JPH0432470B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a tracking device for recorded information reproducing devices such as compact disc players and video disc players.

[Conventional technology]

FIG. 3 shows a block diagram of a tracking device for a conventional recorded information reproducing apparatus.

In the figure, 1 is a tracking error detection device that detects the amount of tracking deviation, 2 is a tracking error signal that is the output of the tracking error detection device, 3 is a tracking servo circuit for controlling the tracking servo system, and 4 is a tracking error detection device. a power stage for driving the tracking actuator 5;
6 is a tracking error zero cross detector for detecting the zero cross of the tracking error signal 2, and 7 is the output of the tracking error zero cross detector, which is a tracking error zero cross signal. 8 is a microcomputer that controls the tracking servo system.

Next, the operation will be explained. Normally, when performing a tracking jump, the microcomputer issues a command to the track servo circuit 3 to cut the track servo loop and send a track kick pulse to the power stage 4 to kick the track actuator in a desired direction. (FIG. 4) This command causes the tracking actuator to start a tracking jump.

On the other hand, when a tracking jump starts, a tracking error signal is generated at the output of the tracking error detection device as shown in FIG. 4 to generate a tracking error.

In the conventional tracking device, a tracking error zero-crossing detector 6 is provided to detect the zero-crossing point of the tracking error signal that occurs during this tracking jump, and the tracking error zero-crossing detector 6 is used to detect the rising or rising edge of the tracking error zero-crossing signal that is the output of this detector. Count the number of drops using a microcomputer,
The number of tracking jumps is detected and the amount of tracking jumps is controlled.

[Problem that the invention seeks to solve]

Since the conventional tracking device is configured as described above, the tracking error signal is superimposed with noise components such as signals leaked from the signal band including the recorded information signal, and tracking error zero cross detection. Sometimes, this noise component caused the tracking error zero-cross detector to malfunction.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a tracking device that can accurately count the number of track crosses during a tracking jump.

[Means for solving problems]

The tracking device of the recorded information reproducing apparatus of the present invention includes a tracking error zero-crossing detector for detecting a tracking error zero-crossing point, and whether the position of a signal pickup is on-track or not.
It consists of an on-track detector that detects whether the track is on off-track, the output of this on-track detector is latched with the output of a tracking zero-cross detector, and the latched signal is counted.

[Effect]

Since the tracking device according to the present invention accepts only the first track cross signal during on-track and off-track, even if an erroneous detection occurs in which tracking zero-cross detection is performed multiple times on the same track, track crosses will be detected more than necessary. No numbers detected.

〔Example〕

Hereinafter, one embodiment of the present invention will be described based on the drawings.

In FIG. 1, numerals 1 to 9 and 14 are exactly the same as the conventional device.

10 is an on-track detector that detects whether the signal pickup is on-track or off-track, and sets the signal level (amplitude) of the recorded information signal read from the disk to "H" and "H" at a certain threshold level. The structure is such that it is distributed to "L".

11 is an on-track signal which is an output signal of this on-track detector 10.

Reference numeral 16 indicates edge detection for detecting edges of the tracking zero-crossing signal 7, and reference numeral 15 indicates this edge signal.

12 is a flip-flop for latching the on-track signal 11 with an edge signal, and 13 is an on-track latch signal which is an output signal of this flip-flop.

Next, the operation of this invention will be explained. The operation up to the start of the tracking jump is the same as in the conventional example.

When a tracking jump is started, in order to detect the number of tracking jumps, the edge of the output of the tracking error zero cross detector 6 is detected during the tracking jump, the on-track signal is latched by this edge signal, and the flip-flop is The on-track latch signal 13 generated from 12 is counted by a microcomputer and the amount of tracking jump is controlled.

〔Effect of the invention〕

As described above, according to the present invention, the number of tracking jumps is detected by using a microcomputer to count the signal obtained by latching the on-track signal with the tracking error zero-crossing signal, so that false detection by the tracking error zero-crossing detector is avoided. Without,
Therefore, since a protection timer at the start of tracking jump counting is not required, the microcomputer software can be simplified and the number of tracking jumps can be accurately counted.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a tracking device according to an embodiment of the present invention, FIG. 2 is a signal waveform diagram thereof, FIG. 3 is a block diagram showing a conventional example, and FIG. 4 is a signal waveform thereof. In the figure, 6 is a tracking error zero cross detector, 8 is a microcomputer, 10 is an on-track detector, and 12 is a flip-flop. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Scope of Claims] 1. A tracking error signal detection device, which is positional information of a track on which information is recorded, and a signal pick-up for reading recorded information based on the output of the tracking error signal detection device, are located on the track. A tracking error zero-crossing detector for detecting a zero-crossing point of a tracking error signal, and a tracking servo means for controlling a tracking error signal, and a tracking error zero-crossing detector for detecting whether the position of a signal pickup is on-track or off-track. It is equipped with an on-track detection device and a track cross number detector for detecting the number of track jumps, and when performing a track jump, the output of the on-track detector is latched with the output of the tracking error zero cross detector, and this latched signal is A tracking device for a recorded information reproducing device, characterized in that tracking jump is controlled by counting. 2. Claims characterized in that the output of the on-track detection device when the track is on off-track is latched with the output of a tracking error zero-cross detector, and tracking jump is controlled by counting this latched signal. A tracking device for a recorded information reproducing device according to item 1.