JPH07254225A - Reproducing device - Google Patents

Abstract

PURPOSE:To read data even if there is a detect in an VFO region. CONSTITUTION:The reproduction of a recording medium l, wherein a drawing region for PLL is provided in a format, is performed. A means 5 generates a signal indicating the data region in the format of the recording medium 1. Means 6 and 7 shift the output timing of the signal indicating the data region when a defect is present in the data regions. These means are provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reproducing apparatus for reproducing information recorded on a recording medium such as a magnetic disk or an optical disk.

[0002]

2. Description of the Related Art In a conventional device of this type, the area function of passing within a predetermined time can be known according to the format of a recording sector of a recording medium. Time is counted from the detection position of the sector mark (mark indicating the start position of each recording sector), and when the time until it passes through the VFO area for pulling in the PLL elapses, the read gate indicating the data section is set. open. As a result, a signal indicating the data portion (data area) is output.

[0003]

In the conventional device as described above, if there is a defect in the VFO area (area for pulling in the PLL), the pulling in of the PLL may fail and the data may become unreadable. . Therefore, an object of the present invention is to provide a reproducing apparatus capable of reading data even if there is a defect in the VFO area.

[0004]

In order to solve the above-mentioned problems, a reproducing apparatus of the present invention is a reproducing apparatus for reproducing a recording medium having a pull-in area for a PLL in the format. The configuration includes a unit for generating a signal indicating the data region and a unit for shifting the output timing of the signal indicating the data region when a defect exists in the data region.

[0005]

According to the present invention, if the read gate cannot be read once (in this case, it is determined that there is a defect in the VFO area), the position where the read gate is opened is not from the predetermined time, Open it a little later. As a result, the PLL can be pulled in by avoiding the defect existing in the first portion of the VFO area, so that the data can be read without the PLL being pulled out.

[0006]

1 shows the structure of a reproducing apparatus according to an embodiment of the present invention. A pickup (not shown) for reading information recorded on the disc-shaped recording medium 1, a binarization circuit 2 for converting a reproduction signal from the pickup into a digital signal,
A PLL circuit 3 for generating a reproduction clock of reproduction data from the binarization circuit 2 and synchronous data, and a DE for demodulating the signal.
C. A circuit 4 is provided. Error correction circuit is also DE
C. Included in circuit 4. When the recording medium 1 is an optical recording medium such as an optical disc or a magneto-optical disc, the pickup reads information by irradiating the recording medium 1 with a laser beam. When the recording medium 1 is rotated by the spindle motor, the relative positional relationship between the irradiated beam and the recording surface of the recording medium 1 changes.
As a result, the information recorded on the recording medium 1 is
You can read them one after another with a pickup.

Furthermore, DEC. The CPU 7 sets the closing delay time of the read gate in response to the fact that the circuit 4 cannot correct the error, the time setting circuit 6 for setting the time, and operates by delaying the read gate by the set time. A gate opening / closing circuit 5 is provided. The operation of this device will be described below.

In this embodiment, the timing for opening the read gate is set in advance based on the format specifications so that the read gate is opened from a position delayed by T time from the detection of the sector mark. FIG. 2 is a diagram showing the timing of opening the read gate in the normal case. As shown in FIG. 2, when the scanning position by the pickup reaches the VFO area,
Change the read gate from high level to low level. Of course, the polar relationship may be reversed.

At this timing, if there is no defect in the VFO area, normal reading can be performed without any error. However, if there is a defect in the VFO area, the PLL fails to pull in and correct data and a synchronous clock are not output. Next, the error cannot be corrected and the data error is C
The PU is notified. When the CPU next reads the data of this sector, the CPU sets the time T to which the time t to be delayed is added to the time setting circuit so as to shift the position where the read gate is set to the low level. When reading this sector next time, the gate opening / closing circuit changes the read gate from the high level to the low level with a delay of t time from the full reading.

FIG. 3 is a diagram showing the timing of opening the read gate when it is determined that there is a defect in the VFO area. When the VFO area has a defect as shown in FIG. 3 and the data cannot be read, the PLL can be pulled in by opening the read gate with a delay as described above. And the data can be extracted correctly.

[0011]

As described above, according to the present invention, even if there is a defect in the VFO area, the data can be read depending on the position of the defect, and there is an effect that the reliability of recording / reproducing on the medium is improved.

[Brief description of drawings]

FIG. 1 is a configuration of a reproducing apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram showing a timing of opening a read gate in a normal case.

FIG. 3 shows a case where it is determined that the VFO area has a defect,
It is a figure which shows the timing which opens a read gate.

[Explanation of Codes] 1 ... Recording medium 2 ... Binarization circuit 3 ... PLL circuit 4 ... DEC. Circuit 5 ... Gate opening / closing circuit 6 ... Time setting circuit 7 ... CPU

Claims (1)

[Claims] 1. A reproducing device for reproducing a recording medium having a pull-in area for a PLL in the format, and a means for generating a signal indicating a data area in the format of the recording medium, and a defect existing in the data area. And a means for shifting the output timing of the signal indicating the data area, the reproducing apparatus.