JPH0224804A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To always set the optimum damping characteristics by switching a damping resistance connected in parallel with the coil of a head to different values between an information writing and information reading out periods. CONSTITUTION:When signals are inputted to a write gate 8, a switching transistor Q7 is turned off during a writing period 9. Therefore, the damping resistance becomes a damping resistance 5 only. The resistance value of the resistance 5 is set so that the write current characteristics can become the optimum. During a reading out period 10, the transistor Q7 is turned on. Therefore, the damping resistance becomes damping resistances 5 and 6 which are connected in parallel with each other and the resultant resistance value is set so that the frequency characteristics of a readout circuit can become the optimum.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic recording/reproducing device used in computer peripheral terminal equipment, etc., and particularly relates to a write/read circuit thereof.

[Conventional technology]

FIG. 5 is a write/read circuit diagram of a conventional magnetic recording/reproducing apparatus of this type disclosed in, for example, Japanese Patent Application Laid-Open No. 60-76007. In the figure, (1) is the coil of the magnetic head;
(2) is the first damping resistor connected in parallel to the coil (1), and (3) is the second damping resistor also connected in parallel to the coil (1) via the analog switch (4). . Here, the analog switch (4) is turned off when the coil (1) is located on the inner side of the magnetic disk (hereinafter referred to as media), and turned on when it is located on the outer side of the magnetic disk. This is for switching the resolution.

Next, the operation will be explained. On the inner peripheral side of the medium, the analog switch (4) is turned off, and only the first damping resistor (2) is inserted into the circuit. In general, the recording density of data on the media is higher on the inner side of the media than on the outer side, and it is necessary to set the resolution of the magnetic head relatively high on this inner side. The resistance value of the first damping resistor (2) is determined. Next, when the coil (1) reaches the outer circumference of the media,
The analog switch (4) is turned on, the first damping resistor (2) and the second damping resistor (3) are connected in parallel to the coil (1), and the overall resistance value decreases, causing the magnetic head to The resolution of is lower than the value on the inner circumferential side.

This is to suppress shield noise that is likely to occur when operating the outer circumferential side, where the recording density is low, while maintaining the high resolution set by the characteristics of the inner circumferential side.

[Problem to be solved by the invention]

Since the conventional magnetic recording/reproducing device is configured as described above, changes in the optimum resolution based on the recording density at the inner and outer peripheries of the media can be changed using the analog switch (4).
) was compensated for by switching the damping resistor.

However, since this damping resistor is maintained at the same value without distinguishing between data writing and reading, there are various problems as described in detail below.

FIG. 6 shows an equivalent circuit of the coil (1) of the magnetic head.

In the figure, R, L and C are the resistance, inductance and capacitance of the coil (1), respectively, and Sono is the damping resistor connected to the coil (1). If the equivalent circuits for write operation and read operation are determined based on the circuit constants of FIG. 6, they will be as shown in FIGS. 7 and 8, respectively. That is, the circuit configurations seen from the constant current source I and the constant voltage source E are different. Therefore, in general, there will be a difference in the optimum value of the damping resistance percentage between the write circuit and the read circuit.

For example, if the damping resistance surface is set so that the write current characteristic has an optimal characteristic with extremely small overshoot as shown in Figure 9(a), the frequency characteristic of the readout circuit will be as shown in Figure 9(b). As shown, the shoulder part rises, resulting in a defective characteristic. Conversely, if the damping resistance surface is set so that the frequency characteristics of the read circuit have good characteristics as shown in Figure 10(b), the write current characteristics in that case will be as shown in Figure 10(a). This may result in a large overshoot.

The present invention has been made to solve the above-mentioned problems, and provides a magnetic recording/reproducing device that can obtain optimal damping characteristics in both the write and read circuits.

[Means to solve the problem]

In the magnetic recording/reproducing device according to the present invention, the damping resistor connected in parallel to the coil of the magnetic head is switched to have different values when writing and reading information.

[Effect]

In this invention, the resistance value of the damping resistor is switched to the optimum value for the write circuit conditions during writing, and switched to the optimum value for the read circuit conditions during read, so that the damping characteristic is always set to the optimum value.

[Conventional example]

FIG. 1 is a write/read circuit diagram of a magnetic recording/reproducing apparatus according to an embodiment of the present invention. In the figure, (1) is the coil of the magnetic head, which is the same as the conventional one. (5) is the first damping resistor connected in parallel to the coil (1), (6) is the second damping resistor also connected in parallel to the coil (1) via the switching transistor (7), ( 3) is a write gate to the switching transistor (7). Note that the damping resistor switching means, which was conventionally provided in consideration of the difference between the inner and outer circumferences of the media, is not shown in Fig. 1. However, an appropriate film may be used as needed.

Next, the operation will be explained. Now, if the signal shown in FIG. 2 is input to the write gate (8), during the write period (9), the signal is at L level and the switching transistor (7) is turned off. As a result, the damping resistance becomes only the first damping resistance (5). The resistance value is set to optimize write current characteristics.

Next, during the read period Qf), the signal is at H level and the switching transistor (7) is turned on.

As a result, the damping resistor becomes one in which the first and second damping resistors (5) and (6) are connected in parallel, and the combined resistance value is set to a value that optimizes the frequency characteristics of the readout circuit.

FIG. 3 shows another embodiment of the present invention, in which when the signal of the write gate (8) is at L level in the write period (9), the switching transistor (7) is turned off, and both damping resistors (5) ( 6) are inserted into the circuit in series with each other. When the signal of the write gate (8) is at H level during the read period αO, the switching transistor (7) is turned on and the second damping resistor (
6) is short-circuited and only the first damping resistor (5) is inserted into the circuit, so as in the case of FIG. 1, the resistance value of the damping resistor becomes smaller than that at the time of writing.

Figure 4 shows still another embodiment, in which the switching transistor (7) and light gate (8) of the circuit in Figure 3 are shown.
), an inverter α〃 is inserted between the two. In this circuit, during writing, the switching transistor (7) is turned on and the second damping resistor (6) is short-circuited, and during reading, the switching transistor (7) is turned off and both damping resistors (5) ( 6) are connected in series. As a result, the resistance value of the damping resistor is
Contrary to the case in FIG. 3, the value when written is smaller than the value when read.

〔Effect of the invention〕

As described above, in this invention, the damping resistor is switched between writing and reading, so that optimal damping characteristics can be obtained in all operating modes regardless of writing or reading operations, improving the overall characteristics. There is an effect.

[Brief explanation of the drawing]

FIG. 1 is a write/read circuit diagram of a magnetic recording/reproducing device according to an embodiment of the present invention, FIG. 2 is a signal characteristic diagram of the write gate of FIG. 1, and FIGS. 3 and 4 are other embodiments of the present invention. FIG. 5 is a write/read circuit diagram of a conventional magnetic recording/reproducing device; FIG. 6 is an equivalent circuit diagram of a magnetic head coil; FIGS. 7 and 8 are write operations of FIG. 6. Equivalent circuit diagram at time and read operation, No. 9
1 and 10 are diagrams showing the write current characteristics and the frequency characteristics of the read circuit. In the figure, (1) is a coil, (5) and (6) are first and second damping resistors, respectively, and (7) is a switching transistor. In each figure, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] A magnetic head disposed close to a rotating magnetic disk writes information to the magnetic disk and reads information from the magnetic disk, wherein the magnetic head is connected in parallel to a coil of the magnetic head. 1. A magnetic recording/reproducing apparatus characterized in that the damping resistor is switched to have a different value when writing and reading the information.