Dynamic magnetic information storage or retrieval – Automatic control of a recorder mechanism – Controlling the head
Reexamination Certificate
2000-09-19
2004-05-04
Hudspeth, David (Department: 2651)
Dynamic magnetic information storage or retrieval
Automatic control of a recorder mechanism
Controlling the head
Reexamination Certificate
active
06731452
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a data recording and/or reproducing apparatus and method in which the helical scanning is adopted to write data to a tape-shaped recording medium by a record head mounted on a rotating drum and read data from the recording medium by a playback head also mounted on the rotating drum.
2. Description of the Related Art
Many of the video tape recorders (VTR) adopt the helical scanning to write/read video data to/from a tape-shaped recording medium (will be referred to as “magnetic tape” hereinafter) by a plurality of magnetic heads mounted on a rotating drum.
The VTR adopts the azimuth recording to reduce, when reading data from recording tracks formed in a magnetic tape, a crosstalk noise caused by the detection of data from adjacent recording tracks.
FIG. 1
explains how the conventional magnetic heads having different azimuth angles record data to adjacent recording tracks, respectively. As shown, data are recorded to adjacent recording tracks
401
and
402
in recording patterns having different azimuth angles in a VTR using a first magnetic head in which a magnetic gap is formed to tilt a positive azimuth angle (+&thgr;) in relation to the width of a magnetic tape and a second magnetic head in which a magnetic gap is formed to tilt a negative azimuth angle (−&thgr;) in relation to that width, both mounted on a rotating drum. Thus in the conventional VTR, the azimuth loss is used to reduce the crosstalk between adjacent recording tracks.
In the conventional VTR, however, when the first and second magnetic heads are mounted on the rotating drum, the mechanical accuracy of the pairing of the magnetic heads and also that of azimuth recording are limited.
To avoid the above problems, it has been proposed and adopted to write or read data to or from recording tracks at a single azimuth angle by a single magnetic head mounted on a rotating drum.
In the VTR in which the helical scanning is adopted, the accuracy of the linearity of the recording pattern formed on the recording tracks is limited by the rotating accuracy of the rotating drum, etc. So, in the helical scanning type VTR, data should desirably be read from a magnetic tape by a non-tracking system, not by tracking of the recording tracks by the playback head.
However, with the use of a magnetic head with a single azimuth angle and data read/write by the non-tracking system as in the above, the crosstalk between the adjacent recording tracks cannot be reduced by using the azimuth loss and the signal-to-noise (S/N) ratio of the read signal is lower, which will result in no good data playback characteristics.
OBJECT AND SUMMARY OF THE INVENTION
It is therefore an object of the present invention to overcome the above-mentioned drawbacks of the prior art by providing a data recording and/or reproducing apparatus and method, which can assure good data playback characteristics even with a tape-shaped recording medium having a narrow track pitch.
The above object can be attained by providing a data recording and/or reproducing apparatus including according to the present invention:
means for feeding a tape-shaped recording medium in which data is recorded along recording tracks tilted in relation to the moving direction of the recording medium;
a writing/playback head having a playback head having a width smaller than the recording width of the recording tracks and which reads data from the tape-shaped recording medium, and a record head to write data along the recording tracks;
a rotating drum having the writing/playback head mounted thereon and on which the tape-shaped recording medium is scanned by the writing/playback head;
a reading controlling means for providing such a control that data recorded on the tape-shaped recording medium is detected with at least two scans of the recording medium by the playback head; and
means for generating data recorded on the tape-shaped recording medium from the data detected by the playback head having been controlled by the reading controlling means to make the plurality of scans of the recording tracks.
In the above data recording and/or reproducing apparatus, the playback head narrower than the recording width of the recording tracks is controlled by the reading controlling means to make a controlled number of scans on the recording pattern. Thus, the playback head is made to scan the recording pattern a plurality of times by the non-tracking system, thereby reading data from the recording tracks. Therefore, data can be read with good characteristics even with a tape-shaped recording medium on which recording tracks are formed perpendicularly to the moving direction of the recording medium.
Also the above object can be attained by providing a data recording and/or reproducing method to be adopted in a data recording and/or reproducing apparatus including:
means for feeding a tape-shaped recording medium;
a writing/playback head having a playback head having a width smaller than the recording width of the recording tracks and which reads data from the tape-shaped recording medium, and a record head to write data along the recording tracks; and
a rotating drum having the writing/playback head mounted thereon to move the writing/playback head on the tape-shaped recording medium, the method including, according to the present invention, steps of:
controlling the playback head to scan the recording tracks at least two times;
detecting data by the playback head having scanned the recording tracks the plurality of times; and
generating, from the detected data, data recorded in the tape-shaped recording medium.
Thus, data can be read with good characteristics even with a tape-shaped recording medium on which recording tracks are formed perpendicularly to the moving direction of the recording medium.
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Kotani Yasutaka
Mizuno Masayuki
Frommer William S.
Polio Bruno
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