CN100437769C - Optical disk reading method - Google Patents

Abstract

A method for reading optical disk is to read an address of the optical disk at a reading speed. The method comprises the following steps: reading an address according to an amplified signal corresponding to the reading speed, wherein the amplified signal is a preset amplified signal; (b) checking whether the reading is successful, if so, ending the method; if not, entering the step (c); (c) adjusting an amplification signal corresponding to the reading speed according to a reading error index value; (d) re-reading the address according to the amplified signal adjusted in the step (c); and (e) checking whether the reading is successful, and if not, repeating the step (c).

Description

How to read CDs

technical field

The present invention relates to a reading method, and in particular relates to a reading method of an optical disc.

Background technique

Please refer to FIG. 1 , which shows a block diagram of a traditional optical read/write control system. The optical read/write control system 100 includes at least an optical pickup head 110 , a radio frequency equalizer (radio frequency equalizer) 120 and a digital signal processing (Digital Signal Processing, hereinafter referred to as DSP) unit 130 . The DSP unit 130 includes a decoder 132 and an error corrector 134 .

When the optical read-write control system 100 reads the data of an address of the optical disc 111 at a reading speed of 52 times, for example, the optical read-write head 110 emits a laser light L to the optical disc 111 and reads the data from the optical disc 111. The reflected radio frequency signal RF1 is output to the radio frequency equalizer 120. The radio frequency equalizer 120 amplifies the radio frequency signal RF 1 according to the amplified signal AS corresponding to the 52-fold speed and the cut off frequency COF, and then outputs the radio frequency signal RF 2 to the decoder 132. The amplified signal AS and the corner frequency COF are set to different predetermined values according to different reading speeds before leaving the factory, and are recorded in the optical read-write control system 100 .

The decoder 132 decodes the radio frequency signal RF 2 and outputs the data DA 1 to the error corrector 134. When the data DA 1 can be corrected by the error corrector 134, the error corrector 134 corrects the data DA 1 and sends out the corrected data DA 2 to complete the reading operation of this address.

When the data DA 1 cannot be corrected to the data DA 2 by the error corrector 134, the traditional solution is to use the optical read-write control system 100 to re-read the same address with the same reading speed, amplified signal AS and corner frequency COF. For reading, if the data of the address to be read cannot be correctly read after 6 times of re-reading, the optical read-write control system 100, for example, lowers the reading speed from 52 times to 48 times, and then re-reads the data. Address data until the data is read correctly.

However, when the radio frequency equalizer 120 amplifies the radio frequency signal RF 1 according to the amplified signal AS corresponding to the reading double speed and the corner frequency COF, it is likely to also amplify the radio frequency signal RF 1 caused by poor burning quality. The noise is also amplified and output to the decoder 132 for decoding, so that the data DA1 output by the decoder 132 is erroneous data and cannot be corrected to the data DA2 by the error corrector 134. At this point, if the same address is re-read with the same read double speed, amplified signal AS, and corner frequency COF according to the traditional processing method for reading errors, the noise existing in the radio frequency signal RF 1 will still be are amplified and decoded as data. In this way, the optical read/write control system 100 still cannot read the data stored in the address correctly, and also increases the time required for reading the address.

Contents of the invention

In view of this, the purpose of the present invention is to provide a reading method, which can accurately and quickly read data stored on an optical disc with poor recording quality, so as to improve the reading ability of the optical disc drive.

According to the purpose of the present invention, a kind of optical disc reading method is proposed, read an address of an optical disc with a read double speed and decode a radio frequency signal, it is characterized in that, the method comprises:

(a). Read the address according to a preset amplification signal corresponding to the read double speed;

(b). Check whether the read is successful, if so, then end the method; if not, then enter step (c);

(c). Adjusting the preset amplified signal to a modified amplified signal according to the number of times the address is unsuccessfully read;

(d). Re-read the address according to the modified amplified signal adjusted in step (c); and

(e). Check whether the reading is successful, if not, repeat step (c).

Wherein step (c) is to adjust the amplitude of the preset amplified signal.

Wherein the amplitude of the modified amplified signal adjusted by step (c) is between the amplitude of the preset amplified signal and the amplitude of a first threshold signal or a second threshold signal, the first threshold signal The amplitude of the second threshold signal is greater than the amplitude of the preset amplified signal, and the amplitude of the second threshold signal is smaller than the amplitude of the preset amplified signal.

Wherein in step (c), when the times of the unsuccessful reads are 1 and 2 respectively, the amplitude of the preset amplified signal is lowered or raised by P units respectively, and P is a positive integer greater than 1.

Wherein in step (c), when the number of unsuccessful reads is 3 and 4 respectively, the amplitude of the preset amplified signal is lowered by Q units respectively, Q is a positive integer greater than 1, and Q is greater than p.

Wherein in step (c), when the number of unsuccessful readings is 5, the amplitude of the preset amplified signal is lowered by R units, R is a positive integer greater than 1, and R is greater than Q.

Wherein, when the number of unsuccessful reads is exceeded, the step (e) is still not successfully read, then the number of unsuccessful reads is set to 0, and the reading speed is lowered, and step (a) is repeated.

Wherein the specific number of times is 5.

Wherein in the step (e), if it is found that the reading is successful, the preset amplified signal is the modified amplified signal adjusted by the step (c).

Description of drawings

In order to make the above-mentioned purposes, features, and advantages of the present invention more comprehensible, a preferred embodiment is specifically cited below, together with the accompanying drawings, and described in detail as follows, wherein:

FIG. 1 shows a block diagram of a conventional optical read/write control system.

FIG. 2 is a flowchart of a reading method according to a preferred embodiment of the present invention.

Figure 3 shows a Bode plot of the amplified signal.

Detailed ways

Please refer to FIG. 2 , which shows a flowchart of a reading method according to a preferred embodiment of the present invention. The method reads an address of an optical disc at a reading double speed. The optical disc is, for example, a disc with poor recording quality such as CDR, CDRW, DVD+R/RW or DVD-R/RW.

When the optical read-write control system, for example, intends to read a certain address of the optical disc at a speed of 52 times, the method starts to be executed. First, set the read error index value EC to 0, as shown in step 210 . Next, read the address according to an amplified signal corresponding to the read double speed, as shown in step 220 . Wherein, the amplified signal corresponding to the reading double speed is a preset amplified signal. The preset amplified signal is set to different predetermined values according to different reading multiple speeds before leaving the factory, and is recorded in the optical read-write control system. Next, check whether the reading is successful, as shown in step 230 . If the reading is successful, the method ends; if the reading is not successful, then enter step 240 .

When step 230 does not read successfully, the shilling read error indicator value EC is incremented by 1, as shown in step 240 . The read error index value EC is equal to the number of unsuccessful reads of this address. Next, if the read error index value EC is 1, then the amplitude of the amplified signal corresponding to the read double speed is lowered by 4 units, as shown in step 242; if the read error index value EC is 2, then the read The amplitude of the amplified signal corresponding to the double speed is increased by 4 units, as shown in step 244; if the read error index value EC is 3, then the amplitude of the amplified signal corresponding to the read double speed is lowered by 8 units, as shown in step 244 246; if the read error index value EC is 4, the amplitude of the amplified signal corresponding to the double speed will be read by 8 units, as shown in step 248; if the read error index value EC is 5, then the The amplitude of the amplified signal corresponding to the read double speed is lowered by 16 units, as shown in step 250 .

The above method of adjusting the amplitude of the amplified signal corresponding to the reading double speed is to make the amplitude of the adjusted amplified signal greater than or smaller than the amplitude of the preset amplified signal, and as the reading error index value EC increases, the amplitude of the amplified signal increases. The adjustment range is also larger. However, the adjustment range of the amplitude of the amplified signal corresponding to the reading double speed is not limited thereto. For example, when the reading error index values EC are 1, 2, 3, 4, and 5 respectively, it can be set to increase the amplitude of the amplified signal corresponding to the read double speed by 3, decrease by 3, and Up 6 units, down 6 units and up 9 units.

Next, read the address again according to the adjusted amplified signal in step 242 , 244 , 246 , 248 or 250 , as shown in step 260 . Next, check whether the read is successful, as shown in step 270 . If the reading is successful, first execute step 280, and then end the method. Wherein, the amplified signal adjusted by step 242, 244, 246, 248 or 250 is a modified amplified signal; step 280 is to make the preset amplified signal be the amplified signal adjusted by step 242, 244, 246, 248 or 250; If not read successfully, go to step 290.

When step 270 fails to read successfully, it is determined whether the read error index value EC is 5, as shown in step 290 . If the read error index value EC is not 5, then repeat step 240; if the read error index value EC is 5, then shill the read error index value EC to 0, and reduce the read speed from 52 to 48 double speed, as shown in step 295, and then repeat step 220.

That is to say, when the optical read-write control system wants to read a certain address of the optical disc at a certain reading speed, it first reads the address according to the amplified signal corresponding to the reading speed. , the amplitude of the amplified signal corresponding to the read double speed is adjusted according to the read error index value EC, and then the address is read again according to the adjusted amplified signal. After re-reading, if it is found that the reading has been successful, then correct the preset amplified signal to the amplified signal used during re-reading and end this method; if the data at this address cannot be read correctly after re-reading 5 times, first lower the reading Double the speed, and then read this address again until the data at this address is read out correctly.

It is found through experiments that when the amplitude of the amplified signal is adjusted within a certain range, the phase of the amplified signal is not affected. To illustrate this phenomenon more clearly, please refer to Figure 3, which shows the Bode diagram of the amplified signal. FIG. 3 can be divided into an upper part and a lower part, wherein the upper part is a magnitude diagram of the Bode diagram, and the lower part is a phase diagram of the Bode diagram. From the amplitude diagram of the Bode diagram, it can be seen that the amplitude of the amplified signal A is between the amplified signals B and C, and from the phase diagram of the Bode diagram, it can be clearly seen that the corresponding phases of the amplified signals A, B and C are same.

That is to say, if the amplified signal A in FIG. 3 is a preset amplified signal corresponding to a 52-fold speed, and the amplified signals B and C are respectively a first threshold signal and a second threshold signal, then when optical reading and writing When the control system uses the amplified signal corresponding to the 52 times speed, that is, the amplified signal A to read a certain address of the optical disc but fails to read, it only needs to adjust the amplitude of the amplified signal corresponding to the 52 times speed between the amplified signals B and C Between, and then re-read the address according to the adjusted amplified signal, so that the amplified signal used for re-reading has the same phase as the preset amplified signal.

In the reading method of this embodiment, when the optical read-write control system reads a certain address of the optical disc according to the amplified signal corresponding to a certain reading double speed but fails to read, the action of re-reading is performed, and Re-reading is limited to 5 times. If the data at this address is still not successfully read after 5 re-readings, lower the reading speed and re-read this address. However, the number of times of rereading can be set before leaving the factory, and it is not necessarily limited to 5 times. For example, the number of times of rereading can also be set to 6 times.

Compared with the traditional reading method, in this embodiment, the amplified signal corresponding to the reading double speed is adjusted within a range according to the reading error index value EC. Therefore, the reading method of this embodiment can read the data on the optical disc more quickly. In addition, when the optical reading control system re-reads the same address with the adjusted amplified signal and reads successfully, the preset amplified signal is corrected to be the amplified signal used for re-reading. In this way, the subsequent reading operation can be performed more smoothly.

The reading method disclosed in the above-mentioned embodiments of the present invention can accurately and quickly read the data stored on the optical disc with poor recording quality, so as to improve the reading capability of the optical disc drive.

In summary, although the present invention has been disclosed as above with a preferred embodiment, it is not intended to limit the present invention. Anyone skilled in the art can make various modifications without departing from the spirit and scope of the present invention. Changes and modifications, so the scope of protection of the present invention should be defined by the scope of the appended patent application.

Claims (9)

1. the read method of a discs is to read speed doubly and decipher a radiofrequency signal and the address of reading a discs with one, it is characterized in that this method comprises:

(a). reading doubly according to this, speed pairing one default amplifying signal reads this address;

(b). check whether to read success, if, method ends then; If not, then enter step (c);

(c). the number of times adjustment of successfully not reading according to this address should default amplifying signal be a correction amplifying signal;

(d). read this address again according to adjusted this correction amplifying signal of step (c); And

(e). check whether to read success, if not, repeating step (c) then.

2. the read method of discs as claimed in claim 1 is characterized in that, wherein step (c) is to adjust the amplitude of this default amplifying signal.

3. the read method of discs as claimed in claim 1, it is characterized in that, be that amplitude and one first between this default amplifying signal faces limited signal or one second and faces between the amplitude of limited signal wherein through the amplitude of adjusted this correction amplifying signal of step (c), this first amplitude that faces limited signal is the amplitude greater than this default amplifying signal, and this second amplitude that faces limited signal is the amplitude less than this default amplifying signal.

4. the read method of discs as claimed in claim 1, it is characterized in that, wherein in step (c), when this number of times that does not successfully read is respectively 1 and 2, be that the amplitude that will preset amplifying signal downgrades or increase P unit respectively, P is the positive integer greater than 1.

5. the read method of discs as claimed in claim 4 is characterized in that, wherein in step (c), when this number of times that does not successfully read is respectively 3 and 4, be that the amplitude that will preset amplifying signal downgrades Q unit respectively, Q is the positive integer greater than 1, and Q is greater than P.

6. the read method of discs as claimed in claim 5 is characterized in that, wherein in step (c), when this number of times that does not successfully read is 5, is that the amplitude with this default amplifying signal downgrades R unit, and R is the positive integer greater than 1, and R is greater than Q.

7. the read method of discs as claimed in claim 1 is characterized in that, wherein when number of times that this does not successfully read, step (e) does not read success yet, makes then that this number of times that does not successfully read is 0, and downgrades this and read doubly speed, and repeating step (a).

8. the read method of discs as claimed in claim 7 is characterized in that, wherein this specific times is 5.

9. the read method of discs as claimed in claim 1 is characterized in that, wherein in step (e), then makes this default amplifying signal for through adjusted this correction amplifying signal of step (c) if find to have read success.

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