KR20070106076A - Method for setting frequency and optical disc driver using the same - Google Patents

Abstract

A method for setting high frequency and an optical disc device using the same are provided to improve playing performance of a disc by minimizing an interference caused by the beam reflected from a disc surface when playing the disc. A method for setting high frequency includes a step of deciding a target value of HFM(High Frequency Modulation) frequency and computing an optional register value including the HFM frequency in an allowance range, and the applicable HFM frequency(S11,S13); a step of detecting the register value outputting the target HFM frequency by increasing or decreasing the optional register value(S15,S16,S17,S18,S19,S20); and a step of outputting an HFM signal of the frequency which is applicable to the detected register value(S21). An optical disc device using the method comprises a frequency setting DA(Digital-to-Analog) switching circuit, an amplitude setting DA switching circuit, a signal generating unit, and a monitoring unit. The frequency setting DA switching circuit sets a frequency value corresponding to the output of a register setting the frequency of a high frequency component. The amplitude DA switching circuit sets the amplitude corresponding to the amplitude value for the high frequency component. The signal generating unit generates the HFM signal by using information on the frequency setting DA switching circuit and the amplitude setting DA switching circuit. The monitoring unit checks an error by monitoring the frequency of the HFM signal output from the signal generating unit.

Description

Method for setting high frequency frequency and optical disc device using same {Method for setting frequency and optical disc driver using the same}

1 is a block diagram showing an oscillator included in a laser diode driver of the prior art.

2 shows specifications for frequency and amplitude of HFM signals.

3 is a block diagram showing an oscillator included in a laser diode driver according to an embodiment of the present invention.

4 is a flow chart for generating an HFM frequency according to an embodiment of the present invention.

5 is a diagram illustrating slope characteristics of a straight line of a frequency and a register value according to an exemplary embodiment of the present invention.

The present invention relates to an optical disk device, and more particularly, to a frequency setting method for minimizing interference caused by a laser diode when a disk is played using the optical disk device, and an optical disk device using the same.

In general, when reading information recorded on an optical information storage medium such as an optical disc or recording predetermined information on the optical information storage medium, an optical pickup apparatus that provides a physical interface of reading and recording is used.

Optical pickup uses a laser diode (LD) that emits a laser beam to transmit (record) information to an optical information storage medium or to interpret (read) information from a beam reflected from the optical information storage medium. The driver driving the laser diode uses a frequency oscillator circuit called a high frequency modulator to control the intensity of the beam emitted by the laser diode.

Here, the light output from the laser diode is reflected on the disk surface, causing interference with the laser diode. In order to minimize this, a high frequency modulation (hereinafter referred to as HFM) signal is transmitted to a laser diode driver (LDD). ) Includes an oscillator that generates an HFM signal with a specific frequency component.

1 is a block diagram showing an oscillator included in a laser diode driver of the prior art.

Referring to Figure 1, to determine the frequency and amplitude of the HFM signal to determine the frequency of the HFM signal through the FADJ1, FADJ2 (11) and the amplitude of the HFM signal through the AADJ1, AADJ2 (12) and FIG. Shows the specification of the frequency and amplitude of the HFM signal determined by the resistances connected to FADJ1, FADJ2 (11) and AADJ1, AADJ2 (12).

In the structure for generating the HFM signal of a specific frequency component according to the prior art, the deviation of the desired HFM signal is generated by the characteristics of the laser diode driver and the error of the connected resistance, which is why the optical disk device When the disc is played back, the disc is subjected to interference caused by the light reflected from the disc, thereby degrading the disc's playback performance and generating a HFM signal corresponding to a desired frequency.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and a frequency setting method for minimizing interference by light reflected from the surface of a disc when the disc is reproduced using the optical disc apparatus and improving the disc reproduction performance and the optical disc apparatus using the same The purpose is to provide.

Frequency setting method according to the present invention for achieving the above object,

Determining a target value of the HFM frequency and obtaining an arbitrary register value that includes the frequency as an allowable range and a corresponding HFM frequency;

Detecting a register value that outputs a desired HFM frequency while increasing or decreasing the arbitrary register value;

And outputting an HFM signal having a frequency corresponding to the detected register value.

In the present invention, the register value may be controlled using a serial interface.

In the present invention, in order to detect the HFM frequency, it is characterized by detecting the two coordinate values of the register and the corresponding frequency value.

In addition, the optical disk device according to the present invention for achieving the above object,

In a laser diode driver that generates an HFM signal,

A frequency setting DA conversion circuit for setting a frequency value corresponding to the output of the register for setting the frequency of the high frequency component;

An amplitude setting DA conversion circuit for setting an amplitude magnitude corresponding to the amplitude value of the high frequency component;

Signal generating means for generating an HFM signal using information of the frequency setting DA converter circuit and amplitude setting DA converter circuit;

And monitoring means for monitoring the frequency of the HFM signal output from the signal generating means to check whether there is an error.

In the present invention, a serial interface signal and a reference clock for setting a frequency value and an amplitude value are input to the laser diode driver.

In the present invention, the register value for generating a frequency can be controlled using the serial interface.

Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

3 is a block diagram illustrating an oscillator included in a laser diode driver according to an exemplary embodiment of the present invention.

3, a frequency setting DA conversion circuit (HFMFREQ DAC) 21 for setting a frequency value corresponding to a register value for setting a frequency of a high frequency component; An amplitude setting DA conversion circuit (HFMON DAC) 22 for setting an amplitude magnitude corresponding to the amplitude value of the high frequency component; Signal generating means (HFM OSC) 23 for generating an HFM signal using information of the frequency setting DA converter circuit (HFMFREQ DAC) 21 and amplitude setting DA converter circuit (HFMON DAC) 22; ; It comprises a monitoring means (COUNTER) 24 for monitoring the frequency of the signal output from the signal generating means 23, serial interface signals (SCLK, SEN) for setting the frequency value and the amplitude value to a desired value , SDATA) and a reference clock (REFCLK) are input.

The present invention can be controlled to generate a desired frequency by setting a specific register, and if an error occurs by monitoring the HFM signal generated in the already set state, it is a DA conversion circuit (HFMFREQ DAC) for frequency setting using a serial interface ( 21) and the frequency setting value and the amplitude setting value of the amplitude setting DA conversion circuit (HFMON DAC) 22 can be changed so that an HFM signal corresponding to a desired frequency is generated.

For example, it is possible to set the frequency value of the frequency conversion DA conversion circuit 21 through the following equation (1).

Here, if the Fmin value is 95MHz and the Fstep is 1.4MHz / step, and the desired HFM frequency is 350MHz, the HFMFREQ value for generating an HFM frequency of 350MHz in the DA converter circuit 21 for frequency setting is 182, and monitors the output frequency using the monitoring means (COUNTER) 24 to control the register value using the serial interface unit to generate the HFM signal of the desired frequency.

In Equation 1, since there is a deviation of the chip itself in the oscillator of the laser diode driver LDD, Fmin and Fstep may be different from the specification.

Therefore, the present invention monitors the frequency of the HFM signal output using the monitoring means 24 to determine whether an error occurs, and adjusts the register value using the serial interface unit so that the desired frequency is output, Equation 2 The monitored value is used to output the HFM signal of the desired frequency.

Here, assuming that the reference clock signal REFCLK is 13MHz, if the monitored register value HFMCOUNT is 107, a desired HFM frequency 347.75MHz is output.

A detailed description for generating the desired HFM frequency will be described below in detail with reference to FIG. 4.

4 is a flowchart illustrating a method of generating an HFM frequency according to an embodiment of the present invention.

Referring to FIG. 4, an HFM frequency target value for generating an initial desired HFM signal is set (S11), and an input clock of the laser diode driver 21 is set (S12). For example, the reference clock signal REFCLK is set.

Subsequently, in order to generate a desired HFM signal, an arbitrary register value, which is sample data, and a frequency measured corresponding thereto are obtained (S13), and the linear equation of the HFM frequency is calculated using the following equation (3) (S14). ).

For example, to obtain sample data as shown in FIG. 5, a frequency corresponding to an arbitrary register signal (dac1, dac2) including an HFM frequency target value as an allowable range is measured, that is, a frequency f1 corresponding to dac1 and A frequency f2 corresponding to dac2 is obtained, and the linear equation of Equation 3 is calculated using two coordinates of (dac1, f1) and (dac2, f2).

Thereafter, the register value corresponding to the desired HFM frequency TgtFrq is calculated using the linear equation through Equation 4 below (S15).

For example, the register value d3 for generating the desired HFM frequency f3 is detected through Equation 4 above, and the register value is increased by one step (1.4 MHz) to approach the target value of the HFM frequency. While measuring the frequency (S16), it is determined whether the measured frequency converges within -5% of the target frequency (S17).

At this time, it is determined whether it is out of the allowable range of the HFM frequency target value, and if it is not out of the allowable range, it is determined whether the measured frequency converges to -5% of the target frequency while increasing the step of the register (S18).

If the determination result is out of the allowable range and becomes higher than the target frequency, it is determined whether the measured frequency converges within + 5% of the target frequency (S19). If not, the frequency is decreased by decreasing the register value by one step (1.4 MHz). By measuring (S20), when the measured frequency converges within + 5% of the target frequency, a register value corresponding to the HFM frequency target value is detected (S21).

Here, the step value for changing the register value to find the desired frequency may be changed.

In this way, the register value for generating the desired HFM frequency is detected, and the monitoring means 24 monitors the frequency of the output HFM signal to determine whether an error occurs, and generates an accurate HFM frequency when an error occurs. The detected register value is input through the serial interface to set a desired frequency for removing optical interference noise to generate an optimal HFM signal.

Accordingly, there is an advantage in that an optical disk device can accurately and efficiently generate a desired HFM signal so that the disk playback performance is improved by minimizing interference caused by light reflected from the disk surface when the disk is played.

So far, the present invention has been described with reference to the embodiments, and those skilled in the art to which the present invention pertains may implement embodiments of the present invention in a different form from the detailed description of the present invention within the essential technical scope of the present invention. Could be. Here, the essential technical scope of the present invention is shown in the claims, and all differences within the equivalent range will be construed as being included in the present invention.

According to the frequency setting method and the optical disk apparatus using the same, the method of monitoring the generated HFM frequency to control the register value to generate the HFM signal corresponding to the desired frequency to minimize the interference by the light reflected from the disk surface disk There is an effect of improving the playback performance.

It also has the effect of setting the desired frequency through register control without changing hardware during frequency conversion.

Claims (6)

Determining a target value of the HFM frequency and obtaining an arbitrary register value that includes the frequency as an allowable range and a corresponding HFM frequency; Detecting a register value outputting a desired HFM frequency while increasing or decreasing the arbitrary register value; And outputting an HFM signal having a frequency corresponding to the detected register value. The method of claim 1, The register value may be controlled using a serial interface. The method of claim 1, And detecting two coordinate values of an arbitrary register and a corresponding frequency value to detect the HFM frequency. In a laser diode driver that generates an HFM signal, A frequency setting DA conversion circuit for setting a frequency value corresponding to the output of the register for setting the frequency of the high frequency component; An amplitude setting DA conversion circuit for setting an amplitude magnitude corresponding to the amplitude value of the high frequency component; Signal generating means for generating an HFM signal using information of the frequency setting DA converter circuit and amplitude setting DA converter circuit; And monitoring means for monitoring the frequency of the HFM signal output from the signal generating means to check whether there is an error. The method of claim 4, wherein And a serial interface signal and a reference clock for setting a frequency value and an amplitude value to the laser diode driver. The method of claim 4, wherein And a register value for generating a frequency using the serial interface.

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