JP2000298806A - Magnetic tape apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent an error in a reading operation to be caused by a speed variation in a writing operation. SOLUTION: A servo head 1 reads out a servo signal that is being written continuously or intermittently on a medium. A servo signal detection circuit 2 converts the servo signal into pulses and supplies them to a write clock phase comparison circuit 5. The write clock phase comparison circuit 5 compares a phase of the servo pulse signal with a phase of a write clock to be generated by a write VCO 6, and applies a difference between the two phases to the write VCO 6 as a control voltage CV. The write VCO 6 generates the write clock in accordance with the control voltage CV. A data synchronization circuit 7 allows write data to be synchronized with the write clock and supplies the data to a write driver 8. The write driver 8 applies a writing current based on the synchronized write data to a write head.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a magnetic tape device for recording information on a magnetic tape and reading the recorded information.

[0002]

2. Description of the Related Art Conventionally, in a magnetic tape device, for example, when data is recorded on a magnetic tape as a medium, write data is synchronized with an internally generated write clock,
A write current was applied from a write driver to a write head to record information on a magnetic tape.

[0003]

However, in the above-mentioned prior art, since the internally generated write clock is used, if the speed of the tape fluctuates, the written data interval fluctuates and the data is read again. However, there is a problem that synchronization is not achieved and a reading error occurs. Also, in recent years, as disclosed in, for example, Japanese Patent Publication No. 2769110, a magnetic tape device for positioning a head based on servo information has been provided. However, if the tape speed fluctuates similarly, synchronization cannot be achieved and a reading error occurs.

The present invention has been made in view of the above-mentioned circumstances, and has as its object to provide a magnetic tape device which can prevent occurrence of an error at the time of reading due to a speed fluctuation at the time of writing.

[0005]

In order to solve the above-mentioned problems, according to the first aspect of the present invention, a servo signal is applied to a magnetic tape on which servo signals are continuously or intermittently written in a tape running direction. In a magnetic tape device that performs positioning control of a magnetic head that writes information on the magnetic tape or reads information based on a signal, a clock generation that generates a write clock synchronized with a servo signal included in the servo information Means, synchronization means for synchronizing write data with the write clock generated by the clock generation means, and application means for applying a write current to the magnetic head according to the write data synchronized by the synchronization means. It is characterized by having.

Further, according to the invention described in claim 2, according to claim 1,
The magnetic tape device according to claim 1, further comprising: a clock phase comparing unit that compares a phase of the servo signal with a phase of a write clock generated by the clock generating unit, and applies a difference between the phases as a control voltage to the clock generating unit. The clock generation means generates the write clock based on the control voltage.

In the present invention, the clock generation means generates a write clock synchronized with the servo signal written continuously or intermittently in the tape running direction. The synchronization means synchronizes the write data with the write clock generated by the clock generation means. The application unit records the write data on the magnetic tape by applying a write current corresponding to the synchronized write data to the magnetic head. Therefore, by using the write clock synchronized with the servo pulse signal, even if a speed variation occurs during the write operation, the write timing follows the medium, so that the data recording interval is kept constant. Therefore, when data is read later, the speed fluctuation difference at the time of writing becomes invisible, and the read margin can be maintained.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. A. Configuration of Embodiment FIG. 1 is a block diagram showing a partial configuration of a magnetic tape device according to an embodiment of the present invention. In the figure, a servo head 1 reads servo information continuously or intermittently written on a medium. The servo detection circuit 2 supplies the read servo signal to the servo level detection circuit 3, converts the servo signal into a pulse, and supplies the pulse to the write clock phase comparison circuit 5. The servo level detection circuit 3 detects the level of the servo signal and supplies it to the positioning control unit 4. The positioning control unit 4 controls the head according to the level detected data from the servo level detection circuit 3.

The write clock phase comparison circuit 5 compares the phase of the servo pulse signal from the servo detection circuit 2 with the write VC signal.
The phase of the write clock generated in O6 is compared, and the difference between the phases is applied to the write VCO 6 as the control voltage CV. The write VCO 6 includes a write clock phase comparison circuit 5
Generates a write clock according to control voltage CV from write clock phase comparison circuit 5 and data synchronization circuit 7
Supply to The data synchronization circuit 7 supplies the write data to the write driver 8 in synchronization with the write clock. The write driver 8 applies a write current corresponding to the synchronized write data to the write head according to the write gate.

B. Next, the operation of the above-described embodiment will be described. When performing the write operation, the servo information which is continuously or intermittently written in the tape running direction on the medium is read by the servo head 1 for positioning. The read servo signal is supplied to the servo level detection circuit 3 in the servo detection circuit 2 and, after being pulsed, supplied to the write clock phase comparison circuit 5. The servo level detection circuit 3 detects the level of the servo signal and transmits the detection data to the positioning control 4. The positioning control unit moves the write head to a target position according to the detected data.

The write clock phase comparison circuit 5 compares the phase of the servo pulse signal supplied from the servo detection circuit 2 with the phase of the write clock generated by the write VCO 6, and determines the difference between the phases as the control voltage CV.
6. The write VCO 6 generates a write clock according to the control voltage CV from the write clock phase comparison circuit 5 and supplies the generated write clock to the write clock phase comparison circuit 5 and the data synchronization circuit 7.
The data synchronization circuit 7 supplies the write data to the write driver 8 in synchronization with the write clock. The write driver 8 applies a write current corresponding to the synchronized write data to the write head according to the write gate. Since the write clock is generated so as to synchronize with the servo pulse signal, the write data also synchronizes with the servo information written continuously or intermittently in the tape running direction on the medium medium.

[0012]

As described above, according to the present invention,
By using the write clock synchronized with the servo pulse signal, even if a speed variation occurs during the write operation, the write timing follows the medium, so that the data recording interval is kept constant. Therefore, when data is read later, the difference in speed fluctuation at the time of writing becomes invisible, and the advantage that a read margin can be maintained can be obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a partial configuration of a magnetic tape device according to an embodiment of the present invention.

[Explanation of symbols]

Reference Signs List 1 servo head 2 servo detection circuit 3 servo level detection circuit 4 positioning control unit 5 write clock phase comparison circuit (clock phase comparison means) 6 write VCO (clock generation means) 7 data synchronization circuit (synchronization means) 8 write driver ( Application means)

Claims (2)

[Claims] 1. A magnetic head for writing information to or reading information from a magnetic tape on which a servo signal is continuously or intermittently written in a tape running direction based on the servo signal. A magnetic tape device that performs positioning control of: a clock generating unit that generates a write clock synchronized with the servo signal; a synchronizing unit that synchronizes write data with the write clock generated by the clock generating unit; Means for applying a write current corresponding to write data synchronized by the means to the magnetic head. 2. A clock phase comparison means for comparing a phase of the servo signal with a phase of a write clock generated by the clock generation means, and applying a difference between the phases as a control voltage to the clock generation means, 2. The clock generator according to claim 1, wherein the clock generator generates the write clock based on the control voltage.
The magnetic tape device according to claim 1.