JPS63164007A - Data reproducing circuit for magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To simplify the externally mount circuit by providing a differentiation circuit in series connection with a series and a parallel resonance circuit so as to provide a function reducing noise thereby eliminating an LPF. CONSTITUTION:A magnetic head 10 converts a recording signal magnetized on a disk into an analog read voltage Vi. An amplifier 11 amplifies the voltage Vi, outputs the result to a differentiation device 23, from which a differentiation signal having a 0V at a point of time corresponding to a peak point of the voltage Vi is outputted. A kind of band stop filter is constituted in the differentiation device 23 by a parallel LC resonance circuit 24 to have a function reducing remarkably high frequency noise. Thus, the differentiation device substitutes the LPF function and the LPF is not required in a data reproducing circuit. Thus, the circuit is simplified as a whole.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a data reproducing circuit for, for example, a floppy disk device.

(Prior Art) Conventionally, in a floppy disk device, a data reproducing circuit reproduces data recorded on a magnetic recording medium (disc). As shown in FIG. 4, the data reproducing circuit is
an amplifier 11 that amplifies the read signal (read voltage Vi) read from the magnetic head 10; a low-pass filter 12;
It consists of a differentiator 13 and a pulse shaping circuit 14.

The low-pass filter 12 is a circuit for removing high-frequency noise in the read signal. The differentiator 13 includes, for example, NPNt transistors 20 and 21, as shown in FIG.
and a series LCR resonant circuit 22.

The differentiator 13 detects the peak of the read voltage Vi and outputs a differentiated output signal (output voltage Vo) whose time point corresponding to this peak is O■. The pulse shaping circuit 14 includes a comparator and a waveform shaping circuit that detect zero-crossing points from the differential output signal, and outputs digital signal level data that is inverted at the zero-crossing points.

By the way, in recent years, data reproducing circuits are becoming integrated into LSIs (Large Scale Integrated Circuits), but in order to make the IC more versatile, the low-pass filter 12 and the differentiator 13 are configured as external circuits. Therefore, in order to simplify the data reproducing circuit, it is necessary to simplify the external connection of the low-pass filter 12 and the differentiator 13.

(Problems to be Solved by the Invention) In the conventional data reproducing circuit, in order to simplify the entire circuit, an external low-pass filter 12, which is an external circuit, is required.
Although it is necessary to simplify the differentiator 13, it is actually difficult to configure each external circuit with a simple configuration.

An object of the present invention is to provide a data reproducing circuit for a magnetic recording medium that can greatly simplify a low-pass filter, which is one of the external circuits, and can simplify the overall circuit configuration.

[Structure of the Invention] (Means and Effects for Solving the Problems) The present invention provides a data reproducing circuit that differentiates a read signal from a magnetic head and outputs read data as a digital signal based on the differentiated output signal. For example, the circuit includes a differential circuit formed by connecting a series resonant circuit and a parallel resonant circuit in series.

Such a differentiating circuit has a function of significantly reducing high-frequency noise, making it possible to eliminate the need for a low-pass filter. Therefore, when the data reproducing circuit is integrated into an IC, the external circuit can be simplified, and the data reproducing circuit can be simplified.

(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 the data reproducing circuit of the same embodiment, and FIG. 2 is a circuit diagram showing the configuration of the differentiator 23 of the same embodiment. In FIG. 1, a magnetic head 10 converts a recording signal magnetized onto a disk into a voltage signal and outputs the voltage signal. The amplifier 11 is an amplifier that amplifies the read voltage Vi read from the magnetic head 10. The differentiator 23 detects the peak of the read voltage Vi and outputs a differentiated output signal (output voltage Vo) whose point of time corresponding to this peak is 0.

The pulse shaping circuit 14 includes a comparator and a waveform shaping circuit that detect zero-crossing points from the differential output signal, and is a circuit that outputs read data of a digital signal that is inverted at the zero-crossing points.

The differentiator 23, as shown in FIG.
Parallel LG resonant circuit 24 connected in series to the resonant circuit 22
Consisting of

Next, the effects of this embodiment will be explained. First, the magnetic head 10 converts a recording signal magnetized onto the disk into an analog read voltage Vi and outputs the analog read voltage Vi.

The amplifier 11 amplifies the read voltage Vi from the magnetic head 10 and outputs it to the differentiator 23. The differentiator 23 outputs a differential signal (output voltage Vo) whose time point corresponding to the peak point of the read voltage Vi is O■. That is, the read voltage V+
Since information is included in the peak point of , this means that the differentiator 23 has detected the peak.

By the way, since the differentiator 23 has the parallel LCC common circuit 4 connected in series to the series LCR resonant circuit 22, as shown in FIG.
C2)) results in a characteristic curve B having parallel resonance. Here, the differentiator 13 of FIG. 5, in which the parallel LCC common circuit 4 is not provided, has a resonance point ω1(ω1-1/(Ll・C1
)) becomes the characteristic song 11A.

That is, the differentiator 23 in FIG. 2 is configured as a kind of band-rejection filter by the parallel LC resonant circuit 24.
It has the ability to significantly reduce high-frequency noise. Therefore, the differentiator 23 can replace the function of the conventional low-pass filter 12 shown in FIG. Therefore, in the data reproducing circuit of the same embodiment, the conventional low-pass filter 12 can be removed, and the circuit as a whole can be simplified. Specifically, when converting the data regeneration circuit into an IC, conventionally the low-pass filter 12 and the differentiator 13 are configured as external circuits, but
Since this low-pass filter 12 can be removed, only the differentiator 23 is required as an external circuit. As a result, the external circuit can be simplified, and the data reproducing circuit as a whole can be simplified.

[Effects of the Invention] As described in detail above, according to the present invention, in a data reproducing circuit using a differentiator, the differentiator can have a function of reducing high-frequency noise. The low-pass filter required for this can be simplified or eliminated. Therefore, as a result, it becomes possible to simplify the data reproducing circuit as a whole, and it is possible to realize a reduction in the number of parts and a reduction in size of an apparatus using the data reproducing circuit.

[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, FIG. 2 is a circuit diagram showing the configuration of a differentiator of the same embodiment, and FIG. 3 is a diagram showing the characteristic curve of the differentiator. , 4th
The figure is a block diagram showing the configuration of a conventional data reproducing circuit, and FIG. 5 is a circuit diagram showing the configuration of a conventional differentiator. 10...Magnetic head, 11...Amplifier, 12...
Low-pass filter, 13.23... Differentiator, 14...
・Pulse shaping circuit.

Claims (1)

[Scope of Claim] A data reproducing circuit of a magnetic recording and reproducing device that converts a recorded signal magnetized on a magnetic recording medium into an analog voltage signal by a magnetic head and reproduces recorded data based on the analog voltage signal, comprising: A differentiating circuit outputs a differential signal that becomes zero volts at a point corresponding to the peak of the analog voltage signal output from the head to reduce high-frequency noise of the analog voltage signal, and a digital signal is generated based on the differential output signal of the differentiating circuit. A data reproducing circuit for a magnetic recording/reproducing device, comprising a pulse shaping circuit that outputs read data.