうち所定の共振手段の出力のレベ
ルを変化するためのレベル変化手段を備える、画質調整
回路。(1) In a video signal reproducing device that includes at least an equalizer circuit configured with a plurality of resonance means for determining the frequency characteristics of a reproduced video signal that is FM modulated, An image quality adjustment circuit that adjusts image quality by changing a gain, the image quality adjustment circuit comprising a level changing means for changing the level of an output of a predetermined resonance means among the plurality of resonance means.
前記所定の周波数に最も近いものが、前記所定の共振手
段として選ばれたことを特徴とする特許請求の範囲第１
項記載の画質調整回路。(2) Among the plurality of resonance means, the one whose resonance frequency is closest to the predetermined frequency is selected as the predetermined resonance means.
Image quality adjustment circuit described in section.
請求の範囲第１項または第２項記載の画質調整回路。(3) The image quality adjustment circuit according to claim 1 or 2, wherein the level changing means is a variable resistor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP57212417A JPS59101987A (en) | 1982-12-01 | 1982-12-01 | Picture quality adjusting circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP57212417A JPS59101987A (en) | 1982-12-01 | 1982-12-01 | Picture quality adjusting circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS59101987A true JPS59101987A (en) | 1984-06-12 |
Family
ID=16622235
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP57212417A Pending JPS59101987A (en) | 1982-12-01 | 1982-12-01 | Picture quality adjusting circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS59101987A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH03132580A (en) * | 1989-10-16 | 1991-06-05 | Sanwa Shutter Corp | Obstacle-sensing structure for electric shutter for building |
-
1982
- 1982-12-01 JP JP57212417A patent/JPS59101987A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH03132580A (en) * | 1989-10-16 | 1991-06-05 | Sanwa Shutter Corp | Obstacle-sensing structure for electric shutter for building |
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