JPH0221403A - Magnetic recording circuit - Google Patents

Abstract

PURPOSE:To obtain a satisfactory S/N by providing a recording current variable circuit to set the optimum recording current on the states of a magnetic medium and a magnetic head, etc. CONSTITUTION:It is recommended to set the variable range of the recording current at a range from 30% less to 30% more of the optimum current value setting the optimum current value as reference, generally, and the levels of a reproducing signal corresponding to the range are assumed as A1, A0, and A2. The maximum value among the data A1, A0, and A2 is detected in an optimum recording current decision step, and the recording current outputting the value is set as the optimum recording current, and it is set on the recording current variable circuit 2 by a control signal 6. The recording and the sampling 8 of test data 7 are interrupted replying to the completion of the setting, and the trigger of the completion is outputted from an end trigger output terminal (b), and the input and the reproduction of data from an ordinary recording terminal 9 and an ordinary reproducing terminal 10 are performed. In such a way, it is possible to improve the S/N at the time of performing reading.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a magnetic recording circuit.

[Conventional technology]

Conventionally, this type of magnetic recording circuit always performs recording by flowing a constant recording current to the magnetic head.

[Problem to be solved by the invention]

In the conventional magnetic recording circuit described above, since the recording current is always constant, the saturation characteristics of the circuit change due to differences in the coercive force of the magnetic media used, variations in the magnetic head, etc., making it impossible to record with the optimum recording current.

The saturation characteristics are shown in FIG. The optimum recording current for digital recording is the saturation point (P) at which the playback output reaches its maximum value.
It is. However, in conventional circuits, there is a possibility of using the unsaturated region 20 and the saturated region 21 as described above. When the unsaturated region 20 is used, there is little interference between adjacent bits, but because the degree of penetration (depth of magnetization) of magnetization recorded on the magnetic medium is weak, the recorded bit information may be erased or read. There is a drawback that the S/N ratio deteriorates. Conversely, when the saturation region 21 is used, the degree of penetration of magnetization is sufficient, and bits may disappear or S/
Although the N ratio does not decrease, there is a drawback that interference between adjacent bits becomes large and peak shift (a phenomenon in which bit positions shift) is likely to occur, which leads to errors during reading.

SUMMARY OF THE INVENTION An object of the present invention is to provide a magnetic recording circuit which eliminates the drawbacks of the above-mentioned conventional circuits.

[Means to solve the problem]

The magnetic recording circuit of the present invention includes a variable recording current circuit that variably adjusts the magnitude of a recording current flowing through a magnetic head, a reproducing circuit that reproduces a recorded signal by the magnetic head, and a reproduced signal reproduced by the reproducing circuit. and a control circuit that controls the recording current variable circuit to set an optimum recording current level so that the level of the recording current reaches a maximum value.

〔Example〕

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of an embodiment of the present invention used in a type of device (eg, a magnetic tape device) in which a recording head and a reproducing head can be used simultaneously. FIG. 3 is a flowchart for explaining the operation of this embodiment, and shows the operation of the control circuit 1.

First, it is determined how many types of recording currents are to be sampled to determine the optimum recording current in the circuit of the present invention.

An example in which sampling is performed at three points will now be described. The variable range of the recording current is usually from 30% decrease to 30% increase based on the generally optimal current value (hereinafter referred to as Go) (0.70G to 1.3G).
). Therefore, here, 0.85Go (hereinafter referred to as Gl), G
, , 1.15Go (hereinafter referred to as G2), test data is recorded at three current values. The levels of the reproduced signals corresponding to this are assumed to be A1pA0 and A2.

The operation of the embodiment shown in FIG. 1 will be explained below with reference to FIG.

First, when the start trigger is applied to control circuit 1,
In an initialization step 11, the control circuit 1 erases previously set constants, etc., and the control signal 6 sets the recording current G1.

Next, in a test data recording step 12, the control circuit 1
The test data 7 outputted from the recording head 4 is recorded on the recording medium with a recording current G through the recording head 4. In the test data reproduction step 13 and the sampling step 14, the reproduction signal level reproduced by the reproduction head 5 and reproduction circuit 3 is stored in the control circuit 1 as data A1.

Next, in the recording current change step 16, the next recording current G
Set to 0. Thereafter, the same processing as described above is performed. The same applies to the recording current.

After holding the data of reproduction signal levels A I, A o, and A2 as described above, in the optimum recording current determination step 17, data A1. The maximum value of Ao and A2 is detected, and the recording current that outputs that value is set as the optimum recording current, and is set in the recording current variable circuit 2 by the control signal 6. In response to the completion of this set, the recording of the test data 7 and the sampling of the test data 8 are discontinued, a completion trigger is output from the end trigger output terminal 6, and data is input and reproduced from the normal recording terminal 9 and the normal playback terminal 10. Make sure to do the following.

The above is an example of the application of the present invention to a device having separate recording heads and reproducing heads.

Next, the application of the present invention to a device in which a recording head and a reproducing head are integrated will be briefly described.

In this case, switching between using the head for recording and reproducing is performed in a test data recording step 12 and a test data reproducing step 13.

The problem here is that it is not possible to play back while recording. In other words, in order to reproduce the recorded data, the head must be moved to the recording start position. Therefore, the control circuit 1 must control the head position and search for the recording start position. the result,
After the test data recording step 12, a head position correction step is performed, and then the test data reproducing step 13
We need to move forward. The following operations are exactly the same.

〔Effect of the invention〕

As explained above, in the present invention, it is possible to set the optimal recording current for the conditions of the magnetic medium, magnetic head, etc., so a sufficient S/N ratio can be obtained, and errors due to peak shifts can be reduced. There is an effect that it can be done.

[Brief explanation of the drawing]

FIG. 1 is a block circuit diagram showing one embodiment of the present invention, and FIG.
FIG. 3 is a graph showing the relationship between recording current and reproduction output level, and FIG. 3 is a flowchart showing an embodiment of the present invention. 1... Control circuit, 2... Recording current variable circuit, 3... Playback circuit, 4... Recording head, 5... Playback head. . Agent Patent Attorney Shinkyo Uchihara

Claims (1)

[Claims] a recording current variable circuit that variably adjusts the magnitude of the recording current flowing through the magnetic head; a reproduction circuit that reproduces the signal recorded by the recording current using the magnetic head; 1. A magnetic recording circuit comprising: a control circuit that controls the recording current variable circuit to set an optimum recording current level so that the recording current level is set to a value of 0.