JPH0713044Y2 - Magnetic disk unit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a magnetic disk device, and more particularly to a recording circuit of the magnetic disk device.

[Conventional technology]

Conventionally, in the recording circuit of this type of magnetic disk device, the write gate is opened by the AND circuit of both the write start signal and the index signal, and the write data is recorded on the recording medium through the magnetic head.

[Problems to be solved by the device]

In the conventional recording circuit described above, information is newly overwritten in a state where information has already been recorded, the signal-to-noise ratio is poor, and as a result, peak shift occurs and the reliability of the device deteriorates. There is. In particular, as the recording density becomes higher and the gap length of the magnetic head becomes narrower as in recent years, the tendency becomes more remarkable.

[Means for Solving the Problems]

The recording circuit for a magnetic disk device of the present invention is a combination of a D-type flip-flop circuit that opens a write gate by a write start signal and an index signal to perform an erasing operation and opens a write data gate by the next index signal to record data. It has a mono-multi circuit for resetting the D-type flip-flop by the index signal of.

〔Example〕

 Next, the present invention will be described with reference to the drawings.

FIG. 1 is a block circuit diagram showing an embodiment of the present invention. FIG. 2 is a time chart showing ON / OFF of signals.

First, this circuit starts its operation by a write start signal sent from the control side. That is, the output signal of the first D-type flip-flop (hereinafter referred to as DT · F / F) is held at the high level (hereinafter referred to as H level) by the write start signal. The output of the AND circuit of this H level and a signal (referred to as an index signal) issued each time the magnetic recording medium makes one rotation causes the second
Set the DT / F / F output signal to H level. This signal becomes the write gate (WG) and the write operation is started by this signal. At this time, the write data gate (WDG) has not been opened yet and the write operation is performed without write data, resulting in the erase operation. Then, at the next index, this operation is ended by the inverted output of the inverted third DT · F / F, and at the same time, the write data gate is opened and the write data is recorded.

Finally, in order to reset this network, a mono-multi (MM) interlocked with the write data gate to be closed is provided by the next index signal. By this reset operation, the erasing and data writing described above can be repeated.

Although the current during the erase operation is not mentioned in this embodiment, the erase effect is further enhanced by changing the current value in conjunction with the erase operation.

[Effect of device]

As described above, the present invention has the effect of significantly improving the signal-to-noise ratio by providing a circuit network for erasing data before writing.

[Brief description of drawings]

FIG. 1 is a block circuit diagram showing an embodiment of the present invention, and FIG.
The figure is a time chart showing the signals of FIG. DT / F / F …… D type Philip flop, MM …… monomulti, WG …… write gate, WDG …… write data gate.

Claims (1)

[Scope of utility model registration request] 1. A magnetic disk device in which information is recorded / reproduced by a magnetic head through a recording / reproducing circuit in a magnetic recording medium, a write start signal and an index signal are used to open a write gate to perform an erasing operation, and the next index is generated. A circuit in which a D-type flip-flop is combined so as to open the write data gate with a signal to record data, and a write circuit having a monomulti for resetting all of the combined D-type flip-flops by a third index signal. A magnetic disk drive having a net.