JPS6236300B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a recording device that sequentially records signals as a spiral recording trajectory on a rotationally driven disc-shaped recording medium using a signal converting element. By keeping the relative speed of the peripheral portion to the signal conversion element constant, the recording density is substantially improved.

Conventional disk-shaped recording medium (hereinafter referred to as disk)
Since the recording device using the disc records signals using a signal conversion element while the disc rotates at a constant speed, the relative speed of the signal conversion element at the outer and inner parts of the disc differs greatly, resulting in a decrease in relative speed. The recording and reproducing characteristics at the inner circumferential portion deteriorated.

The present invention provides a specific means for solving this problem, and uses a simple configuration to make constant the relative speed between the inner and outer peripheral portions of the disk and the signal conversion element.

Description will be given below with reference to the drawings.

In FIG. 1, 1 is a disk placed on a turntable 2;
is rotationally driven by a first synchronous motor 3. 4 is a recording head fixed to a movable table 5, and the movable table 5 is connected to a second synchronous motor 6.
It is connected to a threaded rod 7 that is rotationally driven, and is configured to move sequentially in the diametrical direction of the disk 1 in accordance with the rotation of the threaded rod 7.

Here, x _p is the distance from the center of the disk 1 of the recording head 4 to the recording start point, t=o is the recording start time, and x(t) is the distance from the center of the disk 1 at time t, and the time If the rotational angular velocity of the first synchronous motor 3 at time t is ω(t), the relative speed between the recording head and the disk is V, and the track pitch recorded on the disk is P, then ω(t)・x=V πx ² −πx ² _p = P・V・t From now on Also, ω(t)=V/x......(B) Therefore, in order to maintain a constant relative speed, the angular velocity of the motor 3 must be adjusted to the position of the recording head or the time t from the recording start point (t=o). According to (A)
It can be seen that it must be controlled to the value given by formula or formula (B). The present invention has been embodied as follows.

Figures 2A and 2B show equations (A) and (B) expressed in graphs, respectively.

In FIG. 1, 8 is an oscillator that generates a clock signal of a constant period, and its output is applied to a counter 9. Counting is started by a start signal applied to the terminal 20 when the recording head 4 of the counter 9 is at the recording start point x _p of the disk 1. An output of the counter 9 indicating a count value proportional to the passage of time is applied to a data converter 10. 10 data converters are
It consists of ROM and is programmed in advance to convert the input counter output to approximate equation (A). Therefore, the output of data converter 9 corresponds to the horizontal axis (t) of the graph of formula A in FIG. 2, and the output of data converter 10 corresponds to the vertical axis (ω) of the graph of formula A. The output of this data converter 10 is converted into a DC voltage by 11 D/A converters, and applied to 12 V/F converters.
A frequency proportional to the output of the data converter 10 is generated. The output of this V/F converter 12 is applied to the synchronous motor 3 via a frequency divider 13 and a motor drive circuit 14.

That is, after the motor 3 is started, the number of revolutions of the motor 3 gradually decreases as time passes so that formula A is satisfied.

Further, a part of the output of the V/F converter 12 is applied to the synchronous motor 6 via the frequency divider 15 and the motor drive circuit 16, and after the synchronous motor 6 is started, the number of rotations increases sequentially as time passes. decreases. Therefore, by appropriately determining the frequency division ratios of the frequency dividers 13 and 15, the rotation speed of the disk and the rotation speed of the feed motor can be sequentially changed depending on the recording position of the recording head 4 in the radial direction of the disk 1. However, it is possible to draw a helical recording trajectory with a constant track pitch while keeping the relative speed between the recording head 4 and the disk 1 constant.

At this time, if the signal recorded by the recording head 4 is a signal including a synchronization signal of a constant period, such as a video signal, the intervals of the synchronization signals on the recorded recording trajectory will be equal intervals. During reproduction, the rotation speed of the reproduction disk may be controlled so that the frequency of the synchronization signal in the reproduced signal becomes a predetermined value.

In the embodiment, an example was shown in which a constant cycle signal obtained from the oscillator 8 was used as the clock signal.
Control may also be performed so that equation B is satisfied using pulses generated from a linear encoder or the like that indicates the position of the recording head 4.

In addition, in the embodiment, the output of counter 9 is input to data converter 10 to satisfy the above formula (A), but instead, a variable frequency divider is inserted between counter 9 and oscillator 8. , it is also possible to approximate the curve shown in Figure 2 as a broken line by controlling its frequency division ratio, or by using other arithmetic devices, or by using D/
It is also possible to achieve the same effect by controlling the DC voltage generated after passing through the A converter.

As described above, according to the present invention, since the rotational speed of the disk and the moving speed of the recording head are electrically controlled, the relative speed between the recording head and the disk can be controlled at any point on the disk with a simple configuration and with high precision. It is something that can be kept constant.

Furthermore, since the processing is done digitally, there is no change over time or temperature fluctuations, allowing for stable and highly accurate control. Furthermore, since the disk motor and the feed motor are independently and synchronously controlled, they are stable against disturbances such as load fluctuations. Furthermore, by changing the frequency division ratio of the function generator and variable oscillator, the relative speed and track pitch can be electrically changed freely.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the present invention;
FIG. 2 is a diagram showing the operation of the present invention. 1... Disc-shaped recording medium, 3, 6... Synchronous motor, 4... Recording head, 5... Moving table, 7
……Threaded rod, 8… Oscillator, 9… Counter, 1
0... Data converter, 12... V/F converter, 13, 15... Frequency divider, 14, 16... Motor drive circuit.

Claims (1)

[Claims] 1. In a recording device that sequentially records signals as a spiral recording trajectory on a rotationally driven disc-shaped recording medium by a recording head that sequentially moves in the radial direction of the recording medium, a clock generating means for counting the time of the time, a counting means,
comprising: a function generating means for converting the output of the counting means into a predetermined function output; and a variable oscillator generating a frequency proportional to the output of the function generating means, in synchronization with the output of the variable oscillator, By controlling a motor that rotates the recording medium and a feed motor that transports the recording head in the radial direction in synchronization with the output of the variable oscillator, the relative relationship between the recording head and the disc-shaped recording medium is controlled. A recording device using a disk-shaped recording medium that is characterized by a constant speed. 2. The recording apparatus according to claim 1, wherein the output of a position detector that digitally detects the position of the recording head is used as an input to the function generating means.