The method of adjustment of datum and device
Technical field
The present invention relates to a kind of datum method of adjustment, refer to a kind of method of adjustment device that is applicable to the datum of electro-optical systems such as CD-ROM drive especially.
Background technology
Because discs has high power capacity, can store mass data and advantage such as be easy to carry, the standard that makes CD-ROM drive become personal computer is equipped with, and reading speed also progresses greatly day by day.
Known in the application of electro-optical systems such as CD-ROM drive, the producing method of signal is laser diode (Laser Diode) the emission laser that utilizes in the optical read head (Pickup Head), and this laser beam can produce focus point (Fousing Point) on discs.Because groove (Pit) that the length that has optical disc surface differs and plane (Land), therefore partly light can reflect back in the optical read head optical sensor (Photo sensor) and partly light can not, optical sensor then receives the light of reflection, and will make the drive unit of CD-ROM drive receive a radio frequency analog signal via the conversion of subsequent conditioning circuit.
See also Fig. 1 (a), it is the structural representation of known application in the digital information processing system of CD driver, and it mainly comprises analog to digital converter (ADC) 10, reclocking system (Retiming System) circuit 11, zero and hands over more that level follows rail circuit (Zero-Crossing Level Tracking) 12 and 13 formations of detecting device (Detector).Analog to digital converter (ADC) 10 receives these radio frequency analog signals and the radio frequency analog signal of input is taken a sample (Samples) according to a sample period, and then obtains a plurality of sampling point values; Then, utilize reclocking circuit system 11 to detect to use this sampling point value, undistorted to confirm characteristic that whether it keeps original radio frequency analog signal.If can't reach above-mentioned requirement then readjust these sampling spots, so that obtain preferable sampling value.
Then, handing over more by zero, level follows rail circuit 12 by seeking out the zero level value more of handing in a plurality of sampling point values, for the reference point of subsequent detectors 13 as the judgement output signal levels.Subsequently, can and the relativeness between level value more be should zeroly hand over, output high level signal or low level signal decided according to these a plurality of sampling point values.
See also Fig. 1 (b), it is the structural representation of another known application in the digital information processing system of CD driver, it mainly comprises analog to digital converter, and ((ADC) 14, phase-locked loop (Phase Locked Loop) circuit 15, zero hand over more level to follow rail circuit 16 and detecting device 17 constitutes, the sample period that analog to digital converter (ADC) 14 receives this radio frequency analog signal and provided according to phase-locked loop circuit 15, in order to the radio frequency analog signal of input is taken a sample, and then obtain a plurality of sampling spots.
In addition, this sample period for this phase-locked loop circuit 15 according to the waveform characteristic of this radio frequency analog signal, with and the best sampling frequency that degree was produced of floating.It is identical with Fig. 1 (a) to hand over level more to follow the function mode of rail circuit 16 and detecting device 17 as for zero, so is not narrated at this.
Handing over more level to follow rail circuit 12 as for well-known zero adjusts zero and hand over the calculation mode that level value adopted more as follows: an earlier default reference level value C zero hands over level value more, and when producing each sampling spot, subsequently in the sampling spot (comprising present sampling spot) that special time is accumulated before present sampling spot, carry out these sampling point values greater than the number of this datum and less than the calculating of the number of this reference level value; Then adjust this reference level value according to expression formula as described below again:
1. if A>B, then C=C+D
2. if B>A, then C=C-D
Wherein A=sampling point value is greater than the sampling spot number of reference level value
B=sampling point value is less than the sampling spot number of reference level value
The C=reference level value
The D=particular value
Even the number greater than the sampling spot of this reference level value is more than what come less than the sampling spot number of this reference level value, so just reference level value up must be adjusted a particular value and is become a new reference level value.In like manner, if more than what come, so just reference level value down must be adjusted greater than the sampling spot number of this reference level value less than the sampling spot number of this datum.Then, after obtaining next sampling point value, repeat above-mentioned comparison step again.If greater than the sampling spot number of this reference level value, still inequality with sampling spot number less than this reference level value, then adjust reference level value once more according to testing result; When the sampling spot number is identical, is about to this reference level value and is set at zero friendship level value more.
See also Fig. 1 (c), it is that zero of Fig. 1 (a) and Fig. 1 (b) hands over more that level follows the zero level synoptic diagram more of handing over that the rail circuit is sought.Hand over level value more if begin to seek zero, will converge to this so and the first zero hand over more that level value is the zero level value more of handing over by the sampling spot of this radio frequency analog signal first half; Hand over level value more if begin to seek zero, will converge to the 30 so and hand over more that level value is the zero level value more of handing over by the sampling spot of this radio frequency analog signal Lower Half.Significantly, knownly seek zero and hand over the method for level more too coarse, hand over level value more so can't converge to best zero, for example the second zero among Fig. 1 (c) hands over and gets over level value.In addition, because this first zero hands over more level value and the 30 to hand over that level value is all approaching in the extreme with sampling spot more, therefore be interfered and produce noise in the process that reads the discs signal when CD reading head, or the dc power signal that the CD-ROM drive driving circuit produced is unstable and when rocking, the signal that will cause CD reading head to read produces the phenomenon of floating, and make original zero hand over that level more follows that rail circuit 12 sets the first zero hand over more level value or the 30 to hand over more level value can't meet the requirements, be the high level signal or the correctness of low level signal so just influence detecting device 13 judgement output signal levels.
And how to improve the disappearance of above-mentioned customary means, and make zero to hand over level more to converge to the second zero handing over and get over level value shown in Fig. 1 (c), for inventing fundamental purpose of the present invention.
Summary of the invention
The objective of the invention is for a kind of datum method of adjustment is provided, this method can be handed over level value convergence optimum value more with zero, and making zero to hand over and have a segment distance between the level value and sampling point value more, this will make the zero unsteady phenomenon of signal of handing over level more not read by CD reading head influence.
Another object of the present invention is for a kind of datum adjusting gear is provided, this device can be handed over level value convergence optimum value more with zero, and making zero to hand over and have a segment distance between the level value and sampling point value more, this will make the zero unsteady phenomenon of signal of handing over level more not read by CD reading head influence.
Purpose of the present invention can realize by following measure:
A kind of datum method of adjustment, it is to receive a plurality of sampling point values to adjust a reference level value, wherein these sampling point values be with a sample period to a simulating signal take a sample produced, this method comprises the following step:
In the sampling spot of being accumulated in the special time before a present sampling spot, calculating is positioned at first side of this reference level value and the sampling spot number of second side, when the sampling spot number of this first side during greater than the sampling spot number of this second side, this reference level value is adjusted one first particular value and become a phase one reference level value towards the direction of this first side, when the sampling spot number of this first side during, this reference level value is adjusted this first particular value and become this phase one reference level value towards the direction of this second side less than the sampling spot number of this second side; And
When the sampling point value of the previous sampling spot of this present sampling spot and this present sampling spot lays respectively at first side of this phase one reference level value and second side, detect this first displacement of point value of taking a sample at present respectively to this phase one reference level value, and this previous sampling point value is to second displacement of this phase one reference level value, and when this first displacement during greater than this second displacement, according to this first displacement and this second displacement with should the phase one reference level value towards this at present direction of sampling point value adjust, in order to produce a subordinate phase reference level value, when this first displacement during less than this second displacement, according to this first displacement and this second displacement should the phase one reference level value adjusting, in order to produce this subordinate phase reference level value towards the direction of this previous sampling point value;
Via above-mentioned two stage repeating, so that more approaching the best of adjusted reference level value zero is handed over level value more.
The adjustment mode of this subordinate phase reference level value in the said method comprises the following step:
With this first displacement and this second displacement produced mutually a displacement and;
With this displacement with multiply by one second particular value to produce displacement; And
Should phase one reference level value and this displacement addition, in order to produce this subordinate phase reference level value.
This signal processing method in the said method is applicable in the electro-optical system.
This reference level value in the said method is to be used in 1 of this electro-optical system to hand over level value more.
This electro-optical system in the said method is CD-ROM disc player, CD-RW disc player, DVD-ROM disc player, DVD+R disc player, DVD+RW disc player or DVD-RAM disc player.
Another object of the present invention also can realize by following measure:
A kind of datum adjusting gear, it is to receive a plurality of sampling point values in order to adjust a reference level value, wherein these sampling point values be with a sample period to a simulating signal take a sample produced, this adjusting gear comprises:
One zero hand over more, and level follows the rail device, corresponding to a plurality of sampling spots in order to:
In the sampling spot of being accumulated in the special time before the present sampling spot, calculating is positioned at first side of this reference level value and the sampling spot number of second side, when the sampling spot number of this first side during greater than the sampling spot number of this second side, this reference level value is adjusted one first particular value and become a phase one reference level value towards the direction of this first side, when the sampling spot number of this first side during, this reference level value is adjusted this first particular value and become this phase one reference level value towards the direction of this second side less than the sampling spot number of this second side; And
When the sampling point value of the previous sampling spot of this present sampling spot and this present sampling spot lays respectively at first side of this phase one reference level value and second side, detect this first displacement of point value of taking a sample at present respectively to this phase one reference level value, and this previous sampling point value is to second displacement of this phase one reference level value, and when this first displacement during greater than this second displacement, according to this first displacement and this second displacement with should the phase one reference level value towards this at present direction of sampling point value adjust, in order to produce a subordinate phase reference level value, when this first displacement during less than this second displacement, according to this first displacement and this second displacement should the phase one reference level value adjusting, in order to produce this subordinate phase reference level value towards the direction of this previous sampling point value; And
One pick-up unit is a reference point with this subordinate phase reference level value, in order to detect the signal level of an input signal.
This simulating signal in the said apparatus is a radiofrequency signal.
Said apparatus also comprises:
One analog to digital converter, in order to the received RF simulating signal and according to a sample period to the input radio frequency analog signal take a sample, to obtain this sampling spot; And
One reclocking circuit system is in order to detecting the sampling point value of this sampling spot, to confirm whether this sampling point value keeps the characteristic of original this radio frequency analog signal and undistorted.
Said apparatus also comprises:
One phase-locked loop circuit, in order to produce this sample period, wherein this sample period is the best sampling frequency of this radio frequency analog signal; And
One analog to digital converter in order to receiving this radio frequency analog signal, and according to this sample period that this phase-locked loop circuit provided, so that the radio frequency analog signal of input is taken a sample, and then obtains this sampling spot.
This electro-optical system in the said apparatus is CD-ROM disc player, CD-RW disc player, DVD-ROM disc player, DVD+R disc player, DVD+RW disc player or DVD-RAM disc player.
Description of drawings
Fig. 1 (a) is the structural representation of known application in the digital information processing system of CD driver.
Fig. 1 (b) is the structural representation of another known application in the digital information processing system of CD driver
Level follows the zero level synoptic diagram more of handing over that the rail circuit is sought to Fig. 1 (c) for zero of Fig. 1 (a) and Fig. 1 (b) hands over more.
Fig. 2 is the process flow diagram of the preferred embodiment of datum method of adjustment of the present invention.
The reference level value convergence synoptic diagram that Fig. 3 is produced for using datum method of adjustment of the present invention.
Fig. 4 is the enlarged diagram of depiction 3 subregions.
Concrete embodiment
See also Fig. 2, it is the flow chart of steps of the preferred embodiment of datum method of adjustment of the present invention, datum method of adjustment of the present invention is applied to zero in the circuit diagram shown in Fig. 1 (a) and (b) and hands over more that level follows the rail circuit, the main reception with a sample period carried out the adjustment of reference level value to a radio frequency analog signal a plurality of sampling point values that produced of taking a sample, and this disposal route can comprise the following step:
Step (A): in the coarse adjustment program of phase one, at first calculate and comprise in present sampling spot and special time is accumulated before the sampling spot, be positioned at first side of a reference level value and the sampling point value number of second side, and adjust this reference level value according to expression formula as described below:
1. if E>F, then G=G+H
2. if F>E, then G=G-H
Wherein E=is greater than the sampling spot number of reference level value
F=is less than the sampling spot number of reference level value
The G=reference level value
The H=particular value
Even the number greater than the sampling spot of this reference level value is more than what come less than the sampling spot number of this reference level value, so just reference level value up must be adjusted a particular value and is become a phase one reference level value.In like manner,, so just reference level value down must be adjusted, be produced the phase one reference level value if more than what come greater than the sampling spot number of this reference level value less than the sampling spot number of this datum.It should be noted that above-mentioned controlled reference level value that is G are derived by previous sampling spot.
Wherein particular value H is a preset value, for example fixedly is preset as 0.1 volt.
Step (B): in the fine setting program of subordinate phase, be in that at present sampling spot and previous sampling spot are when laying respectively at the both sides of phase one reference level value, detect subsequently previous sampling point value to the displacement A1 of this phase one reference level value and the point value of taking a sample at present to the displacement A2 of this phase one reference level value, then utilize displacement A1 and A2 and adjust the phase one reference level value according to expression formula as described below:
I=I+ (A1+A2) * J (formula 1)
Wherein
The previous sampling point value of A1=is to the displacement of this reference level value
The A2=displacement of point value of taking a sample at present to this reference level value
The adjustment of J=per unit is apart from size
I=phase one reference level value
Even this previous sampling point value is when sampling point value is to the displacement A2 of this reference level value at present greater than this to the displacement A1 of this reference level value, indication according to above-mentioned (formula 1), the phase one reference level value will be towards the direction adjustment at previous sampling point value place, and then producing the subordinate phase reference level value, the displacement of being adjusted will be (A1+A2) * J.In like manner, greater than A1, then the phase one reference level value will produce the subordinate phase reference level value towards this displacement of direction adjustment (A1+A2) * J at sampling point value place at present as if A2.It should be noted, adjustment in particular value H in the step (A) and the step (B) is apart from big or small J, should being used for of all visual reality adjusted and set, have the knack of skill person of the present invention when changing preferred embodiment of the present invention according to situation, so all do not break away from the equivalence modification that preferred embodiment spirit of the present invention is done, and must be contained among the present patent application scope.
Wherein adjusting the big or small J of distance then can change as requested and to some extent.As when needing to arrive fast a convergency value, then adjust the big or small J of distance and can be set at bigger value, as 0.1 volt, but thus, the error between convergency value and ideal value is bigger and unstable.But be set at less value when adjusting the big or small J of distance, during as 0.05 volt, speed of convergence slow but and the error between ideal value less and comparatively stable.
Fig. 3 describes the reference level value convergence synoptic diagram that the disclosed datum method of adjustment of the present invention is produced.Significantly, when the sampling spot by radio frequency analog signal top begins to seek zero when handing over more level value, will hand over level value more (for example the second zero of Fig. 1 (c) handing over level value more) to restrain towards best zero along curve I; Similarly, when the sampling spot by radio frequency analog signal below begins to seek zero when handing over more level value, will hand over level value more towards best zero along curve II.On reality is implemented, can be to the compute mode of each sampling spot repeated execution of steps (A), so that reference level value is converged to reference level value as shown in Figure 3 with step (B); Or earlier to sampling spot execution in step (A), execution in step (A) all can't be nearly again during step convergence by the time, again in backward sampling spot repeated execution of steps (A) and step (B), so that reference level value is able to nearly step convergence.At last, be about to datum and be set at one zero friendships level value more, can be used to provide the reference point that is used as judging output signal level as the described detecting device of Fig. 1 (a) and (b).Easy speech, can and should zeroly hand over the relativeness between level value more according to these a plurality of sampling point values, decide and export high level signal or low level signal.
For example, the enlarged diagram that Fig. 4 depiction 3A-A ' is interval, and have totally 20 sampling spots such as S1~S20 the time at A-A ', each sampling spot utilizes step (A), (B) to calculate reference level value.With sampling spot S6 is example, after the sampling value that obtains S6, immediately step (A) calculate S6 (containing) before the sampling spot of a special time (comprise S5, S4, S3, S2 ...) in, be positioned at the quantity of reference level value R2 (by Fig. 4 as can be known, R2 is produced by S3) both sides.In addition, because S5 and S6 lay respectively at the sampling spot of reference level value both sides, so must utilize step (B) to come the reference level value is finely tuned again.Because S5 is greater than the displacement d6 of S6 to reference level value R2 to the displacement d5 of reference level value R2, therefore in execution in step (B) afterwards, reference level value R2 will be adjusted into R3 downwards.Significantly, as shown in Figure 4, in two adjacent sampling spots, have respectively greater than and less than the partaker of reference level value, (S2 is arranged respectively, S3), (S5, S6), (S8, S9), (S11, S12), (S14, S15), (S17, S18) six groups, so step (B) will be carried out the adjustment of reference level value at S3, S6, S9, S12, these six sampling spots of S15, S18.In addition, though when in step (B), adjusting reference level value, may pastly sometimes depart from the best zero friendship direction adjustment (for example R3 is adjusted to R4) of level value more, but as a complete unit, still level value can be converged to the best zero friendship by method of the present invention and get on the level value.Moreover, even in step (A) " greater than the sampling spot number of reference level value " taking place equates under the situation of (that is E=F) with " less than the sampling spot number of reference level value ", though the coarse adjustment program can't provide the adjustment of reference level value, but still can come operation that reference level value is finely tuned by step (B).
In addition, preferred embodiment of the present invention is to be applicable to all electro-optical systems, among for example system such as CD-ROM disc player (drive), CD-RW disc player, DVD-ROM disc player, DVD+R disc player, DVD+RW disc player or DVD-RAM disc player even other are used.
The embodiment of said method step (A), (B) can be undertaken by hardware or the software modes such as (for example control programs) that changes above-mentioned electro-optical system.
With reference to figure 1 (a), be a kind of device of datum method of adjustment, this device is based on the improvement of carrying out on the former known basis; It is to receive a plurality of sampling point values in order to adjust a reference level value, wherein these sampling point values be with a sample period to a radiofrequency signal take a sample produced, this adjusting gear comprises:
One analog to digital converter, in order to the received RF simulating signal and according to a sample period to the input radio frequency analog signal take a sample, to obtain this sampling spot; And
One reclocking circuit system is in order to detecting the sampling point value of this sampling spot, to confirm whether this sampling point value keeps the characteristic of original this radio frequency analog signal and undistorted;
One zero hand over more, and level follows the rail device, corresponding to a plurality of sampling spots in order to:
In the sampling spot of being accumulated in the special time before the present sampling spot, calculating is positioned at first side of this reference level value and the sampling spot number of second side, when the sampling spot number of this first side during greater than the sampling spot number of this second side, this reference level value is adjusted one first particular value and become a phase one reference level value towards the direction of this first side, when the sampling spot number of this first side during, this reference level value is adjusted this first particular value and become this phase one reference level value towards the direction of this second side less than the sampling spot number of this second side; And
When the sampling point value of the previous sampling spot of this present sampling spot and this present sampling spot lays respectively at first side of this phase one reference level value and second side, detect this first displacement of point value of taking a sample at present respectively to this phase one reference level value, and this previous sampling point value is to second displacement of this phase one reference level value, and when this first displacement during greater than this second displacement, according to this first displacement and this second displacement with should the phase one reference level value towards this at present direction of sampling point value adjust, in order to produce a subordinate phase reference level value, when this first displacement during less than this second displacement, according to this first displacement and this second displacement should the phase one reference level value adjusting, in order to produce this subordinate phase reference level value towards the direction of this previous sampling point value; And
One pick-up unit is a reference point with this subordinate phase reference level value, in order to detect the signal level of an input signal.
With reference to Fig. 1 (b), the datum adjusting gear of this embodiment removes and includes:
One phase-locked loop circuit, in order to produce this sample period, wherein this sample period is the best sampling frequency of this radio frequency analog signal; And
One analog to digital converter in order to receiving this radio frequency analog signal, and according to this sample period that this phase-locked loop circuit provided, so that the radio frequency analog signal of input is taken a sample, and then obtains this sampling spot.Outside, remaining circuit and the foregoing description are together.
Described above comprehensive, can know by Fig. 3 and to learn, use datum method of adjustment of the present invention, really can hand over level value more to converge to the second zero handing over and get over level value as shown in Fig. 1 (c) figure with zero, and making zero to hand over and have a segment distance between the level value and sampling point value more, this will make the zero unsteady phenomenon of signal of handing over level more not read by CD reading head influence.