CN1246836C - Device for generating RFZC signal in optical disk drive and its generating method - Google Patents
Device for generating RFZC signal in optical disk drive and its generating method Download PDFInfo
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- CN1246836C CN1246836C CN 03103566 CN03103566A CN1246836C CN 1246836 C CN1246836 C CN 1246836C CN 03103566 CN03103566 CN 03103566 CN 03103566 A CN03103566 A CN 03103566A CN 1246836 C CN1246836 C CN 1246836C
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- signal
- slicing level
- radio frequency
- pass filter
- optical disk
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Abstract
The present invention relates to a device for generating RFZC signals in an optical disk drive, which comprises a multiplexer, a low-pass filter, a signal processing device (DSP), a digital to analog converter, an A/D converter and a comparator. When jumping on rail is started, a required demarcation level is firstly generated by the digital to analog converter. Then, when the low-pass filter catches up the variation of the PFRP signals, the filtering is given to the PFRP signals by the low-pass filter by the demarcation level. Next, before the finish of the jumping on rail, the output of the low-pass filter is sampled and converted by the A/D converter, and is delivered to the signal processing device, and then, the demarcation level is generated by DSP and the digital to analog converter.
Description
Technical field
The present invention relates to a kind of signal generation apparatus, and be particularly related to a kind of zero signal generation device and method of cutting signal (RFZC) of radio frequency of CD player.
Background technology
CD player is by the rotary CD sheet and at disc radial direction mobile optical read head, utilize the record surface of laser spots scan light disc to come access data, in operation, can drive optical read head the discs in the rotation is searched the coarse adjustment operation of (seeking), then again by focusing on (focusing) and following the tracks of (tracking) and optical read head is positioned at the data desiring to read sentences reading of data.So-called focusing operation is meant that lens do moving of vertical direction (vertical with discs), correctly to read the data of discs; Follow the tracks of operation and be meant that then lens do moving of horizontal direction (parallel with discs), with the track of the locking reading of data of being wanted.Afterwards, with the laser radiation discs, reflected light can be exported data-signal and the required original signal of various servocontrol on the discs according to this after the optical sensor on the optical read head receives.Then, can be by the resulting signal of optical read head through prime amplifier complex RF signal (Radio Frequency, be designated hereinafter simply as the RF signal) and the required signal of various servocontrol, (the Radio Frequency Ripple of the radio frequency fluctuating signal shown in Fig. 1 for example, be designated hereinafter simply as the RFRP signal) and zero signal (the Radio Frequency Zero Crossing that cuts of radio frequency, be designated hereinafter simply as the RFZC signal) etc., and (Digital Signal Processor DSP) is handled to be input to digital signal processor.
Please refer to Fig. 1, it shows RF signal in the CD player, RFRP signal and the triangular phase relation of RFZC signal.As shown in the figure, the RF signal is a high-frequency signal, and its outer envelope signal by a low frequency is wrapped up, and the i.e. inversion signal of envelope signal for this reason of RFRP signal.On the other hand, RFRP signal and slicing level (slice level) can obtain the RFZC signal after comparing, and wherein slicing level can be considered the mean value of RFRP signal.For when RFRP signal during greater than slicing level, the RFZC signal be on the occasion of, otherwise the RFZC signal is a negative value.But in some cases, the drift of RFRP signal regular meeting, as shown in Figure 2.Figure 2 shows that, when CD player reading of data, RFRP signal schematic representation when striding rail and following the tracks of in orbit.With Fig. 2 is example, before time T 0, can be considered read head reading of data just in orbit, so this moment, the RFRP signal was a certain value.Between time T 0～T3, owing to just striding rail this moment, so the RFRP signal can produce drift.After time T 3, finish all owing to stride rail/tracking, so the RFRP signal reverts back to definite value again.Obviously, T0～T3 during this period of time in, the RFRP signal can produce drift, if will inevitably produce error with constant voltage as the slicing level RFRP signal of demarcating, causes work period (duty cycle) mistake of RFZC signal and influences the usefulness of CD player.
For known technology, generally all be to utilize low-pass filter to obtain slicing level, but the initial stage of striding rail (for example, in time T 0), low-pass filter can't catch up with the variation of RFRP signal.In addition, the RF signal can be by filtering out its too high DC value, so that follow-up processing still, also can reduce the crest value of RFRP signal simultaneously by Hi-pass filter by a Hi-pass filter.The reaction velocity of above-mentioned low-pass filter and high-pass effect will make work period of RFZC signal of gained can't maintain 50%.Another known technology is the digital signal processor (DSP) that utilizes optical disk system itself, the crest retention value (peak-hold) of getting the RFRP signal and trough retention value (bottom-hold) on average calculate required RFZC signal.The method will significantly reduce the performance of optical disk system, thereby increase the weight of the load of its Digital System Processor.Another known technology is to adopt hardware circuit to obtain required RFZC signal, and this hardware circuit is required for dealing with optical disk system, must operate and provide the RFZC value all the time, and then causes the consumption of calculating running unnecessary and electric power.
In addition, striding before rail closes to an end, if obtain slicing level with low-pass filter, then surging will appear in the RFZC signal of gained, and influences the correctness of signal.
Summary of the invention
In view of this, the present invention aims to provide a kind of seeking signal (as RFZC) generation device of CD player, to avoid causing the RFZC signal error because of the drift of RFRP signal.
According to purpose of the present invention, a kind of RFZC signal generation device of CD player is proposed.The RFZC signal generation device comprises: multiplexer, low-pass filter, digital signal processor (DSP), digital analog converter, analog-digital converter and comparer.When beginning to jump onto the tracks, because this moment, low-pass filter still can't catch up with the variation of RFRP signal, so produce required slicing level by digital analog converter earlier.Then when low-pass filter can catch up with the variation of RFRP signal, slicing level at this moment is to be given filtering with the RFRP signal and got by low-pass filter.Then, when being near completion when jumping onto the tracks, analog-digital converter converts the output of low-pass filter digital signal to and is sent to signal processor, produces slicing level by DSP and digital analog converter again.
The RFZC signal generation device of the CD player that the embodiment of the invention is disclosed, it is mean value generation RFZC signal according to the RFRP signal, so can effectively avoid causing the RFZC signal error because of the drift of RFRP signal, with the correctness of guaranteeing the RFZC signal and the tracking power that improves CD player, promote the usefulness of CD player.And the CD player that the present invention was suitable for be meant CD-ROM, DVD-ROM, optical disk recording device (as CD-RW, DVD-RAM) etc. relevant/the phase capacitance device.
For above-mentioned purpose of the present invention, feature and advantage can be become apparent, a preferred embodiment cited below particularly, and be described in detail below in conjunction with the accompanying drawings.
Description of drawings
Fig. 1 shows RF signal in the CD player, RFRP signal and the triangular phase relation of RFZC signal.
Fig. 2 shows when striding rail, the situation the during drift of RFRP signal.
The RFRP signal generation device calcspar of the CD player that provides according to a preferred embodiment of the present invention is provided Fig. 3.
Fig. 4 shows the variation situation of slicing level among Fig. 2.
The drawing reference numeral explanation
310: multiplexer
320: low-pass filter
330: comparer
340: signal processor
350: digital analog converter
360: analog-digital converter
CT: control signal
SL: slicing level
Embodiment
Because when striding rail, can cause the drift of RFRP signal, slicing level (slicer level) certainly will be followed the variation of (follow) RFRP signal averaging, resulting RFZC signal just can be accurate.Then please be simultaneously with reference to Fig. 2 and Fig. 3.Figure 2 shows that when striding rail the synoptic diagram of RFRP signal.As previously mentioned, time point T0 represents and begins to stride rail this moment, and T3 then represents and strides the rail end, that is, be to enter one to seek board pattern (seeking mode) between time point T0 and the T3.In the present invention, then define marginal time point T1 and T2 in addition.The selection of Tl and T2 generally relates to the rail speed of striding, and it is to be defined in spiritual scope of the present invention voluntarily by known this operator.Such as in the following embodiments, on behalf of this moment low-pass filter, T1 caught up with the pace of change (T1 can be depending on the bandwidth of low-pass filter) of RFRP signal; T2 then points out assigning to lock a target track of rail on (track-on) instruction.The time of assigning of last rail (track-on) instruction is usually with to stride rail speed relevant, and (for example, this interval scale of T2 stride rail speed be 10K rail/second or following) can be operated and slow down to the translational speed of optical read head because of carrying out rail.Basically, the bandwidth of above-mentioned low-pass filter and stride rail speed and depend on different application, it can be by known this operator decision of programming voluntarily.
The slicing level of present embodiment obtain that details are as follows.The general mode that adopts is to carry out (calibration) program of proofreading and correct earlier to obtain the basic parameter of desiring the access CD, and the present invention then utilizes this correction program to calculate the required parameter of present embodiment.Therefore, the slicing level of follow the mode starting point can be gone out and stored by digital signal processor (DSP) calculated in advance.Apparently, optical disk system can read stored parameters and utilize a digital analog converter (DAC) to be converted into analog form (a DAC pattern of present embodiment) in the time point of T0～T1, and then avoids low-pass filter because of slow problem that produces and drift phenomenon that Hi-pass filter brought.Afterwards, in T1～T2, because of low-pass filter can be caught up with the pace of change of RFRP signal, slicing level then is the RFRP signal is carried out filtering and to be got by low-pass filter, that is, and and the low-pass filtering pattern of present embodiment.And in T2～T3, analog-digital converter can send the slicing level of gained when the T2 to digital signal processor and digital analog converter again after the analog digital conversion, that is, and and the 2nd DAC pattern of present embodiment.At last, the slicing level behind the T3 time point is identical with slicing level in T2～T3,, has gone up rail to target track and be returned to a follow the mode (following mode) that is.In fact, after rail on T2 assigns (track-on) instruction, also stop the low-pass filtering pattern simultaneously, thereby present embodiment is fit to as slicing level no longer by the value that low-pass filter produced behind T2 with regard to locked target track.
The RFZC signal generation device calcspar of a kind of CD player that provides according to preferred embodiment of the present invention is provided Fig. 3.The RFZC signal generation device of CD player of the present invention comprises a multiplexer 310, a low-pass filter 320, a comparer 330, a signal processing apparatus 340, a digital analog converter (DAC) 350 and an analog-digital converter (ADC) 360.Signal processing apparatus 340 for example is digital signal processor (DSP), can produce a control signal CT and a voltage signal VT according to the output of analog-digital converter (ADC) 360.Multiplexer 310 receives the voltage signal VT after a RFRP signal and the digital-to-analogue conversion simultaneously.The output of control signal CT control multiplexer 310, its voltage signal VT after selecting digital-to-analogue conversion under an above-mentioned DAC pattern and the 2nd DAC pattern.Voltage signal VT after this digital-to-analogue conversion gives and comparer 330 via just producing a slicing level SL after low-pass filter 320 filtering again.Yet under the low-pass filtering pattern, multiplexer 310 is selected output RFRP signal, and handles back generation slicing level SL via low-pass filter 320.The slicing level SL that is produced under the low-pass filtering pattern can be stored in the optical disk system, uses for subsequent treatment.Comparer 330 can obtain the RFZC signal after relatively with RFRP signal and slicing level SL, when the RFRP signal during greater than slicing level the RFZC signal be on the occasion of, otherwise the RFZC signal is a negative value.
On the other hand, after time T 0, begin to stride rail, so the RFRP signal begins drift (the rapidly downward drift phenomenon in T0～T1 of Fig. 2 just).Because the variation that low-pass filter will really catch up with the RFRP signal is still needed and is wanted a period of time.That is to say, in the period,, unsuitable slicing level will occur if still continue to produce slicing level by low-pass filter at this section.So, striding the time (T0 of Fig. 2 just) that rail begins, mainly be to utilize digital analog converter (DAC) 350 to get result of calculation (generally averaging) according to the crest/trough value of RFRP signal, that is, enter an above-mentioned DAC pattern.So, optical disk system can utilize a predetermined slicing level to produce another slicing level by correction program, and this predetermined slicing level is the sequential value that correction program produces.Each value of this sequential value is taken at the crest retention value (peak-hold) adjacent in the radio frequency fluctuating signal and the mean value of trough retention value (bottom-hold) respectively.So the time, DSP 340 will be sent to the RFRP signal DAC 350, and control signal CT also need make multiplexer 310 select the output of DAC 350 to export as it.This result of calculation is delivered to low-pass filter 320 again via multiplexer 310, low-pass filter 320 becomes slicing level SL after with its filtering.At time point T1, because low-pass filter 320 can catch up with the RFRP signal, so control signal CT will make multiplexer 310 select the RFRP signal to export as it, that is, and above-mentioned low-pass filtering pattern.Low-pass filter 320 carries out the RFRP signal to obtain slicing level SL after the filtering.
When stride rail close to an end before (just between time point T2～T3 of Fig. 2), if still directly the RFRP signal is carried out obtaining slicing level after the filtering by low-pass filter 320, the wink property sent out fluctuation (glitch) may appear in the slicing level of gained.Die in the present invention, when time point T2, that is, enter the 2nd above-mentioned DAC pattern, the slicing level that utilizes analog-digital converter (ADC) 360 to incite somebody to action this moment is taken a sample and is sent to DSP 340.The slicing level of time point T2 gained be between follow-up time point T2～T3 with time point T3 after slicing level.
For making the present invention clearer, so especially slicing level SL is shown among Fig. 4, wherein the definition of T0～T3 is substantially the same with the definition of Fig. 2.Behind time point T3,,, just can carry out the storage operation of data this moment so the RFRP signal can converge on certain value gradually because of the locked target track of optical disk system.Curve S L2 representative continue to use the low-pass filtering pattern between time point T2～T3 with time point T3 after the slicing level of gained, curve S L1 then is the curve of slicing level of the present invention.Can find out obviously that in Fig. 4 curve S L2 is a unsuitable slicing level curve, because of it converges on the maximal value of RFRP signal under the rail seeking.
In a word, the present invention discloses a kind of RFZC signal generation device and method of CD player.When optical disk system enters when seeking board pattern (seeking mode), enter a DAC pattern immediately, that is, use digital analog converter conversion one to proofread and correct (calibration) slicing level that program produced.When low-pass filter can catch up with the RFRP signal, enter the low-pass filtering pattern immediately.Low-pass filter carries out the RFRP signal to obtain slicing level SL after the filtering.At last, and, then enter the 2nd DAC pattern, and the slicing level SL value when assigning rail (track-on) instruction is as the slicing level value of assigning after rail instructs to assign rail (track-on) when instruction.
It should be noted that, employed design parameter only is an example of the present invention among the embodiment, be not in order to limiting applicable elements of the present invention, anyly be familiar with this operator and all can adjust design parameter and reach similar function, only still do not break away from spirit of the present invention with the present invention.
In sum; though the present invention discloses as above with a preferred embodiment; right its is not in order to limit the present invention; those of ordinary skill in the art; without departing from the spirit and scope of the present invention; can be used for a variety of modifications and variations, so protection scope of the present invention is looked accompanying Claim and is as the criterion.
Claims (7)
1. one kind is used for optical disk system and produces the method that a radio frequency zero is cut signal, and it comprises the following step:
When optical disk system begins to stride rail, adopt a correction program, utilize a predetermined slicing level to produce one first slicing level;
When a low-pass filter can catch up with the change of radio frequency pulsation signal, by adopting this radio frequency fluctuating signal of this low-pass filter filtering to produce one second slicing level; And
When on one during the rail instruction issuing, second slicing level when keeping assigning rail and instructing, as the 3rd slicing level,
Wherein this radio frequency fluctuating signal and this first slicing level, this second slicing level and the 3rd slicing level compare to produce this radio frequency zero and cut signal.
2. the radio frequency of optical disk system as claimed in claim 1 zero is cut signal generating method, wherein this predetermined slicing level is the sequential value that this correction program produces, and each value of this sequential value is taken at the crest retention value adjacent in the radio frequency fluctuating signal and the mean value of trough retention value respectively.
3. the radio frequency of optical disk system as claimed in claim 1 zero is cut signal generating method, and wherein the 3rd slicing level keeps constant in striding the rail end.
4. one kind is used for optical disk system and produces the device that a radio frequency zero is cut signal, and it comprises:
One comparer, relatively a radio frequency fluctuating signal and a slicing level are cut signal to produce this radio frequency zero;
One low-pass filter is used for this radio frequency fluctuating signal is carried out filtering;
One signal processor, provide a control signal to control the tentative running of a slicing level, wherein this signal processor is when optical disk system begins to stride rail, utilize a predetermined slicing level to produce one first slicing level, when a low-pass filter can catch up with the change of this radio frequency fluctuating signal, control this radio frequency fluctuating signal of this low-pass filter filtering and produce one second slicing level, and on one during the rail instruction issuing, produce one the 3rd slicing level, described the 3rd slicing level is second slicing level when assigning the rail instruction;
One multiplexer, it comprises at least two input ends, a control end and an output terminal, one of them above-mentioned input end is used for receiving this radio frequency fluctuating signal, another input end then is used for receiving this first slicing level and the 3rd slicing level, this control end receives this control signal from this signal processor, so, this output terminal just can be selected the radio frequency fluctuating signal or the slicing level of desire output according to this control end;
One digital analog converter is in order to change this first slicing level and the 3rd slicing level before transferring to this multiplexer; And
One analog-digital converter transfers to before this signal processor in order to change being output in of this low-pass filter.
5. the radio frequency of optical disk system as claimed in claim 4 zero is cut signal generation device, and wherein obtaining of this predetermined slicing level is to adopt a correction program.
6. the radio frequency of optical disk system as claimed in claim 4 zero is cut signal generation device, wherein this predetermined slicing level is the sequential value that this correction program produces, and each value of this sequential value is taken at the crest retention value adjacent in the radio frequency fluctuating signal and the mean value of trough retention value respectively.
7. the radio frequency of optical disk system as claimed in claim 4 zero is cut signal generation device, and wherein the 3rd slicing level keeps constant in striding the rail end.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 03103566 CN1246836C (en) | 2003-01-29 | 2003-01-29 | Device for generating RFZC signal in optical disk drive and its generating method |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 03103566 CN1246836C (en) | 2003-01-29 | 2003-01-29 | Device for generating RFZC signal in optical disk drive and its generating method |
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| CN1431653A CN1431653A (en) | 2003-07-23 |
| CN1246836C true CN1246836C (en) | 2006-03-22 |
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| CN 03103566 Expired - Fee Related CN1246836C (en) | 2003-01-29 | 2003-01-29 | Device for generating RFZC signal in optical disk drive and its generating method |
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| JP4480027B2 (en) * | 2005-11-14 | 2010-06-16 | パナソニック株式会社 | Optical disk device |
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Granted publication date: 20060322 Termination date: 20110129 |