JPS6218681A - Video disc player - Google Patents

Abstract

PURPOSE:To access data at a high speed by moving a detecting part for an extent corresponding to two or more tracks between address data recording parts in case that the feeding speed due to a detecting part feeding means is maximum. CONSTITUTION:The extent of movement in the radial direction of said detecting part in case of the maximum feeding speed due to the detecting part feeding means is equivalent to or longer than two tracks between address data recording parts. The recording position of address data is equal between adjacent tracks; and with respect to contents of address data, high-order bits are not changed but only low-order bits are changed except carry, and therefore, it is sufficient if data on a track (n) is read for low-order bits of address data and data on a track (n+1) is read for high-order bits through a signal detecting sensor 2 is moved for the extent corresponding to two tracks between address data recording parts T.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a video disc player capable of faster random access than conventional video disc players.

(Prior Art) One of the characteristics of video discs is a high-speed random access function.

That is, within a specific horizontal scanning period (H) within the vertical blanking period of a video signal recorded on a video disc,
A desired address is searched for by moving a signal detection light beam or sensor (needle) in the radial direction of the disc while detecting and reproducing address data such as chapters, times, pages, etc. that have been digitally encoded and recorded. .

Data processing during this random access is performed according to the flowchart shown in FIG. 3, for example.

To explain the outline of this data processing, first, the address set manually by the key etc. is stored in memory, the read data G read from the pink up and the setting data X are compared and calculated, and the pickup arm is adjusted based on the difference. It's being moved.

For example, when there is a difference of 3000 tracks or more from the destination address, high-speed search is performed. Even if the disk is crossed at this speed, address signals can be read every 2,000 to 3,000 trunks. When the difference from the destination address falls within 3000 tracks, the search speed is reduced to 1/3 and when it falls within 1000 tracks, the search speed is increased to double speed and the slide motor stops feeding. In this state, output a kick pulse by the difference to the target address, feed the needle tip,
Check if it is the desired street address, and if it matches, unmute the video and audio.

I'm using normal playback. During random access.

Depending on whether the difference from the destination address is positive or negative.

The direction in which the pickup moves is controlled in the forward and reverse directions.

In this random access, high speed is required, and conventionally, one track can be traversed within the address data recording time (approximately 49 microseconds) on the condition that one block of address data is detected with a certain probability. The speed was set to maximum. for example.

When the address data recording time Td is 49 microseconds, the track pitch is 1.35 microseconds, and the diameter of the disk recording section is 73 cm, the time to move from the innermost circumference of the disk to the outermost circumference at maximum speed is approximately 2.6 seconds. Become.

(Object of the Invention) In the present invention, in order to further speed up access, on the recording surface of a video disc whose playback speed is constant,
We focused on the fact that the recording position of address data is the same between adjacent tracks, and even if data from an adjacent trunk is read from the middle of the address data, the data content may be the same.

It is an object of the present invention to provide a video disc player in which the feed speed of a detection unit during access is further increased.

(Structure of the Invention) The video disc player of the present invention includes a detection means for detecting a recording signal of a video disc, a reading means for reading address data from the recording signal detected by the detection means, and a process for processing the address data. and a detection part feeding means for moving the detection part of the detection part in the radial direction of the disk at high speed based on the data processing of the processing means, and when the feeding speed by the detection part feeding means is the highest speed. The moving distance of the detecting section is two tracks or more between the address data recording sections.

(effect) When the feeding speed by the detection unit feeding means is at the maximum speed.

The detecting section of the detecting means moves two or more tracks in the radial direction of the disk between the address data recording sections and detects the recorded signal. The reading means reads address data from this detected recording signal. In this case, when the detection section moves two tracks between the address data recording sections, the upper bits of the address data are read in one track, and the lower bits are read in the next adjacent track. The processing means moves the detection section in the radial direction of the disk at high speed based on this address data.

(Example) Hereinafter, two embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows a schematic block diagram of a video disc player.

A video disc l mounted on a turntable is rotated at a constant speed by a main motor 3 and a motor control circuit 4.

A video signal S1 detected from the video disc 1 by a pickup circuit 10 equipped with a signal detection sensor (detection section) 2 is appropriately amplified by a preamplifier 11, and then sent to an FM demodulation circuit 12 and a tracking servo circuit 15.
is input.

The video signal S2 demodulated by the FM demodulation circuit 12 is subjected to processing such as dropout correction, color subcarrier frequency conversion, and time base correction in the video processing circuit 13, and is reproduced as a standard color television signal. Further, address data consisting of several bits recorded in the vertical blanking of the video signal S2 is read by the ninth-order data read circuit 14 and inputted to the microcomputer 16.

On the other hand, in the tracking servo circuit 15, the video signal S
, separates the signals necessary for tracking control from
A tracking error signal S3 indicating the deviation of the signal detection sensor 2 from the track sensor is detected and inputted to the drive circuit 18. The drive circuit 18 is this tracker.

The tracking coil 23 is driven based on the error signal S, and the signal detection sensor 2 is controlled to trace the center of the track. Further, in the tracking servo circuit 15, the D of the tracking error signal S3 is
The inclination of the signal detection sensor 2, that is, the relative position between the reproduction track and the pickup circuit 10, is detected from the C voltage, and when it exceeds a certain value, the pickup amplifier drive motor 22 is driven via the drive circuit 21. Control is performed so that the trunk to be reproduced is positioned approximately at the center of the pickup circuit 10.

Further, during special playback of stills, slow motion, etc., the microcomputer 16 outputs a control signal S to the kick pulse generation circuit 19 based on the operation signal S4 from the operation button 17.

The kick pulse generating circuit 19 uses this control signal S.

A timing pulse S6 for kicking the signal detection sensor 2 is generated. This timing pulse S6 is input to the drive circuit 18, and controls the signal detection sensor 2 according to the reproduction mode by driving the tracking coil 23 and kicking the signal detection sensor 2 to an adjacent track.

Furthermore, when accessing or rapidly retracting in the forward/reverse direction, the microcomputer 16 uses the operation signal S4 from the operation button 17 to control the motor feed circuit 20 based on the address data input from the data read circuit 14. A control signal S7 is output. The motor feed circuit 20 controls the playback position by rotating the pink amplifier drive motor 22 in the forward and reverse directions according to the control signal S7 and moving the pickup circuit 10 in the radial direction of the video disc l.

Next, in the video disc player described above, the second
This will be explained with reference to Figures (al) and (b).

FIG. 2(a) shows a partially enlarged view of the address data recording section T of the video disc 1, and FIG. 2(b) shows an example of address data recorded in the address data recording section T. .

In FIG. 2 (al), the diagonal arrow B is the locus of the signal detection sensor 2 at the time of access according to the present invention. That is, the signal detection sensor 2 moves two tracks between the address data recording sections T. It is set to .

The maximum speed during conventional access is the speed at which the signal detection sensor 2 enters the trunk at the address data recording start part X and moves to the next trunk at the recording end part Y, as indicated by the diagonal arrow A, i.e. , address data recording section T, the speed is set at a speed of one track movement between the address data recording section T and the address data recording section T.

However, the recording position of the address data is in the adjacent track (
For example, it is the same between trunk n and track n+1),
Also, regarding the contents of the address data, except when increasing by two digits, the upper bits are the same and only the lower bits change, so even if the signal detection sensor 2 is moved two trunks between the address data recording sections T, For the lower bits of the address data, it is sufficient to read the data of trunk n, and for the upper bits, it is sufficient to read the data of trunk n+l.

In this way, even when the signal detecting sensor 2 is moved two tracks between the address data recording sections T, the probability of reading the picked up address data is almost the same as in the conventional case.

In this way, the address data read by the data read circuit 14 is input to the microcomputer 16, where the data is processed.

The motor feed circuit 2o is controlled based on the result.

Note that in this example, the feed speed of the signal detection sensor 2 at the time of 2 accesses is set to the speed of moving 2 trunks between the address data recording sections T, but the signal detection sensor 2 is
It may be moved by more than one track, and even in this case, the probability of reading address data is almost the same as in the conventional case. Also, although 11-bit address data is shown in FIG. 2 (bl), it is actually 24-bit or 29-bit address data.

(Effects of the Invention) As described above, according to the video disc player of the present invention, the feed speed during access can be increased to two to three times that of the conventional system, and access speed can be increased.

[Brief explanation of the drawing]

FIG. 1 is a schematic block diagram of the video disc player of the present invention, FIG. 2(a) is a partially enlarged view of the address data recording section of the video disc, and FIG. 2(b) is a partial enlarged view of the address data recording section of the video disc. Diagram showing an example of address data, 3rd
The figure is a flowchart showing data processing during random access. l...Video disc 2...Signal detection sensor 1
0...Pickup circuit 13...Video process circuit 14...Data read circuit 15...Tracking servo circuit 16...Microcomputer 20...Motor feed circuit Fig. 2(a) Fig. 2( b)) I I ] 1 upper pit lower pit wE3 figure lX-G1+s

Claims (1)

[Claims] 1) detection means for detecting a recording signal of a video disc;
a reading means for reading address data from the recording signal detected by the detecting means; a processing means for processing the address data; a detection unit feeding means for moving the detection unit, and a moving distance of the detection unit in the radial direction when the detection unit feeding unit is fed at the highest speed is two or more tracks between the address data recording units. A video disc player with special features.