JPH0767139A - Video signal recorder - Google Patents

Abstract

PURPOSE:To prevent the generation of colors, shakes or beats by suppressing the generation of the frequency component of luminance signal frequency + or -chrominance signal frequency as much as possible even when the recording current of a chrominance signal is enlarged by enlarging the recording current level of an FM luminance signal when the saturation of the chrominance signal is large. CONSTITUTION:A recording current level control circuit 11 controls the recording current level of the FM luminance signal corresponding to the saturation of the chrominance signal detected by a saturation detection circuit 10. Since there is danger to enlarge the generation of the frequency component of FM luminance signal frequency + or - low frequency converted carrier chrominance signal frequency when the saturation is enlarged, the recording current level of the FM luminance signal is enlarged. Therefore, the FM luminance signal for which the recording current level is controlled is mixed with the chrominance signal converted to a low frequency by a frequency converter 6 by a mixer 3 and recorded through a recording amplifier 7 to a magnetic tape 9 by a recording head 8. Thus, the sharp reproduced picture with no color, shake or beat can be provided.

Description

【発明の詳細な説明】Detailed Description of the Invention

【０００１】[0001]

【産業上の利用分野】本発明は、映像信号中の輝度信号
をＦＭ変調し、色信号を低域変換して両者を周波数多重
して磁気テープに記録するビデオテープレコーダ（ＶＴ
Ｒ）のような映像信号記録装置に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video tape recorder (VT) which FM-modulates a luminance signal in a video signal, converts a color signal into a low frequency band, frequency-multiplexes both signals, and records them on a magnetic tape.
R) such as a video signal recording device.

【０００２】[0002]

【従来の技術】搬送色信号低域変換方式のＶＴＲにてカ
ラー映像信号を磁気テープに記録する場合に、例えば特
開昭６１−２９２４９３号公報（Ｈ０４Ｎ９／７９）に
開示されるように、カラー映像信号を輝度信号及び搬送
色信号に分離し、この輝度信号をＦＭ変調して低搬送波
ＦＭ輝度信号にすると共に、３．５８ＭＨｚの搬送色信
号を、例えば７４３ＫＨｚに周波数変換して低域変換搬
送色信号としている。こうして得られたＦＭ輝度信号と
低域変換搬送色信号とを混合して磁気テープに記録して
いる。2. Description of the Related Art When a color video signal is recorded on a magnetic tape by a VTR of a carrier color signal low frequency conversion system, as disclosed in, for example, Japanese Patent Application Laid-Open No. 61-29493 (H04N9 / 79), color recording is performed. The video signal is separated into a luminance signal and a carrier color signal, and the luminance signal is FM-modulated into a low carrier FM luminance signal, and the carrier color signal of 3.58 MHz is frequency-converted to, for example, 743 KHz, and low-frequency conversion carrier is carried out. It is used as a color signal. The FM luminance signal thus obtained and the low-frequency conversion carrier color signal are mixed and recorded on the magnetic tape.

【０００３】また、映像信号の再生にあたっては、磁気
テープから磁気ヘッドを通して再生された再生映像信号
を、ＦＭ輝度信号と低域変換搬送色信号とに分離し、Ｆ
Ｍ輝度信号（この周波数を以下ｆｙとする）を復調して
輝度信号にすると共に、低域変換搬送色信号（この周波
数を以下ｆｃとする）を周波数変換して３．５８ＭＨｚ
の搬送色信号に直し、これらの両信号を混合したものを
再生カラー映像信号としている。Further, in reproducing the video signal, the reproduced video signal reproduced from the magnetic tape through the magnetic head is separated into an FM luminance signal and a low-frequency conversion carrier color signal, and F
The M luminance signal (this frequency is hereinafter referred to as fy) is demodulated into a luminance signal, and the low-frequency conversion carrier color signal (this frequency is hereinafter referred to as fc) is frequency-converted to 3.58 MHz.
The reproduced color video signal is a mixture of these two signals.

【０００４】図３に前記ＶＴＲの従来の記録系の信号処
理回路ブロック図を示す。図中、入力端子１に入力され
た輝度信号Ｙは、ＦＭ変調器２でＦＭ変調されて加算器
３の一方の入力側に供給される。一方、入力端子４に入
力された色信号Ｃは、オ−トマチック・クロマレベル・
コントロ−ル回路（ＡＣＣ回路）５でバ−スト信号の大
きさが一定になるように信号レベルを調整された上で周
波数変換器６で低域変換された後、加算器３の他方入力
側に供給されてＦＭ輝度信号と混合される。混合された
信号は、記録アンプ７を介して磁気ヘッド８により磁気
テ−プ９に記録される。FIG. 3 is a block diagram of a signal processing circuit of a conventional recording system of the VTR. In the figure, the luminance signal Y input to the input terminal 1 is FM-modulated by the FM modulator 2 and supplied to one input side of the adder 3. On the other hand, the color signal C input to the input terminal 4 has an automatic chroma level
After the signal level is adjusted by the control circuit (ACC circuit) 5 so that the magnitude of the burst signal becomes constant, the frequency is converted by the frequency converter 6, and then the other input side of the adder 3 And is mixed with the FM luminance signal. The mixed signal is recorded on the magnetic tape 9 by the magnetic head 8 via the recording amplifier 7.

【０００５】[0005]

【発明が解決しようとする課題】前記従来の信号処理回
路では、色信号のＳ／Ｎを確保するためには、色信号の
記録電流を大きくして記録するのが効果的であるが、特
にヘッドが帯磁している時等、大レベルの色信号が入力
された場合には再生画面に白や黒の粒状ノイズ（色ヤブ
レ）やビ−トが発生することがある。これは、色信号記
録電流を大きくして記録した場合、再生時に、不要成分
であるｆｙ±ｆｃの周波数成分が大きくなることに起因
している。このｆｙ±ｆｃ成分はＦＭ輝度信号の帯域内
にあるので、そのまま復調器で復調されてビ−トとなっ
て画面に現れたり、反転現象を起こしたりするのであ
る。In the conventional signal processing circuit described above, it is effective to increase the recording current of the color signal for recording in order to secure the S / N of the color signal. When a high-level color signal is input, such as when the head is magnetized, white or black granular noise (color blur) or beats may occur on the reproduction screen. This is because when recording is performed with a large color signal recording current, the frequency component of fy ± fc, which is an unnecessary component, increases during reproduction. Since the fy ± fc components are within the band of the FM luminance signal, they are demodulated by the demodulator as they are to appear as a beat on the screen or cause an inversion phenomenon.

【０００６】上述の理由により、色信号記録電流の大き
さを制限しなければならないという欠点を免れ得ない。
また記録電流が大きくなる色飽和度が高い部分でのみ色
信号記録電流を下げて記録しても色ヤブレを防止できる
が、この場合は色の濃淡表現が悪くなる。For the above-mentioned reason, the drawback that the magnitude of the color signal recording current must be limited is inevitable.
Further, color blurring can be prevented even if the recording is performed by lowering the color signal recording current only in the portion where the recording current is high and the color saturation is high, but in this case, the gradation expression of the color is deteriorated.

【０００７】[0007]

【課題を解決するための手段】本発明は、色信号飽和度
検出手段にて入力される色信号の飽和度を検出し、色信
号の飽和度に応じてＦＭ輝度信号の記録電流レベルをレ
ベル制御手段にて制御し、レベル制御手段出力及び周波
数変換手段出力を混合して磁気テープに記録するように
構成し、色信号の飽和度が大きい場合には、ＦＭ輝度信
号の記録電流レベルを大きくすることを特徴とする。According to the present invention, the saturation level of a color signal input by a color signal saturation level detection means is detected, and the recording current level of an FM luminance signal is leveled according to the saturation level of the color signal. Controlled by the control means, the output of the level control means and the output of the frequency conversion means are mixed and recorded on the magnetic tape. When the saturation of the color signal is high, the recording current level of the FM luminance signal is increased. It is characterized by doing.

【０００８】[0008]

【作用】本発明は上述のように構成したので、色信号の
記録電流を大きくした場合にも、ｆｙ±ｆｃの周波数成
分の発生を極力抑えて色ヤブレの発生を阻止することが
できる。Since the present invention is configured as described above, even if the recording current of the color signal is increased, it is possible to suppress the generation of the frequency component of fy ± fc as much as possible and prevent the generation of the color blur.

【０００９】[0009]

【実施例】以下、図面に従って本発明の一実施例につい
て説明する。図１は本実施例を搭載したＶＴＲの記録系
の信号処理回路ブロック図であり、従来例の図３と同一
部分には同一符号を付して説明を省略する。また、図２
は色信号の記録電流レベルを一定にし、ＦＭ輝度信号の
記録電流レベルを変化させて記録した磁気テープを再生
するという実験を行った場合の、再生アンプの後段にて
得られるｆｙ−ｆｃの周波数成分の再生レベルの関係を
示す図である。この図２の特性は、ＦＭ輝度信号の記録
電流レベルとｆｙ＋ｆｃの周波数成分の再生レベルとの
関係においても同様の特性が得られる。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of a signal processing circuit of a recording system of a VTR equipped with this embodiment. The same parts as those of FIG. Also, FIG.
Is a frequency of fy-fc obtained in the latter stage of the reproducing amplifier when an experiment is conducted in which the recording current level of the color signal is made constant and the recording current level of the FM luminance signal is changed to reproduce the recorded magnetic tape. It is a figure which shows the relationship of the reproduction | regeneration level of a component. The characteristics of FIG. 2 can be obtained in the relationship between the recording current level of the FM luminance signal and the reproduction level of the frequency component of fy + fc.

【００１０】図２より、色信号の記録電流が一定の時
に、ＦＭ輝度信号の記録電流を大きくして記録した方
が、再生時にｆｙ±ｆｃの周波数成分のレベルが小さく
なることがわかる。従って、ビート成分が発生しやすい
色信号の記録電流レベルが大きい場合には、ＦＭ輝度信
号の記録電流を大きくして記録させることにより、再生
時にｆｙ±ｆｃの周波数成分を小さく抑えることが可能
になることが明らかである。It can be seen from FIG. 2 that when the recording current of the chrominance signal is constant, the level of the frequency component of fy ± fc becomes smaller when the recording is performed by increasing the recording current of the FM luminance signal. Therefore, when the recording current level of the color signal in which the beat component is likely to occur is large, the recording current of the FM luminance signal is increased to perform recording, so that the frequency component of fy ± fc can be suppressed to be small during reproduction. It is clear that

【００１１】尚、従来のＦＭ輝度信号の記録電流は本
来、ＦＭ輝度信号にとって最適値（ＦＭ輝度信号再生出
力が最大となる記録電流値）となる様に設定してある。Incidentally, the recording current of the conventional FM luminance signal is originally set to have an optimum value for the FM luminance signal (recording current value at which the FM luminance signal reproduction output becomes maximum).

【００１２】図１において、従来通りＡＣＣ回路５を通
った色信号は、周波数変換器６に入力されると同様に、
飽和度検出回路１０に供給される。この飽和度検出回路
１０では、具体的には色信号を振幅検波して色信号の振
幅レベルを飽和度として出力する。ここで、色信号に関
しては、その振幅が大きさに比例して記録電流レベルが
変化するので、飽和度は記録電流レベルの大きさ、即ち
ｆｙ±ｆｃの周波数成分の発生し易さの目安となる。In FIG. 1, the color signal that has passed through the ACC circuit 5 as in the conventional case is input to the frequency converter 6,
It is supplied to the saturation detection circuit 10. The saturation detection circuit 10 specifically detects the amplitude of the color signal and outputs the amplitude level of the color signal as the saturation. Here, regarding the color signal, the recording current level changes in proportion to the amplitude thereof, so the saturation is a measure of the recording current level, that is, the easiness of generation of the frequency component of fy ± fc. Become.

【００１３】一方、ＦＭ変調器２を経たＦＭ輝度信号
は、記録電流レベル制御回路１１に入力され、ここで記
録電流レベルの調整が為される。即ち、記録電流レベル
制御回路１１は、飽和度検出回路１０にて検出された色
信号の飽和度に応じてＦＭ輝度信号の記録電流レベルを
調整し、飽和度が大きくなると、ｆｙ±ｆｃの周波数成
分の発生が大きくなる恐れが有るので、ＦＭ輝度信号の
記録電流レベルを大きくするように動作する。On the other hand, the FM luminance signal that has passed through the FM modulator 2 is input to the recording current level control circuit 11, where the recording current level is adjusted. That is, the recording current level control circuit 11 adjusts the recording current level of the FM luminance signal according to the saturation of the color signal detected by the saturation detection circuit 10, and when the saturation increases, the frequency of fy ± fc Since the generation of components may increase, the operation is performed to increase the recording current level of the FM luminance signal.

【００１４】こうして記録電流レベルの調整が為された
ＦＭ輝度信号は後段の混合器３にて周波数変換器６にて
低域変換された色信号（低域色変換搬送色信号）と混合
され、記録アンプ７を経て記録ヘッド８にて磁気テープ
９に記録される。The FM luminance signal whose recording current level has been adjusted in this way is mixed with the color signal (low-range color-converted carrier color signal) which has undergone low-frequency conversion by the frequency converter 6 in the mixer 3 in the subsequent stage, Recording is performed on the magnetic tape 9 by the recording head 8 via the recording amplifier 7.

【００１５】この磁気テープ９を再生する場合には、磁
気ヘッドにて再生した映像信号を再生アンプを経た後
に、ＦＭ輝度信号及び低域色変換搬送色信号に分離し、
ＦＭ輝度信号はＦＭ復調され、低域色変換搬送色信号は
周波数変換されて元の色信号に戻される。この再生系の
信号処理回路ブロックは通常のＶＴＲに装備された周知
のものである。When reproducing the magnetic tape 9, a video signal reproduced by the magnetic head is passed through a reproduction amplifier and then separated into an FM luminance signal and a low-frequency conversion carrier color signal.
The FM luminance signal is FM-demodulated, and the low-pass color conversion carrier color signal is frequency-converted and returned to the original color signal. This reproduction system signal processing circuit block is a well-known one equipped in a normal VTR.

【００１６】この再生系において、再生アンプの出力中
のｆｙ±ｆｃの周波数成分は、ＦＭ輝度信号の記録電流
レベルが大きく記録されているために、図２のように小
さく抑えられ、同時に色信号の記録電流レベルも大きく
記録できるので色信号のＳ／Ｎも良好に確保できる。In this reproducing system, the frequency component of fy ± fc in the output of the reproducing amplifier is kept small as shown in FIG. 2 because the recording current level of the FM luminance signal is large, and at the same time, the color signal is suppressed. Since a large recording current level can be recorded, the S / N of the color signal can be excellently secured.

【００１７】[0017]

【発明の効果】上述の如く本発明によれば、色信号のＳ
／Ｎを確保するために色信号記録電流を充分大きく維持
しつつ、色信号の飽和度の高い部分でもｆｙ±ｆｃの周
波数成分の再生レベルを小さく抑えたままで色ヤブレ
（反転現象）やビートのない鮮明な再生画が得られる。As described above, according to the present invention, S of the color signal is
In order to maintain the / N ratio, the color signal recording current is kept sufficiently high, and even in a high saturation portion of the color signal, the reproduction level of the frequency component of fy ± fc is kept small and the color blurring (reversal phenomenon) and the beat A clear reproduction image is obtained.

【図面の簡単な説明】[Brief description of drawings]

【図１】本発明の一実施例の回路ブロック図である。FIG. 1 is a circuit block diagram of an embodiment of the present invention.

【図２】ＦＭ輝度信号の記録電流レベルとｆｙ−ｆｃの
周波数成分の再生レベルの関係を示す図である。FIG. 2 is a diagram showing a relationship between a recording current level of an FM luminance signal and a reproduction level of a frequency component of fy-fc.

【図３】従来例の回路ブロック図である。FIG. 3 is a circuit block diagram of a conventional example.

【符号の説明】[Explanation of symbols]

２ ＦＭ変調器 １０ 飽和度検出回路 ６ 周波数変換器 １１ 記録電流レベル制御回路 ３ 混合器 ８ 磁気ヘッド 2 FM modulator 10 Saturation detection circuit 6 Frequency converter 11 Recording current level control circuit 3 Mixer 8 Magnetic head

Claims (1)

【特許請求の範囲】[Claims] 【請求項１】 入力される輝度信号をＦＭ変調するＦＭ
変調手段と、 入力される色信号の飽和度を検出する色信号飽和度検出
手段と、 色信号を低域変換する周波数変換手段と、 色信号の飽和度に応じてＦＭ変調された輝度信号の記録
電流レベルを制御するレベル制御手段と、 該レベル制御手段出力及び周波数変換手段出力を混合し
て磁気テープに記録する記録手段を備える映像信号記録
装置。1. An FM for FM-modulating an input luminance signal.
Modulation means, color signal saturation detection means for detecting the saturation of the input color signal, frequency conversion means for low-frequency converting the color signal, and luminance signal FM-modulated according to the saturation of the color signal. A video signal recording apparatus comprising level control means for controlling a recording current level, and recording means for mixing the output of the level control means and the output of the frequency conversion means and recording the mixture on a magnetic tape.