JPS5968803A - Magnetic reproducer - Google Patents

Abstract

PURPOSE:To obtain an excellent reproducing signal without cross modulation by satisfying the relation of lambdaS>g>lambdaL, where lambdaS is the shortest recording wavelength in the 1st signal band recorded on a magnetic recording medium, lambdaL is the longest recording length in the 2nd signal band and (g) is the head gap length. CONSTITUTION:When the wavelength of a signal recorded on a magnetic tape 5 is larger sufficiently than the length (g) of the gap 2, a reproducing voltage proportional to the timewise change of magnetic flux of a coil 4 wound on a core 3 is generated. When the frequency is higher and the wavelength lambda is coincident with the length (g), a magnetomotive force applied to the gap 2 is zero. This phenomenon takes place also when the length (g) is coincident with an integral multiple of the wavelength lambda of the recording signal. The signal having the wavelength lambda shorter than the length (g) is increased at present to a degree not being a problem for practical use. The 1st band in frequencies 0-6MHz is used for the recording of a luminance signal in a video signal and the 2nd band in frequencies 6-12MHz is used for the recording of a chrominance signal in the recording of the magnetic tape, from which the video signal without cross modulation is reproduced and separated by a filter, allowing to reproduce an excellent picture.

Description

【発明の詳細な説明】 産業上の利用分野 本発明は磁気再生装置に関するものである。[Detailed description of the invention] Industrial applications The present invention relates to a magnetic reproducing device.

従来例の構成とその問題点 従来の磁気再生装置をビデオテープレコーダ（以下ＶＴ
Ｒという）を用いて説明する。Conventional structure and problems The conventional magnetic playback device is used as a video tape recorder (hereinafter referred to as VT).
This will be explained using R.

従来の回転２ヘツド型ＶＴＲでは複合映像信号を輝度信
号と色信号とに分離し、輝度信号をＦＭ変調してその低
域側に色信号を重畳する、いわゆる周波数多重記録方法
により磁気テープに記録される。次にこの磁気テープを
再生して得られた信号を周波数分離後、検波、ジッタ補
正などの信号処理を行ない輝度信号と色信号とを含む複
合映像信号を取出していた。この際、低域変換された色
信号が輝度信号に混変調妨害を与え、高品位の再生画像
を得ることが困難になるという欠点があった。そのため
、磁気ヘッドのへラドギャップ長を狭くして磁気テープ
に記録できる信号の周波数帯域を広げ、輝度信号と色信
号とを重畳しＡいように分離して記録し再生することが
研究されている。Conventional rotating two-head VTRs record on magnetic tape using the so-called frequency multiplexing recording method, which separates a composite video signal into a luminance signal and a chrominance signal, modulates the luminance signal with FM, and superimposes the chrominance signal on the lower frequency side. be done. Next, the signals obtained by reproducing this magnetic tape are frequency-separated and subjected to signal processing such as detection and jitter correction to extract a composite video signal containing a luminance signal and a chrominance signal. At this time, there is a drawback that the low-frequency converted color signal causes cross-modulation interference to the luminance signal, making it difficult to obtain a high-quality reproduced image. Therefore, research has been conducted into narrowing the head gap length of the magnetic head to widen the frequency band of signals that can be recorded on magnetic tape, and to superimpose the luminance signal and chrominance signal and separate them in order to record and reproduce them. There is.

しかし彦から、磁気ヘッドの構造、加工技術など　′に
限界があり、現在の技術では具体的にはシリンダ径６２
闘、磁気ヘッドと磁気テープの相対速度５．８ｍ／秒　
、ヘッドギャップ長０．３μｍのＶＴＦＩが限界とされ
ており、このよう々ＶＴＲで映像信号のＳ／Ｎを４０ｄ
１３以上を確保するためには輝度信号の帯域を２ＭＨ２
，色度信号の帯域を０．８　ＭＨ２以内にしなければな
らない。したがって、このよう々装置では十分な帯域を
誦保てきないため、混変調妨害は除去でき、でも、狭帯
域なため良好な再生画像を得ることが出来ないという欠
点があった。However, Hiko explained that there are limitations in the structure and processing technology of the magnetic head, and with current technology, specifically, the cylinder diameter is 62 mm.
The relative speed between the magnetic head and magnetic tape is 5.8 m/sec.
, VTFI with a head gap length of 0.3 μm is said to be the limit, and in this way, the S/N of the video signal can be reduced to 40 d with a VTR.
In order to ensure 13 or more, the brightness signal band should be set to 2MH2.
, the band of the chromaticity signal must be within 0.8 MH2. Therefore, since such devices cannot maintain a sufficient band, they have the disadvantage that although cross-modulation interference can be removed, good reproduced images cannot be obtained due to the narrow band.

また、ヘッドギャップ長が狭ギャップになるにつれ、記
録再生能率が低下するという問題も発生する。Further, as the head gap length becomes narrower, a problem arises in that the recording and reproducing efficiency decreases.

発明の目的 本発明は複数の信号を混変調させることなく再生を行な
うことを目的とする。OBJECTS OF THE INVENTION It is an object of the present invention to reproduce a plurality of signals without cross-modulating them.

発明の構成 本発明は磁気記録媒体に記録された第１の信号の帯域中
最も短かし）記録波長λＳと同媒体に記録・″された第
２の信号の帯域中最も長い記録波長λＬ、　　とヘッド
ギャップ長ｇとの間にλｓ＞ｙ＞λＬなる関係を満足す
る磁気ヘッドを同媒体に当接することにより、第１．第
２の信号をヘッド自体で分離して再生でき混変調妨害の
問題を皆無とした磁気再生装置を提供するものである。Structure of the Invention The present invention provides a recording wavelength λS, which is the shortest in the band of a first signal recorded on a magnetic recording medium, and a recording wavelength λL, which is the longest in the band of a second signal recorded on the same medium. By bringing a magnetic head that satisfies the relationship λs > y > λL between the head gap length g and head gap length g into contact with the same medium, the first and second signals can be separated and reproduced by the head itself, thereby eliminating cross-modulation interference. The present invention provides a magnetic reproducing device that is completely free of problems.

実施例の説明 以下、本発明の一実施例を図面を用いて説明する。Description of examples An embodiment of the present invention will be described below with reference to the drawings.

第１図は本発明の一実、施例であるＶＴＲの環状磁気ヘ
ッドの構成図、第２図は同ヘッドの周波数と再生出力と
の関係を示す特性図である。FIG. 1 is a block diagram of a VTR annular magnetic head according to an embodiment of the present invention, and FIG. 2 is a characteristic diagram showing the relationship between frequency and reproduction output of the head.

図中１はコア３にコイル４を巻装した磁気記録再生ヘッ
ド（以下ヘッドという）であり、ヘッド１にはギャップ
長ｇの空隙（ギャップ）２が設けられている。５はヘッ
ド１に当接する磁気テープである。In the figure, reference numeral 1 denotes a magnetic recording/reproducing head (hereinafter referred to as head) in which a coil 4 is wound around a core 3, and the head 1 is provided with a gap 2 having a gap length g. A magnetic tape 5 is in contact with the head 1.

第１図に示す状態でテープを走行させ再生を行々った場
合、磁気テープ５に記録された信号の波長が、磁気テー
プ６のコーティング厚さおよびギャップ２のギャップ長
ｇに比べ十分大きい時はコア３に巻かれたコイル４に磁
束の時間的変化に比例した再生電圧を発生する。しかし
、第２図に示すように周波数が高くなって波長λがギャ
ップ長ｆに一致すると、ギャップ２に加わる起磁力は零
となりコイル４には再生電圧は現れない。これは第２図
に示すようにギャップ長ｇが記録信号の波長λの整数倍
に一致したときにも生じる。例えばテープ５とへラドギ
ャップ長ｇ二０．９７μｍのヘッド１の相対速度が５．
８１秒の回転２ヘツド型ＶＴＲにおける再生出力はｆ、
　＝ｅ　ＭＨｚ　、　ｆ２　＝１２ＭＨｚ　　となり第
２図に示す理論値に近い特性が得られる。また、現在、
テープの表面処理技術も向上し、テープの面粗さによる
隙間損失は非常に小さく々シ、シかも、ヘッド加工技術
の向上に伴ないギヤツブ長ダよりも短かい波長λの信号
を実用上問題がない程度にまで大きくす□ることができ
る。When the tape is run and reproduced in the condition shown in FIG. 1, when the wavelength of the signal recorded on the magnetic tape 5 is sufficiently larger than the coating thickness of the magnetic tape 6 and the gap length g of the gap 2. generates a reproduction voltage in the coil 4 wound around the core 3 that is proportional to the temporal change in magnetic flux. However, as shown in FIG. 2, when the frequency becomes high and the wavelength λ matches the gap length f, the magnetomotive force applied to the gap 2 becomes zero, and no reproduction voltage appears in the coil 4. This also occurs when the gap length g matches an integral multiple of the wavelength λ of the recording signal, as shown in FIG. For example, the relative speed between the tape 5 and the head 1 with a gap length g2 of 0.97 μm is 5.
The playback output on a two-head VTR with a rotation of 81 seconds is f,
= e MHz, f2 = 12 MHz, and characteristics close to the theoretical values shown in FIG. 2 are obtained. Also, currently
Tape surface treatment technology has also improved, and gap loss due to tape surface roughness has become very small.As head processing technology has improved, it has become a practical problem to handle signals with a wavelength λ shorter than the gear lug length. It can be enlarged to the point where there is no □.

そこで本実施例では映像信号のうち輝度信号の記録に周
波数０〜６ＭＨｚ　　の第１次帯域を用い、また映像信
号のうち色信号の記録に周波数６〜１２ＭＨｚ　　の第
２次帯域を用いた磁気テープから、混変調のない映像信
号を再生し良好な画像を再生することができる。Therefore, in this embodiment, a magnetic tape is used in which the primary band with a frequency of 0 to 6 MHz is used to record the luminance signal of the video signal, and the secondary band with a frequency of 6 to 12 MHz is used to record the color signal of the video signal. Therefore, it is possible to reproduce a video signal without cross-modulation and reproduce a good image.

次に上記実施例の具体例を第３図を用いて説明する。Next, a specific example of the above embodiment will be explained using FIG. 3.

第３図は本発明の一実施例であるＶＴＲの要部ブロック
図である。図中、２２は入力端子２１から印加された輝
度信号と色信号とを含む複合映像信号を輝度信号と色信
号に分離する分離回路であり、２３は輝度信号を周波数
偏移量（ＰＩ！：ＡＫ−Ｔｏ　−Ｐ　Ｅ　Ａ　Ｋ　）　
３．ｏ　〜４．５　ＭＨｚ　、中心周波数３．７５　Ｍ
ＨｚのＦＭ信号に変換するだめのＦＭ変調回路、２４は
色信号を中心周波数９ＭＨ２のパルスに１１変調するだ
めのパルス巾変調回路である。FIG. 3 is a block diagram of essential parts of a VTR which is an embodiment of the present invention. In the figure, 22 is a separation circuit that separates a composite video signal containing a luminance signal and a chrominance signal applied from the input terminal 21 into a luminance signal and a chrominance signal, and 23 is a separation circuit that converts the luminance signal into a frequency deviation amount (PI!: AK-To-PEAK)
3. o ~4.5 MHz, center frequency 3.75 M
An FM modulation circuit 24 is used to convert the color signal into an FM signal of Hz, and a pulse width modulation circuit 24 is used to modulate the color signal into 11 pulses with a center frequency of 9MH2.

２５はＦＭ変調回路２３の出力とパルス中“変調回路２
４の出力とを混合し、この混合出力を、テープ２７に当
接する記録ヘッド２６に印加するだめの混合回路である
。25 is the output of the FM modulation circuit 23 and the "modulation circuit 2" during the pulse.
This is a mixing circuit that mixes the output of the recording head 26 and the output of the recording head 26 and applies this mixed output to the recording head 26 that comes into contact with the tape 27.

２８はテープ２７に当接した再生用磁気ヘッド、２９は
再生ヘッド２８の出力を増幅するだめの前置増幅回路、
３０はカットオフ周波数が６ＭＨｚの低域通過型フィル
タ（以下、低域フィルタという）である。28 is a reproducing magnetic head in contact with the tape 27; 29 is a preamplifier circuit for amplifying the output of the reproducing head 28;
30 is a low-pass filter (hereinafter referred to as a low-pass filter) with a cutoff frequency of 6 MHz.

３１はリミッタ回路を有するＦＭ復調回路、３２ハ帯域
通過型フィルタ（以下、バンドパスフィルタという）、
３３はカットオフ周波数が６　ＭＨｚの高域通過フィル
タ（以下、高域フィルタという）、３４はパルス中復調
回路、３５は低域フィルタ、３６Ｌｒｉ混合回路、３７
は出力端子である。31 is an FM demodulation circuit having a limiter circuit; 32 is a band-pass filter (hereinafter referred to as a band-pass filter);
33 is a high-pass filter with a cutoff frequency of 6 MHz (hereinafter referred to as high-pass filter), 34 is a pulse demodulation circuit, 35 is a low-pass filter, 36 is an Lri mixing circuit, 37
is the output terminal.

次に、この装置の動作を説明する。Next, the operation of this device will be explained.

入力端子２１に印加されたＮＴＳＣ方式の複合映像信号
は分離回路２２で輝度信号と色信号とに分離され、輝度
信号はＦＭ変調回路２３でＦＭ変調されて混合回路２５
に印加される。一方分離された色信号はパルス中変調回
路２４を介して混合回路２５に印加される。The NTSC composite video signal applied to the input terminal 21 is separated into a luminance signal and a color signal by a separation circuit 22, and the luminance signal is FM-modulated by an FM modulation circuit 23 and sent to a mixing circuit 25.
is applied to On the other hand, the separated color signal is applied to a mixing circuit 25 via a pulse modulation circuit 24.

混合回路２６で混合された混合信号は磁気へｙド２６を
介してテープ２７上に周波数分離された状態で多重記録
される。The mixed signals mixed by the mixing circuit 26 are multiplex recorded on the tape 27 via the magnetic head 26 in a frequency-separated state.

このようにして多重記録されたテープ２７は再生用磁気
ヘッド２８により再生され、前置増幅回路２９で増幅さ
れた後、両フィルタ３Ｑ、３３に送出される。The tape 27 multiplexed in this manner is reproduced by the reproducing magnetic head 28, amplified by the preamplifier circuit 29, and then sent to both filters 3Q and 33.

低域フィルタ３ｏを通過した分離後の被変調輝度信号は
ＦＭ復調回路３１で復調されて輝度信号に復調され帯域
通過型フィルタ３２および混合回路３６を介して出力端
子３了に送出される。一方、高域通過型フィルタ３３を
通過した分離後の被変調色信号はパルス巾復調回路３４
で色信号に復調され、低域フィルタ３５および混合回路
３６を介して出力端子３了に送出される。The separated modulated luminance signal that has passed through the low-pass filter 3o is demodulated by an FM demodulation circuit 31 into a luminance signal, which is sent to the output terminal 3 through a bandpass filter 32 and a mixing circuit 36. On the other hand, the separated modulated color signal that has passed through the high-pass filter 33 is sent to the pulse width demodulation circuit 34.
The chrominance signal is demodulated into a color signal and sent to the output terminal 3 via the low-pass filter 35 and the mixing circuit 36.

このようにして出力端子３７から入力端子２１に印加さ
れた複合信号と同様の複合信号を得ることができる。In this way, a composite signal similar to the composite signal applied to the input terminal 21 can be obtained from the output terminal 37.

このようにして本実施例では輝度信号を０〜ｅＭＨｚの
第１次帯域内に、又色信号を６ＭＨｚ〜１２ＭＨｚの第
２次帯域内に記録することにより、輝度信号は２．５　
ＭＨｚ［上、色信号は１．５ＭＨ１以上で且つぃずれの
信号もＳ／Ｎ４０ｄＢ以上を確保することができ、良好
が画像再生を行なうことができる。In this way, in this embodiment, by recording the luminance signal within the primary band of 0 to eMHz and the color signal within the secondary band of 6MHz to 12MHz, the luminance signal is
MHz [upper and lower color signals are 1.5 MH1 or higher, and both signals can secure S/N of 40 dB or higher, and good image reproduction can be performed.

また、ヘッドギャップ長を長くすることができるので記
録再生能率をも向上できる。Furthermore, since the head gap length can be increased, recording and reproducing efficiency can also be improved.

なお、本実施例では第１次帯域内に輝度信号を、又第２
次帯域内に色信号を記録し再生した例を示したが輝度信
号と色信号とを入れ替えてもよい。Note that in this embodiment, the luminance signal is included in the first band, and the luminance signal is included in the second band.
Although an example has been shown in which the color signal is recorded and reproduced within the next band, the luminance signal and the color signal may be interchanged.

また、色信号をＰＷＭ変調した例を示しだがＦＭ変調、
ＰＧＭ変調を行々ってもよい。In addition, an example in which the color signal is PWM modulated is shown, but FM modulation,
PGM modulation may also be performed.

発明の効果 以上のように本発明によれば、従来のように第１次帯域
だけを利用して再生する場合に比べ各帯域信号を確実に
分離できるため混変調のない良好な再生信号を得ること
ができる。Effects of the Invention As described above, according to the present invention, each band signal can be separated more reliably than in the conventional case of reproducing using only the primary band, thereby obtaining a good reproduced signal without cross modulation. be able to.

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

第１図は本発明の一実施例であるＶＴＲの環状磁気ヘッ
ドの構成図、第２図は同ヘッドの周波数と再生出力との
関係を示す特性図、第３図は同ＶＴＲの具体例を示す要
部ブロック図である。 １・・・・・・磁気ヘッド、２・・団・空隙、３・・・
・・・コア、１゜ ４・・・・・・コイル、５・・・・・・磁気テープ、２
１・・川・入力端子、２２・・・・・・分離回路、２３
・・・・・・ＦＭ変調回路、２４・・・・・・パルス中
変調回路、２６・・用混合回路、２６・・・・・・記録
用磁気ヘッド、２７・・・・・・磁気テープ、２日・・
・・・・再生用磁気ヘッド、２９・・・・・・前置増幅
回路、３０・・・・・・低域通過フィルタ、３１・・・
・・・ＦＭ復調回路、３２・・・・・・帯域通過型フィ
ルタ、３３・・・・・・高域通過型フィルタ、３４・・
・・・・パルス中復調回路、３５・・・・・・低域フィ
ルタ、３６・・・・・・混合回路、３７・・・・・・出
力端子。Fig. 1 is a configuration diagram of the annular magnetic head of a VTR that is an embodiment of the present invention, Fig. 2 is a characteristic diagram showing the relationship between the frequency and reproduction output of the head, and Fig. 3 is a specific example of the VTR. FIG. 2 is a block diagram showing main parts. 1...Magnetic head, 2...Group/Gap, 3...
...Core, 1゜4...Coil, 5...Magnetic tape, 2
1... River input terminal, 22... Separation circuit, 23
...FM modulation circuit, 24...Pulse modulation circuit, 26...Mixing circuit, 26...Magnetic head for recording, 27...Magnetic tape , 2 days...
...Reproducing magnetic head, 29...Preamplifier circuit, 30...Low pass filter, 31...
...FM demodulation circuit, 32...Band-pass filter, 33...High-pass filter, 34...
...Pulse demodulation circuit, 35...Low pass filter, 36...Mixing circuit, 37...Output terminal.

Claims (3)

【特許請求の範囲】[Claims] （１）帯域を有する第１の信号と、前記第１の信号と重
畳せず、前記第１の信号の帯域より高い周波数域に帯域
を有する第２の信号と、ｓｙ’記録された磁気記録媒体
上に配設され、前記第１の信号の帯域中最も短かい記録
波長λＳと前記第２の信号の帯域中最も長い記録波長λ
、とヘッドギャップ長ｇとの間にλ、＞　ｙ　＞λＬな
る関係を満足する磁気ヘッドと、前記磁気ヘッドの再生
出力から第１の信号成分を分離するだめの第１のフィル
タと、前記磁気ヘッドの再生出力から第２の信号成分を
分離するだめの第２のフィルタとを備えることを特徴と
する磁気再生装置。(1) A first signal having a band, a second signal not overlapping with the first signal and having a band in a higher frequency range than the band of the first signal, and a magnetic record recorded as sy'. The shortest recording wavelength λS in the band of the first signal and the longest recording wavelength λS in the band of the second signal are arranged on the medium.
, and a head gap length g that satisfies the relationship λ, > y >λL; a first filter for separating a first signal component from the reproduction output of the magnetic head; 1. A magnetic reproducing device comprising: a second filter for separating a second signal component from a reproducing output of the head. （２）第１の信号は映像の輝度信号であり第２の信号は
映像の色信号であることを特徴とする特許請求の範囲第
１項記載の磁気再生装置。(2) The magnetic reproducing device according to claim 1, wherein the first signal is a video luminance signal and the second signal is a video color signal. （３）第１の信号は映像の色信号であり、第２の信号は
映像の輝度信号であることを特徴とする特許請求の範囲
第１項記載の磁気再生装置。(3) The magnetic reproducing device according to claim 1, wherein the first signal is a video color signal, and the second signal is a video luminance signal.