JPH02143974A - Track number detecting device for magnetic disk reproducing device - Google Patents

Abstract

PURPOSE:To detect a track number of a track without an error at the time when a reproducing head is brought to tracking to an arbitrary track by detecting a shift distance of a recording track shifted from a reference position, and executing a correcting operation for aligning a scale with its track whenever tracking is ended. CONSTITUTION:A CPU 7 has a tracking function, and a stepping motor 3a is driven to rotate by a motor control circuit 3b. When a reproducing head is brought to tracking to an arbitrary track, in the case of detecting a track number (how many tracks there are from the outermost periphery recording track), even if a position of a recording track is shifted by <=1/2 of a standard track interval from a position determined by a standard due to a temperature variation of the environment of a magnetic disk, a shift distance of a recording track shifted from a reference position is detected, and whenever tracking is ended, a correcting operation for aligning a scale with its track is executed. In such a way, a track number of each recording track on the magnetic disk can be detected exactly.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a system for reproducing a magnetic disk recorded in accordance with a certain standard. The present invention relates to a device for detecting the track number from the track.

[Conventional technology]

As a magnetic disk recorded in accordance with a standard, there is, for example, a still video floppy standard in which a plurality of still images are recorded on a magnetic floppy disk in one track.

Currently, there are magnetic disks of various standards, and depending on the standard, the position of unrecorded tracks may be determined. According to the standard, where the position of an unrecorded track can be determined even if no signal is recorded, it is relatively easy to determine the track number of a given track when the playback head tracks that track. (position at the start of the sequence) must be the outermost recording track position, and record with the playback head (move the head while playing the signal indicating the position of No. 3 or the track, and adjust the peaks of the envelope of the playback signal up and down. You can count it with a counter.

However, in the still video floppy standard, a magnetic floppy disk with a fixed diameter is used, and signals in a format specified by the standard are recorded concentrically at a predetermined position on the disk to form a track. , no signal is recorded on the unrecorded track, so the track position is undetermined.

The track position is determined only after recording is performed. The playback device can perform playback by tracking the playback head to an arbitrary track. Tracking to each track is performed, for example, by moving the head in the radial direction of the disk and determining the position where the peak of the envelope of the reproduced signal output is detected as the position where tracking has been achieved.

The still video floppy standard allows the recording signal of any track to be erased, so the recording status of the video floppy tracks is not necessarily filled in order from the outer track number l without leaving any space. It may be random.

The present invention is applicable to a magnetic disk of a standard in which the position of unrecorded tracks is not fixed, such as the still video floppy standard, and in which recorded tracks are randomly formed, and when tracking is performed on an arbitrary track. The present invention relates to a device for detecting the track number of a truck.

[Conventional technology]

When a magnetic disk with random recording based on the standards for magnetic disks for electronic still cameras is loaded into a playback device and tracked to an arbitrary track, the head when the trunking is completed is used to find out the track number of that track. Calculate the distance between the position in the disk radial direction and the outermost track number 〇 (one track pitch outward from track number 1) from the outermost recording track (track number 1) by the track pinch, and calculate the answer. was displayed as a track number on a CRT, etc.

In other words, the playback device is equipped with a fixed scale, and the track number is determined by measuring the head position when tracking is completed using the fixed scale.In the case of zero determination, the position between the tracks is determined using the fixed scale. A generally considered method is to determine the track number based on which region the head is located as a boundary.

Here, magnetic disks allow some variation in track spacing caused by the head feeding mechanism when forming recording tracks, and the disk also includes errors due to thermal expansion and contraction.

Furthermore, if the temperature and humidity conditions during recording and playback are significantly different, errors will be added. Therefore, for reproduction=2, the position of the recording track naturally includes an error.

When reproducing a magnetic disk with such errors in recorded track positions, when the head is tracked to a certain track, the track number is determined by using the conventional fixed scale as the boundary between the tracks. In this method, the track number is determined based on which area the head is located in. If the head is located near the boundary of the area with a certain track number, when tracking other tracks afterwards, the track number will be incorrect due to the above error. There was a problem that the number could be judged incorrectly.

According to the current standard for still floppy disks, each track has a space to write its own track number, but the track number signal according to this standard is unreliable, so there is a problem that it cannot be used as is.

[Problem to be solved by the invention]

The present invention is a magnetic disk of a standard in which the position of an unrecorded track is not fixed, such as the still video floppy standard, and in which recording tracks are randomly formed, in which a playback head can track any track. When detecting the track number of the track '211, the purpose is to detect the track number of the track without error.

[Means to solve the problem]

In order to achieve the above object, the present invention detects the deviation distance of the recording track from the reference position even when the magnetic disk expands or contracts due to temperature changes, and performs a correction calculation to adjust the scale to the track every time tracking is completed. It was configured like this.

[Effect]

According to the above configuration, if the deviation from the reference position is less than + track pitch, the error from the reference position is calculated for each tracking and this is re-corrected as the correction value for the next tracking. Therefore, an accurate track number can be determined without adding errors.

〔Example〕

FIG. 1 is a block diagram showing the configuration of a magnetic recording/reproducing apparatus according to an embodiment of the present invention, and FIG. 2 is a flowchart of an embodiment of the present invention.

In FIG. 1, a magnetic disk is rotated by a servo motor (not shown). A reproduction head 2 that tracks concentric recording tracks formed on the magnetic disk 1 is moved in the radial direction of the disk 1 by a stepping motor 3a. Is step 7 pin motor 3a motor-controlled? 1
1 circuit 3b. Stepping motor 3a
and motor control circuit 3b constitute head moving means 3.

The reproduction signal from the reproduction head 2 is input to the reproduction amplifier 4, and the RF (high frequency) signal outputted by the reproduction amplifier 4 is converted to a voltage level by the envelope line detection circuit 5.
The /D converter 6 outputs the data to the CPU (central processing unit) 7 as, for example, 8-bit digital data.

The CPU 7 has a known tracking function.

Tracking searches for the position where the reproduced signal is the largest and positions the head at that position. For example, when sampling digital data from the A/D converter 6 at 15 times per rotation of the disk, the digital data acquisition pulse is output 15 times during one rotation of the disk. In order to find the maximum value of the reproduction signal level, the CPU 7 compares the maximum value of the 15 digital data captured by the digital data capture timing pulse with the size of the data captured at the previous head position, so that the data always increases. The head moving means 3 is controlled, and when the data becomes small for the first time, the previous head position is set to the maximum position of the reproduced signal level, and tracking is performed to that position.

FIG. 2 is a flowchart showing the operation when detecting a track number.

Step ■ Set the O track at a certain position on the outer circumference from the first track position (outermost recording track) determined by the standard. 0 track = 1 track pitch according to the standard outside the first track > Position the head on the XSO track. .

(In this embodiment, it is assumed that one track pitch is moved by 12 pulses.) Step (2) The head is moved to the inner circumferential side of the magnetic disk to track the first recorded track (nth track).

Step (2) If the track number Tn becomes O as a result of step (2) (the first track has already been recorded and its position has shifted toward the outer circumference), Tn is forcibly set to 1.

When Tn is other than O, the value of Tn is used as the track number.

Step ■ Tn is displayed on a display means such as a CRT.

Step (2) Load the integrated value An of pulses required for the head to move from the O track into the CPU.

Step ■ To obtain the track number (Tn), divide An by the track pitch (ie, 12 pulses) and round off to the nearest whole number.

Step (2) The difference Hn from n times the track pitch (travel distance for 12 pulses) (hereinafter referred to as standard position) is stored as a correction value for the next tracking.

Step (2) Move the head further toward the inner circumferential side of the magnetic disk and track the next recorded track (n'th track).

Step (2) The integrated value An' of the pulses required for the head to move from the 0 track is taken into the CPU.

step [phase] Add +In obtained in ■ to An' to obtain A'n'.

As a result, the difference between A l n+ and the standard position is N+1
Track pitch error from track to first track (
(errors during recording, thermal expansion, contraction), and if there are no errors, the position will always be the standard position.

Step (2) To obtain the track number (Tn'), divide A'n' by the track pitch (12 pulses) and round off to the nearest whole number.

Step @ CR the track number (Tn') obtained in step 0
It is displayed using a display means such as T.

Step (2) Calculate the difference 12Xn'-A'n' from the standard position of A'n', add it to Hn, and store it as a correction value for the next tracking.

If another track is to be played back, the process returns to step (3) and the process continues.

As is clear from the explanation using the above flowchart, in the present invention, a conventional playback device is provided with a fixed scale, and the head determines the track number within a range of 10 tracks on either side from the reference track position using the solid scale. In contrast to this method, the scale is adjusted to the track every time tracking is completed, and if the error in the distance between adjacent recording tracks is within 10 track pitches, the track number can be determined accurately. .

〔Effect of the invention〕

As described above, according to the present invention, even if the position of the recording track deviates from the position determined by the standard by within 10 of the standard track interval due to expansion and contraction due to temperature changes in the environment of the magnetic disk, the recording track deviates from the standard position. Since the track deviation distance is detected and a correction calculation is performed to match the scale to that track every time tracking is completed, each recording track on the magnetic disk,
Thus, it is possible to obtain a track number detection device for a magnetic disk reproducing device that can accurately detect the track number of a magnetic disk.

Claims (1)

[Claims] A device for reproducing a standard magnetic disk in which a plurality of concentric tracks are recorded at a standard track pitch determined by the standard, and recording tracks are formed randomly without determining the position of unrecorded tracks. Head moving means for moving the reference track pitch using a plurality of head movement pulses; Tracking means for tracking the reproduction head to an arbitrary track; and said movement from track 0 to an arbitrary tracked track (n track). an integrating means for integrating the number of pulses (An); a dividing means for dividing the output (number of pulses An) of the integrating means by the number of head movement pulses required to move the reference track pitch; and a calculation result of the dividing means is 0. track number calculating means for rounding off to the nearest whole number when there is a remainder, displaying means for displaying the output of the track number calculating means, and any tracked track from track 0. a storage means for storing the difference (error Hn) between the number of movement pulses (An) up to track n and the standard number of movement pulses up to the reference position as a correction value; correction value addition means for adding the number of movement pulses produced by the integration means at the position to the correction value Hn at the previous tracking position stored in the storage means (An'+Hn=A'n'); The output (A'n') of the value addition means is input to the track number calculation means to calculate a track number and display it on the display means, and the storage means stores information from track 0 for second and subsequent tracking. Track number detection for a magnetic disk reproducing device, characterized in that the difference (error Hn') between the number of moving pulses (An) and the standard number of moving pulses to a reference position is sequentially updated and stored as a new correction value. Device.