JPS63140459A - Information recording and reproducing device - Google Patents

Abstract

PURPOSE:To attain pseudo overwriting and to eliminate erasing action beforehand by providing a control means to repeat alternately the erasing and a time base compression recording at the time of recording. CONSTITUTION:A spindle motor 17 is controlled by a spindle motor control circuit 112 so that the rotational speed of a rotary disk 15 at the time of recording can be two times compared with the time of reproducing, for the laser spot, erasing is executed at a first trace by a tracking control circuit 111, the time base compressing recording is executed at a second rotation trace, the spot is moved to the next track and the above-mentioned actions are repeated. At such a time, the information in the compressing recording time including the erasing time is written once into memories 21 and 22 in an information compressing circuit 110, the time base is compressed to two times, and thereafter, written into the rotary disk 15. Thus, it is not necessary to erase the recording medium only for the part necessary to recording beforehand, and the pseudo overwriting can be executed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an information recording and reproducing apparatus that reproduces recorded information.

BACKGROUND OF THE INVENTION In recent years, information recording and reproducing apparatuses capable of recording and reproducing large volumes and high density have been actively developed. DESCRIPTION OF THE PREFERRED EMBODIMENTS An example of a recording and erasing method of a conventional information recording/reproducing apparatus will be described below with reference to the drawings, taking a magneto-optical disk as an example.

FIG. 4 shows a recording and erasing method of a conventional information recording/reproducing device. In FIG. 4, 41 is a laser drive circuit, 42 is a laser, 43 is a beam splitter, and 44 is an objective lens, which focuses the light emitted from the laser 42 onto a minute spot. 45 is a rotating disk which is a recording medium, and 46 is a bias magnetic field applying device that applies reverse magnetic fields to the laser beam irradiation section during recording and erasing.

47 is a spindle motor, 48 is an analyzer, and 49 is a photodetector.

The operation of the information recording/reproducing apparatus configured as described above will be explained below.

During recording, the input signal is modulated by the laser drive circuit 41 to fully control the output light of the laser 42. The laser beam emitted from the laser 42 passes through a beam splitter 43, is focused into a minute spot by an objective lens 44, and is irradiated onto a rotating disk 45 which is being rotated at a constant speed by a spindle motor 47. This laser spot is used to raise the temperature of the medium and lower its coercive force. At this time, if a bias magnetic field is applied from the outside by the bias magnetic field applying device 46, the magnetization of only the portion irradiated with the laser beam is reversed, and information is recorded.

For erasing, reverse the direction of the bias magnetic field from that for recording.
This is done by irradiating all the laser beams that are not intensity modulated and aligning all the magnetizations on the medium in the same direction.

Reproduction uses the Kerr effect, in which a linearly polarized laser beam is incident on the entire medium, and the direction of rotation of the polarization plane of the reflected light is reversed due to the reversed polarity of magnetization. The laser beam is incident on a rotating disk 45 rotated at the same speed as during recording, and its reflected light is input to an analyzer 47 via a beam splitter 46. Analyzer 4
7 converts the direction of rotation of the deflection surface into a change in the amount of light,
It is detected by a photodetector 48.

Problems to be Solved by the Invention However, with the above-described recording method, it is necessary to erase the information once before recording on a portion of the medium that has already been recorded. Therefore, when recording a temporally continuous signal such as an audio signal, it is very inconvenient to enter an erasing operation in advance, erase all the area required for recording, and then return to the initial position and perform the recording operation again. It had the problem that.

The present invention has been made in view of the above-mentioned problems, and it is an object of the present invention to provide an information recording and reproducing apparatus that can perform direct recording without entering an erasing operation in advance and erasing the entire area required for recording.

Means for Solving the Problems In order to solve the above-mentioned problems, the information recording and reproducing apparatus of the present invention includes means for compressing and recording the entire time axis of information on a recording medium, and means for erasing the recorded information. and a reproduction means, and a control means for alternately repeating recording, erasing, and time axis compression recording.

Effect: With this configuration, since the recording medium is erased while moving along the track immediately before recording, it is unnecessary to erase the recording medium in advance by the amount necessary for recording, and pseudo override is possible.

Embodiment Hereinafter, an information recording/reproducing apparatus according to an embodiment of the present invention will be described using a magneto-optical disk as an example, with reference to the drawings. FIG. 1 shows an information recording/reproducing apparatus according to an embodiment of the present invention, and FIG. 2 shows details of its main parts. In Figure 1,
11 is a laser drive circuit, 12 is a laser, 13 is a beam splitter, and 14 is an objective lens, which focuses the laser beam emitted from the laser 12 onto the micro spot 7).

15 is a rotating disk, and 16 is a bias magnetic field applying device that applies reverse magnetic fields to the laser beam irradiation section during recording and erasing. 17 is a spindle motor, 18 is an analyzer, and 19 is a photodetector.

Reference numeral 110 denotes an information compression circuit, which compresses the information in the time axis. Further, 111 is a tracking control circuit;
12 is a spindle motor control circuit, and 113 is a system control circuit.

The operation of the information recording/reproducing apparatus configured as described above will be explained below. The basic principles of recording, erasing, and reproducing the information recording and reproducing apparatus of this embodiment are the same as those of the conventional example, so they will not be explained here.

First, the information compression circuit 110 is well known and is composed of, for example, two memories 21, 22 and two switches 23, 24 as shown in FIG. The input signal is switched to switch 2.
3 to one memory 21, the clock frequency fw
At the same time, the signal written in the other memory 22 is read out via the switch 24 at the read clock frequency fr. The time compression rate of this circuit 11o is 0, which is expressed by the following equation (1).

K0= fW/fr(1-・・・・・・・・・・(1
) These writing and reading operations are appropriately alternately performed in both memories 21 and 22, and both switches 23 and 24 are also switched.

In this embodiment, 0=172, and the information compression circuit 110
outputs a signal that is twice the time axis of the input signal. The time-axis compressed signal is modulated by the laser drive circuit 11 to control the output light of the laser 12. A spindle motor control circuit 112 controls the spindle motor 17 so that the rotational speed of the rotating disk 15 during recording is twice that during reproduction. The laser beam emitted from the laser 12 passes through the entire beam splitter 13 and passes through the objective lens 14.
The light is focused on a tiny spot by The focused laser spot traces the same track twice by the tracking control circuit 111, and then moves to the next track. That is, the operation of erasing with the first trace, time-base compressed recording with the second trace, and moving to the next track is repeated. At this time, the information during the compressed recording time, including the erase time, is stored in the memo in the information compression circuit 110 once.
721.22, and after compressing the time axis twice, it is written to the rotating disk 15. In order to appropriately perform the above operations, the system control circuit 113 includes the laser drive circuit 11, the bias magnetic field application device 16, and the information compression circuit 1.
10, controls a tracking control circuit 111 and a spindle motor control circuit. FIG. 3 shows the alternately repeated erasing and compression recording, and the laser output and bias magnetic field during erasing and compression recording.

As described above, according to this embodiment, since erasing and recording of time axis compression information are repeated, pseudo overriding becomes possible. Furthermore, this method is industrially extremely useful because it is compatible with conventional examples.

Similarly, although this embodiment has been explained using a magneto-optical disk as an example, it may also be a video tape recorder or a tape recorder that changes the relative position of a recording means such as a magnetic head and a recording medium such as a magnetic tape. be.

Effects of the Invention As described above, according to the present invention, it is possible to perform a pseudo override, and it is possible to provide an excellent information recording/reproducing device that does not require an erase operation in advance. Furthermore, since the present invention can be realized with one head and one beam, it can be realized with a simple configuration.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of an information recording and reproducing apparatus according to the present invention, FIGS. 2 and 3 are block diagrams and conceptual diagrams for explaining the embodiment, and FIG. 4 is a conventional information recording and reproducing apparatus. It is a block diagram showing an example. 11... Laser, drive circuit, 12... Group laser, 13... Beam splitter, 14...
...Objective lens, 16゛°°°°゛rotating disk, 16
...Bias magnetic field applying device, 17...°...
Spindle motor, 18... Analyzer, 19...
...Photodetector, 110... Information compression circuit,
111... Tracking control circuit, 112...
・°°゛Hindle motor control circuit, 113...
・System control circuit, 21.22...Memory,
23.24...Switch.

Claims (8)

[Claims] (1) A recording means for recording time-axis compressed information on a recording medium, an erasing means for erasing the recorded information, a reproduction means for reproducing the recorded information, and erasing and time-axis compressed recording during recording. An information recording/reproducing apparatus characterized by comprising a control means for alternately repeating the following. (2) The recording means for recording time-axis compressed information on a recording medium records by changing the relative position of the recording means and the recording medium. information recording and reproducing device. (3) The information recording and reproducing apparatus according to claim 1, wherein the recording medium is a disc-shaped recording medium. (4) The information recording and reproducing apparatus according to claim 1, wherein the recording means and the reproducing means use optical means. (5) The recording means for compressing and recording information on a recording medium on a time axis increases the relative speed with respect to the recording medium according to the information bit speed after compression. The information recording and reproducing device described. (6) The information recording and reproducing apparatus according to claim 1, wherein the recorded information bit rate before compression and the reproduced information bit rate are the same. (7) The recording means for recording information in a time-axis compressed manner sequentially performs two operations of erasing the area and time-axis compression recording within the predetermined time on a medium area that can be reproduced within a predetermined time during reproduction. An information recording and reproducing apparatus according to claim 1, characterized in that: (8) The information recording and reproducing apparatus according to claim 7, wherein the relative speed of the recording medium is more than twice that during reproduction.