JPS62141676A - Magnetic recording and reproducing circuit - Google Patents

Abstract

PURPOSE:To distinguish reproduced signals of high density recording with fidelity by adding a time reference signal (synchronizing signal) to recording signals at the time of magnetic recording, and oscillating a variable frequency oscillating circuit (VFO circuit) by reproducing synchronizing signal voltage. CONSTITUTION:Recording signals 1 are inputted to a modulating circuit 2 in a recording circuit, and time compressed information signals 3 and synchronizing signals 4 utilized for a VFO circuit are generated. Input signals 28' produced in a reproducing circuit are the same in relative positional relation with the synchronizing signals 4 obtained by the modulating circuit 2 at the time of recording, and accordingly, the VFO circuit 31 can output an exact distinguishing window signals 32. The synchronizing signals are recorded in lower frequency compared with the information signals, and the synchronizing signals in the reproduced signals become larger reproduction voltage compared with the information signals, and accordingly, the separation of the synchronizing signals and information signals becomes easy, and the reproduction of high density recording becomes possible.

Description

【発明の詳細な説明】 〔発明の利用分野〕 本発明は磁気記録装置に係り、特に高密度記録に好適な
記録再生回路に関する。DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a magnetic recording device, and particularly to a recording/reproducing circuit suitable for high-density recording.

〔発明の背景〕[Background of the invention]

磁気記録装置において磁化された記録媒体はモータ等に
よって駆動されるためその再生信号は記録時のような正
確な時間間隔としては得られず、モータの回転むら、記
録媒体の膨縮等に影響された信号となる。このため従来
とられている方法としては特開昭５２−１２３２１４号
に記載のように再生信号に同期した周波数で発振する発
振回路、すなわち可変周波数発振回路（以下ＶＦＯ回路
と称す）　（Ｖａｒｉａｂｌｅ　Ｆｒｅｑｕｅｎｃｙ　
０ｓｃｉｌｌａｔｏｒ　）が用いられ再生信号中に営ま
れる信号部分を分離、すなわち弁別を行ってきた。しか
るに記録密度が上がることによって再生信号の時間間隔
に影響を与える因子として、先に上げたモータの回転む
ら、記録媒体の膨縮なと外部的要因だけでなく高密度記
録そのものに起因するパターンピークシフト、再生電圧
低下に伴うＳ／Ｎ比の悪化による影響が大きな割合をし
めてきた。そのため従来の再生信号を利用したＶＦＯ回
路はその影響を直接受けるため、信号再生の信頓度を上
げるうえで一定の限界が出てくることがさけられないも
のとなってきた。In a magnetic recording device, the magnetized recording medium is driven by a motor, etc., so the reproduced signal cannot be obtained at accurate time intervals as during recording, and is affected by uneven rotation of the motor, expansion and contraction of the recording medium, etc. It becomes a signal. For this reason, the conventional method is to use an oscillation circuit that oscillates at a frequency synchronized with the reproduced signal, as described in Japanese Patent Application Laid-Open No. 52-123214, that is, a variable frequency oscillation circuit (hereinafter referred to as a VFO circuit).
0scillator) has been used to separate, ie, discriminate, the signal portions present in the reproduced signal. However, as the recording density increases, factors that affect the time interval of the reproduced signal include not only external factors such as the aforementioned uneven rotation of the motor and expansion and contraction of the recording medium, but also pattern peaks caused by high-density recording itself. The influence of deterioration of the S/N ratio due to shifts and reductions in reproduction voltage has accounted for a large proportion. For this reason, conventional VFO circuits using reproduced signals are directly affected by this, and it has become inevitable that certain limits will arise in increasing the reliability of signal reproduction.

〔発明の目的〕[Purpose of the invention]

本発明は上述の如き欠点を除き、筒密度記録の再生信号
を忠実に弁別することに好適な記録再生回路を提供する
ことにある。An object of the present invention is to provide a recording/reproducing circuit suitable for faithfully discriminating reproduction signals of cylindrical density recording, while eliminating the above-mentioned drawbacks.

〔発明の概要〕[Summary of the invention]

本発明は記録信号の周波数によって、記録電流に対する
再生読出電圧の飽和値が異なることに着目し、ＶＦＯ回
路に専用の時間基準信号（以下同期信号）を記録信号中
に低い周波数で加え、大きな再生同期信号電圧でＶＦＯ
回路を高精匿で発振させ、高い弁別信頼度を得ることを
特徴としている。The present invention focuses on the fact that the saturation value of the reproduction readout voltage with respect to the recording current differs depending on the frequency of the recording signal, and by adding a dedicated time reference signal (hereinafter referred to as a synchronization signal) to the VFO circuit at a low frequency into the recording signal, a large reproduction VFO with synchronous signal voltage
It is characterized by highly precise oscillation of the circuit and high discrimination reliability.

〔発明の実施例〕[Embodiments of the invention]

本発明の実施例を第１図〜第３図によって説明する。第
１図は記録回路を示し、第２図は再生回路を示す。第３
図は第１図、第２図中の信号をタイムチャートで示して
いる。Embodiments of the present invention will be described with reference to FIGS. 1 to 3. FIG. 1 shows a recording circuit, and FIG. 2 shows a reproducing circuit. Third
The figure shows the signals in FIGS. 1 and 2 in the form of a time chart.

第１図において記録信号１は変調回路２に入力される。In FIG. 1, a recording signal 1 is input to a modulation circuit 2. In FIG.

変調回路の目的は記録信号１を時間的に圧縮した情報信
号５と、後述する■℃回路に利用される同期信号４を生
成することである、ＮＯＲゲート５によって生成された
信号６はトリガラブルＦＦ７によって７′の信号となる
。一方同期信号４もトリガラブルＦＦ９に入力され、そ
の出力（ｇ号９′はトランジスタ１２をオンオフさせて
、電流源設定用抵抗Ｒ２を接続あるいはショートさせる
。従って記録ヘッド８に流れる電流Ｉ２−　Ｉ、は第３
図１１−１０で示す波形となる。The purpose of the modulation circuit is to generate an information signal 5 which is a temporally compressed recording signal 1, and a synchronization signal 4 used in the ■℃ circuit described later.The signal 6 generated by the NOR gate 5 is transmitted to the triggerable FF 7. This results in a signal of 7'. On the other hand, the synchronizing signal 4 is also input to the triggerable FF 9, and its output (g 9' turns the transistor 12 on and off, and connects or shorts the current source setting resistor R2. Therefore, the current I2-I flowing through the recording head 8 is Third
The waveform is shown in FIG. 11-10.

第２図において１５０波形は第３図１１−１０で示す記
録電流のため第５図１５で示す波形となる。In FIG. 2, the 150 waveform becomes the waveform shown in FIG. 5, 15 because of the recording current shown in FIG. 3, 11-10.

微分回路１６の出力波形１７はリミッタ２１によって２
１’、２１“の位置でスライスされ出力波形２３　、２
４を得る。一方、波形１５を増幅回路２９．ゼロクロス
回路３０をとおすことによって波形２５を得る。そして
ゲート回路２６　、２７　、２８によって”日゛Ｏ回路
の入力信号２８′が生成される。信号２８′は記録再生
回路によって得られた同期信号４に相対的な位置関係を
同一とする。従ってＶＦＯｕ路３１は正確な弁別窓信号
３２を出力することが出来る。The output waveform 17 of the differentiating circuit 16 is divided into 2 by the limiter 21.
Output waveforms sliced at positions 1' and 21'' 23 and 2
Get 4. On the other hand, the waveform 15 is transferred to the amplifier circuit 29. A waveform 25 is obtained by passing through a zero cross circuit 30. The gate circuits 26, 27, and 28 generate an input signal 28' for the "O" circuit. The signal 28' has the same relative position as the synchronizing signal 4 obtained by the recording/reproducing circuit. The VFOu path 31 can output an accurate discrimination window signal 32.

フィルタ１８．ゼロクロス回路１９．弁別復調回路２０
は従来技術で構成されている。Filter 18. Zero cross circuit 19. Discrimination demodulation circuit 20
is constructed using conventional technology.

〔発明の効果〕〔Effect of the invention〕

本発明によれば、情報信号に比較して同期信号が低い周
波数で記録されているため、再生信号中の同期信号は情
報信号罠くらべて大きな褥生電圧となる。このことの効
果は第１に同期信号と情報信号との分離が容易であるこ
と。第２に清報信号にくらべて重要性が高い同期信号が
、ノイズ等の影響を受けに（いこと。＠３に同期信号の
前後の磁化変化は比較的離れて（・るためその影響を受
けにくいことである。第４に従来性なわれてきた、隣接
した磁化変化相互間の影響を記録時に時間的に補償する
いわゆるライトコンペンセーションがさらに有効になっ
て（る。According to the present invention, since the synchronization signal is recorded at a lower frequency than the information signal, the synchronization signal in the reproduced signal has a larger pressure voltage than the information signal trap. The first effect of this is that it is easy to separate the synchronization signal and the information signal. Second, the synchronization signal, which is more important than the alert signal, is less susceptible to the effects of noise, etc. (@3) The magnetization changes before and after the synchronization signal are relatively far apart, so the effects are less affected by noise. Fourthly, so-called write compensation, which temporally compensates for the influence of adjacent magnetization changes during recording, which has been practiced in the past, has become more effective.

以上の効果によってさらに高密度の記録再生が可能とな
る。The above effects enable even higher density recording and reproduction.

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

第１図は本発明の一実施例の記録回路図、第２図は再生
回路図、第３図は第１図・第２図の主要部分の波形、タ
イムチャートである。 １・・・記・録侶号、　　　　２・・・変調回路、６・
・・情報信号、　　　　４・・・同期信号、５・・・Ｎ
ＯＲゲート、　　　６・・・ＮＯＲゲート出力、７・・
・情報信号ＦＦ、　　　８・・・記録ヘッド、９・・・
同期信号ＦＦ、　　１０・・・記録電流、１２・・・電
流値切替用トランジスタ、１３・・・再生ヘッド、　　
１４・・・前置増幅器、１６・・・微分回路、　　　１
８・・・フィルタ、１９・・・ゼロクロス回路、２０・
・・弁別復調回路、２１・・・リミッタ。 一＼FIG. 1 is a recording circuit diagram of an embodiment of the present invention, FIG. 2 is a reproduction circuit diagram, and FIG. 3 is a waveform and time chart of the main parts of FIGS. 1 and 2. 1...Recorder number, 2...Modulation circuit, 6.
...Information signal, 4...Synchronization signal, 5...N
OR gate, 6...NOR gate output, 7...
・Information signal FF, 8...recording head, 9...
Synchronization signal FF, 10... Recording current, 12... Current value switching transistor, 13... Playback head,
14... Preamplifier, 16... Differential circuit, 1
8... Filter, 19... Zero cross circuit, 20.
...Discrimination demodulation circuit, 21...Limiter. one\

Claims (1)

【特許請求の範囲】[Claims] １、磁気記録において、記録信号を低周波数の同期信号
と、高周波数の情報信号に変調し、前記同期信号は、情
報信号に比較して大きな記録電流を流す記録回路と、再
生においては同期信号と再生信号の再生電圧の違いによ
って同期信号と情報信号を分割し、前記同期信号によっ
てのみ情報弁別用の可変周波数発振器を同期することを
特徴とする磁気記録再生回路。1. In magnetic recording, a recording signal is modulated into a low-frequency synchronization signal and a high-frequency information signal, and the synchronization signal is used by a recording circuit that flows a large recording current compared to the information signal, and during reproduction, the synchronization signal is A magnetic recording/reproducing circuit characterized in that a synchronization signal and an information signal are divided based on the difference in reproduction voltage between the reproduction signal and the reproduction signal, and a variable frequency oscillator for information discrimination is synchronized only by the synchronization signal.