JPH0467244B2 - - Google Patents

Description

[Detailed Description of the Invention] (a) Technical Field of the Invention In a method for reproducing data written on a disc-shaped magnetic recording medium, waveform shaping is performed based on physical position information of a magnetic head on the magnetic recording medium. The present invention relates to a magnetic recording/reproducing device that changes the slice level of a circuit.

(b) Background of the technology The recording density of data written on a disc-shaped magnetic recording medium differs depending on the physical position on the recording medium. For example, in the case of a magnetic disk, there is a difference of approximately twice the recording density between the innermost side and the outermost side of the magnetic disk.

Under these conditions, the output level and resolution of the data reproduction signal differ depending on the physical position on the magnetic recording medium, so it is possible to perform optimal reproduction that matches the conditions of the physical position on the magnetic recording medium. There is a desire to realize a magnetic recording/reproducing device.

(c) Prior art and problems The prior art and problems will be explained with reference to the drawings.

FIG. 1 shows reproduction signal waveforms by a conventional magnetic recording and reproducing device, where A is an analog reproduction signal on the inner side of the disk-shaped magnetic recording medium, B is an analog reproduction signal on the outer side of the disk-shaped magnetic recording medium, and C is an analog reproduction signal on the outer side of the disk-shaped magnetic recording medium. 1 shows an outer reproduction signal of a pattern with a long bit interval, and D shows an outer reproduction signal obtained by reading a very small defect on a disc-shaped magnetic recording medium.

In the figure, 1 is the outer side analog playback signal A, 2 is the differential waveform, 3 is the pulse waveform A, 4 is the outer side analog playback signal B, 5 is the pulse waveform B, and a.
indicates a zero crossing point, and b indicates a defective portion.

In the figures, the analog reproduction signal waveforms in Figures A and B are general analog reproduction signal waveforms, and the reproduction signal waveforms in Figures C and D are reproduction signal waveforms that may cause problems, and the analog reproduction signal waveforms on the outer side are typical reproduction signal waveforms. is the outer side analog playback signal waveform with a long bit interval pattern, pulse waveform A3 is the pulse waveform of the outer side analog playback signal A1, and outer side analog playback signal B4 is the waveform of the outer side analog playback signal with a pattern with a long bit interval. The read outer side reproduction signal waveform and pulse waveform RO 5 respectively show the pulse waveform of the outer side analog reproduction signal RO 4.

As mentioned above, since the recording density is different between the outer side and the inner side of the disk-shaped magnetic recording medium, the reproduced signals are also different as shown in FIGS. 1A and 1B. Under such conditions, the reproduction signal on the inner side and the reproduction signal on the outer side will have different output levels and resolutions. That is, the closer to the outer side the better the characteristics become.

However, as the resolution improves, as shown in Figure 1C, the outer analog playback signal I1, which has a pattern with a long bit interval, becomes flat between bits, and when the data read signal is differentiated, zero crossings occur in the differential waveform 2. Point a is made,
For this reason, even if an increase in bits occurs or a very small defect occurs on the magnetic recording medium, the resolution on the outer side is good, so this defect will be clearly reproduced as defect part b in the analog playback signal RO4 on the outer side. , if the slice level is constant, there is a possibility of a data error.On the other hand, on the inner side, the level of the reproduced signal decreases due to peak shift, etc., so it is difficult to reproduce data if the slice level is constant. There is.

(d) Purpose of the Invention The object of the present invention is to provide a novel magnetic recording/reproducing device that eliminates the above-mentioned drawbacks, and in particular, a signal is transmitted from a magnetic recording medium to a waveform shaping circuit that pulses an analog waveform of a reproduced signal. Based on the physical position information on the magnetic recording medium of the magnetic head being played,
By changing the slice level of the noise removal circuit of the waveform shaping circuit and reproducing the reproduced data, the disadvantages in data reproduction due to the physical position on the magnetic recording medium can be removed, and highly reliable data can be reproduced. The goal is to realize a playback device.

(e) Structure of the Invention The present invention is a magnetic recording and reproducing device equipped with a waveform shaping circuit that pulses an analog waveform signal obtained by reproducing data written on a disk-shaped magnetic recording medium by a magnetic head, and By providing a circuit that changes the slice level of the noise removal circuit section of the waveform shaping circuit to n stages based on the physical position information on the magnetic recording medium of the magnetic head that has read the waveform signal, the magnetic recording medium can be This can be achieved by using a magnetic recording and reproducing device that eliminates the above-mentioned disadvantages in data reproduction due to the physical location and can reproduce data with high reliability.

(f) Examples of the invention The present invention will be explained below with reference to the drawings.

FIG. 2 shows an embodiment of the magnetic recording and reproducing apparatus according to the present invention, where A shows a block diagram of the magnetic recording and reproducing apparatus, and B shows an outline of the operation of A.

In the figure, 6 is a differential circuit, 7 is a pulse generator, 8 is a flip-flop circuit, 9 is a slice circuit, 10 is a decoder circuit, and 11 is a slice level generation circuit. In the figure, ~
are the reproduced signal waveforms at each position in the block diagram of the magnetic recording/reproducing device, CLY n, CLY 0××, CLY
2xx indicates a signal representing the physical cylinder position on the magnetic recording medium, and a indicates a very small defect portion on the magnetic recording medium.

This device includes a differentiating circuit 6 that differentiates the reproduced analog input signal and converts the peak signal of the reproduced analog input signal into a zero-crossing signal, and a differentiating circuit 6 that converts the input waveform from the differentiating circuit 6 into pulses and outputs the pulse output waveform to the flip-flop circuit 8. pulsing circuit 7,
A flip-flop circuit 8 outputs the pulse output waveform input from the pulse generation circuit 7 to a demodulation circuit (not shown) using a clock pulse of the slice output waveform from the slice circuit 9; A slicing circuit 9 that slices and pulses at a constant level according to a level signal and outputs a clock pulse with a slice output waveform to the flip-flop circuit 8, and magnetic recording from a magnetic head positioning control circuit (not shown) to a magnetic head (not shown). A decoder circuit 1 receives a cylinder position signal representing a physical position on a medium (not shown) and translates it into an input signal to a slice level generation circuit 11.
0, n depending on the input signal from the decoder circuit 10
It consists of a slice level generation circuit 11 that generates slice levels divided into stages.

Assume that a reproduced analog input signal having a tiny defect a on a magnetic recording medium (not shown) is read and input to the differentiating circuit 6 and the slicing circuit 9.
The peak signal of the reproduced analog input signal inputted to the differentiating circuit 6 is converted into a zero-crossing signal as shown in FIG. Output to.

On the other hand, CLY 0 is a cylinder position signal representing the physical position of a magnetic head (not shown) that is reproducing data on a magnetic recording medium (not shown).
XX, CLY 2XX, CLY n are outputted from a magnetic head positioning control circuit (not shown) to a decoder circuit 10, and the decoder circuit 10 translates these input signals and outputs them to a slice level generation circuit 11. The slice level generation circuit 11 creates a slice level according to the input signal (creates slice levels divided into n stages) and outputs it to the slice circuit 9.

The slice circuit 9 removes unnecessary portions such as noise that do not reach the slice level inputted from the slice level generation circuit 11 from the reproduced analog input signal, and outputs a pulsed slice output waveform to the flip-flop circuit 8.

The flip-flop circuit 8 outputs the output waveform Q of the flip-flop circuit 8 to a demodulation circuit (not shown) in response to the clock pulse of the slice output waveform from the pulse output waveform from the pulse generation circuit 7.

As described above, the redundant waveform of the defective portion a reproduced in the pulse output waveform is removed because it does not match the slice output waveform depending on the combination conditions, and only the necessary data waveform is reproduced and output.

(g) Effects of the invention As described above, by changing the slice level of the noise removal circuit section of the waveform shaping circuit to n stages based on the physical position information of the magnetic head on the magnetic recording medium and reproducing the reproduced data, Eliminating drawbacks in data reproduction due to physical location on magnetic recording media,
This has the effect of providing a magnetic recording and reproducing device that can reproduce highly reliable data.

[Brief explanation of the drawing]

FIG. 1 shows a reproduced signal waveform by a conventional magnetic recording/reproducing device, and FIG. 2 shows an embodiment of the magnetic recording/reproducing device according to the present invention. In the figure, 1 is the outer analog playback signal A, 2 is the differential waveform, 3 is the pulse waveform A, 4 is the outer analog playback signal B, 5 is the pulse waveform B, and 6
1 is a differential circuit, 7 is a pulse generation circuit, 8 is a flip-flop circuit, 9 is a slice circuit, 10 is a decoder circuit, and 11 is a slice level generation circuit.

Claims (1)

[Claims] 1. A magnetic recording and reproducing device equipped with a waveform shaping circuit that pulses an analog waveform signal obtained by reproducing data written on a disk-shaped magnetic recording medium by a magnetic head, the magnetic head reading the analog waveform signal. 1. A magnetic recording/reproducing apparatus comprising: a circuit for changing a slice level of a noise removal circuit section of the waveform shaping circuit based on physical position information on the magnetic recording medium.