JPS6243872A - Magnetic recording and reproduction equalizing system - Google Patents

Abstract

PURPOSE:To apply a reproduction equalization with a small bit shift by adding inversely an original signal subjected to delay and attenuation to a differentiated reproduction signal. CONSTITUTION:The output of a reproduction amplifier is converted into a sufficiently low impedance by a buffer 1 and the result is branched into two. One signal is given to a differentiation circuit comprising a capacitor 3 and a resistor 4, the other is given to a delay element 6 via a resistor 5 and the delayed signal is attenuated by a variable resistor 7. A signal (b) obtained by differentiating the reproduction signal (a) and a signal (c) being the result of delayed and attenuated reproduction signal are given to a differential input amplifier 2, where they are added inversely to obtain a symmetrical reproduced waveform (d) and to decrease the bit shift.

Description

Detailed Description of the Invention (Industrial Application Minute Hand) The present invention is a device in which longitudinal magnetization mode and perpendicular magnetization mode coexist, such as in an isotropic medium or a perpendicular magnetic recording medium with insufficient perpendicular magnetic anisotropy. Reproduction equalization method for reducing bit shift in digital magnetic recording devices using media and ring-type magnetic heads (prior art and its problems) Perpendicular magnetic recording with isotropic media and insufficient perpendicular magnetic anisotropy In magnetic recording using a medium and a ring-type head, an asymmetrical reproduced waveform as shown in FIG. 2, where the fall is slower than the rise, is produced. Furthermore, even in longitudinal recording, if the orientation is insufficient or if recording is performed with a head that has a narrow gap compared to the thickness of the medium, a similar reproduced waveform will be observed.

When such an asymmetrical reproduced signal is demodulated by a conventional demodulation circuit (Fig. 3) using zero-point detection, its differential waveform becomes vertically asymmetric, as shown in Fig. 2 (bl), and bit shift occurs. This may cause an increase in errors.

(Object of the Invention) In view of the above point O), the present invention provides a differentiated reproduction signal,
By adding the delayed and attenuated reproduced signal in reverse phase,
(Structure of the Invention) The present invention is constructed by adding a delayed and attenuated original signal to a differentiated reproduced signal in reverse phase, thereby achieving reproduction equalization with a small bit shift. can be done.

(Outline of the invention I FIG. 1 is a block diagram showing the configuration of the invention.

A signal obtained by differentiating the reproduced signal [Fig. 2 (a)] [Fig. 2 (b)]
)], the reproduced signal is delayed and attenuated [Figure 2 (
C)] by a differential input amplifier in reverse phase, a symmetrical reproduced waveform [Fig. IIjIJ2 (d)] is obtained, and the bit shift is reduced.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings. ◎ Fig. 4 shows a concrete TN1 diagram of an example of the present invention. The output of the reproducing amplifier is converted into a sufficiently low impedance by the buffer l, and is branched into two. One side is connected to a differentiating circuit consisting of a 3309P capacitor 3 and a 500Ω resistor 4. The other end is connected to the delay element 6 through a resistor 5 having the same value as the characteristic impedance of the delay element 6, and the delayed signal is terminated at a volume 7 having the same value as the characteristic impedance of the delay element. , is attenuated by 1zrium. These two
The two signals are added in opposite phases by the differential amplifier 2.

1iiA Figure 0) The equalization circuit was applied to a digital recording device consisting of a Co-γFe1O medium with a magnetic layer thickness of 1°4 μIn, and a ring-shaped magnetic head with a gap length of 0.25 μm. The head/medium amount relative speed is 1 m/s.

FIG. 5 is a graph plotting the shift amount of the bit interval in the central l1 portion in the 101101 pattern against the recording density. The prior art shown in the figure was measured using the circuit shown in FIG. As can be seen from FIG. 5, according to the present invention, the bit shift amount can be reduced and the recording density can be increased.

(Effects of the Invention) According to the present formula of the present invention, bit shifts could be reduced to a high density.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of the present invention, and FIG. 2 is a diagram showing the waveform of the first section when a solitary wave is input. FIG. 3 is a block diagram of a conventional example. ◎FIG. 4 is a circuit diagram of an embodiment of the present invention. FIG. 5 is a diagram plotting the bit shift amount of the central 11 portions of the 101101 pattern in the present invention and the conventional example against the recording density. FIG. 6 is a circuit diagram of the conventional example. In Figure 4, 1 is a buffer, 2 is a differential amplifier, 3 is a capacitor, 4 and 5 are resistors, 6 is a delay element, and 7 is a volume. Waveform Figure 3 Part equivalent to the equivalent circuit Figure 4 Figure 5 D (kFRPI)

Claims (1)

[Claims] A magnetic recording/reproduction equalization method characterized in that bit shift is reduced by adding a delayed original signal in reverse phase to a differentiated reproduction signal in digital magnetic recording where the isolated reproduction waveform is asymmetric.