JPS61182609A - Write circuit - Google Patents

Abstract

PURPOSE:To shift a peak at the side of a magnetic recorder and to correct the timing of information by detecting information for showing the minimum current inverting interval of recorded information and reducing the current amplitude in the minimum current inverting section after receiving the signal of the information. CONSTITUTION:The inversion timing b' of a current flowed into the coil of a magnetic head is applied to the inverter 12 of a write circuit, an OR circuit 15 and a delay circuit 20. A signal d' from the circuit 15 is applied to a re- triggerable monostable multiplexer 14, and an output f' and a signal e' from the circuit 20 are ORed at an OR circuit 16 and an AND circuit 17 and outputs h' and g' are applied to an SR-FF18. A signal i' at a high level, where the pulse interval of a memory information signal is taumin, is outputted to the output Q of the FF18, and applied as the current limiting signal of the coil 5 to a diode connection TR24 connected to switching transistors TRs 2 and 3 through a diode 21. The signal e' from the circuit 20 is applied to the TRs 2 and 3 through buffers 22 and 23, thereby correcting the timing of the memory informa tion.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a write circuit for a magnetic LE device, and more particularly, to a write circuit for correcting a timing shift when reproducing data recorded on a magnetic recording medium.

[Conventional technology]

In a magnetic recording device, a data word to be recorded is converted into a code word, and the code word is used to form a busy magnetization reversal in the magnetic recording medium 1 to record data. At this time, if two adjacent magnetization reversals with the shortest magnetization reversal interval (Ttnis) are located a little farther apart than other magnetization reversals, a large peak shift occurs in the read waveform.

A normal write circuit consists of a magnetic head drive circuit having a configuration as shown in the taS diagram (-). It is a 1-digit D7 lip-flop, 2.3 is a switching transistor, 4 is a constant current source, and 5-digit magnetic to 9-digit winding. When a sickle information signal like () in Figure 3 is applied to the OPm child of the D flip-flop dub, the switching transistors 2.3 alternately switch to KO? An alternating current shown in FIG. 185(c) flows through winding IIIK of the l10FFL magnetic head. In this case, in the magnetization reversal on the magnetic recording medium formed by current reversals 6 and 7, a peak shift occurs in the direction of the arrow in the figure during reading and writing. Conventionally, in order to correct the timing deviation caused by this peak shift, as disclosed in Japanese Patent Application Laid-open No. 12115/1983, the recorded information signal in FIG. 3(b) was changed to the recorded information signal in FIG. 3(d). #c As shown, make sure to correct the timing # in the opposite direction to the direction in which the peak shift occurs.

[Problems to be Solved by the Invention] In such a conventional method, it is necessary to correct the timing of the recording information signal that is input to the write circuit. However, some interfaces of magnetic recording devices supply a recording information signal that provides the timing of current reversal from outside the magnetic recording device. floppy m-disk
This corresponds to a drive interface, a standard interface for small-diameter hard disk drives (sT-SA6 interface), and the like. In these interfaces, the detailed timing correction of the peak shift correction must be performed outside the magnetic recording apparatus, specifically 1'c, by the control device of the magnetic recording apparatus.

However, the optimal value of the timing correction amount described above differs depending on the magnetic head, magnetic recording device, and readout circuit. Therefore, it is natural that the optimum value of the timing correction number will be different for magnetic recording devices of different designs, and the control device of the magnetic recording device will have to set the optimum amount of correction for different models or magnetic recording devices of different manufacturers. To respondb
Although it is desirable, the reality is that it is complicated, so a fixed timing correction amount is applied to every magnetic recording device. There are no busy circumstances.

Wood f! ! 4 is intended to receive a recorded information signal without timing correction and perform peak shift correction to eliminate such defects.

Ninth Means for Solving Problem C] The present invention provides a magnetic recording device comprising a magnetic head drive circuit that receives a recording information signal that provides timing for reversing the current flowing through a magnetic head and alternately reverses the current. In the write circuit, a shortest inversion interval detection circuit receives the recording information signal and detects in advance the position of the shortest inversion interval of the current, and a shortest inversion interval detection circuit receives the signal from the shortest inversion interval detection circuit and detects the shortest inversion interval of the current. In addition, a current amplitude control circuit is provided to reduce the amplitude of the current.

[Effect]

According to the above configuration of the present invention, the peak shift can be corrected by reducing the current amplitude at the shortest current reversal interval.

〔Example〕

The present invention will be explained in detail with reference to FIGS. 1 and 2. Figure 1 is a circuit diagram showing an embodiment of the present invention.
2 is a diagram of signal waveforms for explaining the operation of the circuit shown in FIG. 1;

In the first voltage, 12 is an inverter, 13 and 14 are retriggerable monostable multivibrators, and the oscillation pulse width is approximately t1 times the shortest magnetization reversal interval Tm1n.

15 and 16 are an OR circuit and a 17-digit AND circuit. 18
is an 8-R flip-flop dub, and ? ? #: tD7 lip 70 lip. 20 is a delay element that provides a delay time approximately 1.5 times T tn,in. It is a switching element with 21 open collector outputs, and 22 and 23 buffers.

2 and 3#: t switching transistor, D
Q N10 alternately after receiving the signal of 7supufu ptsubu 19
F1! An alternating current is passed through the winding 5 of the IL magnetic head.

This is an ordinary constant current circuit composed of a transistor 24, a Zener diode 25, a diode 26, and resistors 27 and 28. It is a winding of 29 resistors and 5 magnetic heads.

The operation of this embodiment will be explained below with reference to () to (2) in FIG. #r1 Figures (M) to (A) are signal waveforms at points VC (65 to (00) in the circuit diagram of the tai diagram, respectively.

) in FIG. 2 is a recording information signal that provides the timing of current reversal. In this description, an encoding method (for example, MFM) in which the pulse interval of the recording information signal is Tm1n, 15 times Tm1n, and twice Tm1n is taken as an example.

The recording information signal of the monostable multivibrator 13 is triggered at the rising edge of FIG. It will look like Figure 2 cc). In Figure 2 (C), the delay caused by the inverter 12 and monostable multivibrator 13 is emphasized to make the explanation easier to understand. As a result, the output of the OR circuit becomes as shown in Figure 2, and this output is applied to the recorded information signal at an interval T.
When there is one pull-in, it becomes a turret that emits one pulse. The output QFi of the retriggerable monostable multivibrator 14, which uses the output of this OR@ path 15 as a signal, becomes the signal shown in FIG. 1 (G). On the other hand, the recording information signal that has passed through the delay element 20 is delayed by approximately 15 T min.
It's busy as shown in Figure 42 (S+). Therefore, the output of the AND circuit 17 is as shown in FIG. 2, and the output of the OR circuit 16 is as shown in FIG. The output of the R-87 bus 18, which is set and reset as both of them are busy falling, becomes Fig. 1 (ffl), and the pulse interval of the recording information signal shown in Fig. 112 (#) is 7 m 1 fL. Only the current signal is at high level, and this becomes the signal that controls the current amplitude. The recording information signal of FIG. 2(g) is passed through the D7 lip-flop 19 to the switching transistors 2 and 3.
The current waveform flowing when ON10PIPL is as shown in Fig. 2 σ). When the control signal shown in FIG. 2(i) is at a low level, the switching element 21 with the open collector output is turned off. Therefore, it does not affect the current source constituted by the transistor 24, but when this control signal is no-repel, the switching element z1bt turns ON and the resistor 29
When the current source becomes grounded, part of the current b' of the current source is diverted to the low resistance 9, and the current flowing through the magnetic winding 5 is reduced. Therefore, in Fig. 2G) k, the current reversal interval is T.
The amplitude of the current in the portion where tniti is small becomes small.

In this way, by reducing the current amplitude when the current reversal interval becomes Ttnin, the peak shift can be corrected. This phenomenon will be explained with reference to FIG. As shown in Fig. 4), if the amplitude of the countercurrent inversion wake is larger than
In the situation shown in ) in the figure, the magnetization reversal position 30 is shifted to a position 31 when the positive and negative amplitudes of the current are equal. In the opposite case, move backwards. This amount of deviation can be set to an optimal value by adjusting the difference in current amplitude before and after inversion. That is, by setting the value of the resistor 29, optimum peak shift correction can be easily performed. It should be noted that although the dormitory example will be described here, it is not limited thereto.

〔Effect of the invention〕

In addition to the above, the present invention provides the shortest recording information signal 11) IF
By installing a shortest reversal interval detection circuit that extracts information indicating the reversal interval, and a current amplitude control circuit that reduces the current amplitude at the shortest reversal interval of the current based on the signal of the shortest reversal interval detection circuit, It is possible to receive a recording information signal whose timing has not been corrected from outside the magnetic recording device and to correct the peak shift at the side of the magnetic recording device.

Furthermore, compared to peak shift correction using conventional timing correction, correction based on current amplitude difference allows the correction amount to be set more easily, making it easier to optimize the peak shift correction amount.

As a result, Katsutomo is now able to bring out the full performance of magnetic recording devices, compared to conventional methods that required fixed amount timing correction. In addition, the control device of the magnetic recording device no longer needs to perform timing correction, reducing the burden on it.

[Brief explanation of the drawing]

Figure fa1 is a diagram showing an embodiment of the write circuit of the present invention. ) to (j) in FIG. 2 are timing charts illustrating the operation of the embodiment. FIGS. 3(tL) to 3(tL) are explanatory diagrams of a conventional write λ circuit and timing correction method. The fourth review (b) is an explanatory diagram of the principle of P-multishift correction according to the present invention. 1...D flip-flop 2.3...Switching transistor 4...
... Constant current source 5 ... Magnetic head winding 6.7 ... Current reversal interval 12 ... Inverter 13.14 ... Re-trigger Possible monostable multivibrator 15, j6...OR circuit 17...AND circuit 18...S-R flip-flop 19...
...D7 lip-flop 20...Delay element 21...Open collector switching element 22,23...Parameter 24...Transistor 25...・Zena diode 26...Diode 27, 28.29...Resistance! 10.31... Magnetization reversal position tool Genjin Kamide Suwa Seikosha Co., Ltd. Figure 2

Claims (1)

[Claims] In a write circuit of a magnetic recording device that includes a magnetic head drive circuit that receives a recording information signal that provides timing for reversing the current flowing through the magnetic head and alternately reverses the current, the current is shortest in response to the recording information signal. a shortest reversal interval detection circuit that detects in advance the position of the reversal interval;
A write circuit comprising: a current amplitude control circuit that receives a signal from the shortest reversal interval detection circuit and reduces the amplitude of the current at the shortest reversal interval of the current.