JPH0736258B2 - Error correction operation unit with track search function in disk player - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an error correction operation unit in a disc player such as a CD (compact disc) player.

<Prior Art> In a conventional signal processing device (LSI) for a CD player, an error correction calculation unit and a track search calculation unit are separately provided. The reason is that it is difficult to unify (share) both the units due to the following reasons.

The error correction operation unit has to execute the operation process of the first error correction (C1 correction) and the operation process of the second error correction (C2 correction) once for each frame (136 μsec).

Here, the first error correction (C1 correction) means that only one symbol or two symbols are erroneous among a plurality of symbols forming a data word input from a compact disc via a pickup and a demodulator. To detect and correct it. In addition, the second error correction (C2
The correction is to detect that one symbol or two symbols are erroneous among the plurality of symbols de-interleaved after the C1 correction and correct it.

The function of the track search calculation unit is mainly to judge whether it is large or small, and it is necessary to take a sufficiently long processing time to perform severe tracking control.

Therefore, when an arithmetic unit is formed by simply sharing the error correction arithmetic unit and the track search arithmetic unit, both the error correction arithmetic function and the track search arithmetic function by the common arithmetic unit are sufficient. Can not be demonstrated to.

That is, if the error correction calculation function is prioritized, the time for the track search calculation is insufficient, and the tracking control function is deteriorated. On the contrary, if the track search calculation function is given priority in order to perform severe tracking control, a considerable amount of time is required for the calculation, and there is no time margin for the error correction calculation, so that the error correction calculation function is provided. Will fall.

Then, in order to avoid this inconvenience, there is a problem that the capacity of the shared arithmetic unit (LSI chip) must be increased.

<Objects of the Invention> The present invention has been made in view of the above circumstances, and an error is corrected in a single arithmetic unit without causing a decrease in the error correction arithmetic function and the track search arithmetic function and an increase in capacity. It is an object of the present invention to provide both a correction calculation function and a track search calculation function.

<Structure of the Invention> The present invention has the following structures in order to achieve such an object.

That is, the error correction operation unit with the track search function in the disc player of the present invention comprises a search command detecting means for detecting that there is a search command for the track of the disc, and time information for detecting the input of the time information from the disc. Detecting means; first error correcting means for detecting that only one symbol or two symbols are erroneous among a plurality of symbols forming the data word input from the disk and correcting the error; After completing the first correction by the error correction means 1
Second error correction means for detecting whether only one symbol or two symbols are erroneous for a plurality of interleaved symbols and correcting the error, and a track search operation for tracking the disk. Track search calculation means to be executed, the first error correction means and the second error correction means when the search command detection means does not detect a track search command or when the time information detection means does not detect time information.
Error correction means is operated, when the search command detection means detects a track search command and the time information detection means detects time information, the operation of the first error correction means is prohibited, 2 error correction means and control means for operating the track search calculation means.

The operation of this configuration is as follows.

(I) When the search command detecting means does not detect the track search command, or when the time information detecting means does not detect the time information, the control means operates the first error correcting means and the second error correcting means. As a result, the first error correction means detects that only one symbol or two symbols are erroneous among the plurality of symbols forming the data word input from the compact disc, and corrects the error. Error correction means detects the fact that only one symbol or two symbols are erroneous with respect to a plurality of symbols de-interleaved after the processing by the first error correction means is completed, and corrects them. To do.

(Ii) When the search command detecting means detects the track search command and the time information detecting means detects the time information, the control means prohibits the operation of the first error correcting means and the second error correcting means. And operating the track search calculation means. As a result, the second error correction and the track search calculation are executed, but the first error correction is prohibited, so that a sufficient time can be taken for the track search calculation.

As a result of the above (i) and (ii), a single arithmetic unit can be provided with both the error correction arithmetic function and the track search arithmetic function. (Iii) In the above (ii), the first error correction can be performed. Although prohibited, the second error correction is executed, and the first error correction can be replaced to some extent by the second error correction. Therefore, the error correction operation is caused by sharing the operation unit. The deterioration of the function is avoided as much as possible.

<Example> Hereinafter, an example of the present invention is described in detail based on a drawing.

FIG. 1 is a block circuit diagram of a signal processing device for a CD player including an error correction operation unit with a track search function and peripheral devices according to an embodiment of the present invention.

In FIG. 1, 1 is EFM for music data and time information.
It is a compact disc that is modulated and recorded.
EFM modulation (Eight to Fourteen Modulation) is a modulation method for increasing the recording density. The 16 bits that make up the data word to be recorded on the compact disc 1 are converted into two symbols, the upper 8 bits and the lower 8 bits. Divide,
Each 8-bit symbol is converted into 14 channel bits.

2 is an optical pickup for reading music data and time information recorded on the compact disc 1, 3 is EFM modulation of the signal read by the optical pickup 2,
It is an EFM demodulator that outputs a symbol for the first error correction. Reference numeral 17 denotes a de-interleave processor between the first error correction (C1 correction) and the second error correction (C2 correction).

Reference numeral 4 is a track for executing both an error correction operation such as a first error correction (C1 correction) and a second error correction (C2 correction) for EFM demodulated or de-interleaved music data and a track search operation. An error correction operation unit with a search function (hereinafter referred to as a track search / error correction operation unit 4).

As described above, the first error correction (C1 correction) means only one of a plurality of symbols forming the data word input from the compact disc 1 through the optical pickup 2 and the EFM demodulator 3, or 2 Detecting that a symbol is wrong and correcting it. Also, the second error correction (C2 correction) means that the de-interleave processing unit ends the processing of the first error correction (C1 correction).
In 17, it is to detect that only one symbol or two symbols are erroneous with respect to a plurality of deinterleaved symbols and correct it.

5 is a Q signal processor for extracting time information from the EFM demodulated signal and outputting it to the track search / error correction operation unit 4, 6 is an operation of the signal processing system for the CD player,
It is a system controller that generates commands such as stop and search and outputs them to the track search / error correction operation unit 4. The system controller 6 outputs a muting command for inhibiting the external output of an erroneous music signal during a period in which the first error correction (C1 correction) is not executed, that is, in a tracking control execution period. It is configured.

Reference numeral 7 denotes a servo interface for exchanging signals with the track search / error correction arithmetic unit 4 and controlling the servo mechanism of the optical pickup 2.

The track search / error correction operation unit 4 is a microprogram operation unit, and has a basic function of performing first error correction (C1 correction) and second error correction (C2 correction) of music data. However, in addition to this, the size determination function for tracking control and the like have been enhanced, and it also has a track search calculation function.

FIG. 2 shows the configuration of the track search / error correction calculation unit 4, which will be described below.

In FIG. 2, reference numeral 11 is a search command detecting means for detecting that there is a track search command for the compact disc 1 from the system controller 6, and the track search command includes a target time for tracking control. . Reference numeral 12 is a time information detecting means for detecting that time information has been input from the Q signal processor 5. Numeral 13 detects only one symbol or two symbols erroneous among a plurality of symbols constituting the data word inputted from the compact disc 1 through the optical pickup 2 and the EFM demodulator 3, and corrects them. The first error correction means 14, which performs the first error correction means, completes the processing by the first error correction means, and in the de-interleave processor 17, one or two symbols among the plurality of symbols de-interleaved are erroneous. It is a second error correction means for detecting the occurrence of the error and executing the correction.

Reference numeral 15 is a comparison between the target time input from the search command detecting means 11 and the time information on the compact disc 1 input from the time information detecting means 12, that is, the compact disc 1
Track search calculation means for executing the track search calculation for the tracking control and outputting the calculation result to the servo interface 7.

Reference numeral 16 denotes the first error correction means 13 and the second error correction means 13 when the search command detecting means 11 does not detect a track search command or when the time information detecting means 12 does not detect time information.
When the search instruction detecting means 11 detects the track search instruction and the time information detecting means 12 detects the time information while operating the error correcting means 14 of the first error correcting means 13 of FIG.
This is a control means for prohibiting the operation of the above and operating the second error correction means 14 and the track search calculation means 15.

Next, the operation of this embodiment will be described with reference to FIG.

FIG. 3 is a flow chart for explaining the operation of one cycle in the track search / error correction operation unit 4. The one cycle is performed every one frame (about 136 μsec).

At step # 1, it is determined whether the search command detecting means 11 has input a track search command from the system controller 6. When no input is made, the process proceeds to step # 2, and the control means 16 drives the first error correction means 13 to perform the first
Error correction (C1 correction) is performed once, and in step # 3, the control means 16 drives the second error correction means 14 to perform the second error correction (C2 correction) once.

When the track search command is input in the determination in step # 1, the process proceeds to step # 4, and it is determined whether the time information detecting means 12 has input the time information from the Q signal processor 5. If you have not entered, go to Step # 2 → # 3,
The control means 16 drives the first error correction means 13 and the second error correction means 14 to execute the first error correction (C1 correction) and the second error correction (C2 correction) once, respectively.

When the time information is input, the process proceeds to step # 5, and the control means 16 prohibits the operation of the first error correction means 13, that is, the first error correction (C1 correction), and the symbol includes an error. C1 error flag that indicates possible In the next step # 6, the control means 16 drives the second error correction means 14 to execute the second error correction (C2 correction) once. Further, in step # 7, the control means 16 drives the track search calculation means 15, and the track search calculation means 15 is driven.
Is a search command detecting means 11 from the system controller 6.
The target time input together with the track search command via the time signal is compared with the time information on the compact disc 1 input from the Q signal processor 5 via the time information detecting means 12, and the optical pickup is based on the result of the determination. A command for driving 2 is output to the servo interface 7.

The time information on the compact disc 1 is 98 frames (1
It is sent to the Q signal processor 5 every 3.3 msec. Therefore, the tracking control is performed only when the track search command is sent from the system controller 6 and when the time information on the compact disc 1 is extracted once every 98 frames. That is, instead of first performing the first error correction (C1 correction), the second error correction (C2 correction) is performed, and then the track search operation is performed to perform the tracking control, so that the processing time of the tracking control is sufficient. It can be taken long. Therefore, it is possible to perform severe tracking control.

As described above, the period in which the first error correction (C1 correction) is not executed is the tracking control execution period. In this period, the muting command is output from the system controller 6, so the first error correction is performed. Even if (C1 correction) is not executed, there is almost no possibility that erroneous data will be output as an audio signal to the outside (speaker).

Even if erroneous data remains immediately before the tracking control is finished, that is, immediately before the muting is released, the EFM is performed before the second error correction (C2 correction) is executed.
Since the demodulator 3 has been subjected to de-interleave processing,
The erroneous data is likely to be corrected by the second error correction (C2 correction). Even if it cannot be corrected, since the C1 error flag is set, the processing such as the average value interpolation and the previous value holding, which are generally performed in the past, are performed. It can be said that there is virtually no possibility that erroneous data may be directly output as an audio signal to the outside (speaker) due to the correction (C1 correction) not being performed.

<Effect of the Invention> As described above, according to the present invention, when the search command detecting means does not detect a track search command, or when the time information detecting means does not detect time information, the first error correcting means and When the second error correcting means is operated, the search command detecting means detects the track search command and the time information detecting means detects the time information, the operation of the first error correcting means is prohibited, and the second error correcting means operates. The error correction means and the track search calculation means are operated, that is, the error correction operation by the first error correction means is prohibited only when the track search calculation is executed so that the track search calculation processing time is extended. At the same time, the error correction operation by the second error correction means is made to avoid the deterioration of the error correction operation function as much as possible. Thus, the effect that the single arithmetic unit can be provided with both the error correction arithmetic function and the track search arithmetic function can be exerted without lowering the track search arithmetic function and increasing the capacity.

[Brief description of drawings]

1 to 3 relate to an embodiment of the present invention. FIG. 1 is a block circuit diagram of a signal processing device for a CD player, FIG. 2 is a block circuit diagram of an error correction operation unit with a track search function, and FIG. FIG. 3 is a flow chart for explaining the operation of the error correction operation unit with the track search function. 1 ... Compact disc 4 ... Error correction arithmetic unit with track search function 11 ... Search command detection means 12 ... Time information detection means 13 ... First error correction means 14 ... Second error correction means 15 ... … Track search calculation means 16 …… Control means 17 …… De-interleave processor

Claims (1)

[Claims] 1. A search command detecting means for detecting the presence of a search command for a track on a disk, a time information detecting means for detecting an input of time information from the disk, and a data word input from the disk. A first error correction unit that detects that only one symbol or two symbols are erroneous among the plurality of symbols and executes the correction, and a first error correction unit that finishes the first correction by the first error correction unit.・
Second error correction means for detecting whether only one symbol or two symbols are erroneous for a plurality of interleaved symbols and correcting the error, and a track search operation for tracking the disk. Track search calculation means to be executed, the first error correction means and the second error correction means when the search command detection means does not detect a track search command or when the time information detection means does not detect time information.
Error correction means is operated, when the search command detection means detects a track search command and the time information detection means detects time information, the operation of the first error correction means is prohibited, 2. An error correction operation unit with a track search function in a disc player, comprising: 2 error correction means and control means for operating the track search operation means.