JPS618776A - Magnetic reproducing device - Google Patents

Abstract

PURPOSE:To suppress zero level variation due to the influence of an AC coupling element which trasmits an electric signal from a mangnetic head magnetically by providing an amplifier which amplifies the output of the AC coupling element and a frequency characteristic correcting circuit which improves frequency characteristics of the amplified signal. CONSTITUTION:A magnetic signal recorded on a magnetic recording medium is converted electromagnetically by the magnetic head 1 and outputted as an electric signal. This electic signal is transmitted by the AC coupling element 2, which outputs a tranmission output signal having no low frequency component. This transmission output signal is amplified by the amplifier 3 and supplied to the low-band emphasis type filter consisting of a resistance 5, capacitor 6, and resistance 7. A signal appearing at a playback output terminal 4 has the low-frequency component, lost by the element 2, corrected greatly. Thus, the influence of the element 2 is suppressed and variation in zero level is suppressed, thereyby reading an accurate playback signal.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a magnetic reproducing device for reproducing magnetic signals recorded on a magnetic recording medium.

[Conventional technology]

As this type of magnetic reproducing device, the one shown in Fig. 1 is generally known. In Fig. 9, (1) outputs a magnetic signal recorded on a magnetic recording medium (not shown) as an electric signal. A magnetic head, (2) is an AC coupling element consisting of a transformer that magnetically transmits the electric signal from this magnetic head, and No. 13 is an amplifier that amplifies the transmitted output signal from this AC coupling element, and its output end is used for reproduction. It is connected to the output terminal (4).

Next, to explain the operation of the magnetic reproducing apparatus configured in this way, first, when a magnetic recording medium on which a recording signal as shown in FIG. 2(a) is recorded is reproduced by the magnetic head (1). , the second peak has a peak at the magnetization reversal position of the recorded signal.
An electrical signal as shown in Figure (b) is output from the magnetic head (1). The electrical signal from this magnetic head (υ) is transmitted to the AC coupling element (2), and a transmitted output signal as shown in FIG. 2(C) is output.

The signal is amplified by the amplifier (3) and output to the reproduction output terminal (4).

At this time, the AC coupling element (2) is a transformer.

The transfer function A of the low frequency signal has a characteristic as expressed by the following equation (1), and its one frequency characteristic is curve 1 shown by the solid line in FIG.

(However, a and b are constants, and θ is jw.)
Therefore, the transmitted output signal from the AC coupling element (2) loses one frequency component and is distorted, resulting in a waveform as shown in FIG. 2(C).

Furthermore, a problem occurred in that the zero level of the transmission signal from the AC coupling element (2) fluctuated. [Summary of the Invention] This invention was made in view of the above points, and it In a magnetic reproducing device that reproduces magnetic signals recorded on a [Embodiment of the Invention] An embodiment of the invention will be described below based on FIG. 3. In FIG. A first resistor is connected between the output terminal (4), (6) is a capacitor whose one electrode is connected to the reproduction output terminal (4), and (7) is a capacitor whose other electrode is connected to the ground. A resistor connected between the first resistor (5) and the capacitor (7), which serves as a constant for determining waveform shaping characteristics.
) constitutes a low-frequency emphasis filter.

Next, the operation of the magnetic reproducing apparatus configured in this manner will be explained. First, when a magnetic recording medium on which a recording signal as shown in FIG. 2(a) is recorded is reproduced by a magnetic head tll, as shown in FIG. 2(b), which has a peak at the magnetization reversal position of the recorded signal. An electrical signal is output from the magnetic head +IJ. Electric signals from this magnetic head (1) are transmitted to an AC coupling element (2).

Since the transformer, which is this AC coupling element (2), has a low frequency blocking lfr% property as shown in curve 1 shown in FIG.
A transmission output signal in which the low frequency component is lost as shown in FIG. 3(c) is output, and this transmission output signal is amplified by an amplifier (3). The amplified signal from this amplifier (3) is transmitted through the first resistor (5), the capacitor (6) and the second resistor +7.
The low-frequency component is greatly corrected by the low-frequency emphasizing filter consisting of 1, and a waveform approximately similar to bl in FIG. 2 is obtained, which is output to the reproduction output terminal (4). Become.

At this time, the transfer function B of the low frequency emphasizing filter composed of the first resistor (5), the capacitor (6), and the second resistor (7) has a characteristic as shown in the following equation (2), and the AC coupling element (2
) is the characteristic of the transformer (curve 1 shown by the solid line in Figure 4)
) is determined to match the 6ir frequency of the filter, and its frequency characteristics are curve H shown by the dotted line in FIG.

(However, bl is c(R+r), b2 is cr, s is jw, C is the capacitance value of the capacitor (6), and R is the first
The resistance value of the resistor (5), r is the resistance value of the second resistor. )
Therefore, the frequency characteristics of the entire circuit shown in FIG. 3 are the sum of the frequency characteristics of the AC coupling element (2) and the frequency characteristics of the low-frequency emphasizing filter, and the frequency characteristics of the entire circuit shown in FIG. It is marked I.

As a result, the signal appearing at the reproduction output terminal (4) is:

The low frequency components lost by the AC coupling element (2) are largely corrected, the influence of the AC coupling element (2) is suppressed, and the fluctuation of the zero level is also suppressed.

In the above embodiment, one frequency characteristic correction circuit includes the first and second resistors t5) (71 and the capacitor (6)
Although this is a low-frequency emphasis filter consisting of
A similar effect can be achieved if it improves the frequency characteristics inevitably deteriorated due to 2).

Further, in the above embodiments, a magnetic reproducing device in which the AC coupling element (2) is a transformer is described, but a magnetic reproducing device in which an element having low-frequency cutoff characteristics is used as the AC coupling element (2) may also be used. It is something.

〔Effect of the invention〕

As described above, the present invention is configured such that a magnetic signal recorded on a magnetic recording medium is converted into an electric signal by a magnetic head, and this electric signal is transmitted by an AC coupling element and amplified by an amplifier. Since we installed a frequency characteristic correction circuit that improves the frequency characteristics of the signal amplified by the amplifier in the magnetic reproducing device, fluctuations in the zero level due to the influence of the AC coupling element are suppressed, making it possible to read out the reproduced signal accurately. This has the effect of making it possible.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of the main parts of a conventional magnetic reproducing device. FIG. 2 is a waveform diagram of each part of the magnetic reproducing device, FIG. 3 is a circuit diagram of a main part showing an embodiment of the present invention, and FIG. 4 is a diagram showing frequency characteristics. In the figure, +1) is a magnetic head, and (2) is an AC coupling element. (3j is the amplifier, (5) is the first If resistor, (6) is the capacitor, and (7) is the second @ resistor. In each figure, the same symbol indicates the same or equivalent part.

Claims (3)

[Claims] (1) A magnetic head that electromagnetically converts a magnetic signal recorded on a magnetic recording medium and outputs it as an electrical signal, an AC coupling element that magnetically transmits the electrical signal from this magnetic head, and an AC coupling element that magnetically transmits the electrical signal from the magnetic head. an amplifier that amplifies the signal;
A magnetic reproducing device equipped with a frequency characteristic correction circuit that improves the frequency characteristics of the signal amplified by this amplifier. (2) Claim 1, characterized in that the AC coupling element is a transformer, and the frequency characteristic correction circuit is a low frequency emphasis filter that compensates for the low frequency attenuation characteristics of this transformer.
The magnetic reproducing device described in Section 1. (3) The low-pass emphasis filter consists of a first resistor whose one end is connected to the output terminal of the amplifier, a capacitor and a second resistor connected in series between the other end of the first resistor and ground. A magnetic reproducing device according to claim 2, characterized in that the magnetic reproducing device has: