Servo writer, signal output control method and manufacturing method of magnetic tape using the signal output control method
AssigneeFUJIFILM Corporation
InventorHiroki Ohtsu
Life of this patent
Estimating the term…
Abstract
A recording current to be supplied to a magnetic head is regulated by a signal output control unit. A peak value (either of positive-going peak value and a negative-going peak value) is detected in each pulse of a digital signal resulting from analog-to-digital conversion of a servo signal recorded on a servo band of a magnetic tape. The peak value is transmitted as an input value which is allowed to follow a change in the peak value as long as a frequency calculated based upon times of detection of respective peak values is below a predetermined frequency. An output value of the recording current is determined based upon the transmitted input value.
Claims18
A servo writer comprising:
- a direct-current erasing head configured to magnetize a servo band of a magnetic tape, wherein a direction of magnetization thereof is a first direction of lengthwise directions of the magnetic tape;
- a servo signal write head configured to record a servo signal on the servo band by magnetization of which a direction is a second direction opposite to the first direction;
- a verification head configured to retrieve the servo signal recorded on the servo band;
- an analog-to-digital converter configured to convert the servo signal retrieved by the verification head to a digital signal;
- and
- a signal output controller configured to regulate a recording current to be supplied to at least one of the direct-current erasing head and the servo signal write head, wherein the signal output controller comprises:
- a peak value detection unit configured to detect a peak value in each pulse of the digital signal output from the analog-to-digital converter, wherein the peak value comprises either of a positive-going peak value and a negative-going peak value;
- a low-pass filter unit configured to transmit as an input value the peak value received from the peak value detection unit, wherein the input value is allowed to follow a change in the peak value as long as a frequency calculated based upon times of detection of respective peak values is below a predetermined frequency;
- and
- an output determination unit configured to determine an output value of the recording current, based upon the input value transmitted through the low-pass filter unit.
A servo writer comprising:
- a direct-current erasing head configured to magnetize a servo band of a magnetic tape, wherein a direction of magnetization thereof is a first direction of lengthwise directions of the magnetic tape;
- a servo signal write head configured to record a servo signal on the servo band by magnetization of which a direction is a second direction opposite to the first direction;
- a verification head configured to retrieve the servo signal recorded on the servo band;
- an analog-to-digital converter configured to convert the servo signal retrieved by the verification head to a digital signal;
- a signal output controller configured to regulate a recording current to be supplied to at least one of the direct-current erasing head and the servo signal write head, wherein the signal output controller comprises:
- a peak value detection unit configured to detect a positive-going peak value and a negative-going peak value in each pulse of the digital signal output from the analog-to-digital converter;
- an absolute value calculation unit configured to calculate an absolute value of a difference of the positive-going peak value and the negative-going peak value in each pulse;
- a low-pass filter unit configured to transmit as an input value the absolute value received from the absolute value calculation unit, wherein the input value is allowed to follow a change in the absolute value as long as a frequency calculated based upon times of detection of respective peak values corresponding to the absolute values is below a predetermined frequency;
- and
- an output determination unit configured to determine an output value of the recording current, based upon the input value transmitted through the low-pass filter unit.
A signal output control method for regulating a recording current to be supplied to a magnetic head which is configured to effect a change in magnetization on a magnetic tape, the method comprising:
- receiving a digital signal resulting from analog-to-digital conversion of a servo signal recorded on a servo band of the magnetic tape;
- detecting a peak value in each pulse of the received digital signal, wherein the peak value comprises either of a positive-going peak value and a negative-going peak value;
- transmitting the peak value as an input value which is allowed to follow a change in the peak value as long as a frequency calculated based upon times of detection of respective peak values is below a predetermined frequency;
- and
- determining an output value of the recording current, based upon the transmitted input value.
A signal output control method for regulating a recording current to be supplied to a magnetic head which is configured to effect a change in magnetization on a magnetic tape, the method comprising:
- receiving a digital signal resulting from analog-to-digital conversion of a servo signal recorded on a servo band of the magnetic tape;
- detecting a positive-going peak value and a negative-going peak value in each pulse of the received digital signal;
- calculating an absolute value of a difference of the positive-going peak value and the negative-going peak value in each pulse;
- transmitting the absolute value as an input value which is allowed to follow a change in the absolute value as long as a frequency calculated based upon times of detection of respective peak values corresponding to the absolute values is below a predetermined frequency;
- and
- determining an output value of the recording current, based upon the transmitted input value.
Dependencies are inferred from the claim text.