JP3063339B2 - Moving direction detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a moving direction detecting device for an optical information recording disk reproducing device.

[0002]

2. Description of the Related Art A conventional moving direction detecting device will be described below.

FIG. 4 is a circuit diagram of the conventional moving direction detecting device. 4, 41 and 42 input
<br/> edge detector for generating a pulse by detecting both positive and negative changes in force signals, 43 and 44 and 45 of the clock input
Latch data from D input to Q output at rising edge
D flip-flop (hereinafter referred to as FF).

[0004] The read beam is the inner circumference of the disk of the track.
The CROSS signal A produced by punching out the tracking error signal which is positive on the side and negative on the outer side at the reference level is input to the D input of the edge detector 41 and the FF 43 to detect that the read beam has deviated from the track. shows to "H level
OFTR signal B, which becomes “ L ”, is supplied to the edge detector 42 and the FF4
4 is input to the D input. Edge detector 41 is CR
When a change in the logical value of the OSS signal occurs, a pulse C is output, which is input to the clock input of the FF 44. Similarly, the output D of the edge detector 42 is input to the clock input of the FF 43. The Q output E of the FF 43 is input to the D input of the FF 45, the Q output F of the FF 44 is input to the clock input of the FF 45, and the Q output G of the FF 45 is a movement direction detection result.

[0005] The operation of the moving direction detecting device constructed as described above will be described below.

FIG. 5 is a timing chart showing the operation of the conventional example, in which the read beam moves in the outer circumferential direction from the inner circumferential side of the disk, and reverses and moves in the inner circumferential direction just before the n-th track. In this case, the change of each signal from A to G is shown. However, “n−2” and “n−1” in FIG.
The stored positions are the (n-2) th track and the (n-th) track.
1) Indicates the center of the track.

The FF 43 samples the CROSS signal A at the moment when the OFTR signal B changes.
The OFTR signal B at the moment when the OSS signal A changes is sampled. As a result, the Q output E of the FF 43 becomes OFTR when the read beam is moving in the outer peripheral direction.
Inverted signal of signal B, O when moving in the inner circumferential direction
The signal matches the FTR signal B. Similarly, FF44
Q output F in the outer peripheral direction matches the CROSS signal A in the outer circumferential direction .
That signal, an inverted signal of the CROSS signal A at the inner circumferential direction.

In the FF 45, a direction detection result G is obtained by sampling the Q output E of the FF 43 with the Q output F of the FF 44.

[0009]

However, in the above-described conventional configuration, if the moving direction does not reach the midpoint of the track after passing one track after the moving direction actually changes, the moving direction detection result becomes a correct value. And the circuit configuration is complicated.

An object of the present invention is to solve the above-mentioned conventional problems, and an object of the present invention is to provide a moving direction detecting device in which the timing at which a moving direction detection result becomes a correct value is earlier and the circuit configuration is simpler. .

[0011]

In order to achieve the above object, a moving direction detecting apparatus according to the present invention provides an edge for generating a pulse with respect to a change in both positive and negative directions of a CROSS signal which is a result of discrimination of a tracking error signal. A detector, a first sampling unit for sampling an OFTR signal indicating whether a read beam is on a track or between tracks by an output pulse of an edge detector, and a logic of an inverted signal of the output and the OFTR signal The CROSS signal is sampled and shifted at the rising edge of the product signal.
And a second sampling unit that outputs the moving direction detection signal .

[0012]

According to the present invention, the timing of the signal for determining the direction detection result is made earlier, the timing at which the movement direction detection result becomes a correct value is made earlier, and at the same time, the edge detector and the flip-flop are connected. Each is reduced one by one to realize a simpler circuit configuration.

[0013]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a circuit diagram of a moving direction detecting device according to an embodiment of the present invention. In FIG. 1, 1 is an edge detector, 2 and 4 are flip-flops, 3 is AN
D gate.

The CROSS signal A is input to the edge detector 1, and the output C is input to the clock input of the FF2. The OFTR signal B is input to the D input of FF2. The Q input of FF2 is applied to the two inputs of AND gate 3.
The inverted output D of the force and the OFTR signal B are input. A
The output E of the ND gate 3 is input to the clock input of the FF4, and the CROSS signal A is input to the D input of the FF4.

The operation of the moving direction detecting device according to the present embodiment configured as described above will be described below.

FIG. 3 is a timing chart of each signal in this embodiment when the read beam operates in the same manner as in the conventional example.

The edge detector 1 detects a change in the logical value of the CROSS signal A and generates a pulse.
By sampling the instantaneous value of the signal B, the signal D is the inverse of the CROSS signal A when the read beam is moving in the outer circumferential direction, and the CROSS signal A when the read beam is moving in the inner circumferential direction. The result is the same signal. Signals D and O
By taking an AND with the FTR signal B, at the same timing as the OFTR signal B, in the case of the outer circumferential direction, CROSS
It is possible to obtain a signal E which rises at a logical value 0 of the signal A and at a logical value 1 in the inner circumferential direction. The FF 2 outputs the moving direction detection signal F by sampling the CROSS signal A by the signal E.

As described above, according to the present embodiment, the CROS
A first edge detector for generating a pulse in response to a change in the S signal in both the positive and negative directions, and a first pulse for sampling an OFTR signal indicating whether the read beam is on a track or between tracks by an output pulse of the edge detector; A second sampling unit for sampling the CROSS signal at a rising edge of a signal obtained by ANDing the inverted signal of the output and the OFTR signal, and outputting the sampled signal as a movement direction detection signal;
By the provision of the sampling unit, the conventional preparative
Direction detection signal that was not output until it reached the rack midpoint
Signal of the rising edge of the OFTR signal B earlier.
It can be output by imming .

Further, the circuit configuration can be simplified as compared with the conventional example.

[0021]

As described above, according to the present invention, an edge detector for generating a pulse in response to both positive and negative changes in the CROSS signal, which is a result of the positive / negative determination of the tracking error signal, and whether the read beam is on the track or not. A first sampling unit that samples an OFTR signal indicating whether there is between tracks by an output pulse of an edge detector;
A second sampling unit that samples a CROSS signal at a rising edge of a signal obtained by logically ANDing the inverted signal of the output and the OFTR signal and outputs the signal as a movement direction detection signal, so that the movement direction detection result can be obtained. It is possible to obtain a moving direction detection device with a simpler circuit configuration by making the timing of obtaining a correct value earlier.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of a moving method detection device according to an embodiment of the present invention.

FIG. 2 is a diagram for explaining operations of the embodiment and a conventional example.
Schematic diagram showing the read beam moving state

FIG. 3 is a timing chart showing an operation state of the embodiment.

FIG. 4 is a circuit diagram of a conventional example.

FIG. 5 is a timing chart showing an operation state of a conventional example.

[Explanation of symbols]

 1 edge detector 2 flip-flop 3 AND gate 4 flip-flop

Claims (1)

(57) [Claims] 1. An edge detector for generating a pulse in response to a change in both the positive and negative directions of a CROSS signal which is a result of a positive / negative determination of a tracking error signal, and an OFTR signal indicating whether a read beam is on a track or between tracks. A first sampling unit for sampling the output signal by the output pulse of the edge detector;
R at the rising edge of the signal that is ANDed with the R signal
The ROSS signal is sampled and used as a moving direction detection signal.
And a second sampling unit for outputting the moving direction.