JPH01107307A - Flexible disk drive device - Google Patents

Abstract

PURPOSE:To prevent the occurrence of a read error extending to an inner and an outer circumference by preventing zero cross caused by a saddle strap occurring to a differential wave form at the outer circumference where resolution is high. CONSTITUTION:A differentiation circuit 4a detects the peak point of a wave form outputted from an amplification circuit and a band pass filter 3b eliminates the basic frequency (1f) component of recording frequency. As an odd number order higher harmonics (3f) component is set to be passed through, a noise component over 3f is eliminated. Then, the resolution is raised in a differentiation circuit 4b having an amplitude limiting function, the limiting function is operated at the outer circumference of a magnetic sheet and the amplitude of the differential wave form is controlled to be fixed. Besides, these differential output is composed by a composing circuit and made to be last differential output. Therefore, as the amplitude of the 3f component is limited, the zero cross caused by the saddle strap does not occur to the last differential outputted wave form. Thus, the resolution can be set to high and the occurrence of the read error can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a flexible disk drive device, and particularly to improving the performance of a flexible disk drive device.

[Conventional technology]

FIG. 2 shows a recorded information reading circuit in a conventional flexible disk drive device. In FIG. 2, +1) is a magnetic head that reads recorded information from a magnetic sheet, and C2) is an amplifier circuit that amplifies the output of the magnetic head.

(3) removes unnecessary noise components using a low-pass filter. (4! is a differentiating circuit that detects the peak point of the amplifier circuit output waveform. (5) is a comparator that detects the zero point of the differential waveform.
Outputs 11-to0 data at the cross point.

Next, the operation will be explained. The information recorded on the magnetic sheet is
Magnetic head blame! ) is converted into an electrical signal, and since it is a minute signal, it is amplified by an amplifier circuit (21) and then passed through a low-pass filter 4.
- removes high-frequency noise components and unnecessary signal components.

Thereafter, in order to detect the peak point of the signal waveform, it is differentiated by a differentiating circuit, and the low-pass filter J-+31 has a frequency three times the recording frequency (hereinafter referred to as "low-pass filter J-+31").

It's called 3f. ), the output waveform of the differentiator circuit has a depression (hereinafter referred to as a saddle) in the center. When reading the outer circumference of a magnetic sheet with high resolution, the saturation reaches Ov.

Since the Combare 4C5) outputs incorrect 1st summer code data, a reading error occurs. Furthermore, if the resolution is suppressed to such an extent that reading sherrer does not occur on the outer periphery, when reading the inner periphery of the magnetic sheet, reading@scheler will occur and it will be difficult to set zero resolution. [Problems to be solved by the invention] Conventional flexible・The disk stripe device is configured as described above, and the reading is performed on the outer periphery of the magnetic sheet [
Since the resolution was suppressed to such an extent that errors would not occur, reading errors were more likely to occur on the inner circumference where the resolution decreased.

This invention was made to solve the above-mentioned problems, and even if the resolution is increased by placing it on the outer periphery, the differential waveform will not cross zero, so the 9 resolution can be set high.
It is possible to provide a high-performance flexible disk drive that is resistant to the occurrence of read sheller.

[Means for solving problems]

The flexible disk drive device according to this invention includes:
The fundamental frequency of the recording frequency (hereinafter referred to as 1f) and the odd-numbered harmonics (hereinafter referred to as 3f) are differentiated using separate thread paths, and only the third frequency is given an amplitude of 11 mit, and the combined waveform is the final differentiated waveform. This is what I did.

[Effect]

By limiting the amplitude of the differential waveform in this invention by 3f&, the differential waveform will not cross zero even if the resolution is increased.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings. 1st
In the figure, (1) is a magnetic head that reads recorded information from a magnetic sheet, (2) is an amplifier circuit that amplifies the output of the magnetic head, and (3a) is a low-pass filter that removes the 3f component and unnecessary noise components. ing.

(4a) is a differentiating circuit that detects the peak point of the amplifier circuit output waveform. (3b) is a band pass filter that is set to remove the 1f component and pass the 3f component, so 3
Noise components exceeding f are removed.

(4b) is a differential circuit with an amplitude + 3 mit function, which increases the resolution.At the outer periphery of the magnetic sheet where the amplitude of the 3f differential waveform becomes thick, the I+ mit function works to keep the amplitude of the differential waveform constant. (51 is a synthesis circuit (4
The differential outputs of a) and (4b) are combined to form the final differential output. Since the 3f component has an amplitude of 1), zero crossings due to saturation do not occur in the final differential output waveform. (5) is a comparator which outputs 1-mode data at the zero-crossing point of the differential output waveform.

Next, the operation will be explained.

The output of the magnetic head (11 is 0) Normally, it is composed of the fundamental frequency 1f and its harmonic components, and the waveform of each part for the signal consisting of the fundamental frequency 1f and odd harmonics 3f generated by the sattle is as shown in Figure 1. .If the differentiator circuit (4a) has an amplitude II mitter function, the amplitude of the signal waveform of 3f will be limited above the set value.

No subtle zero crossing occurs in the final differential waveform.

Since the recording density of the magnetic sheet is dense on the inner circumference and sparse on the outer circumference, there is little loss in readout output by the magnetic head for odd harmonics 3f in the outer cylinder, but loss increases on the inner circumference.

The readout error on the outer circumference is often due to the zero crossing of the saddle of the differential waveform, and the readout error on the inner circumference is attributable to a change in the signal (that is, a decrease in resolution of 1) K due to a loss of 3f of the readout signal. According to the present invention, when zero crossings of the differential waveform due to the outer circumference are eliminated, it is possible to set the two resolutions high, and the readout performance of the inner circumference is improved.

〔Effect of the invention〕

As described above, according to the present invention, zero crossings due to the zero point do not occur in the differential waveform on the outer periphery where resolution is high, so that high resolution can be maintained also on the inner periphery. This has the effect of providing a high-performance device that does not cause p-reading errors across the inner and outer circumferences.

[Brief explanation of the drawing]

FIG. 1 shows a recorded information reading circuit of a flexible disk drive device according to an embodiment of the present invention. FIG. 2 shows a recorded information reading circuit of a conventional flexible disk drive device. 1st ffl ”:BJ!” L-92ka □ Fig. 2

Claims (1)

[Claims] A first signal system consisting of a magnetic head that reads recorded information from a magnetic sheet, an amplifier circuit that amplifies the output of the magnetic head, a low-pass filter and a differentiation circuit that are connected to the output of the amplifier circuit, and a first signal system that is connected to the output of the amplifier circuit. A second signal system consisting of a differential circuit having a bandpass filter and an amplitude limiter function, a synthesis circuit for synthesizing the signals of the first signal system and the second signal system, and a synthesis circuit connected to the output of the synthesis circuit, so that the synthesis output is A flexible disk drive device comprising a comparator circuit that outputs a read data signal when a set threshold value is reached.