JPH01201806A - Data reproduction circuit for floppy disk device - Google Patents

Abstract

PURPOSE:To surely perform the peak detection of a reproducing signal by providing a pulse output means to output a pulse signal corresponding to the zero cross point of a differential signal whose phase is shifted by a phase control means. CONSTITUTION:A phase control circuit 14 outputs a signal C with a waveform in which the peak of the differential signal B outputted from a differentiation circuit 13 is delayed by a prescribed time T. A comparator 15 generates the pulse signal P whose level changes at the zero cross point of the signal C whose phase is controlled by a phase control circuit 14, and a rapping circuit 16 generates read data RD obtained by the form arrangement of the pulse signal P from the comparator 15. Thus, since the read data RD is reproduced based on the phase control signal C in which the peak of the differential signal B is shifted, a state where the timing of the peak of the reproducing signal A with the peak of the read data RD is shifted compared with an on-going case is generated, and thereby, it is possible to prevent the state where the peak of the reproducing signal A coincides with that of the read data RD from being generated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a data reproducing circuit for a floppy disk device that reproduces data recorded on a magnetic recording medium.

(Prior Art) Conventionally, a floppy disk device is provided with a data reproduction circuit that generates read data based on a reproduction signal output from a magnetic head that performs read/write operations. The data reproducing circuit includes an amplifier circuit that amplifies the reproduced signal output from the magnetic head, a low-pass filter that removes high-frequency noise of the reproduced signal, a differentiation circuit that differentiates the reproduced signal, and a comparator that outputs a pulse signal. We are prepared. The differential circuit is a circuit for detecting the peak of the reproduced signal, and generates a differential signal that crosses zero at the peak point. The comparator outputs a pulse signal whose level changes at the zero-crossing point of the differential signal. moreover,
The data reproducing circuit includes a shoulder elimination circuit, which pulse-shapes the output pulse signal of the comparator (deletes erroneous pulses generated at the shoulder portion of the reproduced signal) to generate read data (read pulses).

By the way, data reproducing circuits are more easily affected by noise between circuits due to integrated circuits and other reasons. In particular, switching noise from digital comparators, shoulder cutout circuits, etc. may affect amplifier circuits and the like, disturbing the peak of the reproduced signal and making peak detection unstable.

In this case, when the peak of the read data and the peak of the reproduced signal match, a situation occurs in which the peak of the reproduced signal is disturbed.

(Problem to be Solved by the Invention) In conventional data reproducing circuits, digital switching noise affects the amplifier circuit, etc., and when the peak of the read data and the peak of the reproduced signal match, the reproduced signal The peak may be disturbed and peak detection may become unstable.

An object of the present invention is to prevent disturbance of the peak of the reproduced signal due to digital switching noise, realize reliable peak detection of the reproduced signal, and, as a result, provide a floppy disk that can accurately reproduce the data. An object of the present invention is to provide a data reproducing circuit for a disk device.

[Structure of the Invention] (Means and Effects for Solving the Problems) The present invention provides a data reproducing circuit for a floppy disk device that generates read data based on a reproduced signal reproduced from a magnetic recording medium by a magnetic head. A phase adjustment means for shifting the phase of the differential signal outputted from the means by a predetermined time, and a pulse output means for outputting a pulse signal according to the timing of a zero-crossing point of the differential signal whose phase has been shifted by the phase adjustment means. This is a circuit with a The present invention also provides a phase adjusting means for shifting the phase of a reproduced signal output from a magnetic head by a predetermined time, a differentiating means for differentiating the reproduced signal whose phase has been shifted by the phase adjusting means, and a differential signal output from the differentiating means. This data reproducing circuit includes pulse output means for outputting a pulse signal according to the timing of a zero-crossing point of a differential signal.

This configuration prevents the peak of the read data generated by the digital circuit from matching the peak of the reproduced signal (or differential signal), and prevents the reproduction signal from being distorted by switching noise caused by the digital circuit. It is possible to prevent a situation in which the peak of

(Example) The present invention will be described in detail below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of a data reproducing circuit in the floppy disk device of the same embodiment. As shown in FIG. 1, the data reproducing circuit of the same embodiment generates a reproduction signal (analog signal) corresponding to magnetic recording from a magnetic recording medium (not shown).
A magnetic head 10 that detects and outputs. This magnetic head 1
The apparatus includes an amplifier circuit 11 for amplifying a reproduced signal outputted from zero and a low-pass filter 12 for removing high-frequency noise from the reproduced signal.

The reproduced signal A output from the low-pass filter 12 is input to the differentiating circuit 13. The differentiating circuit 13 is a circuit for differentiating the reproduced signal A and detecting the peak of the reproduced signal A. The phase adjustment circuit 14 is composed of a filter circuit such as an LC circuit, and the differential signal B output from the differentiating circuit 13 is
This circuit shifts only the phase (that is, the peak) of the signal so that it is delayed by a predetermined time. The comparator 15 is a circuit that outputs a pulse signal P whose level changes at the timing of the zero cross point of the phase adjustment signal C output from the phase adjustment circuit 14. The shoulder removal circuit 16 is a circuit that pulse-shapes the output pulse signal P of the comparator 15 (deletes erroneous pulses generated in the shoulder portion of the reproduced signal) and generates read data (read pulse) RD.

That is, as shown in FIG. 2, a read pulse RD delayed by the shoulder release time is generated.

Next, the operation of this embodiment will be explained. First, in a floppy disk device, a magnetic recording medium is rotated during read/write, and the magnetic head 10 seeks on this magnetic recording medium to a target track. magnetic head 10
The reproduced signal read by is amplified by an amplifier circuit 11 and then input to a low-pass filter 12 . After removing high-frequency noise, the low-pass filter 12 outputs a reproduced signal A having a waveform as shown in FIG. Differential circuit 1
3 outputs a differential signal B obtained by differentiating the reproduced signal A.

The phase adjustment circuit 14 outputs a signal C whose waveform is shifted so that the peak of the differential signal B output from the differentiator circuit 13 is delayed by a predetermined time T. The comparator 15 generates a pulse signal P whose level changes at the zero-crossing point of the differential signal C whose phase has been adjusted by the phase adjustment circuit 14. The shoulder removal circuit I6 generates read data (read pulse) RD obtained by pulse shaping the pulse signal P output from the comparator 15.

In this way, the read data RD is reproduced based on the phase adjustment signal C obtained by shifting the peak of the differential signal B. Therefore, the timing between the peak of the reproduced signal A and the peak of the read data RD is shifted from the timing in the conventional case. Thereby, it is possible to prevent a situation where the timings of the peak of the reproduced signal A and the peak of the read data RD coincide.

Conventionally, the read data RD may be generated at a timing near the peak of the reproduced signal (signal passed through the low-pass filter I2) A. In such a situation,
Switching noise of the digital circuits of the comparator 15 and the shoulder removal circuit 16 has an influence on the reproduced signal to disturb its peak. Therefore, in the present invention, by shifting the peak of the differential signal B, a situation in which the timing of the peak of the reproduced signal and the peak of the read data RD coincide is prevented, and the peak of the reproduced signal A is prevented from being disturbed. be able to.

In the above embodiment, a case has been described in which the phase adjustment circuit 14 is provided between the differentiating circuit 13 and the comparator 15, but the present invention is not limited to this. A configuration provided in the above may also be used. In this case, the peak of the reproduced signal A output from the low-pass filter 12 is shifted, but the effect is the same as in the case of FIG. 1.

[Effects of the Invention] As detailed above, according to the present invention, it is possible to prevent the influence of disturbance of the peak of the reproduction signal due to switching order noise of the digital circuit in the data reproduction circuit of a floppy disk device. . Therefore, it is possible to always reliably detect beats in the reproduced signal, and it is possible to generate accurate read data based on this peak detection.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of a data reproducing circuit according to an embodiment of the present invention, and FIG. 2 is a timing chart for explaining the operation of the embodiment. lO...Magnetic head, 13...Differential circuit, 14...
・Phase adjustment circuit, 15... Comparator, 16...
Shoulder circuit. Applicant's agent Patent attorney Takehiko Suzue

Claims (2)

[Claims] (1) In a data reproducing circuit of a floppy disk device that generates read data based on a reproduced signal reproduced from a magnetic recording medium by a magnetic head, there is provided a differentiating means for differentiating the reproduced signal output from the magnetic head, and a differentiator for differentiating the reproduced signal output from the magnetic head. a phase adjustment means for shifting the phase of the differential signal output from the means by a predetermined time; and a pulse output means for outputting a pulse signal according to the timing of a zero-crossing point of the differential signal whose phase has been shifted by the phase adjustment means. , read data generation means for generating the read data based on the pulse signal output from the pulse output means. (2) In a data reproducing circuit of a floppy disk device that generates read data based on a reproduced signal reproduced from a magnetic recording medium by a magnetic head, a phase that shifts the phase of the reproduced signal output from the magnetic head by a predetermined time; an adjusting means, a differentiating means for differentiating the reproduced signal whose phase has been shifted by the phase adjusting means, and a pulse output means for outputting a pulse signal according to the timing of a zero-crossing point of the differential signal output from the differentiating means. , read data generation means for generating the read data based on the pulse signal output from the pulse output means.