JP3049998B2 - Disk recording device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disk recording apparatus for recording a video signal and an audio signal on an optical or magnetic disk.

[0002]

2. Description of the Related Art When a computer or audio digital data is recorded on a conventional optical or magnetic disk device, recording tracks are previously set on a disk to be recorded, and sectors are also recorded on the recording tracks. An area divided into sections of an appropriate length to which address data called beforehand is added is set, and the recording data is recorded for each sector.

The upper limit of the recording speed of data recorded on a disk is physically determined by the recording wavelength, the relative speed between the recording head and the disk, and the like. In the current data file device that records computer data, etc., the data sent from the computer is much faster than the recording speed to the disk device, and in fact, it is slightly faster than the recording speed of the disk on the computer side. It responds by sending out data one by one.

On the other hand, a recently practically used apparatus for digitally compressing and recording audio has a recording / reproducing speed enough to record digital data before compression, for example, it is compressed to a quarter. In the case of recording digital voice, recording can be performed at four times the speed of input recording data. Therefore, as an actual recording operation, an operation of storing data to be recorded in a buffer memory, and recording the data on a disk after a certain amount of data is accumulated is repeated.

As described above, in a conventional apparatus for recording digital data, there is a large gap between the recording speed and the input speed of the data to the apparatus. .

[0006]

However, in a device such as a digital video disk which digitizes and records a television image signal, the speed of the digital image signal data to be recorded is at a speed close to the limit of the recording speed of the recording device. Moreover, since the data is supplied in real time, it is technically difficult for the recording speed of the recording device to greatly exceed the supplied digital data speed.

Therefore, in practice, the supplied video signal digital data speed and the recording speed are made to coincide with each other, that is, recording is performed in synchronization. However, in this configuration, if the track goes off due to an external impact during recording, the recording will be interrupted from that moment, and even if it returns to the original track, the data until the return will be lost. Become. If such an event occurs while recording an important scene, there is a problem that this device may be fatal.

The present invention has been made in view of the above problems, and provides a disk recording apparatus capable of performing continuous recording even when a track is deviated due to an external impact or the recording speed of the recording apparatus fluctuates. .

[0009]

In order to achieve the above object, a disk recording apparatus according to the present invention is provided on a disk recording medium.
Record digital data on a track composed of
Recording means including a recording head;
Error signal and / or pre-recorded on the track
Address data to detect track deviation
Check that the digital data to be recorded is
Buffer memory means for temporarily storing and reading out data,
When the off-track detector detects the off-track,
Recording head system that returns to the track to be recorded
Control means and the off-track detection means
The buffer memory means stops the recording at the same time as the detection.
While storing digital data to be temporarily recorded in
After the recording means returns to the original track,
Record digital data stored in buffer memory means
And rewrite on the disk recording medium.
Digit for one sector, which is the smallest unit block that can be
Record data in the buffer memory
The recording means is off track and the original recording
When returning to the recording sector of the track to be
From the beginning of the sector at the moment when the
Record digital data stored in memory means
And a memory control means for controlling the above.

[0010]

According to the present invention, recording can be continuously performed on the disk without interruption even if the disk recording means is out of track due to an external impact or the rotational speed of the disk fluctuates.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of a signal recording process according to the first embodiment of the present invention for coping with an off-track.

In FIG. 1, reference numeral 1 denotes a digital video signal processing circuit which digitizes an input video signal such as a television signal and converts it into digital data suitable for recording on a disk 5; A buffer memory circuit for storing data, which is controlled by a write address generation circuit 9 and a read address generation circuit 10 which will be described later. Reference numeral 3 denotes a recording modulation circuit for modulating a signal to a modulation method suitable for recording on the disk 5 and adding an error correction signal. Reference numeral 4 denotes an optical head for recording a signal on the disk.
Is a motor for rotating the disk 5, and 7 is a disk rotation control circuit for controlling the rotation of the motor 6, which is typically a rotation reference signal (not shown) obtained by dividing the output clock of a fixed clock generation circuit 8 described later. To control the disk 5 to rotate at a constant rotational speed.

Reference numeral 8 denotes a fixed clock generation circuit for generating a reference clock of the disk drive. If the input clock signal is synchronized, a genlock oscillator is used. When the genlock is applied to the input video signal, the rotation of the disk is synchronized with the time axis of the input video signal. Reference numeral 9 denotes a write address generation circuit that controls writing in the buffer memory circuit 2 based on a clock supplied from the fixed clock generation circuit 8, and 10 denotes a read address generation circuit that controls reading in the buffer memory circuit 2, which is usually described later. Fixed clock generation circuit 8 through clock switch 15
Clock is supplied.

Here, it is assumed that the optical head 4 has deviated from the track due to an external factor such as an impact applied to the apparatus. In this case, the sector address detection circuit 11, which constantly monitors the sector address during recording, can detect the off-track since consecutive sector numbers become discontinuous or cannot be read. Also, if the tracking signal is also monitored by the tracking control circuit 12 for controlling the optical head 4, a large waveform disturbance occurs at the moment when the track goes off, so that it can be detected. Reference numeral 13 denotes an off-track detection circuit that detects an off-track from the output signals of the sector address detection circuit 11 and the tracking control circuit 12.

When an off-track is detected, first, the reading of the buffer memory circuit 2 is stopped, and at the same time, the recording of the optical head 4 is interrupted. The optical head 4 is returned to the track number or the sector number immediately before the optical head 4 comes off by an optical head control device (not shown).

Next, after the optical head returns to the beginning of the sector of the original sector number of the original track, the clock changeover switch 15 is set from the fixed clock side in the normal state.
For example, the output is switched to the high-speed clock generation circuit 14 having a high frequency of 20%, reading of the buffer memory circuit 2 is started, and the recording operation is restarted. The reason for returning to the beginning of the original sector and restarting the recording is that the recording on the disk is performed in sector units. Although not shown, the disk rotation control circuit 7 is supplied with a fixed clock and a high-speed clock, and when the track goes off the track, the disk rotation is controlled to increase according to the high-speed clock.
Note that the fixed clock generation circuit 8 and the high-speed clock generation circuit 14 do not necessarily need to be separate circuits, and may have outputs that can be switched integrally.

As described above, when an off-track occurs, the recording is interrupted until the optical head 4 returns to the original track, so that the digital data for that period is stored in the buffer memory circuit 2. . Now, for example, assuming that the normal recording rate is 50 Mbps and it takes 100 msec before the optical head returns, 5 Mbit data is stored in the buffer memory circuit 2. Therefore, when the rotation speed is increased by, for example, 20%, the recording rate becomes 60 Mbps, and the 5 Mbps data stored in the buffer memory circuit 2 becomes empty in 0.5 seconds. When the buffer memory circuit 2 becomes empty, the disk rotation speed is restored.

Next, a block diagram of a signal recording process according to a second embodiment of the present invention for coping with fluctuations in the rotational speed will be described with reference to FIG. The same blocks as those in FIG. 1 are given the same numbers.

In FIG. 2, reference numeral 1 denotes a digital video signal processing circuit which digitizes an input video signal such as a television signal and converts it into digital data suitable for recording on a disk 5; A buffer memory circuit for storing data, 3 is a recording modulation circuit for modulating a modulation method suitable for recording on the disk 5 and adding an error correction signal, 4 is an optical head for recording a signal on the disk 5, and 6 is a disk Reference numeral 7 denotes a motor for rotating the motor, and 7 denotes a disk rotation control circuit for controlling the rotation of the motor 6.

Reference numeral 8 denotes a fixed clock generating circuit for generating a reference clock for the disk drive. If the input clock signal is synchronized with the input video signal, a genlock oscillator is used. Reference numeral 9 denotes a write address generation circuit that controls writing to the buffer memory circuit 2 based on a clock supplied from the fixed clock generation circuit 8, and 10 denotes a read address generation circuit that controls reading from the buffer memory circuit 2. A clock is supplied from a clock generation circuit 17. 11
Is a sector address detection circuit that constantly monitors sector addresses during recording on the disk 5 to be recorded, and 12 is an FG pulse detection circuit that detects the number of revolutions of the motor 6.

At the time of normal recording, the sector address is always monitored, and recording of predetermined data is started when the head approaches the sector at the address. If the head is moved, the apparatus is moved during recording. Assuming that the rotation of the disk fluctuates due to external factors such as swinging or swinging, the relative speed between the head and the disk fluctuates instantaneously, and the time required for the head to scan the corresponding sector fluctuates. I do. For example, if the rotation speed of the disk 5 instantaneously increases, there is no time to write all data to the sector to which the head is going to write during that period, and data that cannot be recorded comes out.

In order to cope with such a situation, the relative speed of the disk is detected from the sector address data read by the sector address detection circuit 11, and the rotation speed of the disk is detected by the FG pulse detection circuit 16. The variation of the disk rotation is detected, and a signal corresponding to the variation is supplied to the variable clock generation circuit 17. The variable clock generation circuit 17 generates a clock corresponding to the change in the rotation speed of the disk 5 and supplies the clock to the read address generation circuit 10.

With this configuration, even if the rotational speed of the disk 5 fluctuates, the speed of the data to be written can be made variable in accordance with the fluctuation, and the write data can always be accurately contained in the sector. Become.

Reference numeral 18 denotes a first arithmetic circuit for measuring the amount of data stored in the buffer memory circuit 2 from the write address and the read address. Generates a corresponding signal. Reference numeral 19 denotes a second arithmetic circuit, and the first arithmetic circuit 18
Is added to or subtracted from the rotation reference signal supplied to the disk rotation control circuit 7 to change the rotation speed of the disk 5.

According to this configuration, it is possible to automatically make the data to be recorded stored in the buffer memory circuit 2 at the time of recovery after an instantaneous rotation speed fluctuation occur automatically constant.
It also automatically responds to the increase in the number of revolutions after returning from the off-track state described in FIG.

[0026]

As described above, the present invention is effective in recording a high transfer rate signal, that is, in the case of a video disk in which the recording speed of the recording device has little margin for the speed of the data to be recorded. In particular, it is possible to realize a system that is resistant to shock, vibration, and rolling with respect to a portable system.

[Brief description of the drawings]

FIG. 1 is a block diagram of a disk recording device according to a first embodiment of the present invention.

FIG. 2 is a block diagram of a disk recording device according to a second embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 1 digital video signal processing circuit 2 buffer memory circuit 3 recording modulation circuit 4 optical head 5 disk 6 motor 7 disk rotation control circuit 8 fixed clock generation circuit 9 write address generation circuit 10 read address generation circuit 11 sector address detection circuit 12 tracking Control circuit 13 Off-track detection circuit 14 High-speed clock generation circuit 15 Clock switch 16 FG pulse detection circuit 17 Variable clock generation circuit 18 First operation circuit 19 Second operation circuit

Claims (1)

(57) [Claims] 1. A recording means including a recording head for recording digital data on a track formed on a disk recording medium, and monitoring a tracking error signal and / or address data previously recorded on the track during recording. Off-track detection means for detecting off-track;
Buffer memory means for temporarily storing and reading digital data to be recorded; recording head control means for performing an operation of returning to the original track to be recorded when the off-track detecting means detects an off-track; At the same time as the off-track detecting means detects the off-track, the recording is interrupted and the digital data to be temporarily recorded is stored in the buffer memory means while the recording means returns to the original track, and the data is again stored in the buffer memory means. by controlling so as to record the accumulated digital data was collected by
Also, the smallest rewritable unit block on the disk recording medium
Record one sector of digital data that is locked
At the same time, store the data in the buffer memory
Recording of the original track to be recorded after the step goes off track
The moment when the track is detected when returning to the sector to be
Stored in the buffer memory means from the beginning of the sector between
A disk recording device, comprising: a memory control means for controlling digital data to be recorded .