JPH05182378A - Disk type data recorder - Google Patents

Abstract

PURPOSE:To make a data rate constant in the disk type data recorder adopting the MCAV system. CONSTITUTION:A 1st head 1 is arranged to an inner circumference of a data recording medium disk 5 subject to drive control at a prescribed rotating speed and a 2nd head is arranged on an outer circumference respectively and head seek control circuits 3, 4 and a recording and reproducing control circuit 7 or the like are used to apply seek control to the heads reciprocally and the recording frequency is controlled and recording and reproducing information is shared by the heads 1, 2 in a signal processing circuit 10. For example, when the 1st head is sought to the inside of the disk, the 2nd head is sought to the outside. Furthermore, each recording frequency of each head is changed according to each track number.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data recording device,
In particular, it relates to a disk type data recording device.

[0002]

2. Description of the Related Art In a conventional disk type data recording device,
Basically, the rotation speed of the disk is constant regardless of the track to be accessed. This method is CAV
(Constant Angular Velocity) method. CA
In the V method, since the data density on the outer circumference of the disk becomes low, an MCAV (Modified-CAV) method is considered in which the recording frequency is increased toward the outer circumference of the disk to make the data density almost constant.

A method of controlling the number of revolutions of the disk so that the speed of the head with respect to the disc is constant, that is, a CLV (Constant Linear Velocity) in which the number of revolutions is increased at the time of inner circumference access and lowered at the time of outer circumference access.
There is also a method. Further, an MCLV (Modified-CLV) system is considered in which the number of tracks is fixed instead of continuously changing the number of revolutions of the disk, and the number of revolutions is changed stepwise. These CAV, MCAV, CL
The V and MCLV methods are shown together in Fig. 3 (M. Onoe:
"Optical disk technology", Radio Technology Co., Ltd., 1990).

[0004]

[Problems to be Solved by the Invention] Conventional CLV, M
The CLV has a problem that the control circuit is complicated because the rotation speed of the disk is changed. Further, since reaction torque is generated with the change in rotation of the disk, there is a problem that it becomes a disturbance torque when it is used as a data recorder of an artificial satellite.

From the above, an MCAV that solves the low data density on the outer periphery of the CAV is desirable, but in this system, the data rate at the time of recording and reproducing is not constant. Therefore, it is not suitable for recording sensor data or the like in real time. Further, even when reproducing and transmitting data, it is difficult to transmit the data as it is unless the data rate is constant. It is an object of the present invention to provide a data recording device capable of making the data rate constant in the MCAV system.

[0006]

According to the present invention, a first head is arranged on the inner peripheral side and a second head is arranged on the outer peripheral side of a data recording medium disk whose rotation is controlled at a constant rotational speed. And a recording frequency are controlled reciprocally, and recording / reproducing information is shared by the heads. That is, when the first head seeks to the inside of the disk, the second head seeks to the outside, and when the first head seeks to the outside, the second head seeks to the inside, and each head goes to its own track. Each recording frequency is changed according to the number. or,
At the time of recording, the data is divided into heads and recorded on the disk, and at the time of reproduction, the data read from the heads are combined and output.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of an embodiment of the present invention.
With respect to the recording disk 5, the first head 1 is arranged on the inner circumference side, the second head 2 is arranged on the outer circumference side, and the head seek control circuits 3 and 4 are respectively made to seek. The heads 1 and 2 are connected to a signal processing circuit 10 via input / output buffers 8 and 9, respectively. The signal processing circuit 10 and the head seek control circuits 3 and 4 are connected to the recording / reproducing control circuit 7, respectively. The recording data 11 is input to the signal processing circuit 10, and the reproduction data 12 is output. Reference numeral 6 is a disk rotation control circuit for controlling the rotation of the disk 5.

According to this structure, the recording / reproducing control circuit 7 performs recording at a high frequency on the outer circumference and at a low frequency on the inner circumference in almost proportion to the radius of the tracks accessed by the heads 1 and 2. Then, the signal processing circuit 10 is controlled. That is, the track radius is r [m] and the disc rotation speed is Ω.
[Rad / sec], the bit interval on the track is δ
_{When B} [m] is set, the recording frequency f is expressed by the following equation. f = Ω · r / δ _B (1) Here, as shown in FIG. 2, the tracks on the disk 5 are track 0, track 1, ..., Track (2
n-1). When the radius of the track 0 is r ₀ and the track interval is δ _T , the radius r _N of the track number _N is expressed by the following equation. r _N = r ₀ + N · δ _T (2)

Further, the recording / reproducing control circuit 7 controls the seek of the two heads 1 and 2 as follows. First head 1,
The initial position of the second head 2 is set to track 0 and track (2n-1), respectively. As the first head 1 seeks from track 0 to track 1 and track 2, the second head 2 moves from track (2n-1) to track (2n-2),
Seek to track (2n-3). That is, assuming that the track number accessed by the first head 1 is N1 and the track number accessed by the second head 2 is N2, N1 and N2 are controlled so as to have the relationship shown by the following equation. It N1 + N2 = 2n-1 (3)

Here, the time t required for the disk rotating at the rotation speed Ω [rad / sec] to rotate θ [rad].
Is expressed by the following equation. t = θ / Ω (4) The number of bits D written by both the first head 1 and the second head 2 during this t is calculated by the following equation. D = (f _N1 + f _N2 ) · t (5) From equations (1) to (3), it is understood that D is represented by the following equation. D = Ω · t {2r ₀ + (2n−1)} / δ _B (5) ′

As described above, the first head 1 and the second head 2
Is controlled so as to have a relationship as shown in equation (3), the number of bits written by both heads becomes constant. The signal processing circuit 10 divides the D-bit data into D1 and D2 represented by the following equation and supplies them to the first head 1 and the second head 2. D1 = f _N1 · t (6) D2 = f _N2 · t (7) Similarly, at the time of data reproduction, D1 bit data and D2 bit data are read between head 1 and heads 2 to t, respectively. The signal processing circuit 10 combines this data with the D-bit data and outputs it. In this way, the recording / reproducing data rate becomes constant.

[0012]

As described above, according to the present invention, by combining two heads for the inner circumference and the outer circumference for recording / reproducing at a frequency proportional to the radius of the track, MCAV
Even though the system is adopted, there is a result that the data rate of recording and reproducing can be made constant.

[Brief description of drawings]

FIG. 1 is a block diagram of a disk type data recording device of the present invention.

FIG. 2 is a conceptual diagram showing tracks on a disc.

FIG. 3 is an explanatory diagram showing various conventional methods.

[Explanation of symbols]

 1 1st head 2 2nd head 3,4 head seek control circuit 5 disk 7 recording / reproducing control circuit 10 signal processing circuit

Claims (2)

[Claims] 1. A disk-type data recording apparatus comprising a data recording medium disk whose rotation is controlled at a constant rotational speed, and a recording / reproducing head which is seek-controlled to the disk. A means for arranging one head and a second head on the outer peripheral side, respectively, reciprocally performing seek control of these heads and controlling the recording frequency thereof, and controlling the recording / reproducing information to be shared by the respective heads is provided. A disk-type data recording device, comprising: 2. When the first head seeks inward, the second head seeks outward, when the first head seeks outward, the second head seeks inward, each head 2. The disk-type data recording device according to claim 1, wherein each recording frequency is changed according to the track number, the data is divided into respective heads for recording on the disk at the time of recording, and the data read from each head is combined and outputted at the time of reproduction. ..