CN1296915C - Gain correction device and method of differential push-pull type rail searching error signal - Google Patents

Abstract

The present invention discloses a gain correction device and a method of a differential push-pull type rail searching error signal in an optical disk access system and processes synthetic gains of auxiliary beams in a component of the DPP rail searching error signal corresponding to main beams. The present invention has the correction principle that an objective lens controlling an optical read head is used to shift the optical read head or control relative slope angles of the objective lens and an optical disk sheet, and the synthetic DPP rail searching error signal generates corresponding signal change amount due to the change of an optical path. Synthetic gains are corrected to enable the signal change amount to be minimum, and corrected synthetic gains are optimal. People do not need to suppose that the intensity of the two auxiliary beams is the same or the positions of the two auxiliary beams are symmetric to the main beams and do not need to know about a proportion of a space of the two auxiliary beams and a rail space with the method and the device, and the optimal synthetic gains of the auxiliary beams can be accurately calculated.

Description

Differential push-pull type is sought the gain correcting device and the method for rail error signal

Technical field

The present invention is about differential push-pull type (the Differential Push-Pull in the optical disc accessing, hereinafter to be referred as DPP) seek the gain correcting device and the method for rail error signal, particularly at means for correcting and the method for the auxiliary beam in the DPP component of signal with respect to the synthetic gain (SPPG) of main light beam.

Background technology

Figure 1 shows that the discs laser facula structure of seeking the rail error analysis of differential push-pull type framework.As shown in Figure 1, general differential push-pull type framework sought rail error (Tracking Error, TE) analyze, have three laser beam and beat on discs, be respectively main light beam (Main beam) 12, first auxiliary beam (First Sub beam) 13 and second auxiliary beam (Second Sub beam) 14.Therefore, DPP seeks push-pull signal SPP differential synthetic that rail error signal TE can be expressed as the push-pull signal MPP of main light beam 12 and auxiliary beam 13,14, suc as formula (1):

TE＝MPP-α·SPP (1)

Wherein, α is the synthetic gain SPPG of the push-pull signal SPP of auxiliary beam 13,14 with respect to the push-pull signal MPP of main light beam 12.

Arrange configuration according to the laser facula on Fig. 1 discs, the push-pull signal MPP of main light beam 12 and the push-pull signal SPP of auxiliary beam 13,14 can represent an accepted way of doing sth (2) and formula (3):

$\mathrm{MPP}=A_m\·\sin \left(\frac{2\mathrm{\πx}}{P}\right)+A_m\·K\left(\mathrm{tilt}\right)+C_m---\left(2\right)$

$\mathrm{SPP}=\mathrm{SPA}+\mathrm{SPP}2$

$=[A_{\mathrm{<figure-callout\; id="1"\; label="S"\; filenames="C0214222900181.png"\; state="\{\{state\}\}">S</figure-callout>}1}\&CenterDot;\sin \left(\frac{2\mathrm{\&pi;}\&CenterDot;(x-Q_1)}{P}\right)+A_{\mathrm{<figure-callout\; id="1"\; label="S"\; filenames="C0214222900181.png"\; state="\{\{state\}\}">S</figure-callout>}1}\&CenterDot;K\left(\mathrm{tilt}\right)+C_{S1}]+[A_{S2}\&CenterDot;\sin \left(\frac{2\mathrm{\&pi;}\&CenterDot;(x+Q_2)}{P}\right)+A_{S2}\&CenterDot;K\left(\mathrm{tilt}\right)+C_{S2}]$

$=(A_{\mathrm{<figure-callout\; id="1"\; label="S"\; filenames="C0214222900181.png"\; state="\{\{state\}\}">S</figure-callout>}1}\&CenterDot;\cos \left(\frac{{2\mathrm{\&pi;Q}}_1}{P}\right)+A_{S2}\&CenterDot;\cos \left(\frac{{2\mathrm{\&pi;Q}}_2}{P}\right))\&CenterDot;\sin \left(\frac{2\mathrm{\&pi;x}}{P}\right)+(A_{S2}\&CenterDot;\sin \left(\frac{{2\mathrm{\&pi;Q}}_2}{P}\right)-{\mathrm{<figure-callout\; id="1"\; label="A\; S"\; filenames="C0214222900181.png"\; state="\{\{state\}\}">A</figure-callout>}}_S\&CenterDot;\sin \left(\frac{{2\mathrm{\&pi;Q}}_1}{P}\right))\&CenterDot;\cos \left(\frac{2\mathrm{\&pi;x}}{P}\right)$

$+(A_{\mathrm{<figure-callout\; id="1"\; label="S"\; filenames="C0214222900181.png"\; state="\{\{state\}\}">S</figure-callout>}1}+A_{S2})\&CenterDot;K\left(\mathrm{tilt}\right)+({\mathrm{<figure-callout\; id="1"\; label="C\; S"\; filenames="C0214222900181.png"\; state="\{\{state\}\}">C</figure-callout>}}_S+C_{S2})$

(3)

Wherein, x is the side-play amount of the spot center 15 of main laser beam 12 to track (Groove) center 10, and is the function of time t.The project relevant with x is so-called AC component (than Tilt variation high frequency), and is subjected to discs off-centre and strides rail amount (RUNOUT) influence.Q1, Q2 are the distance of the spot center 16,17 of first, second auxiliary beam 13,14 to the spot center 15 of main laser beam 12.P is the data track pitch on the discs, i.e. distance between the orbit centre 10,10 '.Am, As1, As2 are the AC amplitude of seeking rail error signal TE, just eccentric amplitude of striding the rail amount.And Cm, Cs1, Cs2 are the circuit signal side-play amount (OFFSET) of the OP amplifier of pre-amplifier (RFIC) and optical signalling amplifier (PDIC).K (tilt) is for being proportional to the variable of optical read head tilt quantity, and this optically read head tilt is that the error by lens skews (lens-shift) or optical facilities is caused.

Therefore, bring formula (2) and (3) into formula (1), then seek rail error signal TE and can represent an accepted way of doing sth (4):

$\mathrm{TE}=\mathrm{MPP}-\mathrm{\&alpha;}\&CenterDot;\mathrm{SPP}$

$=(A_m-\mathrm{\&alpha;}\&CenterDot;(A_{\mathrm{<figure-callout\; id="1"\; label="S"\; filenames="C0214222900181.png"\; state="\{\{state\}\}">S</figure-callout>}1}\&CenterDot;\cos \left(\frac{{2\mathrm{\&pi;Q}}_1}{P}\right)+A_{S2}\&CenterDot;\cos \left(\frac{{2\mathrm{\&pi;Q}}_2}{P}\right)))\&CenterDot;\sin \left(\frac{2\mathrm{\&pi;x}}{P}\right)$

$-\mathrm{\&alpha;}\&CenterDot;(A_{S2}\&CenterDot;\sin \left(\frac{{2\mathrm{\&pi;Q}}_2}{P}\right)-{\mathrm{<figure-callout\; id="1"\; label="A\; S"\; filenames="C0214222900181.png"\; state="\{\{state\}\}">A</figure-callout>}}_S\&CenterDot;\sin \left(\frac{{2\mathrm{\&pi;Q}}_1}{P}\right))\&CenterDot;\cos \left(\frac{2\mathrm{\&pi;x}}{P}\right)$

$+(A_m-\mathrm{\&alpha;}\&CenterDot;({\mathrm{<figure-callout\; id="1"\; label="A\; S"\; filenames="C0214222900181.png"\; state="\{\{state\}\}">A</figure-callout>}}_S+A_{S2}))\&CenterDot;K\left(\mathrm{tilt}\right)+(C_m-\mathrm{\&alpha;}\&CenterDot;({\mathrm{<figure-callout\; id="1"\; label="C\; S"\; filenames="C0214222900181.png"\; state="\{\{state\}\}">C</figure-callout>}}_S+C_{S2}))$

(4)

Seeking the influence that rail error signal TE is not subjected to K (tilt) variable in order to make, generally is to set suitable synthetic gain SPPG value, makes that the 3rd in the formula (4) is 0.Existing mode is first hypothesis

1.A _s1＝A _s2＝A _s

2.Q ₁＝Q ₂＝Q

3.Q/P be known

Therefore, if bring above-mentioned default into formula (4), then formula (4) can be simplified an accepted way of doing sth (5):

$\mathrm{TE}=\mathrm{MPP}-\mathrm{\&alpha;}\&CenterDot;\mathrm{SPP}$

$=(A_m-\mathrm{\&alpha;}\&CenterDot;2\&CenterDot;A_S\&CenterDot;\cos \left(\frac{2\mathrm{\&pi;Q}}{P}\right))\&CenterDot;\sin \left(\frac{2\mathrm{\&pi;x}}{P}\right)+(A_m-\mathrm{\&alpha;}\&CenterDot;2\&CenterDot;A_S)\&CenterDot;K\left(\mathrm{tilt}\right)$

$+(C_m-\mathrm{\&alpha;}\&CenterDot;({\mathrm{<figure-callout\; id="1"\; label="C\; S"\; filenames="C0214222900181.png"\; state="\{\{state\}\}">C</figure-callout>}}_S+C_{S2}))$

(5)

So main light beam 12 can be used to proofread and correct the α value with the push-pull signal MPP of auxiliary beam 13,14 and the AC item of SPP.Its bearing calibration is as follows:

Step 1: the OFFSET value C that adjusts circuit _m, C _s1 and C _S2Be 0;

Step 2: measure the amplitude of the AC item of MPP, MA=A _m

Step 3: measure the amplitude of the AC item of SPP, $\mathrm{SA}=2\&CenterDot;A_s\cos \left(\frac{2\mathrm{\&pi;Q}}{P}\right)$

Step 4: the synthetic gain of definition SPP $\mathrm{\&alpha;}=\frac{\mathrm{MA}\&CenterDot;\cos \left(\frac{2\mathrm{\&pi;Q}}{P}\right)}{\mathrm{SA}}=\frac{A_m}{2\&CenterDot;A_s}$

Step 5: bring the α value of step 4 into formula (5), can obtain to have only the function of AC item, as the formula (6):

$\mathrm{TE}=\mathrm{MPP}-\mathrm{\&alpha;}\&CenterDot;\mathrm{SPP}$

$=(A_m-\mathrm{\&alpha;}\&CenterDot;2\&CenterDot;A_S\&CenterDot;\cos \left(\frac{2\mathrm{\&pi;Q}}{P}\right))\&CenterDot;\sin \left(\frac{2\mathrm{\&pi;x}}{P}\right)+(A_m-\mathrm{\&alpha;}\&CenterDot;2\&CenterDot;A_S)\&CenterDot;K\left(\mathrm{tilt}\right)$

$+(C_m-\mathrm{\&alpha;}\&CenterDot;({\mathrm{<figure-callout\; id="1"\; label="C\; S"\; filenames="C0214222900181.png"\; state="\{\{state\}\}">C</figure-callout>}}_S+C_{S2}))$

$=A_m\&CenterDot;(1-\cos \left(\frac{2\mathrm{\&pi;Q}}{P}\right))\&CenterDot;\sin \left(\frac{2\mathrm{\&pi;x}}{P}\right)$

(6)

But above-mentioned existing method must satisfy three hypothesis.Yet, Q/P, A _S1, A _S2, Q ₁, Q ₂Value can change because of different optical read head and discs.Therefore, can't during the correction of SPP gain, obtain these information.So, can't be with the gain alpha of the correct SPP of this prior art acquisition.

Summary of the invention

In view of the above problems, the bearing calibration and the device that the purpose of this invention is to provide the synthetic gain SPPG of the differential push-pull type track-seeking signal in a kind of optical disc accessing, be used for to suppose that identical the and position of two auxiliary beam intensity is symmetrical in main light beam, and need not know under the situation of ratio of two auxiliary beam spacings and track space, can accurately calculate best SPPG value.

For achieving the above object, the invention provides differential push-pull type in a kind of optical disc accessing and seek the gain calibration method of rail error, the amplifier gain that is used for proofreading and correct auxiliary beam is with respect to the value of the amplifier gain of main light beam, and this gain calibration method comprises the following step: open LASER Light Source and also carry out light beam and focus on; Start spindle motor and set initial value gain, promptly set the initial value gain of auxiliary beam push-pull amplifier; The control object lens are in the first relative variable condition with disc; Measure the eigenwert that is offset the push-pull signal of relevant main light beam with object lens, with as the first main beam characteristics value; Measure the eigenwert that is offset the push-pull signal of relevant auxiliary beam with object lens, with as the first auxiliary beam eigenwert; The control object lens are in the second relative variable condition with disc; Measure the eigenwert that is offset the push-pull signal of relevant main light beam with object lens, with as the second main beam characteristics value; Measure the eigenwert that is offset the push-pull signal of relevant auxiliary beam with object lens, with as the second auxiliary beam eigenwert; And calculated gains is promptly according to the gain of the first main beam characteristics value, the first auxiliary beam eigenwert, the second main beam characteristics value and the second auxiliary beam eigenvalue calculation auxiliary beam.

For achieving the above object, the differential push-pull type that the invention provides in a kind of optical disc accessing is sought the gain correcting device of rail error, the amplifier gain that is used for proofreading and correct auxiliary beam is with respect to the value of the amplifier gain of main light beam, this gain correcting device comprises: an optical signalling amplifier, receive main light beam and auxiliary beam signal, and be output into main light beam radiofrequency signal and auxiliary beam radiofrequency signal after amplifying via the disc reflection; One radio frequency receiver, via main light beam radiofrequency signal and the auxiliary beam radiofrequency signal differential amplification of prime with the optical signalling amplifier, again with these amplifying signals via main beam signal amplifier and the differential amplification of auxiliary beam signal amplifier after, produce main light beam push-pull signal and auxiliary beam push-pull signal, and the difference of exporting these main light beam push-pull signals and auxiliary beam push-pull signal is sought the rail error signal as differential push-pull type; One analog-digital converter, the main light beam push-pull signal and the auxiliary beam push-pull signal of received RF receiver, and produce main light beam push-pull signal of numeral and digital auxiliary beam push-pull signal; And, one digital signal processor, receive main light beam push-pull signal of numeral and digital auxiliary beam push-pull signal, and utilize a feature extractor to extract the eigenwert of main light beam push-pull signal of this numeral and digital auxiliary beam push-pull signal, and by a gain calculation module according to the auxiliary beam signal amplifier of the eigenvalue calculation radio frequency receiver of these push-pull signals with respect to main beam signal Amplifier Gain.

Therefore, means for correcting of the present invention and method can guarantee that the differential push-pull type of being synthesized seeks rail error (DPP) signal and rock angle of inclination (Tilt) the optical path disturbance of etc.ing that (lens-shift), object lens or discs form because of mechanism's tolerance (tolerance) when making a variation what meet with as seek object lens in the rail process, signal level is interference-free, make the center of discs track (Groove) maintain the datum of DPP signal, guarantee to lock the center of the servo-controlled laser facula of rail (Laser Spot) alignment rail.Simultaneously, in the repetitive process of the rail of jumping onto the tracks-locking, the DPP signal level is because of presenting the conformance with standard waveform of positive and negative amplitude equalization (Balanced) without interruption.And synthetic gain (SPPG) value of this means for correcting gained is not subjected to the influence of the factors such as gauge (Track Pitch) variation of the formed laser spot position error of internal mechanism tolerance of optical read head or different discs sheet.So consistance is good with stability, is easy to be extended to commercial Application.

Description of drawings

With reference to the accompanying drawing detailed description of the present invention, above-mentioned purpose of the present invention, feature and advantage will become clearer, in the accompanying drawing:

Figure 1 shows that the discs laser facula structure of seeking the rail error analysis of differential push-pull type framework;

Figure 2 shows that differential push-pull type seeks the corrective system of rail error signal;

Figure 3 shows that the calcspar of the digital signal processor in the corrective system of Fig. 2;

Figure 4 shows that differential push-pull type seeks another embodiment of the corrective system of rail error signal;

Figure 5 shows that differential push-pull type in the optical disc accessing of the present invention seeks the process flow diagram of mathematical justification of the gain calibration method of rail error; With

Figure 6 shows that differential push-pull type in the optical disc accessing of the present invention seeks the process flow diagram of embodiment of the gain calibration method of rail error.

Embodiment

Seek the gain calibration method of rail below with reference to the differential push-pull type in the graphic detailed description optical disc accessing of the present invention.Below explanation is to adopt the embodiment of stepping response (Step response) with the control of object lens being made offset movement and the mode of controlling all.

Fig. 2 seeks the corrective system of rail error signal for differential push-pull type proposed by the invention.This corrective system 20 comprise pre-amplifier (RFIC) 21, analog/digital converter (Analog/Digital Converter, A/D) 22, digital signal processor (DSP) 23, object lens motion actuator 24 and optical devices 25.

Pre-amplifier 21 is used to receive the signal (A that detects the optical read head of being exported with amplifier 254 from optical signalling, B, C, D, E, F, G, H) and with it amplify, be blended into the required signal of lock rail servocontrol, comprise the push-pull signal MPP ' of main light beam, the push-pull signal SPP ' and the differential push-pull error signal DPP of auxiliary beam.The push-pull signal SPP of auxiliary beam utilizes OP amplifier 214 earlier with the optical read head signal E of first auxiliary beam and second auxiliary beam, F, and differential again amplification after G, the H merging earlier can be saved the quantity of the input pin of pre-amplifier 21.The push-pull signal SPP of auxiliary beam amplifies the push-pull signal SPP ' that the back produces auxiliary beam via OP amplifier 212.And the push-pull signal MPP of main light beam utilizes OP amplifier 213 earlier with optical read head signal A, B, and differential again amplification after C, D merge is earlier amplified the push-pull signal MPP ' that the back produces main light beam via OP amplifier 211 again.

Analogue-to-digital converters 22 can be for further processing it by digital signal processor 23 in order to the push-pull signal MPP ' of the main light beam of the converting analogue form extremely digital with the push-pull signal SPP ' signal of auxiliary beam.Digital signal processor 23 extracts required characteristic component from the push-pull signal MPP ' of main light beam and the push-pull signal SPP ' of auxiliary beam, and, adjust the synthetic gain SPPG gain (α) of differential push-pull type track-seeking signal in the pre-amplifier 21 according to the push-pull signal MPP ' of main light beam 12 and the number of the middle characteristic component of push-pull signal SPP ' of auxiliary beam 13,14.In addition, digital signal processor 23 and control object lens 253 change its object lens side-play amount (Lens-shift) or pitch angle (lens-tilt) with the mode of motion of a certain specific waveforms.Moreover, digital signal processor 23 is also controlled the electronic signal side-play amount (MPP_offset and SPP_offset) of push-pull signal MPP ' with the push-pull signal SPP ' of auxiliary beam 13,14 of main light beam 12 in the pre-amplifier 21, uses to cooperate in the correction program.

The object lens motion control signal of object lens motion actuator 24 receiving digital signals processors 23 is with the motion of control object lens 253.This object lens motion actuator 24 can be the actuator (trackingactuator) of striding the rail direction to produce object lens offset movements (Lens-shift) or be that the actuator (tiltactuator) of gig minute surface is to produce object lens inclining move (Lens-tilt).

Optical devices 25 comprise laser generation and driving circuit (LD) 251, beam splitting lens group (Splitter) 252, object lens (Objective lens) 253, reach optical signalling detection and amplifier (PDIC) 254.Laser beam is produced by laser and driving circuit 251 produces, and after forming main light beam 12, first auxiliary beam 13 and second auxiliary beams 14 via beam splitting lens group 252, sees through 253 dozens on object lens near the data-track of discs 26.Via discs 26 beam reflected, detect and amplifier (PDIC) 254 generation light commentaries on classics electric signal A, B, C, D, E, F, G, H by optical signalling.And light to change electric signal A, B, C, D be that to change signal that electric signal F and G are first auxiliary beam and light commentaries on classics electric signal E and H be the signal of second auxiliary beam for signal, the light of main light beam.Light change electric signal A, B, C, D, E, F, G, H corresponding to the position optical signalling detect with the position of amplifier 254 as shown in Figure 2.

Figure 3 shows that the calcspar of the digital signal processor 23 of Fig. 2.As shown in the drawing, digital signal processor 23 comprises electronic signal offset correction module 231, feature extractor 232, gain calculating unit 233 and control waveform generator 234.Electronic signal offset correction module 231 is used for proofreading and correct the electronic signal side-play amount MPP_offset and the SPP_offset of OP amplifier 211 and the OP amplifier 212 of auxiliary beam of the main light beam of pre-amplifier 21.Among the push-pull signal MPP ' that feature extractor 232 is used for extracting main light beam and the push-pull signal SPP ' of auxiliary beam with the lens skew or rotate relevant component.For example, lens skew one apart from the time when (stepping is moved), the DC component that is characterized as of the push-pull signal MPP ' of main light beam and the push-pull signal SPP ' of auxiliary beam, perhaps lens produce the triangular wave displacement of fixed frequency, and the push-pull signal MPP ' of main light beam can be mean value with the feature of the push-pull signal SPP ' of auxiliary beam.

The OP amplifier of the feature calculation auxiliary beam that gain calculating unit 233 is extracted according to feature extractor 232 is with respect to the OP Amplifier Gain α of main light beam.Control waveform generator 234 is then given object lens motion actuator 24 according to control waveform parameter output control waveform signal, is used to control object lens 253 and moves or turn to needed position.Therefore, the push-pull signal MPP ' of the main light beam that this digital signal processor 23 can be exported according to pre-amplifier 21 and the push-pull signal SPP ' of auxiliary beam calculate pre-amplifier 21 parameters needed, and the moving of control object lens.

In addition, Fig. 4 shows that the differential push-pull type of the present invention seeks another embodiment of the corrective system of rail error signal.This embodiment and the corrective system maximum differential shown in Figure 2 light that to be pre-amplifier 21 ' change electric signal F, G and second auxiliary beam 14 with the light of first auxiliary beam 13 changes electric signal E, H respectively via remerging after amplifier 214 ', 212 ', 215 ', 213 ' the differential amplification.Signal after the merging is output as DPP after the differential amplification of push-pull signal MPP ' via amplifier 216 ' and main light beam again.And the framework of digital signal processor 23 ' is identical with the framework of digital signal processor 23, and difference is that digital signal processor 23 ' must be given birth to SPP2_offset by fecund.

Illustrate that below with reference to Fig. 5 and Fig. 6 the differential push-pull type in the optical disc accessing of the present invention seeks the gain calibration method of rail error.Figure 5 shows that differential push-pull type in the optical disc accessing of the present invention seeks the process flow diagram of mathematical justification of the gain calibration method of rail error.Figure 6 shows that differential push-pull type in the optical disc accessing of the present invention seeks the process flow diagram of embodiment of the gain calibration method of rail error.Gain calibration method of the present invention need not considered A _S1, A _S2, Q ₁, Q ₂Value, also need not know Q/P, can calculate the OP Amplifier Gain α of correct auxiliary beam.This bearing calibration obtains the eigenwert of the push-pull signal that the different side-play amount (lens-shift) of twice lens or rotation amount (lens-tilt) produced, and utilizes the computing of these eigenwerts can obtain gain alpha.The lens side-play amount of the embodiment of the invention or rotation amount adopt the mode of stepping response (Step response), so the eigenwert of push-pull signal is a DC component.With reference to figure 3, the process flow diagram of mathematical justification of the present invention is as follows:

Step S502: the OFFSET value C that adjusts circuit _m, C _s1 and C _S2Be 0; Certainly this step also can be omitted.

Step S504: activate lens, the control waveform signal that utilizes digital signal processor 23 to be exported moves actuator for objective lenses 24 or relay lens 253, makes these lens 253 form the first side-play amount tilt1.

Step S506: calculate main light beam push-pull signal MPP (tilt1) and auxiliary beam push-pull signal SPP (tilt1) value under the first side-play amount tilt1.The MPP (tilt1) that produces under the first side-play amount tilt1 according to formula (2) and formula (3) is worth with SPP (tilt1), shown in (7) and formula (8).

$\mathrm{MPP}\left(\mathrm{tilt}1\right)=A_m\&CenterDot;\sin \left(\frac{2\mathrm{\&pi;x}}{P}\right)+A_m\&CenterDot;K\left(\mathrm{tilt}1\right)+C_m---\left(7\right)$

$\mathrm{SPP}\left(\mathrm{tilt}1\right)=(A_{\mathrm{<figure-callout\; id="1"\; label="S"\; filenames="C0214222900181.png"\; state="\{\{state\}\}">S</figure-callout>}1}\&CenterDot;\cos \left(\frac{{2\mathrm{\&pi;Q}}_1}{P}\right)+A_{S2}\&CenterDot;\cos \left(\frac{{2\mathrm{\&pi;Q}}_2}{P}\right))\&CenterDot;\sin \left(\frac{2\mathrm{\&pi;x}}{P}\right)$

$+(A_{S2}\&CenterDot;\sin \left(\frac{{2\mathrm{\&pi;Q}}_2}{P}\right)-{\mathrm{<figure-callout\; id="1"\; label="A\; S"\; filenames="C0214222900181.png"\; state="\{\{state\}\}">A</figure-callout>}}_S\&CenterDot;\sin \left(\frac{{2\mathrm{\&pi;Q}}_1}{P}\right))\&CenterDot;\cos \left(\frac{2\mathrm{\&pi;x}}{P}\right)$

$+(A_{\mathrm{<figure-callout\; id="1"\; label="S"\; filenames="C0214222900181.png"\; state="\{\{state\}\}">S</figure-callout>}1}+A_{S2})\&CenterDot;K\left(\mathrm{tilt}1\right)+({\mathrm{<figure-callout\; id="1"\; label="C\; S"\; filenames="C0214222900181.png"\; state="\{\{state\}\}">C</figure-callout>}}_S+C_{S2})$

(8)

Step S508: the eigenwert (DC value) that extracts MPP (tilt1) and SPP (tilt1) under the first side-play amount tilt1.That is filtering the AC component of formula (7) and formula (8), its DC value is suc as formula shown in (9) and the formula (10).

DC{MPP(tilt1)}＝A _m·K(tilt1)+C _m (9)

DC{SPP(tilt1)}＝(A _S1+A _S2)·K(tilt1)+(C _S1+C _S2)?(10)

Step S510: activate lens again No. one time, make lens form the second side-play amount tilt2.

Step S512: calculate MPP (tilt2) and SPP (tilt2) value under the second side-play amount tilt2.The MPP (tilt2) that produces under the second side-play amount tilt2 according to formula (2) and formula (3) is worth with SPP (tilt2), shown in (11) and formula (12).

$\mathrm{MPP}\left(\mathrm{tilt}2\right)=A_m\&CenterDot;\sin \left(\frac{2\mathrm{\&pi;x}}{P}\right)+A_m\&CenterDot;K\left(\mathrm{tilt}2\right)+C_m---\left(11\right)$

$\mathrm{SPP}\left(\mathrm{tilt}2\right)=(A_{\mathrm{<figure-callout\; id="1"\; label="S"\; filenames="C0214222900181.png"\; state="\{\{state\}\}">S</figure-callout>}1}\&CenterDot;\cos \left(\frac{{2\mathrm{\&pi;Q}}_1}{P}\right)+A_{S2}\&CenterDot;\cos \left(\frac{{2\mathrm{\&pi;Q}}_2}{P}\right))\&CenterDot;\sin \left(\frac{2\mathrm{\&pi;x}}{P}\right)$

$+(A_{S2}\&CenterDot;\sin \left(\frac{{2\mathrm{\&pi;Q}}_2}{P}\right)-{\mathrm{<figure-callout\; id="1"\; label="A\; S"\; filenames="C0214222900181.png"\; state="\{\{state\}\}">A</figure-callout>}}_S\&CenterDot;\sin \left(\frac{{2\mathrm{\&pi;Q}}_1}{P}\right))\&CenterDot;\cos \left(\frac{2\mathrm{\&pi;x}}{P}\right)$

$+(A_{\mathrm{<figure-callout\; id="1"\; label="S"\; filenames="C0214222900181.png"\; state="\{\{state\}\}">S</figure-callout>}1}+A_{S2})\&CenterDot;K\left(\mathrm{tilt}2\right)+({\mathrm{<figure-callout\; id="1"\; label="C\; S"\; filenames="C0214222900181.png"\; state="\{\{state\}\}">C</figure-callout>}}_S+C_{S2})$

(12)

Step S514: the eigenwert (DC value) that extracts MPP (tilt2) and SPP (tilt2) under the second side-play amount tilt2.That is filtering the AC component of formula (11) and formula (12), its DC value is suc as formula shown in (13) and the formula (14).

DC{MPP(tilt2)}＝A _m·K(tilt2)+C _m (13)

DC{SPP(tilt2)}＝(A _S1+A _S2)·K(tilt2)+(C _S1+C _S2) (14)

Step S516: calculate MPP under the first side-play amount tilt1 and the second side-play amount tilt2 occasion and DC side-play amount MD and the SD of SPP.Shown in (15) and formula (16).

MD＝DC{MPP(tilt2)}-DC{MPP(tilt1)}＝A _m·{K(tilt2)-K(tilt1)} (15)

SD＝DC{SPP(tilt2)}-DC{SPP(tilt1)}＝(A _s1+A _s2)·{K(tilt2)-K(tilt1}?(16)

Step S518: definition is also calculated $\mathrm{\&alpha;}=\frac{\mathrm{MD}}{\mathrm{SD}}=\frac{A_m}{A_{s1}+A_{s2}},$ And bring this formula into formula (4), can obtain formula (17).

$\mathrm{TE}=\mathrm{MPP}-\mathrm{\&alpha;}\&CenterDot;\mathrm{SPP}$

$=(A_m-\frac{A_m}{A_{s1}+A_{s2}}\&CenterDot;(A_{\mathrm{<figure-callout\; id="1"\; label="s"\; filenames="C0214222900181.png"\; state="\{\{state\}\}">s</figure-callout>}1}\&CenterDot;\cos \left(\frac{{2\mathrm{\&pi;Q}}_1}{P}\right)+A_{s2}\&CenterDot;\cos \left(\frac{{2\mathrm{\&pi;Q}}_2}{P}\right)))\&CenterDot;\sin \left(\frac{2\mathrm{\&pi;x}}{P}\right)$

$-\mathrm{\&alpha;}\&CenterDot;(A_{s2}\&CenterDot;\sin \left(\frac{{2\mathrm{\&pi;Q}}_2}{P}\right)-{\mathrm{<figure-callout\; id="1"\; label="A\; s"\; filenames="C0214222900181.png"\; state="\{\{state\}\}">A</figure-callout>}}_s\&CenterDot;\sin \left(\frac{{2\mathrm{\&pi;Q}}_1}{P}\right))\&CenterDot;\cos \left(\frac{2\mathrm{\&pi;x}}{P}\right)$

$+0\&CenterDot;K\left(\mathrm{tilt}\right)+(C_m-\mathrm{\&alpha;}\&CenterDot;({\mathrm{<figure-callout\; id="1"\; label="C\; S"\; filenames="C0214222900181.png"\; state="\{\{state\}\}">C</figure-callout>}}_S+C_{S2}))$

(17)

Therefore, it is irrelevant to find to seek rail error signal TE and K (tilt) parameter according to formula (17), that is seeks inclination or the lens bias effect that rail error signal TE is not subjected to optical read head.And method of the present invention does not need to know the ratio of P/Q, and restriction A _S1, A _S2, Q ₁, Q ₂Value.So,, can calculate the OP Amplifier Gain value α of auxiliary beam as long as calculate MPP under the first side-play amount tilt1 and the second side-play amount tilt2 occasion and DC side-play amount MD and the SD of SPP.

Above-mentioned process flow diagram is the principle that is used for illustrating bearing calibration of the present invention, and Fig. 6 seeks the process flow diagram of embodiment of the gain calibration method of rail error for the differential push-pull type in the optical disc accessing of the present invention.The lens side-play amount of this embodiment or rotation amount adopt the mode of stepping response, so the eigenwert of push-pull signal is a DC component.Certainly, lens side-play amount or rotation amount also can adopt the continually varying waveform response.The step of this process flow diagram is described below with reference to Fig. 6.

Step S602: power-on and close LASER Light Source.In this case, be pre-amplifier 21 and the electronic signal side-play amount of optical signalling detection by digital signal processor 23 measured MPP and spp signals with amplifier 254.

Step S604: calibration MPP_offset value.Under the situation of step S602, measure the MPP value by digital signal processor 23, and produce the main light beam amplifier 211 that MPP_offset gives pre-amplifier 21.

Step S606: calibration SPP_offset value.Under the situation of step S602, measure the SPP value by digital signal processor 23, and produce the auxiliary beam amplifier 212 that SPP_offset gives pre-amplifier 21.

Step S608: start LASER Light Source, and focused beam.

Step S610: start spindle motor (spindle motor).Drives spindle motor is with the rotating disc sheet, and the off-centre of generation MPP, SPP and TE is striden the rail amount.At this moment, spindle motor can be controlled in fixed angular speed (CAV) or alignment speed (CLV) control model, uses to keep the discs rotation.

Step S612: initialization α.Set the gain initial value of the auxiliary beam amplifier 212 of pre-amplifier 21.

Step S614: control lens to a deviation post.The control waveform signal that utilizes digital signal processor 23 to be exported moves actuator for objective lenses 24 or relay lens 253, makes these lens 253 form skew or rotation.

Step S616: measurement features value.After lens are stable, measure the eigenwert MD of MPP and the DC eigenwert SD of SPP with digital signal processor 23.Measuring method can utilize measure the peak to peak value after, with after peak value and the valley addition divided by 2, or directly directly obtain eigenwert with low-pass filter (low-pass filter).

Step S618: set new α value.New α value defined is $\mathrm{\&alpha;}=\frac{\mathrm{MD}}{\mathrm{SD}}.$

Step S620: finish.

The difference of the principle of Fig. 5 and Fig. 6 and the process flow diagram of embodiment is the OP Amplifier Gain (SPPG) that DC off-set value that this principle directly obtains pairing MPP of twice object lens side-play amount (lens-shift) and SPP is calculated SPP, use the feasibility of this method of proof, and embodiment is a DC value that the DC value of initial value is used as the MPP and the SPP of first side-play amount, and be adjusted into 0, and with the DC off-set value of the MPP of another side-play amount tilt and SPP as the 2nd DC value, and then calculate the OP Amplifier Gain (SPPG) of SPP.

Though more than with embodiment the present invention is described, therefore do not limit scope of the present invention, only otherwise break away from main idea of the present invention, the one of ordinary skilled in the art can carry out various distortion or change.For example, come calculating optimum gain ratio with MD/SD among the embodiment, but also can utilize by various gain ratio, the gain when therefrom choosing MD=SD is as optimum setting value.Extraction mode of the control mode of object lens or disc, control waveform, characteristic signal etc. for example again, import (Step input) and get DC value component with stepping control among the embodiment to proofread and correct, but also can utilize the low-frequency sine different, square wave, sawtooth wave as the control input with the RUNOUT frequency field, and extract MPP and SPP in the component of this controlled frequency as eigenwert.

Claims (21)

1, the differential push-pull type in a kind of optical disc accessing is sought the gain calibration method of rail error, and the amplifier gain that is used for proofreading and correct auxiliary beam is with respect to the ratio of the amplifier gain of main light beam, and this gain calibration method comprises the following step:

Open LASER Light Source and carry out light beam and focus on;

Start spindle motor;

Control object lens and discs are in the first relative variable condition;

Measure the eigenwert that is offset the push-pull signal of relevant main light beam with object lens, with as the first main beam characteristics value;

Measure the eigenwert that is offset the push-pull signal of relevant auxiliary beam with object lens, with as the first auxiliary beam eigenwert;

Control object lens and discs are in the second relative variable condition;

Measure the eigenwert that is offset the push-pull signal of relevant main light beam with object lens, with as the second main beam characteristics value;

Measure the eigenwert that is offset the push-pull signal of relevant auxiliary beam with object lens, with as the second auxiliary beam eigenwert; And

Calculated gains is according to the aforementioned first main beam characteristics value, the first auxiliary beam eigenwert, the second main beam characteristics value and the aforementioned auxiliary beam of the second auxiliary beam eigenvalue calculation gain ratio with respect to aforementioned main light beam.

2, differential push-pull type as claimed in claim 1 is sought the gain calibration method of rail error, and wherein aforementioned gain ratio is approximately:

(the main beam characteristics value of the second main beam characteristics value-first)/(the second auxiliary beam eigenwert-first auxiliary beam eigenwert).

3, differential push-pull type as claimed in claim 1 is sought the gain calibration method of rail error, and the wherein aforementioned first relative variable condition is that aforementioned object lens and discs remain in first fixed angle and position.

4, differential push-pull type as claimed in claim 3 is sought the gain calibration method of rail error, and the wherein aforementioned second relative variable condition is that aforementioned object lens and discs remain in second fixed angle and position.

5, differential push-pull type as claimed in claim 4 is sought the gain calibration method of rail error, the DC component that wherein aforementioned main beam characteristics value is the push-pull signal of aforementioned main light beam.

6, differential push-pull type as claimed in claim 5 is sought the gain calibration method of rail error, and wherein aforementioned auxiliary beam eigenwert is the DC component of the push-pull signal of aforementioned auxiliary beam.

7, the differential push-pull type in a kind of optical disc accessing is sought the gain calibration method of rail error, and the amplifier gain that is used for proofreading and correct auxiliary beam is with respect to the ratio of the amplifier gain of main light beam, and this gain calibration method comprises the following step:

Power-on is also closed LASER Light Source;

Calibrate the circuit signal side-play amount of main light beam amplifier, promptly set the circuit signal side-play amount of the main light beam amplifier in the radio frequency IC, make this amplifier be output as the first main beam characteristics value;

Calibrate the circuit signal side-play amount of auxiliary beam amplifier, promptly set the circuit signal side-play amount of the auxiliary beam amplifier in the radio frequency IC, make this amplifier be output as the first auxiliary beam eigenwert;

Open LASER Light Source and carry out light beam and focus on;

Start spindle motor;

Change the relativity shift value of lens and discs;

Measure the eigenwert of the push-pull signal of the main light beam relevant, as the second main beam characteristics value with the object lens skew;

Measure the eigenwert of the push-pull signal of the auxiliary beam relevant, as the second auxiliary beam eigenwert with the object lens skew; And

Calculated gains is promptly according to the aforementioned first main beam characteristics value, the first auxiliary beam eigenwert, the second main beam characteristics value and the aforementioned auxiliary beam of the second auxiliary beam eigenvalue calculation gain ratio with respect to aforementioned main light beam.

8, differential push-pull type as claimed in claim 7 is sought the gain calibration method of rail error, and wherein aforementioned gain ratio is approximately:

(the main beam characteristics value of the second main beam characteristics value-first)/(the second auxiliary beam eigenwert-first auxiliary beam eigenwert).

9, differential push-pull type as claimed in claim 7 is sought the gain calibration method of rail error, and the wherein aforementioned first main beam characteristics value is 0.

10, differential push-pull type as claimed in claim 9 is sought the gain calibration method of rail error, and the wherein aforementioned first auxiliary beam eigenwert is 0.

11, differential push-pull type as claimed in claim 10 is sought the gain calibration method of rail error, and wherein aforementioned gain ratio is approximately:

Second main beam characteristics value/second auxiliary beam eigenwert.

12, the differential push-pull type in a kind of optical disc accessing is sought the gain correcting device of rail error, and the amplifier gain that is used for proofreading and correct auxiliary beam is with respect to the ratio of the amplifier gain of main light beam, and this gain correcting device comprises:

One optical signalling amplifier receives main light beam and the auxiliary beam signal via the discs reflection, is output into main light beam radiofrequency signal and auxiliary beam radiofrequency signal after the amplification;

One radio frequency receiver, via main light beam radiofrequency signal and the auxiliary beam radiofrequency signal differential amplification of prime with aforementioned optics signal amplifier, again with these amplifying signals via main beam signal amplifier and the differential amplification of auxiliary beam signal amplifier after, produce main light beam push-pull signal and auxiliary beam push-pull signal, and the difference of exporting this main light beam push-pull signal and auxiliary beam push-pull signal is sought the rail error signal as differential push-pull type;

One analog-digital converter receives the main light beam push-pull signal and the auxiliary beam push-pull signal of aforementioned radio frequency receiver, and produces main light beam push-pull signal of numeral and digital auxiliary beam push-pull signal; And

One digital signal processor, receive main light beam push-pull signal of aforementioned numeral and digital auxiliary beam push-pull signal, and utilize a feature extractor to extract the eigenwert of main light beam push-pull signal of this numeral and digital auxiliary beam push-pull signal, and by a gain calculation module according to the auxiliary beam signal amplifier of the aforementioned radio frequency receiver of eigenvalue calculation of this push-pull signal with respect to aforementioned main beam signal Amplifier Gain ratio.

13, differential push-pull type as claimed in claim 12 is sought the gain correcting device of rail error, and wherein aforementioned digital signal processor also has a control waveform generator, is used for giving objective driver according to control waveform parameter generating control signal.

14, differential push-pull type as claimed in claim 13 is sought the gain correcting device of rail error, and wherein aforementioned objective driver is used for controlling the relative position and the angle of object lens and discs.

15, differential push-pull type as claimed in claim 12 is sought the gain correcting device of rail error, wherein aforementioned digital signal processor also has the circuit signal offset correction module that contains an amplifier, be used for calculating the circuit signal side-play amount of aforementioned main beam signal amplifier and auxiliary beam signal amplifier, and export the circuit signal side-play amount of this amplifier to aforementioned radio frequency receiver according to the main light beam push-pull signal of aforementioned numeral and digital auxiliary beam push-pull signal.

16, differential push-pull type as claimed in claim 12 is sought the gain correcting device of rail error, and wherein aforementioned feature extractor extracts the signal of the relative position that is subjected to object lens and discs in aforementioned main light beam push-pull signal and the auxiliary beam push-pull signal and angle influence.

17, the differential push-pull type in a kind of optical disc accessing is sought the gain calibration method of rail error, and the amplifier gain that is used for proofreading and correct auxiliary beam is with respect to the ratio of the amplifier gain of main light beam, and this gain calibration method comprises the following step:

Open LASER Light Source and carry out light beam and focus on;

Start spindle motor;

Control object lens and disc are in the first relative variable condition;

Measure the eigenwert that is offset the push-pull signal of relevant main light beam with object lens, with as the first main beam characteristics value;

Measure the eigenwert that is offset the push-pull signal of relevant auxiliary beam with object lens, with as the first auxiliary beam eigenwert;

Control object lens and discs are in the second relative variable condition;

Measure the eigenwert that is offset the push-pull signal of relevant main light beam with object lens, with as the second main beam characteristics value;

Measure the eigenwert that is offset the push-pull signal of relevant auxiliary beam with object lens, with as the second auxiliary beam eigenwert; And

Adjust the gain ratio of auxiliary beam, make the difference of the second main beam characteristics value and the first main beam characteristics value approach the difference of the second auxiliary beam eigenwert and the first auxiliary beam eigenwert with respect to main light beam.

18, differential push-pull type as claimed in claim 17 is sought the gain calibration method of rail error, and the wherein aforementioned first relative variable condition is that aforementioned object lens and disc remain in first fixed angle and position.

19, differential push-pull type as claimed in claim 18 is sought the gain calibration method of rail error, and the wherein aforementioned second relative variable condition is that aforementioned object lens and disc remain in second fixed angle and position.

20, differential push-pull type as claimed in claim 19 is sought the gain calibration method of rail error, the DC component that wherein aforementioned main beam characteristics value is the push-pull signal of aforementioned main light beam.

21, differential push-pull type as claimed in claim 20 is sought the gain calibration method of rail error, and wherein aforementioned auxiliary beam eigenwert is the DC component of the push-pull signal of aforementioned auxiliary beam.

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