JPH0311598B2 - - Google Patents
Info
- Publication number
- JPH0311598B2 JPH0311598B2 JP57202603A JP20260382A JPH0311598B2 JP H0311598 B2 JPH0311598 B2 JP H0311598B2 JP 57202603 A JP57202603 A JP 57202603A JP 20260382 A JP20260382 A JP 20260382A JP H0311598 B2 JPH0311598 B2 JP H0311598B2
- Authority
- JP
- Japan
- Prior art keywords
- switches
- period
- recording
- turned
- video
- 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 - Lifetime
Links
- 239000003990 capacitor Substances 0.000 description 10
- 238000010586 diagram Methods 0.000 description 5
- 230000005669 field effect Effects 0.000 description 5
- 238000004804 winding Methods 0.000 description 4
- 230000005540 biological transmission Effects 0.000 description 2
- 230000008878 coupling Effects 0.000 description 2
- 238000010168 coupling process Methods 0.000 description 2
- 238000005859 coupling reaction Methods 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 238000009825 accumulation Methods 0.000 description 1
- 239000000969 carrier Substances 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000002093 peripheral effect Effects 0.000 description 1
- 230000008054 signal transmission Effects 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N5/00—Details of television systems
- H04N5/76—Television signal recording
- H04N5/78—Television signal recording using magnetic recording
- H04N5/782—Television signal recording using magnetic recording on tape
Landscapes
- Engineering & Computer Science (AREA)
- Multimedia (AREA)
- Signal Processing (AREA)
- Television Signal Processing For Recording (AREA)
Description
【発明の詳細な説明】
産業上の利用分野
本発明は磁気記録再生装置に係り、特に回転体
に90゜等間隔で取付けられた４個の磁気ヘツドを
順次切換えて、磁気テープ上に信号を記録するに
際し、磁気ヘツド切換点付近の信号を重複して記
録する（所謂オーバーラツプ記録する）磁気記録
再生装置に関する。DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a magnetic recording/reproducing device, and more particularly, to a magnetic recording/reproducing device that sequentially switches four magnetic heads attached to a rotating body at equal intervals of 90 degrees to record signals on a magnetic tape. The present invention relates to a magnetic recording and reproducing apparatus that records signals in the vicinity of a magnetic head switching point in an overlapping manner (so-called overlap recording).
従来技術
本出願人は先に例えば実願昭57−122921号に
て、第１図に示す如きヘツド配置とされた磁気記
録再生装置を提案した。同図中、回転ドラムや回
転プレート等の回転体１の直径Ｌは、磁気テープ
が180゜強に亘つて添接巻回され、回転体上に180゜
等間隔で取付けられた２個のビデオヘツドにより
記録再生を行なう現行の２ヘツドヘリカルスキヤ
ンニング方式のVTRの回転体の直径Ｍに比し、
２／３倍の値に選定されており、図示を省略したモ
ータにより記録再生される映像信号のフイールド
周波数に関連した回転数（例えば45rps）で反時
計方向に回転せしめられる。この回転体１には記
録再生用ビデオヘツドＡ，Ｂ，Ｃ及びＤが夫々
90゜の等角度間隔で取付固定されている。ビデオ
ヘツドＡとＣは夫々同一のアジマス角度のギヤツ
プを有しており、またビデオヘツドＢとＤとは
夫々同一アジマス角度のギヤツプを有し、かつ、
ビデオヘツドＡとＣのそれとは異なるアジマス角
度のギヤツプを有している。Prior Art The present applicant has previously proposed, for example, in Utility Model Application No. 122921/1987, a magnetic recording/reproducing apparatus having a head arrangement as shown in FIG. In the figure, the diameter L of a rotating body 1 such as a rotating drum or a rotating plate is the same as that of two video tapes on which a magnetic tape is spliced and wound over 180 degrees and mounted on the rotating body at equal intervals of 180 degrees. Compared to the diameter M of the rotating body of the current two-head helical scanning VTR, which performs recording and playback using the head,
The value is selected to be 2/3 times as large, and is rotated counterclockwise by a motor (not shown) at a rotation speed (for example, 45 rps) related to the field frequency of the video signal to be recorded and reproduced. This rotating body 1 has video heads A, B, C, and D for recording and reproducing, respectively.
They are mounted and fixed at equal angular intervals of 90°. Video heads A and C each have the same azimuth angle gap, video heads B and D each have the same azimuth angle gap, and
Video heads A and C have a different azimuth angle gap.
更に、回転体１の外周側面には、磁気テープ２
がガイドポール３ａ，３ｂにより案内されて270゜
にオーバーラツプ記録分の角度を加えた270゜強度
の角度に亘つて添接巻回されている。このテープ
巻付角度はテープ走行にあまり無理を与えない角
度であり、自動ローデイングも可能であり、回転
体１の直径Ｌも現行の２ヘツドヘリカルスキヤン
ニング方式VTRのそれの2/3倍になるので、回転
体の直径縮小率も大とすることができる。磁気テ
ープ２はキヤプスタン及びピンチローラ（いずれ
も図示せず）に挾持駆動されて矢印Ｘ方向へ走行
せしめられるが、その走行速度は、ビデオヘツド
Ａ〜Ｄのうちの一個のビデオヘツドが270゜強の角
度範囲を45rpsで回転するときに１トラツクピツ
チ分走行する値に選定されている。 Furthermore, a magnetic tape 2 is placed on the outer peripheral side of the rotating body 1.
are guided by guide poles 3a and 3b and are spliced and wound over an angle of 270°, which is 270° plus the angle for the overlap recording. This tape winding angle is an angle that does not put too much strain on the tape running, and automatic loading is also possible.The diameter L of the rotating body 1 is also 2/3 times that of the current 2-head helical scanning VTR. Therefore, the diameter reduction rate of the rotating body can also be increased. The magnetic tape 2 is held between a capstan and a pinch roller (none of which are shown) and is driven to run in the direction of arrow X, but the running speed is such that one of the video heads A to D is at a speed of over 270 degrees. The value has been selected to cover one track pitch when rotating at 45 rps in the angle range of .
これにより、テープ巻付角度における磁気テー
プ２の円周距離は現行の２ヘツドVTRのそれに
等しいので、磁気テープ２上のビデオトラツク軌
跡は現行のそれに等しく、またテープ・ヘツド間
相対線速度は現行のそれに等しく、ビデオヘツド
Ａ，Ｂ，Ｃ及びＤにより以下に詳述する如くフイ
ールド周波数60Hz（又は59.94Hz）の映像信号が
１本のトラツク宛１フイールド分の割合で順次に
記録され、現行VTRと完全にテープ互換性のあ
るテープパターンが形成される。 As a result, the circumferential distance of the magnetic tape 2 at the tape winding angle is equal to that of the current two-head VTR, so the video track locus on the magnetic tape 2 is equal to that of the current one, and the relative linear velocity between the tape and the head is the same as that of the current two-head VTR. As described in detail below, video signals with a field frequency of 60 Hz (or 59.94 Hz) are sequentially recorded by video heads A, B, C, and D at a rate of one field per track. A completely tape-compatible tape pattern is formed.
なお、フイールド周波数50Hzの映像信号を１本
のトラツク宛１フイールドの割合で記録、再生す
る場合は、回転体１は37.5rpsで回転されること
は明らかである。 It is clear that when a video signal with a field frequency of 50 Hz is recorded and reproduced at a rate of one field per track, the rotating body 1 is rotated at 37.5 rps.
上記の４ヘツドVTRにおける４個のビデオヘ
ツドＡ〜Ｄによる走査軌跡は第２図に示す如くに
なり、現行の２ヘツドVTRのそれと異なる。す
なわち、いまビデオヘツドＡがガイドポール３ａ
側に位置して磁気テープ２上を走査し始めたもの
とすると、第２図に実線４Ａで示す走査軌跡が描
かれ始め、その軌跡４Ａの下から1/3程度の長さ
にきた所で、回転方向に対し90゜後行する位置に
設けられたビデオヘツドＤが磁気テープ２と接触
し始め、更に軌跡４Ａの2/3程度の長さを記録す
る時点にビデオヘツドＡがくると、ビデオヘツド
Ｃが磁気テープ２と接触し始め、更に軌跡４Ａが
形成され終る時点でビデオヘツドＢが磁気テープ
２に接触し始める。従つて、ビデオヘツドＡによ
る第２図に実線４Ａで示すヘツド軌跡が描かれる
と、同図に二点鎖線４Ｄで示すビデオヘツドＤに
よるヘツド軌跡と同図に一点鎖線４Ｃで示すビデ
オヘツドＣによるヘツド軌跡とが夫々一定時間遅
れて順次に描かれ、ヘツド軌跡４Ａが描かれ終つ
た時点で、同図に破線５Ｂで示すビデオヘツドＢ
によるヘツド軌跡が描かれ始める。 The scanning trajectory by the four video heads A to D in the above-mentioned 4-head VTR is as shown in FIG. 2, which is different from that of the current 2-head VTR. That is, video head A is now on guide pole 3a.
Assuming that the magnetic tape 2 is positioned at the side and begins scanning, a scanning locus shown by a solid line 4A in FIG. When the video head D, which is placed at a position 90 degrees behind the rotational direction, begins to come into contact with the magnetic tape 2, and when the video head A comes to record about 2/3 of the trajectory 4A, The video head C starts to come into contact with the magnetic tape 2, and the video head B starts to come into contact with the magnetic tape 2 at the point when the trajectory 4A is finished being formed. Therefore, when the head trajectory shown by the solid line 4A in FIG. 2 is drawn by the video head A, the head trajectory by the video head D shown by the two-dot chain line 4D in the same figure and by the video head C shown by the one-dot chain line 4C in the same figure are drawn. The head trajectories are drawn sequentially with a certain time delay, and when the head trajectories 4A have been drawn, the video head B shown by the broken line 5B in the figure is drawn.
The trajectory of the head begins to be drawn.
以下、上記と同様にして、第２図に５Ａ，５
Ｄ，６Ｃ，６Ｂ，６Ａ，７Ｄ，７Ｃ，７Ｂ，８
Ａ，……という順序でヘツドＡ，Ｄ，Ｃ，Ｂによ
り順次トラツク軌跡が描かれていく（なお、第２
図では図示の便宜上、各トラツク軌跡のトラツク
幅はトラツクピツチに等しいものとして図示して
ある。）。また第２図中、テープ長手方向に沿うト
ラツク９はコントロールトラツクで、例えば２フ
イールド周期でコントロールパルスが記録され
る。 Hereinafter, in the same manner as above, 5A, 5
D, 6C, 6B, 6A, 7D, 7C, 7B, 8
A track locus is drawn sequentially by heads A, D, C, B in the order of
In the figure, for convenience of illustration, the track width of each track locus is shown as being equal to the track pitch. ). Also, in FIG. 2, a track 9 along the longitudinal direction of the tape is a control track, on which control pulses are recorded, for example, at a two-field period.
ここで、現行の２ヘツドVTRと同一の第３図
に示す如きテープパターンを記録形成するために
は、第２図に丸で囲んだ軌跡４Ａ，５Ｂ，６Ｃ，
７Ｄ，８Ａ，……を描いているビデオヘツドにの
み映像信号を供給することにより、第３図にt1で
示すビデオトラツクはビデオヘツドＡにより記録
形成されたトラツクとなり、同様にビデオヘツド
Ｂ→Ｃ→Ｄ→Ａ→……という順序で約１フイール
ド期間毎に記録するヘツドを切換えることによ
り、ビデオトラツクがt2→t3→t4→t5→……とい
う順序で順次形成される。 Here, in order to record and form the tape pattern as shown in FIG. 3, which is the same as the current two-head VTR, it is necessary to follow the traces 4A, 5B, 6C circled in FIG.
By supplying video signals only to the video heads depicting 7D, 8A, . . . , the video track indicated by t1 in FIG. By switching the recording head approximately every one field period in the order C→D→A→..., video tracks are sequentially formed in the order t2 → t3 → t4 → t5 →....
発明が解決しようとする問題点
ところで、回転体に180゜強の角度範囲に亘つて
巻回した磁気テープを走行させて２個のビデオヘ
ツドにより交互に信号を記録し、又は再生をする
現行の２ヘツドヘリカルスキヤンニング方式
VTR（２ヘツドVTR）では、一方のビデオヘツ
ドが磁気テープ上を走査している期間は他方のビ
デオヘツドが磁気テープと非接触の状態にある期
間と略等しいから、２個のビデオヘツドに記録電
流を流し続けても何ら差し支えない。また或る
VTRで記録した磁気テープを別のVTRで再生す
る所謂互換再生時において、２個のビデオヘツド
の切換点のずれによつて再生信号の一部欠落又は
一部重複を生じることがあるので、機械的なテー
プ巻付角度を180゜よりも前後に5゜程度ずつ更に多
く巻付けると共に、上記２個のビデオヘツドに常
時記録電流を流し続けることにより、一方のビデ
オヘツドが１本のトラツクに記録し終る直前の信
号は、他方のビデオヘツドにより次の１本のトラ
ツクの記録開始部分にも同時に記録（所謂オーバ
ーラツプ記録）して、上記の再生信号の一部欠落
又は一部重複を防止することができる。Problems to be Solved by the Invention By the way, in the current method, signals are alternately recorded or played back by two video heads by running a magnetic tape wound around a rotating body over an angular range of over 180 degrees. 2-head helical scanning method
In a VTR (two-head VTR), the period during which one video head scans the magnetic tape is approximately equal to the period during which the other video head is out of contact with the magnetic tape, so recording is performed on two video heads. There is no problem even if the current continues to flow. There is again
During so-called compatibility playback, in which a magnetic tape recorded on a VTR is played back on another VTR, part of the playback signal may be missing or overlapped due to a shift in the switching points of the two video heads. By wrapping the tape more than 180 degrees at a tape winding angle of about 5 degrees both front and back, and by continuously supplying a recording current to the two video heads, one video head can record on one track. The signal immediately before the end of the recording is simultaneously recorded on the recording start portion of the next track by the other video head (so-called overlap recording) to prevent the reproduction signal from being partially omitted or partially overlapped. Can be done.
これに対して、上記の第１図に示す如き４ヘツ
ドヘリカルスキヤンニング方式VTR（４ヘツド
VTR）の場合は、第２図にヘツド走査軌跡を示
したように、３個のビデオヘツドが磁気テープ２
上を同時に走査しているために、各ビデオヘツド
走査軌跡は別のビデオヘツド走査軌跡と一部重複
している。このため、２ヘツドVTRの如く記録
電流を常時流しておくことはできず、４ヘツド
VTRの場合は前記した如く、回転体１の270゜の
角度範囲回転期間、すなわち１フイールド期間毎
に記録電流を順次切換えて一のビデオヘツドにの
み記録電流を流す必要がある。 In contrast, a 4-head helical scanning VTR (4-head helical scanning system) as shown in Figure 1 above
In the case of a VTR), three video heads are connected to the magnetic tape 2, as shown in the head scanning trajectory in Figure 2.
Each video head scan trajectory partially overlaps another video head scan trajectory due to simultaneous scanning over the video head. For this reason, it is not possible to keep the recording current flowing all the time like in a 2-head VTR, but in a 4-head VTR.
In the case of a VTR, as described above, it is necessary to sequentially switch the recording current every 270° angle range rotation period of the rotating body 1, that is, every one field period, so that the recording current flows only to one video head.
しかるに、上記の４個のビデオヘツドＡ〜Ｄに
順次に１フイールド期間ずつ記録電流を流すよう
に切換えると、前記の互換再生等において、ヘツ
ド切換付近の再生信号が一部欠落してしまうこと
があるという問題点があつた。 However, if the recording current is sequentially applied to the four video heads A to D for one field period at a time, a part of the reproduction signal near the switching of the heads may be lost during the above-mentioned compatible playback. There was a problem.
そこで、本発明は記録電流の切換えを１フイー
ルド期間よりもやや長くすると共に、回転体への
テープ巻付角度を270゜＋α（たとえばαは20゜程
度）とすることにより、上記の問題点を解決した
磁気記録再生装置を提供することを目的とする。 Therefore, the present invention solves the above problems by making the switching of the recording current slightly longer than one field period and by setting the tape winding angle around the rotating body to 270° + α (for example, α is about 20°). The purpose of the present invention is to provide a magnetic recording/reproducing device that solves the above problems.
問題点を解決するための手段
本発明は270゜強の角度範囲に亘つて磁気テープ
が巻回されており、かつ、４個のヘツドが夫々
90゜等間隔で取付けられた回転体を、記録再生す
べき映像信号の１フイールド期間当り270゜回転す
る回転数で回転させて記録再生を行なう磁気記録
再生装置において、記録用増幅器の出力端と前記
４個のヘツドの入力端との間に夫々設けられた互
いに独立してスイツチング制御される４個の第１
のスイツチと、該４個の第１のスイツチの出力端
と接地との間に設けられ記録時は常時オフされ再
生時は常時オンされる４個の第２のスイツチと、
記録時は記録すべき映像信号の１フイールド期間
よりもやや長い所定期間ずつ４個の第１のスイツ
チを順次オンとして記録用増幅器の出力映像信号
をオンとされた第１のスイツチに接続された一の
該ヘツドに供給させ、かつ、４個の第１のスイツ
チのうち現にオンとされている第１のスイツチの
オン期間の終りの一定期間と次にオンとされるべ
き第１のスイツチのオン期間の始めの一定期間と
が夫々重複するように４個の第１のスイツチをス
イツチング制御し、再生時は４個の第１のスイツ
チを常時オフにする第４の第３のスイツチと、４
個のヘツドの出力端と接地との間に設けられ、記
録時は常時オンされ、再生時は１フイールド期間
ずつ時分割的にスイツチング制御される４個の第
４のスイツチとを具備し、４個の第２のスイツチ
を常時オフし、４個の第１のスイツチを順番に前
記所定期間ずつ順次にオンして前記磁気テープ上
に該所定期間ずつ映像信号が記録されたトラツク
を記録形成するよう構成したものであり、以下図
面と共にその一実施例について説明する。Means for Solving the Problems In the present invention, a magnetic tape is wound over an angular range of over 270 degrees, and each of the four heads is
In a magnetic recording and reproducing apparatus that performs recording and reproduction by rotating rotating bodies mounted at equal intervals of 90 degrees at a rotation speed of 270 degrees per field period of the video signal to be recorded and reproduced, the output end of the recording amplifier and Four first switches are provided between the input terminals of the four heads and are independently controlled by switching.
four second switches, which are provided between the output terminals of the four first switches and the ground, and are always turned off during recording and always turned on during playback;
During recording, the four first switches were turned on in sequence for a predetermined period slightly longer than one field period of the video signal to be recorded, and the output video signal of the recording amplifier was connected to the first switch that was turned on. A certain period at the end of the on period of the first switch that is currently turned on among the four first switches and the period of the first switch that is to be turned on next. a fourth third switch that controls switching of the four first switches so that the initial fixed period of the on period overlaps with each other, and always turns off the four first switches during playback; 4
4 fourth switches are provided between the output terminals of the four heads and the ground, and are always on during recording, and time-divisionally controlled switching for each field period during playback. The four second switches are always turned off, and the four first switches are sequentially turned on for each of the predetermined periods to record and form a track on the magnetic tape in which the video signal is recorded for each of the predetermined periods. One embodiment of the present invention will be described below with reference to the drawings.
実施例
第４図は本発明装置の一実施例の回路図を示
す。同図中、第１図と同一構成部分には同一符号
を付してある。記録用増幅器１２の出力端よりビ
デオヘツドＡ，Ｂ，Ｃ及びＤの夫々に到る４つの
伝送路には、第１のスイツチであるスイツチング
用NPNトランジスタQ2A，Q2B，Q2C，Q2Dのコレ
クタ、エミツタが介挿接続されており、またトラ
ンジスタQ2A，Q2B，Q2C及びQ2Dの各エミツタと
結合コンデンサC1A，C1B，C1C及びC1Dとの接続点
は第２のスイツチであるスイツチング用NPNト
ランジスタQ3A，Q3B，Q3C及びQ3Dのコレクタに
接続されている。アナログスイツチを構成する上
記トランジスタQ2A，Q2B，Q2C及びQ2Dは特にオ
ンからオフ状態へ切換わる時にキヤリアの蓄積の
ためオフしにくいので、そのベースが第３のスイ
ツチであるNPNトランジスタQ1A，Q1B，Q1C及
びQ1Dのコレクタに接続されてスイツチングスピ
ードを高めるように構成されている。Embodiment FIG. 4 shows a circuit diagram of an embodiment of the device of the present invention. In the figure, the same components as in FIG. 1 are designated by the same reference numerals. The four transmission lines from the output end of the recording amplifier 12 to each of the video heads A, B, C, and D include switching NPN transistors Q 2A , Q 2B , Q 2C , and Q 2D , which are first switches. The collectors and emitters of transistors Q 2A , Q 2B , Q 2C and Q 2D are interposed and connected, and the connection points between the emitters of transistors Q 2A , Q 2B , Q 2C and Q 2D and coupling capacitors C 1A , C 1B , C 1C and C 1D are connected to a second It is connected to the collectors of switching NPN transistors Q 3A , Q 3B , Q 3C and Q 3D which are switches. The above transistors Q 2A , Q 2B , Q 2C and Q 2D composing the analog switch are difficult to turn off due to the accumulation of carriers especially when switching from on to off state, so the base of the transistor is the NPN transistor Q which is the third switch. It is configured to be connected to the collectors of 1A , Q 1B , Q 1C and Q 1D to increase switching speed.
また、ビデオヘツドＡ，Ｂ，Ｃ及びＤより結合
コンデンサC2A，C2B，C2C及びC2Dを介して前置増
幅器１７Ａ，１７Ｂ，１７Ｃ及び１７Ｄの入力端
に至る伝送路の途中にはエミツタが接地された第
４のスイツチであるスイツチング用NPNトラン
ジスタQ4A，Q4B，Q4C及びQ4Dのコレクタが接続
されている。 In addition, there is an emitter in the transmission path from the video heads A, B, C, and D to the input terminals of the preamplifiers 17A, 17B , 17C, and 17D via the coupling capacitors C 2A , C 2B , C 2C, and C 2D. The collectors of switching NPN transistors Q 4A , Q 4B , Q 4C and Q 4D , which are the fourth switches whose transistors are grounded, are connected.
上記回路の記録時の動作につき説明するに、記
録時には入力端子１６Ａ，１６Ｂ，１６Ｃ及び１
６Ｄにハイレベルの電圧が常時入来され、抵抗
R4A，R4B，R4C及びR4Dを介してトランジスタ
Q4A，Q4B，Q4C及びQ4Dのベースに印加されてこ
れらをオンとすると同時に、入力端子１４より抵
抗R2A，R2B，R2C及びR2Dを介してトランジスタ
Q1A，Q1B，Q1C及びQ1Dの各コレクタとトランジ
スタQ2A，Q2B，Q2C及びQ2Dの各ベースに夫々ハ
イレベルの電圧が印加される。一方、入力端子１
５より抵抗R3A，R3B，R3C及びR3Dを介してトラ
ンジスタQ3A，Q3B，Q3C及びQ3Dのベースにロー
レベルの電圧が印加され、これらをオフとする。
トランジスタQ4A〜Q4Dのオンにより前置増幅器
１７Ａ〜１７Ｄの入力端が交流的に接地される。 To explain the operation of the above circuit during recording, the input terminals 16A, 16B, 16C and 1
A high level voltage is constantly applied to 6D, and the resistance
Transistors through R 4A , R 4B , R 4C and R 4D
It is applied to the bases of Q 4A , Q 4B , Q 4C and Q 4D to turn them on, and at the same time the transistor is applied from the input terminal 14 through the resistors R 2A , R 2B , R 2C and R 2D
High-level voltages are applied to the collectors of Q 1A , Q 1B , Q 1C and Q 1D and the bases of transistors Q 2A , Q 2B , Q 2C and Q 2D , respectively. On the other hand, input terminal 1
5, a low level voltage is applied to the bases of transistors Q 3A , Q 3B , Q 3C and Q 3D via resistors R 3A , R 3B , R 3C and R 3D to turn them off.
By turning on the transistors Q 4A to Q 4D , the input ends of the preamplifiers 17A to 17D are AC grounded.
また、入力端子１３Ａ，１３Ｂ，１３Ｃ及び１
３Ｄには前記回転体１の回転位相の検出パルスを
１／３分周して得たパルスを基準にして生成された、
第５図Ａ，Ｂ，Ｃ及びＤに示す如き４フイールド
周期のパルスａ，ｂ，ｃ及びｄが夫々入来し、抵
抗R1A，R2A，R3A及びR4Aを介してトランジスタ
Q1A，Q1B，Q1C及びQ1Dの各ベースに印加される。
パルスａ，ｂ，ｃ及びｄは第５図Ａ〜Ｄに示す如
く、夫々ローレベル期間が１フイールド期間より
もやや大なる期間（これはビデオヘツドＡ〜Ｄの
夫々が磁気テープ２上を摺動走査する270゜強の角
度範囲を回転する期間に略等しい）に選定されて
おり、またパルスａ，ｂ，ｃ，ｄの各ローレベル
期間の終りの一定期間Ｔと、パルスｂ，ｃ，ｄ，
ａの各ローレベル期間の始めの一定期間Ｔとが
夫々重複するように発生される。第５図Ｅは記録
されるべき映像信号の各フイールド期間を模式的
に示しており、例えばハイレベルは奇数フイール
ド、ローレベルは偶数フイールドを示す。 In addition, input terminals 13A, 13B, 13C and 1
3D is generated based on a pulse obtained by dividing the rotational phase detection pulse of the rotating body 1 by 1/3,
Pulses a, b , c and d of four field periods as shown in FIG.
Applied to each base of Q 1A , Q 1B , Q 1C and Q 1D .
As shown in FIGS. 5A to 5D, the pulses a, b, c, and d each have a period in which the low level period is slightly longer than one field period (this is because each of the video heads A to D slides on the magnetic tape 2). The fixed period T at the end of each low level period of pulses a, b, c, and d, and the fixed period T at the end of each low level period of pulses a, b, c, and d, d,
The constant period T at the beginning of each low level period of a is generated so as to overlap with each other. FIG. 5E schematically shows each field period of the video signal to be recorded; for example, a high level indicates an odd field, and a low level indicates an even field.
パルスａのローレベル期間はトランジスタQ1A
がオフとされるため、そのコレクタ電位とトラン
ジスタQ2Aのベース電位とが夫々ハイレベルとな
り、よつてトランジスタQ2Aがオンとなる。また
パルスａのハイレベル期間はトランジスタQ1Aが
オンとされるため、そのコレクタ電位とトランジ
スタQ2Aのベース電位とが夫々ローレベルとなる
ので、トランジスタQ2Aがオフとなる。同様にし
て、パルスｂ，ｃ及びｄのローレベル期間はトラ
ンジスタQ2B，Q2C及びQ2Dが夫々オンとなり、ハ
イレベル期間ではオフとなる。従つて、トランジ
スタQ2A，Q2B，Q2C及びQ2Dは夫々１フイールド
強の期間ずつ順次にオンとされていく。 During the low level period of pulse a, transistor Q 1A
Since Q2A is turned off, its collector potential and the base potential of transistor Q2A each become high level, and thus transistor Q2A is turned on. Further, since the transistor Q 1A is on during the high level period of the pulse a, its collector potential and the base potential of the transistor Q 2A are both at a low level, so the transistor Q 2A is turned off. Similarly, transistors Q 2B , Q 2C and Q 2D are turned on during the low level periods of the pulses b, c and d, respectively, and are turned off during the high level periods of the pulses b, c and d. Therefore, transistors Q 2A , Q 2B , Q 2C and Q 2D are each turned on sequentially for a period of just over one field.
従つて、入力端子１１に入来して記録用増幅器
１２より取り出される記録用映像信号は、パルス
ａのローレベル期間はトランジスタQ2A、コンデ
ンサC1A及びロータリートランスRTAを介してビ
デオヘツドＡに供給され、次の１フイールド強の
期間はトランジスタQ2B、コンデンサC1B及びロー
タリートランスRTBを介してビデオヘツドＢに供
給され、次の１フイールド強の期間はトランジス
タQ2C、コンデンサC1C及びロータリートランス
RTCを介してビデオヘツドＣに供給され、更に次
の１フイールド強の期間はトランジスタQ2D、コ
ンデンサC1D及びロータリートランスRTDを介し
てビデオヘツドＤに供給され、以下上記と同様の
動作が巡回的に繰り返されていく。 Therefore, the recording video signal that enters the input terminal 11 and is taken out from the recording amplifier 12 is sent to the video head A via the transistor Q 2A , the capacitor C 1A , and the rotary transformer RT A during the low level period of the pulse a. It is supplied to the video head B via the transistor Q 2B , the capacitor C 1B and the rotary transformer RT B for the next one field period, and is supplied to the video head B via the transistor Q 2C , the capacitor C 1C and the rotary transformer RT B for the next one field period. Trance
The signal is supplied to video head C via RT C , and for the next one field period, it is supplied to video head D via transistor Q 2D , capacitor C 1D and rotary transformer RT D , and thereafter the same operation as above occurs. It is repeated cyclically.
ここで、ビデオヘツドＡ〜Ｄのうち記録用映像
信号が供給されるビデオヘツドはそのとき磁気テ
ープを摺動走査しているように、パルスａ〜ｄの
位相が予め設定されているから、記録用映像信号
は磁気テープ上に順次のトラツクを形成して記録
されていく。ここで、いまトランジスタQ2Aがオ
ンとされているものとすると、そのオン期間の終
りの一定期間Ｔと、次にオンとされるべきトラン
ジスタQ2Bのオン期間の始めの一定期間Ｔとは
夫々重複するようにスイツチング制御されるた
め、この期間ＴではビデオヘツドＡとＢとにより
同じ区間の記録用映像信号が夫々別々のトラツク
に同時に記録されることとなる（所謂オーバーラ
ツプ記録される）。 Here, among the video heads A to D, the phase of the pulses a to d is set in advance so that the video head to which the recording video signal is supplied is slidingly scanning the magnetic tape. Video signals for use in the magnetic tape are recorded by forming successive tracks on the magnetic tape. Here, assuming that the transistor Q 2A is currently turned on, a certain period T at the end of its on period and a certain period T at the beginning of the on period of the transistor Q 2B to be turned on next are, respectively. Since the switching is controlled in an overlapping manner, during this period T, recording video signals of the same section are simultaneously recorded on separate tracks by video heads A and B (so-called overlap recording).
同様にして、ビデオヘツドＢ，Ｃ及びＤにより
記録形成されるトラツクの終りの期間Ｔと、次に
ビデオヘツドＣ，Ｄ及びＡにより記録形成される
隣接トラツクの始めの期間Ｔとは夫々同一区間の
記録用映像信号が記録される。 Similarly, the end period T of the track recorded by video heads B, C and D and the beginning period T of the adjacent track recorded by video heads C, D and A are respectively the same section. A video signal for recording is recorded.
次に再生時の動作につき説明するに、再生時に
は入力端子１４にはローレベルの信号が入来し、
トランジスタQ2A，Q2B，Q2C及びQ2Dを夫々常時
オフとする。また一方、入力端子１５にはハイレ
ベルの信号が入来し、トランジスタQ3A，Q3B，
Q3C及びQ3Dは夫々常時オンとされる。なお、ト
ランジスタQ3A，Q3B，Q3C及びQ3Dのオンにより、
ロータリートランスRTA，RTB，RTC及びRTDの
一端は交流的に接地されるので、直接他のヘツド
からのクロストークがあるわけではないが、トラ
ンジスタスイツチにもオン抵抗があり、それによ
りクロストークが生じる。そのため、本実施例で
はトランジスタQ2A，Q2B，Q2C及びQ2Dを夫々再
生時は常時オフとすることにより、上記のクロス
トークを防止するようにしている。 Next, to explain the operation during playback, during playback, a low level signal enters the input terminal 14,
Transistors Q 2A , Q 2B , Q 2C and Q 2D are always turned off. On the other hand, a high level signal enters the input terminal 15, and the transistors Q 3A , Q 3B ,
Q 3C and Q 3D are each always on. Note that by turning on transistors Q 3A , Q 3B , Q 3C and Q 3D ,
One end of the rotary transformers RT A , RT B , RT C , and RT D is grounded in an AC manner, so there is no direct crosstalk from other heads, but the transistor switches also have on-resistance, which causes Crosstalk occurs. Therefore, in this embodiment, the above-mentioned crosstalk is prevented by always turning off the transistors Q 2A , Q 2B , Q 2C , and Q 2D during reproduction.
更に入力端子１６Ａ〜１６Ｄには４フイールド
周期で、かつ、１フイールド期間ずつ時分割的に
ローレベルとなるパルスが夫々入力するため、ト
ランジスタQ4A，Q4B，Q4C及びQ4Dは夫々時分割
的にオフとされる。ここで、ビデオヘツドＡがト
ラツクを再生しているときはトランジスタQ4Aが
オフとされるように構成されているので、ビデオ
ヘツドＡからの再生信号は、ロータリートランス
RTA、コンデンサC2A、前置増幅器１７Ａを夫々
通して出力端子１８Ａへ出力される。以下、同様
にして、ビデオヘツドＢ，Ｃ及びＤの各１フイー
ルド再生信号は、出力端子１８Ｂ，１８Ｃ及び１
８Ｄへ夫々順次に出力される。 Furthermore, since the input terminals 16A to 16D are each input with a pulse that goes to a low level in a time-division manner with a four-field period and one field period at a time, the transistors Q 4A , Q 4B, Q 4C , and Q 4D are each input in a time-division manner. It is said to be turned off. Here, when video head A is playing back a track, transistor Q4A is turned off, so the playback signal from video head A is transferred to the rotary transformer.
The signal is outputted to the output terminal 18A through RT A , the capacitor C 2A and the preamplifier 17A, respectively. Similarly, one field playback signal from each of video heads B, C and D is transmitted to output terminals 18B, 18C and 1.
The signals are sequentially output to each 8D.
なお、第４図に示す入力端子１４と１６Ａ〜１
６Ｄとを夫々共通に接続してもよく、その場合
は、出力端子１８Ａ〜１８Ｄから取り出される再
生信号はスイツチ回路（図示せず）に出力されて
各ヘツドからの再生信号が順次取り出されるよう
選択出力される。 In addition, the input terminals 14 and 16A to 1 shown in FIG.
6D may be connected in common to each head. In that case, the playback signals taken out from the output terminals 18A to 18D are output to a switch circuit (not shown), and the playback signals from each head are selected so as to be taken out in sequence. Output.
次に他の実施例につき説明するに、第６図は本
発明装置の要部の他の実施例の回路図を示す。
NPNトランジスタQ5及びPNPトランジスタQ6は
記録用増幅器１２の出力段トランジスタで、それ
らのエミツタ抵抗R5及びR6の接続中点から取り
出された記録用映像信号は、電界効果トランジス
タQ7のドレインに印加される。ここで、ビデオ
ヘツドＨ（これは前記ヘツドＡ〜Ｄのうちのいず
れか一つのヘツドである）が磁気テープ上を摺動
走査する１フイールド強の期間は、入力端子１９
に入来し、抵抗R8及びR9により分圧されるハイ
レベルの信号によりNPNトランジスタQ8がオン
とされるため、電界効果トランジスタQ7もオン
となる。これにより、記録用映像信号は、電界効
果トランジスタを通して更に抵抗R10、コンデン
サC3、ロータリートランスRTを夫々経てヘツド
Ｈに供給されこれにより記録される。 Next, referring to another embodiment, FIG. 6 shows a circuit diagram of another embodiment of the main part of the apparatus of the present invention.
The NPN transistor Q 5 and the PNP transistor Q 6 are output stage transistors of the recording amplifier 12, and the recording video signal taken out from the connection point between their emitter resistors R 5 and R 6 is transferred to the drain of the field effect transistor Q 7 . is applied to Here, during a period of a little over one field during which the video head H (this is any one of the heads A to D) slides and scans the magnetic tape, the input terminal 19
Since the NPN transistor Q 8 is turned on by the high level signal input to the transistor and divided by the resistors R 8 and R 9 , the field effect transistor Q 7 is also turned on. Thereby, the recording video signal is supplied to the head H through the field effect transistor, the resistor R 10 , the capacitor C 3 and the rotary transformer RT, and is thereby recorded.
なお、第６図示の回路は各ヘツドの記録信号伝
送路毎に計４回路設けられており、またQ7及び
これに相当する他の３つの電界効果トランジスタ
も、第４図に示すトランジスタQ2A〜Q2Dと同様
にスイツチング制御されるため、オーバーラツプ
記録をすることができる。 A total of four circuits of the circuit shown in FIG. 6 are provided for each recording signal transmission path of each head, and Q 7 and the other three field effect transistors corresponding thereto are also replaced by the transistor Q 2A shown in FIG. 4. ~Q Since switching is controlled in the same way as 2D , overlapping recording is possible.
なお、アナログスイツチを構成するトランジス
タQ2A〜Q2D，Q7のエミツタ又はソースと接地と
の間に、従来は1KΩ程度の抵抗を接続していた
が、上記の各実施例ではこれを省いている。これ
により、部品点数を削減できると共に、アナログ
スイツチがオンからオフしたとき、コンデンサ
C1A〜C1D，C3に蓄積されていた電荷が放電し、放
電電流がロータリートランスRTA〜RTD，RTに
流れるのを防止することができ、しかもアナログ
スイツチが高速でスイツチングされるため上記コ
ンデンサが放電しきらず、出力のDC値を略一定
に保つことができる。 Note that conventionally, a resistor of about 1KΩ was connected between the emitter or source of transistors Q 2A to Q 2D and Q 7 that constitute the analog switch and ground, but this was omitted in each of the above embodiments. There is. This reduces the number of parts, and when the analog switch turns from on to off, the capacitor
The charges accumulated in C 1A to C 1D and C 3 can be discharged and the discharge current can be prevented from flowing to the rotary transformers RT A to RT D and RT, and the analog switches can be switched at high speed. The capacitor is not completely discharged, and the DC value of the output can be kept approximately constant.
効 果
上述の如く、本発明によれば、回転体に90゜等
間隔角度で取付けられた４個の磁気ヘツドを、こ
の回転体に270゜強の角度範囲に亘つて添接巻回さ
れた磁気テープ上に映像信号を１フイールド強の
期間ずつ順次に切換えて記録しているため、或る
磁気ヘツドにより記録形成されるトラツクの終り
の一定期間と、次に別の磁気ヘツドにより記録形
成される隣接トラツクの始めの一定期間とに夫々
同じ区間の映像信号をオーバーラツプ記録でき、
従つて、この磁気テープを別の磁気記録再生装置
で再生してもヘツド切換位置付近で再生映像信号
の一部欠落を生ずることを防止することができる
等の特長を有するものである。Effects As described above, according to the present invention, four magnetic heads attached to a rotating body at equal angles of 90° are attached and wound around the rotating body over an angular range of over 270°. Since the video signal is recorded on the magnetic tape by switching sequentially for a period of just over one field, there is a certain period at the end of a track recorded by one magnetic head, and then a certain period of time at the end of a track recorded by another magnetic head. The video signal of the same section can be recorded overlappingly with the beginning fixed period of the adjacent track.
Therefore, even if this magnetic tape is reproduced by another magnetic recording/reproducing device, it is possible to prevent a portion of the reproduced video signal from being omitted near the head switching position.
第１図は本発明装置に適用し得る本出願人が先
に提案したヘツド配置関係の一例を示す図、第２
図は第１図の各ヘツドの走査軌跡を示す図、第３
図は第１図図示ヘツドによる記録トラツクパター
ンの一例を示す図、第４図は本発明装置の一実施
例を示す回路図、第５図Ａ〜Ｅは夫々第４図図示
回路の記録時の動作説明用タイムチヤート、第６
図は本発明装置の要部の他の実施例を示す回路図
である。
１……回転体、２……磁気テープ、１１……記
録用映像信号入力端子、１２……記録用増幅器、
１３Ａ〜１３Ｄ……スイツチング信号入力端子、
１７Ａ〜１７Ｄ……前置増幅器、１８Ａ〜１８Ｄ
……再生信号出力端子、Ａ，Ｂ，Ｃ，Ｄ，Ｈ……
磁気ヘツド（ビデオヘツド）、Q7……電界効果ト
ランジスタ。
FIG. 1 is a diagram showing an example of the head arrangement relationship previously proposed by the applicant that can be applied to the device of the present invention, and FIG.
The figure shows the scanning locus of each head in Figure 1, and Figure 3 shows the scanning locus of each head.
The figures show an example of a recording track pattern by the head shown in Fig. 1, Fig. 4 is a circuit diagram showing an embodiment of the apparatus of the present invention, and Figs. Time chart for operation explanation, No. 6
The figure is a circuit diagram showing another embodiment of the main part of the device of the present invention. 1... Rotating body, 2... Magnetic tape, 11... Recording video signal input terminal, 12... Recording amplifier,
13A to 13D...Switching signal input terminal,
17A-17D...Preamplifier, 18A-18D
...Reproduction signal output terminal, A, B, C, D, H...
Magnetic head (video head), Q7 ...field effect transistor.
Claims (1)
されており、かつ、４個のヘツドが夫々90゜等間
隔で取付けられた回転体を、記録再生すべき映像
信号の１フイールド期間当り270゜回転する回転数
で回転させて記録再生を行なう磁気記録再生装置
において、 記録用増幅器の出力端と該４個のヘツドの入力
端との間に夫々設けられた互いに独立してスイツ
チング制御される４個の第１のスイツチと、 該４個の第１のスイツチの出力端と接地との間
に設けられ記録時は常時オフされ再生時は常時オ
ンされる４個の第２のスイツチと、 記録時は記録すべき映像信号の１フイールド期
間よりもやや長い所定期間ずつ該４個の第１のス
イツチを順次オンとして該記録用増幅器の出力映
像信号をオンとされた該第１のスイツチに接続さ
れた一の該ヘツドに供給させ、かつ、該４個の第
１のスイツチのうち現にオンとされている第１の
スイツチのオン期間の終りの一定期間と次にオン
とされるべき第１のスイツチのオン期間の始めの
該一定期間とが夫々重複するように該４個の第１
のスイツチをスイツチング制御し、再生時は該４
個の第１のスイツチを常時オフにする第４個の第
３のスイツチと、 該４個のヘツドの出力端と接地との間に設けら
れ、記録時は常時オンされ、再生時は１フイール
ド期間ずつ時分割的にスイツチング制御される４
個の第４のスイツチとを具備し、 該４個の第２のスイツチを常時オフし、該４個
の第１のスイツチを順番に前記所定期間ずつ順次
にオンして前記磁気テープ上に該所定期間ずつ映
像信号が記録されたトラツクを記録形成すること
を特徴とする磁気記録再生装置。[Scope of Claims] 1. A rotating body on which a magnetic tape is wound over an angular range of more than 270 degrees, and four heads are mounted at equal intervals of 90 degrees, is used to record and reproduce images. In a magnetic recording and reproducing device that performs recording and reproducing by rotating at a rotation speed of 270 degrees per one field period of a signal, mutually connected Four first switches that are independently controlled, and four switches that are installed between the output terminals of the four first switches and the ground and are always turned off during recording and always turned on during playback. During recording, the output video signal of the recording amplifier is turned on by sequentially turning on the four first switches for a predetermined period slightly longer than one field period of the video signal to be recorded. is supplied to one of the heads connected to the first switch connected to the first switch, and for a certain period of time at the end of the on period of the first switch that is currently turned on among the four first switches, and the next one. The four first switches are switched on so that the fixed period at the beginning of the on period of the first switch that is to be turned on overlaps with each other.
Switching control is performed on the switch of the corresponding 4 during playback.
Four third switches are provided between the output terminals of the four heads and the ground, and are always on during recording, and one field switch during playback. Switching is controlled in a time-division manner for each period 4
and four fourth switches, the four second switches are turned off at all times, and the four first switches are sequentially turned on for each of the predetermined periods to record the magnetic tape on the magnetic tape. A magnetic recording/reproducing device characterized in that it records and forms tracks on which video signals are recorded for each predetermined period.
Priority Applications (9)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP57202603A JPS5991783A (en) | 1982-11-18 | 1982-11-18 | Magnetic recorder and reproducer |
| AU21353/83A AU558680B2 (en) | 1982-11-18 | 1983-11-15 | 4-head type v.t.r. signal switching |
| FR8318350A FR2536619B1 (en) | 1982-11-18 | 1983-11-17 | RECORDING / REPRODUCING SIGNAL SWITCHING SYSTEM FOR A FOUR-HEADED RECORDING AND REPRODUCING APPARATUS |
| US06/552,721 US4614985A (en) | 1982-11-18 | 1983-11-17 | Recording/reproduced signal switching system for a 4-head type recording and reproducing apparatus |
| KR1019830005494A KR890000356B1 (en) | 1982-11-18 | 1983-11-18 | Magnetic recording reproducing apparatus |
| GB08330788A GB2132403B (en) | 1982-11-18 | 1983-11-18 | Recording/reproduced signal switching system for a 4-head type recording and reproducing apparatus |
| DE3341644A DE3341644C2 (en) | 1982-11-18 | 1983-11-18 | Recording / reproducing signal switching system for a 4-head type recording and reproducing apparatus |
| BR8306353A BR8306353A (en) | 1982-11-18 | 1983-11-18 | RECORDING AND REPRODUCED SIGNAL SWITCHING SYSTEM |
| MY87295A MY8700295A (en) | 1982-11-18 | 1987-12-30 | Recording/reproduced signal switching system for a 4-head type |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP57202603A JPS5991783A (en) | 1982-11-18 | 1982-11-18 | Magnetic recorder and reproducer |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5991783A JPS5991783A (en) | 1984-05-26 |
| JPH0311598B2 true JPH0311598B2 (en) | 1991-02-18 |
Family
ID=16460170
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP57202603A Granted JPS5991783A (en) | 1982-11-18 | 1982-11-18 | Magnetic recorder and reproducer |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5991783A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS62279502A (en) * | 1986-05-28 | 1987-12-04 | Victor Co Of Japan Ltd | Magnetic recording/reproducing device |
| JP2615899B2 (en) * | 1988-09-01 | 1997-06-04 | 松下電器産業株式会社 | Recording and playback device |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5683811A (en) * | 1979-12-13 | 1981-07-08 | Matsushita Electric Ind Co Ltd | Magnetic recording and reproducing device |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS56424Y2 (en) * | 1975-04-22 | 1981-01-08 |
-
1982
- 1982-11-18 JP JP57202603A patent/JPS5991783A/en active Granted
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5683811A (en) * | 1979-12-13 | 1981-07-08 | Matsushita Electric Ind Co Ltd | Magnetic recording and reproducing device |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5991783A (en) | 1984-05-26 |
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