JPS603265B2 - SECAM color television signal recording and reproducing system - Google Patents

Description

【発明の詳細な説明】 本発明はＳＥＣＡＭ方式カラーテレビジョン信号の記録
再生方式に関するもで、特に、記録時にＳＥＣＡＭ方式
カラーテレビジョン信号の搬送色信号を分周して低周波
に変換して記録し、再生時に再生低周波搬送色信号を元
の周波数に変換する方式に関するものである。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a recording and reproducing method for SECAM color television signals, and in particular, the present invention relates to a method for recording and reproducing SECAM color television signals, and in particular, the carrier color signal of the SECAM color television signal is frequency-divided and converted into a low frequency signal for recording. The present invention relates to a method for converting a reproduced low frequency carrier color signal to its original frequency during reproduction.

従来の２ヘッドヘリカルスキャンＶＴＲでは第１図に示
すように、回転ヘッドにより記録された記録トラックＴ
の隣接するトラック間の信号妨害を防ぐための適当なガ
ードバンドＷが設けられている。In a conventional two-head helical scan VTR, as shown in FIG.
A suitable guard band W is provided to prevent signal interference between adjacent tracks.

このようなＶＴＲでカラーテレビジョン信号を記録する
代表的な信号処理方法のブロック図を第２図に示し、簡
単に説明する。入力端子１に入ったカラーテレビジョン
信号は低域フィル夕２、帯域フィル夕３により、輝度信
号と色信号（搬送波周波数ｆｃ）に分離される。輝度信
号は周波数変調器４で変調され、高城フィル夕５でその
低域を除去される。一方色信号は周波数ｆｃ＋ｆｓ′な
る発振器６の出力と周波数変換器７で低域（搬送波周波
数ｆｓ′）に変換され、低減を除去された輝度信号の周
波数変調信号に重畳され記録増幅器８、ヘッド９を通じ
てテープに記録される。再生時、ヘッド９より、ヘッド
アンプ１０を通じて再生された信号は、高城フィル夕１
１、低域フィル夕１２によって、周波数変調された輝度
信号と低域に変換された色信号に分離され、輝度信号は
周波数復調器１３で復調される。色信号は、周波数ｆｃ
十ｆｓ′なる発振器１４の出力と周波数変換器１５でも
との周波数ｆｃにもどされ、輝度層‐号と加えられ、出
力端子１６に再生カラーテレビジョン信号が得られる。
上述の小型ＶＴＲで高密度化をはかるための方法に、第
１図に示したガードバンドをなくする方法が考えられて
いる。A block diagram of a typical signal processing method for recording color television signals on such a VTR is shown in FIG. 2, and will be briefly described. A color television signal input to an input terminal 1 is separated into a luminance signal and a color signal (carrier frequency fc) by a low-pass filter 2 and a band filter 3. The luminance signal is modulated by a frequency modulator 4, and its low frequency is removed by a Takagi filter 5. On the other hand, the color signal is converted to a low frequency (carrier frequency fs') by the output of the oscillator 6 having the frequency fc+fs' and the frequency converter 7, and is superimposed on the frequency modulation signal of the luminance signal from which the reduction has been removed, and is sent to the recording amplifier 8 and the head 9. recorded on tape. During playback, the signal played from the head 9 through the head amplifier 10 is sent to the Takagi filter 1.
1. A low-pass filter 12 separates the frequency-modulated luminance signal and a low-pass chrominance signal, and the luminance signal is demodulated by a frequency demodulator 13. The color signal has a frequency fc
The output of the oscillator 14 of 10fs' is returned to the original frequency fc by the frequency converter 15 and added to the luminance layer signal, and a reproduced color television signal is obtained at the output terminal 16.
A method of eliminating the guard band shown in FIG. 1 has been considered as a method for achieving higher density in the above-mentioned small VTR.

この場合、走行むら、五換時のＩＪニアリティ差等によ
り、再生時ヘッドが本来再生すべきトラックのみならず
、隣接するトラックにわたって走行し、隣接トラックの
信号を妨害信号として拾うことになる。これを妨ぐため
、２つのヘッドギャップ間に角度（アジムス角）を設け
る方法がある。この時の記録軌跡を第３図に示す。第３
図において、ＡヘッドがＡトラックを再生している時、
ＢトラックにまたがってもＡヘッドのギャップとＢトラ
ックに記録された軌跡にはＱの角度差があるため、アジ
ムス損失によりＢトラックよりの信号は減衰する。この
アジムス損失は記録波長が短か〈、アジムス角度Ｑが大
きい程大きい。例えばＡ，Ｂヘッドのアジムス角度を±
６０〜±７０（Ｑ；１〆〜１４０）とすると、第２図の
記録方式では、輝度信号に関しては周波数変調され、周
波数が十分高いため、アジムス損失により隣接信号の妨
害を十分防ぐことができる。ところが色信号については
輝度信号の帯城との兼ね合い他からｆｓ′は通常６００
〜７０皿日２に設定されるため、アジムス損失だけでは
十分隣接妨害を除去することができない。十方、ＳＥＣ
ＡＭ方式カラーテレビジョン信号の色信号は、第４図に
示すように、Ｒ−Ｙ信号で４．４０８ＭＨＺの搬送波Ｄ
Ｒ′をＢ−Ｙ信号で４．２８ＭＨＺの搬送波ＤＢ′を周
波数変調し、１ラインごとに交互に送られており、変調
周波数偏移は両信号で３．９ＭＨＺ〜４．８ＭＨＺに及
び、側帯波として土５０皿ＨＺの帯域をとると、３．４
ＭＨ２〜５．３ＭＨＺに拡がる。このような信号を第２
図の方法で例えばｆｃ＋ｆｓ＝９Ｍ日２で低域に変換す
ると、第５図に示すようにＤＲ′は５９必ＨＺ、Ｄｓ′
は７５皿ＨＺになり、周波数偏移は０．２けＨＺ〜１．
１ＭＨＺ、側帯波の帯城は０〜１．８ＭＨ２になる。こ
のような低周波で広い帯域の信号を第３図のようなパタ
ーンで記録するとァジムス損失では、隣接信号の妨害を
防ぐことは難しい。また色信号の帯域が制限されるため
、低域に変換後特に低い周波数になる色信号に関しては
色反転現象を生じやすい。これらの現象を少なくするた
めには、変換色信号周波数をもっと高くすれば良いが、
第５図の場合でも側帯波の帯城は１．８ＭＨＺにまで及
び輝度信号帯城との関係でそれ程上げられない。以上の
点にかんがみ、ＳＥＣＡＭ方式カラーテレビジョン信号
をガードハンドを設けることなく、隣接妨害を防ぎ、か
つ有効に帯城を利用し、色反転現象を防ぐ方式が提案さ
れた。その方式の色信号処理ブロック図を第６図に示し
説明する。輝度信号系は第２図と同じであるので省略し
ている。第６図において、第２図と同じ番号は同じもの
を表わし同じ動作をする。帯域フィル夕３により分離さ
れた色情号（搬送波周波数をｆｃで代表する）は４分周
器１７で搬送波周波数ｆｓ＝ｆｃ／４に分周され、周波
数変調された輝度信号の低域に童畳して記録される。こ
のときの記録される色信号の周波数スベクトラムは第７
図に示すようにＤＲ′は１．皿ＭＨＺに、ＤＢ′は１．
０母ＭＨＺに、周波数偏移は０．斑ＭＨＺ〜１．２ＭＨ
Ｚになり、側帯域を入れても０．９ＭＨｚ〜１．７ＭＨ
Ｚの帯城になる。これを第５図と比べると搬送波周波数
は高く、周波数偏移１′４になっている。従って側帯波
のエネルギーも１／４になっており、エネルギー成分の
大きい周波数偏移の部分は０．９母ＭＨＺ〜１．２ＭＨ
Ｚで、また側帯波の帯域を５０皿ＨＺとっても最低０．
９ＭＨ２であるので、ァジムス損失で十分隣接信号の妨
害を防ぐことができ、色信号帯城も第５図の場合に比べ
て十分広くとれるので色反転現象も生じない。このよう
に記録された色信号は、再生時、低域フィル夕１２によ
って輝度信号と分離され４溝倍器１８によってもとの周
波数ｆｃにもどされ、復調された輝度信号と加えられ、
出力端子１６に隣接妨害や色反転のない良好な再生ＳＥ
ＣＡＭ信号を得ることができる。本発明は第６図で示し
た方式を実現するための具体的な構成を提供するもので
ある。In this case, due to running unevenness, IJ nearness difference at the time of five changes, etc., the head during reproduction travels not only over the track to be originally reproduced, but also over adjacent tracks, and picks up the signal of the adjacent track as an interfering signal. In order to prevent this, there is a method of providing an angle (azimuth angle) between the two head gaps. The recording trajectory at this time is shown in FIG. Third
In the figure, when A head is playing track A,
Since there is an angular difference of Q between the gap of the A head and the locus recorded on the B track even when spanning the B track, the signal from the B track is attenuated due to azimuth loss. This azimuth loss increases as the recording wavelength becomes shorter or the azimuth angle Q becomes larger. For example, change the azimuth angle of heads A and B to ±
60 to ±70 (Q; 1 to 140), in the recording method shown in Figure 2, the luminance signal is frequency modulated and the frequency is sufficiently high, so interference with adjacent signals due to azimuth loss can be sufficiently prevented. . However, for color signals, fs' is usually 600 due to the band width of the luminance signal and other factors.
Since it is set to ~70 days 2, the azimuth loss alone is not sufficient to remove adjacent disturbances. Jukkata, SEC
The color signal of the AM color television signal is a 4.408 MHz carrier wave D as an R-Y signal, as shown in Figure 4.
The carrier wave DB' of 4.28 MHZ is frequency-modulated by the B-Y signal of R', and is sent alternately for each line, and the modulation frequency deviation ranges from 3.9 MHZ to 4.8 MHZ for both signals, and the sideband If we take the band of 50 Hz as a wave, it is 3.4
Expands from MH2 to 5.3MHZ. A second signal like this
When converting to low frequency using the method shown in the figure, for example, fc+fs=9Mday2, DR' is 59 HZ, Ds' as shown in Figure 5.
becomes 75 HZ, and the frequency deviation is 0.2 Hz to 1.
At 1 MHZ, the band width of sideband waves is 0 to 1.8 MH2. When such a low frequency, wide band signal is recorded in a pattern as shown in FIG. 3, it is difficult to prevent interference with adjacent signals due to the azimuth loss. Furthermore, since the band of the color signal is limited, a color inversion phenomenon is likely to occur especially in the color signal which becomes a low frequency after being converted to a low frequency band. In order to reduce these phenomena, it would be better to make the converted color signal frequency higher, but
Even in the case of FIG. 5, the band width of the sideband wave is up to 1.8 MHZ and cannot be raised that much due to the relationship with the luminance signal band width. In view of the above points, a system has been proposed that prevents adjacent interference with SECAM system color television signals without providing a guard hand, and effectively utilizes band castles to prevent color reversal phenomena. A color signal processing block diagram of this method is shown in FIG. 6 and will be explained. The luminance signal system is the same as in FIG. 2, so it is omitted. In FIG. 6, the same numbers as in FIG. 2 represent the same things and perform the same operations. The sensual signal separated by the band filter 3 (the carrier frequency is represented by fc) is divided by a 4-frequency divider 17 to a carrier frequency fs=fc/4, and is added to the low range of the frequency-modulated luminance signal. and recorded. The frequency spectrum of the color signal recorded at this time is the seventh
As shown in the figure, DR' is 1. On plate MHZ, DB' is 1.
At 0 mother MHZ, the frequency deviation is 0. Spot MHZ ~ 1.2MH
Z, even if you include the side band, it is 0.9MHz to 1.7MHz
Becomes Z's obi castle. Comparing this with FIG. 5, the carrier frequency is high, with a frequency deviation of 1'4. Therefore, the energy of the sideband is also reduced to 1/4, and the frequency shift part with large energy component is 0.9 MHZ to 1.2 MHZ.
In Z, the sideband band is 50 Hz, and the minimum is 0.
Since it is 9MH2, the interference of adjacent signals can be sufficiently prevented by the azimuth loss, and the color signal band can be made sufficiently wider than in the case of FIG. 5, so that no color reversal phenomenon occurs. During reproduction, the color signal recorded in this manner is separated from the luminance signal by the low-pass filter 12, returned to the original frequency fc by the four-groove multiplier 18, and added to the demodulated luminance signal.
Good playback SE with no adjacent interference or color inversion at output terminal 16
CAM signals can be obtained. The present invention provides a specific configuration for realizing the system shown in FIG.

第８図に本発明の一実施例を示し説明する。第８図にお
いて、第２図、第６図と同じ番号は同じものを表わし同
じ動作をする。輝度信号系は第２図および第６図と同じ
である。帯城フィル夕３の出力である色信号（周波数ｆ
ｃ）は、ＳＥＣＡＭ信号のベルフィルタ特性に従って、
中心心周波数（４．２８８ＭＨＺ）より離れるに従って
振幅が大きくなっている。この振幅特性を平坦にするた
め帯城フィル夕３の出力は逆ベルフィル夕１９に通され
た後、リミツタ２川こよって整形され、フリップフロッ
プのような４分周器１７によって搬送波周波数をｆｓ（
＝ｆｃ／４）に分周される。この４分周器１７の出力信
号は矩形波であるため奇数倍の高周波をもつているので
、低域フィル夕で高調波を除かれるとともに、帯域フィ
ル夕３の出力と同じ振幅特性をもたせるための記録ィコ
ラィザーに通される。２１はその低域フィル夕と記録ィ
コラィザーである。An embodiment of the present invention is shown and explained in FIG. In FIG. 8, the same numbers as in FIGS. 2 and 6 represent the same things and perform the same operations. The luminance signal system is the same as in FIGS. 2 and 6. The color signal (frequency f
c) is according to the bell filter characteristic of the SECAM signal,
The amplitude increases as the distance from the central frequency (4.288 MHZ) increases. In order to flatten this amplitude characteristic, the output of the Obishiro filter 3 is passed through an inverse filter 19, then shaped by a limiter 2, and the carrier frequency is changed to fs (
= fc/4). Since the output signal of this 4-frequency divider 17 is a rectangular wave, it has a high frequency that is an odd number multiple. Therefore, the harmonics are removed by the low-pass filter, and the output signal is made to have the same amplitude characteristics as the output of the band filter 3. The record is passed through the equalizer. 21 is its low frequency filter and recording equalizer.

２１の出力はちようど帯域フィル夕３の出力を振幅特性
はそのままで１／４に分周したものであり、第７図のよ
うな周波数スベクトラムをもち、周波数変調された輝度
信号に童畳して記録される。The output of 21 is the output of the bandpass filter 3 divided into 1/4 with the amplitude characteristics unchanged, and has a frequency spectrum as shown in Fig. 7, and is divided into a frequency modulated luminance signal. recorded.

再生時は、低域フィル夕１２により輝度信号と分離され
た色信号（周波数ｆｓ）は、記録と逆特性をもつ再生ィ
コラィザー２２によって振幅特性を平坦にされ、非線形
回路であるリミツタ２３に導かれる。During reproduction, the color signal (frequency fs) separated from the luminance signal by the low-pass filter 12 has its amplitude characteristic flattened by the reproduction equalizer 22, which has characteristics opposite to those of recording, and is guided to the limiter 23, which is a nonlinear circuit. .

リミッタ２３の出力は第９図に示すようにｆｓと高調波
成分、ａｓ，８ｓ・・・・・・の成分をもち、その搬送
波のエネルギーはｆｓをＷ旧とすると、漁は約一１比旧
、ａｓは約一１４ｄＢ……となり、また周波数偏移はｆ
ｓが０．９母ＭＨ２〜１．２ＭＨＺ、３ｓは２．８ＭＨ
ｚ〜３．８ＭＨｚ、５ｆｓは４．８ＭＨｚ〜６‐ｍＭＨ
ｚに側帯波を土５００ＫＨＺとった時の帯域は、ｆｓが
０．９ＭＨＺ〜１．７ＭＨＺ、乳ｓが２．３ＭＨＺ〜４
．１ＭＨ２、８ｓが４．３ＭＨＺ〜６．９ＭＨＺになる
。リミッタ２３の出力より低域フィル夕２４、帯城フィ
ル夕２５により、それぞれ第９図のｆｓとその高調波成
分の１つ乳ｓの成分が取り出され、周波数変換器２６、
帯域フィル夕２７により、それらの和周波数をもつ色信
号（周波数４ｆｓ＝ｆ。）が得られる。この帯域フィル
夕２７の出力信号は振幅成分をもっていないので、ベル
フィルタ２８でＳＥＣＡＭ信号の振幅成分を与え、復調
された輝度信号と加えて出力端子１６に前述のように良
好な再生ＳＥＣＡＭ信号を得ることができる。更に、本
発明による方式によれば、再生時リミッタ２３により記
録再生時に生じる振幅変動を除去するとともにリミッタ
効果により、変調ノイズを減少せしめることができＳ／
Ｎの良い色信号を再現することができる。As shown in Fig. 9, the output of the limiter 23 has components of fs, harmonic components, as, 8s, etc., and the energy of the carrier wave is approximately 11%, assuming that fs is W old. In the old version, as was approximately 14 dB...and the frequency deviation was f.
s is 0.9 MH2~1.2MHZ, 3s is 2.8MH
z~3.8MHz, 5fs is 4.8MHz~6-mMH
When the sideband wave is taken at 500KHz, the band for fs is 0.9MHZ to 1.7MHZ, and the band for milk s is 2.3MHZ to 4.
．． 1MH2, 8s becomes 4.3MHZ to 6.9MHZ. From the output of the limiter 23, a low-pass filter 24 and a band filter 25 extract fs in FIG. 9 and one of its harmonic components, s, respectively, and the frequency converter 26
A color signal having the sum frequency (frequency 4fs=f.) is obtained by the band filter 27. Since the output signal of this band filter 27 does not have an amplitude component, the bell filter 28 gives the amplitude component of the SECAM signal, and in addition to the demodulated luminance signal, a good reproduced SECAM signal is obtained at the output terminal 16 as described above. be able to. Further, according to the method according to the present invention, amplitude fluctuations occurring during recording and reproduction can be removed by the reproduction limiter 23, and modulation noise can be reduced by the limiter effect.
N good color signals can be reproduced.

また、第９図でわかるように、４遼倍の過程でスベクト
ラムの重なりがなく、このように、本発明では、再生時
の再生色信号の逓倍過程でスベクトラムの重なりがなく
、ビート防筈が生じにくいものである。すなわち、４逓
倍を通常の手法、例えば、２濁倍した後に、さらに２逓
倍して４逓倍信号を得るよう緩成した場合は、第１０図
に示すように、再生色信号ｆｓを２逓倍する段階で、Ｆ
Ｍ波の側帯波帯城がオーバーラップする領域が存在し、
この成分はモワレ成分となり、カラーテレビジョン受像
機でビート成分となって現はれる。In addition, as can be seen in FIG. 9, there is no overlap of spectrum in the process of multiplication by 4 times, and in this way, in the present invention, there is no overlap of spectrum in the process of multiplying the reproduced color signal during reproduction, and the beat prevention is prevented. This is something that is unlikely to occur. In other words, when quadrupling is carried out using a normal method, for example, if the reproduction color signal fs is moderately adjusted to obtain a quadrupled signal after double turbidity multiplication, the reproduced color signal fs is doubled as shown in FIG. At the stage, F
There is a region where the M-wave sidebands overlap,
This component becomes a moiré component and appears as a beat component on a color television receiver.

このような方法にくらべ、本発明は低域変換ミれた再生
搬送色信号を非線形回路を通すことによって得られる基
本波成分と高調波成分とを周波数変換器に印加し、その
和の周波数成分を得て元の搬送色信号を得るため、前述
のようなオーバーラップ領域が存在せず、ビート成分が
発生しないものであり、良好なＳＥＣＡＭ信号の記録再
生が望めるものである。Compared to such methods, the present invention applies a fundamental wave component and harmonic components obtained by passing a reproduced carrier color signal that has undergone low frequency conversion through a nonlinear circuit to a frequency converter, and calculates the sum of the frequency components. Since the original carrier color signal is obtained by obtaining the original carrier color signal, there is no overlapping area as described above, and no beat component is generated, so that good SECAM signal recording and reproduction can be expected.

【図面の簡単な説明】[Brief explanation of the drawing]

第１図は、従来の小型ＶＴＲの記録軌跡図、第２図は、
従来のカラーＶＴＲの信号処理方式を示すブロック図、
第３図は、高密度４・型ＶＴＲの記録軌跡図、第４図は
、ＳＥＣＡＭ方式カラーテレビジョン信号の色信号の周
波数スベクトラム図、第５図は従釆のカラーＶＴＲのＳ
ＥＣＡＭ色信号の記録スベクトラム図、第６図は、ＳＥ
ＣＡＭ信号の高密度化記録方式の信号処理を示すブロッ
ク図、第７図は、第６図の記録方式の色信号の記録スベ
クトラム図、第８図は、本発明の一実施例を示すブロッ
ク図、第９図は、本発明における色信号スベクトラム図
、第１０図は従来方式の色信号スベクトラム図である。 １・・・入力端子、３，２５，２７・・・帯域フルタ、
８・・・記録増中器、１０・・・ヘッドアンプ、１２，
２４…低域フィル夕、１６・・・出力端子、１７・・・
４分周器、２０・・・逆ベルフィル夕、２１・・・記録
ィコライザー、２２・・・再生イコライザー、２３・・
・リミツタ、２６・・・周波数変換器、２７・・・ベル
フィルタ。第１図第２図 第３図 第４図 第５図 第６図 第７図 第８図 第９図 第１０図Figure 1 is a recording trajectory diagram of a conventional small VTR, and Figure 2 is a recording trajectory diagram of a conventional small VTR.
A block diagram showing a signal processing method of a conventional color VTR,
Fig. 3 is a recording trajectory diagram of a high-density 4-inch VTR, Fig. 4 is a frequency spectrum diagram of a color signal of a SECAM system color television signal, and Fig. 5 is a recording locus diagram of a color signal of a secondary color VTR.
Recording spectrum diagram of ECAM color signal, Figure 6 is SE
A block diagram showing signal processing of a high-density recording method for CAM signals, FIG. 7 is a recording spectrum diagram of color signals in the recording method of FIG. 6, and FIG. 8 is a block diagram showing an embodiment of the present invention. , FIG. 9 is a color signal spectrum diagram according to the present invention, and FIG. 10 is a color signal spectrum diagram of a conventional system. 1... Input terminal, 3, 25, 27... Bandwidth filter,
8... Recording intensifier, 10... Head amplifier, 12,
24...Low frequency filter, 16...Output terminal, 17...
4 frequency divider, 20... Reverse bell filter, 21... Recording equalizer, 22... Playback equalizer, 23...
- Limiter, 26... Frequency converter, 27... Bell filter. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10

Claims (1)

【特許請求の範囲】 １ 記録すべきＳＥＣＡＭ方式カラーテレビジヨン信号
より搬送色信号を分離し、その搬送色信号を分周して低
周波に変換して記録し、再生時、再生された低周波搬送
色信号からその高調波搬送色信号を作成し、前記低周波
搬送色信号と前記高調波搬送色信号を周波数変換しても
との周波数の搬送色信号を得ることを特徴とするＳＥＣ
ＡＭ方式カラーテレビジヨン信号記録再生方式。 ２ 搬送色信号を１／４の周波数に分周して記録し、再
生時に再生された低周波搬送色信号を非線形回路を通す
ことによって、その基本波成分信号と３倍の高調波成分
信号を得て、この３倍の高調波成分信号と基本波成分信
号との周波数的和出力を得て、元の周波数の搬送色信号
を得ることを特徴とする特許請求の範囲第１項記載のＳ
ＥＣＡＭ方式カラーテレビジヨン信号記録再生方式。[Claims] 1. Separate a carrier color signal from a SECAM color television signal to be recorded, divide the frequency of the carrier color signal, convert it to a low frequency and record it, and when playing back, the reproduced low frequency SEC characterized in that a harmonic carrier color signal is created from the carrier color signal, and the frequency of the low frequency carrier color signal and the harmonic carrier color signal is converted to obtain a carrier color signal of the original frequency.
AM color television signal recording and playback system. 2 The carrier color signal is divided into a frequency of 1/4 and recorded, and the reproduced low frequency carrier color signal is passed through a nonlinear circuit during playback to generate its fundamental wave component signal and 3 times higher harmonic component signal. The S according to claim 1, wherein the frequency sum output of the triple harmonic component signal and the fundamental wave component signal is obtained to obtain the carrier color signal of the original frequency.
ECAM color television signal recording and playback system.