JPH0438630Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a spindle servo device, and can be applied to video disk devices such as optical disks and magneto-optical disks.

[Conventional technology]

Conventional video disk devices have been used for a variety of purposes, such as recording still images such as photographs and graphic images, in addition to recording video signals mainly consisting of moving images such as television signals. Development is underway.

When recording video signals on a disk, marks corresponding to horizontal and vertical synchronization signals (these are called synchronization signal marks) are recorded on the disk in the direction of track rotation, and the video signals are recorded on the disk. When recording, the horizontal and vertical synchronization signal marks are reproduced while the disk is rotated by a spindle, and the reproduced horizontal and vertical synchronization signals are compared with the phases of the reference horizontal and vertical synchronization signals,
The spindle servo device is controlled so that the phase difference is eliminated.

In this way, the video signal of each scanning line can be recorded on each track of the disk at a position synchronized with the horizontal and vertical synchronizing signals recorded on the disk.

[Problem that the invention attempts to solve]

By the way, the frequencies of the horizontal and vertical synchronization signals recorded on the disk take different values depending on the resolution (in other words, the number of scanning lines) of the video signal to be recorded. The number of signal marks differs depending on the resolution of the video signal, so when trying to record video signals with the same disk device using disks for different purposes, the rotation speed of the spindle motor for driving the disk and the phase becomes out of synchronization with the recorded video signal.

In order to solve this problem, a standard synchronization signal source adapted to the horizontal and vertical synchronization signals recorded on the disk has been prepared in the disk device each time.

However, in this case, if the recording mode of the horizontal and vertical synchronization signals recorded on the disk differs, the disk device must be newly designed each time. It has the disadvantage of low compatibility.

This idea was created taking the above points into consideration.
This is an attempt to further improve the compatibility of disk devices with various types of disks.

[Means for solving problems]

In order to solve the above problems, in the present invention, the video signal VD1 of the camera 1 is applied to the first frequency down-converting circuit 5, and the recording horizontal drive signal is sent to the output terminal of the first frequency down-down circuit 5.
HD _R is obtained and input to servo circuit 6, and disk 2
The detected horizontal drive signal HD _D detected from the servo circuit 6 is applied to the second frequency down-down circuit 11 to obtain the reproduction horizontal drive signal HD _P at its output terminal and input it to the servo circuit 6. The servo circuit 6 outputs the recording horizontal drive signal HD. The spindle motor 12 that drives the disk 2 is servo-controlled based on the phase comparison result of _R and the reproduced horizontal drive signal HD _P , and the first and second frequency down-converting circuits 5 and 1
1 transmits a recording horizontal drive signal HD _R and a reproduction horizontal drive signal HD _P having a reference frequency corresponding to a common divisor of the number of scanning lines of the video signal VD1 and the number of scanning lines of the detected horizontal drive signal HD _D. A step-down factor has been selected.

[Effect]

The video signal VD1 is down-converted by the first frequency down-down circuit 5, and the recording horizontal drive signal _HDR having the reference frequency is sent out from the first frequency down-down circuit 5.
In addition, the detected horizontal drive signal HD _D is down-converted by the second frequency down-down circuit 11, and the reproduced horizontal drive signal HD _P having the reference frequency is sent down to the second frequency down-down circuit 1.
1 is sent. Since the recording horizontal drive signal HD _R and the reproduction horizontal drive signal HD _P have the same frequency, the servo circuit 6 can send out a servo drive output to the spindle motor 12 based on the phase comparison result. In this way, a servo circuit having substantially the same configuration can be used for various types of disks, and thereby a disk device having high compatibility with various types of disks can be obtained.

〔Example〕

The following drawings show how this invention can be used to transmit X-ray photographs with a higher resolution than standard television video signals.
A detailed description will be given as an example in which the present invention is applied to a disk device that records on a DRAM (Direct Read After Write) disk.

In FIG. 1, numeral 1 denotes a camera that sends out a high-resolution video signal VD1. In the case of this embodiment, the camera 1 has 1375 scanning lines, the frequency of the horizontal drive signal HD is 4.125 [kHz], and the frequency of the vertical drive signal VD is 6
It has a signal format that satisfies the conditions of [Hz] and disk rotation speed of 900 [rpm].

2 is a disk, and as shown in Fig. 2, a horizontal synchronization signal mark M _HD corresponding to a horizontal synchronization signal is placed circumferentially along the video signal recording track on the inner circumference of the video signal recording area. They are recorded at equal angular intervals. The first mark of this horizontal synchronization signal mark M _HD is the vertical synchronization signal mark M _VD , which corresponds to the vertical synchronization signal.
M _HD is recorded as a longer mark, and thus when the disk 2 rotates once, 525 horizontal synchronizing signal marks M _HD are detected, and the first
The vertical synchronization detection signal is generated at the timing when the th horizontal synchronization detection signal is obtained.

This disk 2 has 525 scanning lines, the frequency of the horizontal drive signal HD is 15.75 [kHz], and the vertical drive signal VD
The frequency is 60 [Hz], the rotation speed of the disk is 1800
It is designed to satisfy the [rpm] condition.

Therefore, the frequency is 15.75 [k] from the detector 3 for detecting the horizontal synchronization signal mark M _HD of the disk 3.
A detected horizontal drive signal HD _D with a frequency of 60 [Hz] is sent out, and a detected vertical drive signal VD _D with a frequency of 60 [Hz] is sent from the detector 4 for detecting the vertical synchronization signal mark M _VD .
is obtained.

Thus, the 4.125[k] contained in the video signal VD1
Hz] horizontal drive signal HD has its frequency downgraded to 1/K1 in a frequency down-down circuit 5, and then is input to a servo circuit 6 as a recording horizontal drive signal HD _R.

Further, the recording horizontal drive signal HD _R obtained at the output terminal of the frequency down-converting circuit 5 is further given to the frequency down-converting circuit 7, and after the frequency is down-done to 1/K2, it is output as the recording vertical drive signal _VDR to the servo circuit. 6 is input.

Here, the frequency step-down circuit 5 determines that the number of pulses per frame of the recording horizontal drive signal HD _R obtained at the output terminal is equal to the number of scanning lines represented by the horizontal drive signal HD included in the video signal VD1 and the detected horizontal drive signal
It is determined based on equation (1) so that a relationship that is a common divisor with the number of scanning lines represented by _HDD can be obtained.

K1=[VD1]/[HD _R ]...(1) Here, [VD1] represents the number of scanning lines of the video signal VD1, and [VD1]=1375. In addition, [HD _R ] shows the common divisor, and the number of scanning lines of the video signal VD1 is 1375, and the detected horizontal drive signal HD _D of disk 2 is the number of scanning lines of 525.
25 is selected among the common divisors between , and thus the coefficient K1 is selected to be 55 by K1=1375/25=55 (2).

On the other hand, the detected horizontal drive signal obtained from disk 2
The frequency of HD _D is stepped down to 1/K3 in a frequency down-down circuit 11, and its output is inputted to the servo circuit 6 as a reproduction horizontal drive signal HD _P. Here, the down-down coefficient K3 of the frequency down-down circuit 11 is calculated based on the following formula K3=[HD _D ]/[HD _P ]...(3), so that the value of the reproduced horizontal drive signal HD _P becomes the above-mentioned common divisor 25. The value is selected so that Here, [HD _D ] is the number of scanning lines of the detected horizontal drive signal HD _D (=
525 lines), and [HD _P ] is the above-mentioned common divisor (=25). Therefore, in this example the coefficient K3
is selected as 21 by K3=525/25=21...(4).

In equations (3) and (4), we have described the case where disk 2 is operated with standard specifications, but in reality, the video signal VD1 of camera 1 is output with the disk rotation speed at 900 [rpm]. In contrast,
Since the rated rotational speed of the disk 2 is selected to be 1800 [rpm], the coefficient K3 of the frequency down-conversion circuit 11 is set with the modification described below. That is, since the disk 2 is used at a rotation speed of 900 [rpm], the reading frequency of the horizontal synchronization signal mark _MHD of the disk is 15.75 [kHz]÷2=7.875 [kHz] (5). If we divide this by the coefficient K2=21 mentioned above, we get
The frequency of the reproduced horizontal drive signal HD _P should be 7.875 [kHz] ÷ 21 = 375 [Hz] ... (6). Therefore, the recording horizontal drive signal HD _R obtained from the camera 1 side only needs to be corrected so that it matches the frequency of equation (6), so the following equation is used: 4.125 [kHz] ÷ 375 [Hz] = 11... (7) Recording horizontal drive signal in servo circuit 6
It can be seen that correction can be made by further dividing HD _R by 11.

In this way, the recording horizontal drive signal HD _R supplied from the camera 1 side to the servo circuit 6 and the disk 2
The frequencies of the reproduced horizontal drive signals HD _P supplied from the side will match each other, and their phases will be compared in the comparison circuit built in the servo circuit 6, and the difference will be eliminated using the comparison result as one condition. Such a servo drive output DV is given to the spindle motor 12.

In addition to the above configuration, the detected vertical drive signal VD _D detected by the detector 4 is compared in phase with the recording vertical drive signal VD _R obtained from the frequency down-down circuit 7. In this embodiment, the frequency of the detected vertical drive signal _VDD on the disk 2 side is reproduced at 15 [Hz], and this is given to the servo circuit 6 as the reproduced vertical drive signal _VDP .

The servo circuit 6 compares the phases of the reproduction vertical drive signal VD _P and the recording vertical drive signal VD _R.
The down-down coefficient K2 of the frequency down-down circuit 7 is selected to a value that allows the frequency of the recording vertical drive signal _VDR to match the frequency of the reproduction vertical drive signal _VDP . In this example, the detection vertical drive signal VD _D
Since the frequency of is reproduced at 15 [Hz], the frequency down-down circuit 7 divides the recording horizontal drive signal HD _R so that the frequency of the recording vertical drive signal _VDR obtained is 15 [Hz].
Coefficient K2 is set to [Hz].

The servo circuit 6 compares the phases of the recording vertical drive signal _VDR and the reproduction vertical drive signal _VDP , and based on the comparison result, provides the spindle motor 12 with a servo drive output DV that makes the difference zero.

In the above configuration, the servo circuit 6 compares the phase between the recording horizontal drive signal HD _R and the reproduction horizontal drive signal HD _P , and at the same time compares the phase between the recording vertical drive signal _VDR and the reproduction vertical drive signal VD _P. Generates a servo drive signal output that eliminates the phase of That is, the frequency down-converting circuits 5 and 11 divide the frequency so that the frequency of the recording horizontal drive signal HD _R obtained from the camera 1 side matches the frequency of the reproduction horizontal drive signal HD _P obtained from the disk 2 side. Here, the down-down coefficients of frequency down-down circuits 5 and 11
Video signals obtained from camera 1 from K1 and K3
By selecting a value corresponding to a common divisor of the number of scanning lines included in VD1 and the number of scanning lines recorded on disk 2, disk 2
Even if the number of scanning lines recorded in the camera 1 is changed, the frequency of the resulting reproduced horizontal drive signal HD _P can easily be changed to the recorded horizontal drive signal obtained from camera 1.
Can be tuned to HD _R frequency.

Therefore, the configuration of the servo circuit 6 does not need to be changed each time the number of scanning lines recorded on the disk 2 is changed, which further increases the compatibility of the servo device with various disks. become.

As described above, the servo circuit 6 of the disk device is
By obtaining a horizontal drive signal having a frequency corresponding to a common divisor of the number of scanning lines of the video signal recorded on disk 2 and the number of scanning lines of video signal VD1 of camera 1, The resulting video signal can be reliably recorded on the disk.

Therefore, when using various disks with different numbers of scanning lines as the disk 2, the number of scanning lines of the disk and
The video signal of the camera 1 can be recorded on the disk 2 by using a common divisor between the video signal VD1 of the camera 1 and the number of scanning lines.

In the case of the embodiment shown in FIG. 1, the case has been described in which the disk 2 has 525 scanning lines and the coefficient K3 of the frequency down-converting circuit 11 is set to 21. Number of lines is 625
Even if the numbers are different, such as 1,125 lines, the common divisor for the number of scanning lines of the video signal VD1 of the camera 1 is 25, so the servo circuit 6 operates in the same way as in the above case. , video signal VD1 to disk 2
You can reliably record on the top. In this case, the coefficient K3 of the frequency down-converter 11 may be selected to be 25 and 45, respectively.

In fact, in this type of disk device, the number of scanning lines of camera 1 and the number of scanning lines of disk 2 are:
In many cases, the common divisor is selected to be 25. Therefore, the frequencies of the recording horizontal drive signal HD _R and the reproduction horizontal drive signal HD _D obtained at the output terminals of the frequency down-converting circuits 5 and 11 can be easily set to the common divisor of 25. Can be set to the corresponding value.

If a higher resolution camera is used as the camera 1 than in the case of Fig. 1, various adjustments may be made by selecting an appropriate value for the frequency division coefficient of the frequency down-down circuit. Video signals can be recorded on the disc 2 with the specifications of .

For example, for camera 1, the number of scanning lines is 1525,
Using a horizontal drive signal HD with a frequency of 38.125 [kHz] and a vertical drive signal VD with a frequency of 50 [Hz],
When recording this video signal VD1 on a disk with a rotation speed of 1500 [rpm], a horizontal drive signal HD frequency of 15.625 [kHz], a vertical drive frequency of 50 [Hz], and a rotation speed of 1500 [rpm], The frequency division coefficient of the frequency down-converter may be selected as follows. In other words, the number of scanning lines on disk 2 is determined by the frequency of the horizontal drive signal (=
15.625 [kHz]) and the rotation speed of disk 2 (=1500
[rpm]) becomes 625, and this value has a common divisor of 25 with the number of scanning lines of camera 1. Therefore, if the frequency division coefficient K3 of the frequency down-down circuit 11 in FIG. 1 is 25, the frequency of the reproduced horizontal drive signal HD _P supplied to the servo circuit 6 is 15.625 [kHz] ÷ 25 = 625 [Hz]... (8), and this frequency of 625 [Hz] is determined as the reference frequency for the recording horizontal drive signal _HDR on the video signal VD1 side of the camera 1.

In order to match the frequency of the horizontal drive signal to the video signal VD1 with this reference frequency, the frequency down-conversion circuit 5 follows the relationship expressed by the following formula: 38.125 [kHz] ÷ 625 [kHz] = 61...(9) The descending coefficient K1 is set so that
is set to 61.

In this way, the servo circuit 6 can be connected to the disk 2.
Since the value of the detected horizontal drive signal HD _D obtained from the camera 1 has a common divisor with respect to the horizontal drive signal of the video signal VD1 of the camera 1, the video signal VD1 can be reliably recorded on the disk 2.

[Effect of idea]

As described above, according to the present invention, the common divisor between the horizontal drive signal of the video signal VD1 of the camera 1 and the horizontal drive signal obtained from the disk 2 is set as the reference frequency, and the recording horizontal drive signal HD _R By lowering the frequency of the horizontal drive signal HD _P using the frequency down-converting circuits 5 and 11 to match this reference frequency, the servo circuit 6 can be used even when a disk 2 with different specifications is used. ,
By making it possible to perform the servo operation correctly, the video signal VD1 of the camera 1 can be reliably recorded on the disk 2.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a spindle servo device according to the present invention, and FIG. 2 is a schematic diagram showing synchronization signal marks recorded on a disk 2 thereof. 1... Camera, 2... Disk, 3, 4... Detector, 5, 7, 11... Frequency down-down circuit, 6...
Servo circuit, 12... spindle motor.

Claims (1)

[Claims for Utility Model Registration] A first frequency step-down circuit that steps down a video signal and outputs a recording horizontal drive signal at a reference frequency; and a first frequency step-down circuit that steps down a video signal and outputs a recording horizontal drive signal at a reference frequency; a second frequency step-down circuit that outputs a reproduction horizontal drive signal; a phase comparison means that compares the phases of the recording horizontal drive signal and the reproduction horizontal drive signal and outputs a phase comparison signal representing the comparison result; a servo circuit having a control means for controlling a spindle motor that drives the disk based on the phase comparison signal outputted from the comparison means; The coefficients are set to values that output the recording horizontal drive signal and the reproduction horizontal drive signal having the reference frequency corresponding to a common divisor of the number of scanning lines of the video signal and the number of scanning lines of the detected horizontal drive signal, respectively. A spindle servo device characterized by being selected.