CN101025953A - Method and device for generating signal of frequency multiplier motor frequency pulse generator of optical drive - Google Patents

Abstract

The invention discloses a method and a device for generating a frequency multiplication motor frequency pulse generator signal of an optical drive, wherein the method is operated according to a reference signal with a period of t, and comprises the following steps: receiving an FG signal, a reference signal and a frequency multiplication value to obtain an ideal frequency multiplication FG signal and a period thereof, wherein the period of the ideal frequency multiplication FG signal is between Qt and (Q +1) t, and Q is an integer; generating an actual frequency multiplication FG signal according to the reference signal and the ideal frequency multiplication FG signal; the pulse period of the actual frequency doubling FG signal can be selected to be Qt or (Q +1) t, so that the pulse trigger time of the actual frequency doubling FG signal and the ideal frequency doubling FG signal can be less than t/2. The invention can solve the problems of poor tracking and poor servo loop of the CD driver caused by poor centrifugal error compensation effect of the servo control unit due to overlarge positioning error in the well-known CD driver servo control system.

Description

The double frequency motor frequency pulse generator signal generating method of CD-ROM drive and device

Technical field

The present invention is about a kind of double frequency motor frequency pulse generator signal generating method and device, and especially in regard to the double frequency motor frequency pulse generator signal generating method and the device that are applied in the CD-ROM drive servo-control system.

Background technology

Please refer to Fig. 1, it is depicted as the synoptic diagram of known CD-ROM drive servo-control system.This CD-ROM drive servo-control system mainly comprises: an optical read-write head 11, a Spindle Motor 13, an optical read-write head driving device 15, a Spindle Motor drive unit 17 and a servo control unit 19.At first, by the light signal of optical read-write head 11 outputs, servo control unit 19 can be controlled the action that optical read-write head 11 focused on, jumps onto the tracks, locked rail (tracking on) and follows rail (track following) by optical read-write head driving device 15.In addition, servo control unit 19 also can be controlled the rotation of Spindle Motor 13 by Spindle Motor drive unit 17, and Spindle Motor 13 also can be according to the rotating speed of itself, export a motor frequency pulse generator signal (Frequency generator signal, hereinafter to be referred as the FG signal) and export servo control unit 19 to, after servo control unit 19 receives the FG signal, can learn the rotating speed of Spindle Motor 13 and carry out the rotating speed control of Spindle Motor 13 by Spindle Motor drive unit 17.

Please refer to Fig. 2, it is depicted as the track of discs coideal and the synoptic diagram of the track of reality.In general, desirable discs track 20 can be considered just round, but because the manufacturing process error, actual discs track 21 can present irregular non-positive circle, and is for example oval, promptly is referred to as centrifugal error (Run-Out Error).In order to grasp the centrifugal error of discs accurately, and the compensation of carrying out centrifugal error effectively makes optical read-write head 11 can accurately lock rail and follows rail.Discs is reading the data of discs after loading CD-ROM drive before, must know the skew track of discs track earlier, also promptly, learn the centrifugal error of discs earlier, make servo control unit 19 to provide the suitable side-play amount of optical read-write head 11 in order to the compensation centrifugal error according to centrifugal error.That is to say that CD-ROM drive is when carrying out follow-up read-write motion, CD-ROM drive can provide optical read-write head 11 suitable side-play amount according to the position of discs rotation.Therefore, no matter CD-ROM drive operates in the fixed angular speed of high power speed or low power speed (Constant AngularVelocity in the time of CAV), all can lock rail accurately and follow rail.

In general, the sensor that Spindle Motor 13 uses is Hall element (Hall Sensor), and the configuration between three sensors (U, V, W) differs 120 degree.Can produce FG signal as shown in Figure 3A when therefore, Spindle Motor 13 rotates.And the servo control unit 19 of CD-ROM drive can utilize the FG signal to locate the position of rotation of discs.That is to say that Spindle Motor 13 revolves in the FG signal of turn around (revolution) and comprises 3 pulses (pulse U, pulse V, pulse W).In addition, the circuit in the Spindle Motor 13 also can and then produce Spindle Motor synchronizing signal (revolution0,1,2) shown in Fig. 3 B according to the FG signal.And be depicted as relation between discs position of rotation and the FG signal as Fig. 3 C.And servo control unit 19 can utilize 3 location that the discs track is done in pulse that produced in the FG signal.That is to say, utilize 3 pulses in the FG signal to can be used as the anchor point of discs.

In order to obtain more anchor point, make that the position of rotation of discs can more accurate Be Controlled.The known frequency of utilizing frequency doubling technology to improve the FG signal makes frequency multiplication FG signal comprise more number of pulses, in the hope of obtaining the position of rotation that more anchor point accurately determines discs.In general, the frequency multiplication numerical value of frequency multiplication FG signal can be set between 1 to 64 times according to actual state.Please refer to Fig. 4 A, it is depicted as the synoptic diagram that frequency multiplication numerical value is 3 frequency tripling FG signal.That is to say that Spindle Motor 13 turns around revolving, frequency multiplication FG signal comprises 9 pulses (pulse 0, pulse 1, pulse 2, pulse 3, pulse 4, pulse 5, pulse 6, pulse 7, pulse 8).And Fig. 4 B be the discs anchor point with corresponding pulse between synoptic diagram.And servo control unit 19 can be learnt the position of rotation of discs and provide optical read-write head 11 suitable skews to compensate centrifugal error according to frequency multiplication FG signal.

Yet, owing to need utilize a reference signal (Reference Clock) that frequency is higher when carrying out the frequency multiplication of FG signal, and produce frequency multiplication FG signal according to the relation between reference signal and the FG signal.If the frequency ratio of reference signal and FG signal is not to be the integer multiple relation, thereby can cause cycle of each pulse of frequency multiplication FG signal also inequality, and cause CD-ROM drive can't compensate centrifugal error accurately.For example, cycle of 9 pulses of frequency tripling FG signal and inequality, make that 9 anchor points on the discs produce difference with actual position.

Owing in digital circuit is carried out the process of frequency multiplication, must utilize counter and reference signal to calculate the cycle of FG signal, and cycle of FG signal is obtained cycle of the single pulse of frequency multiplication FG signal divided by frequency multiplication numerical value.With frequency tripling FG signal is example, suppose that it is Trev that Spindle Motor 13 revolves the time of turning around, and reference signal can produce 22 clocks (Clock), and the cycle of each clock is t.Then ideally, the cycle of 9 pulses of frequency tripling FG signal is Also be

Shown in Fig. 5 A.Yet, on Design of Digital Circuit, be difficult to realize the signal of non-cycle reference signal integral multiple, therefore, known frequency multiplication generation circuit is directly cast out remainder makes each recurrent interval only differ 2t, shown in Fig. 5 B, thus, then can produce truncation error (truncation error), make actual frequency multiplication FG signal produce the time of 9 pulses less than the actual period T rev that turns around that revolves of Spindle Motor; Perhaps as Fig. 5 C, with any poor the benefit between 9 pulses of remainder.As shown in the figure, because remainder is 4, so many frequency periods of cycle (t) of back 5 pulses of cycle of preceding 4 pulses.After interpolation, the cycle that actual frequency multiplication FG signal produces 9 pulses still be Trev, and to revolve the time of turning around identical with Spindle Motor 13, but owing to 4 recurrence intervals of front will be 3t, and 5 recurrence intervals of back will be 2t.Therefore, can cause actual position of rotation generation error on time that actual frequency multiplication FG signal pulse produces and the discs.The time point that serious situation can cause the pulse of actual frequency multiplication FG signal and desirable frequency multiplication FG signal to produce differs more than the 1t, makes the centrifugal error compensation effect not good.

Please refer to Fig. 6, it is depicted as the comparison between above-mentioned frequency tripling FG signal and the desirable frequency tripling FG signal.As shown in Figure 6, desirable each recurrence interval of frequency tripling FG signal is all

And actual each recurrence interval of frequency tripling FG signal is 2t or 3t.Therefore, the trigger action time error maximum of actual frequency tripling FG signal and desirable frequency tripling FG signal can reach To cause the error between the trigger action position of the trigger action position of actual frequency tripling FG signal and desirable frequency tripling FG signal excessive thus, just the anchor point error is excessive, cause the centrifugal error compensation effect of servo control unit 19 not good, with cause CD-ROM drive relatively poor follow rail (track following) and relatively poor servo loop (servo loop).This situation is more obvious when frequency multiplication numerical value is above greater than 30.

Because the fixed angular speed (CAV) of CD-ROM drive is more and more fast, servo control unit 19 must utilize more anchor point to control and proofread and correct the mobile in order to the compensation centrifugal error of optical read-write head 11, with the Blu-ray Disc sheet, its anchor point may be up to dozens of, so in fact the positioning error that is produced may be up to several frequency periods.Therefore, CD-ROM drive being operated under any fixed angular speed, made to remain in the particular value between the trigger action position of the trigger action position of actual frequency multiplication FG signal and desirable frequency multiplication FG signal, will be main target of the present invention.

Summary of the invention

In order to address the above problem, the objective of the invention is to propose a kind of double frequency motor frequency pulse generator signal generating method of CD-ROM drive, make no matter CD-ROM drive is being operated under operation or the slow-speed of revolution fixed angular speed under the high rotating speed fixed angular speed, and the trigger action time phase difference of actual FG signal and desirable FG signal is within a special time.

Therefore, the present invention proposes a kind of CD-ROM drive servo-control system, comprising: an optical read-write head is used for reading discs and produces a light signal; One Spindle Motor rotates this discs by control, and exports a FG signal and a Spindle Motor synchronizing signal; One frequency multiplication FG signal generation device can receive and produce an actual frequency multiplication FG signal behind this FG signal, this Spindle Motor synchronizing signal, a reference signal and the frequency multiplication numerical value; And a servo control unit, control this Spindle Motor and this optical read-write head and carry out the centrifugal compensation of this discs according to this actual frequency multiplication FG signal; Wherein, this frequency multiplication FG signal generation device can be according to the cycle of this reference signal and this frequency multiplication numerical evaluation one desirable frequency multiplication FG signal, and makes the trigger action time point gap of this actual frequency multiplication FG signal and this ideal frequency multiplication FG signal within half cycle reference signal.

According to described CD-ROM drive servo-control system, wherein this double frequency motor frequency pulse generator signal generation device comprises: a frequency period computing unit, revolve when turning around in order to calculate this Spindle Motor according to this motor frequency pulse generator signal and this reference signal, this reference signal can produce M frequency, and should can produce N pulse by actual double frequency motor frequency pulse generator signal, and carry out according to this frequency multiplication numerical evaluation

Calculating and obtain (Q+R/N), wherein the Q value is a quotient, and the R value is a remainder; This R value is kept in and transmitted to one residual value register; Adjustment unit, one location receives this Spindle Motor synchronizing signal, this actual double frequency motor frequency pulse generator signal, this R value and this N value, calculates this Pn value of a Rn value and Pn value back output, wherein, and Rn=Rn-1+R-N * Pn-1, $\mathrm{Pn}=\left[\right|2\×\frac{R_n}{N}\left|\right],$ And 0≤n≤N-1, n are integer; And a double frequency pulse generation unit, receive this Q value and this Pn value, and produce this actual double frequency motor frequency pulse generator signal according to (Q+Pn) value and this reference signal.

According to described CD-ROM drive servo-control system, wherein this adjustment unit, location comprises: a totalizer receives this a R value and a Rn-1 value, and then produces one (Rn-1+R) value; One subtracter receives and is somebody's turn to do (Rn-1+R) value and this N value and produces one (Rn-1+R-N) value; One first multiplexer, receive should (Rn-1+R) value with should (Rn-1+R-N) value and selection by a Pn-1 value, should (Rn-1+R) value or be somebody's turn to do (Rn-1+R-N) and be worth as a Rn value; One second multiplexer receives this Rn value and this Rn-1 value and the selection by this actual double frequency motor frequency pulse generator signal, this Rn value or this Rn-1 value are exported and is become this Rn value; One Rn register is connected in this second multiplexer, and the control by this reference signal receives this Rn value, and is set at this Rn-1 value when output; One multiplier after receiving this Rn value and multiply by 2, is exported a 2Rn value; And a comparer, receive this N value and this 2Rn value, when N value during greater than the 2Rn value, a Pn value of output is 0, otherwise this Pn value of output is 1.

The present invention also proposes a kind of double frequency motor frequency pulse generator signal generating method of CD-ROM drive, according to the cycle is that the reference signal of t is moved, comprise the following steps: to receive a FG signal, this reference signal and revolve when turning around in order to calculate a Spindle Motor, this reference signal can produce M clock; Receive a frequency multiplication numerical value and revolve in order to calculate this Spindle Motor that an actual frequency multiplication FG signal can produce N pulse when turning around; Calculate

And obtain (Q+R/N), wherein the Q value is a quotient, and the R value is a remainder; Calculate R _nWith P _n, R wherein _n=R _N-1+ R-N * P _N-1, $P_n=\left[\right|2\×\frac{R_n}{N}\left|\right],$ And 0≤n≤N-1, and n is an integer; And, as (Q+P _n) when value equaled the Q value, this actual frequency multiplication FG signal generation cycle was the pulse of Qt, as (Q+P _n) when value equaled (Q+1) value, this actual frequency multiplication FG signal generation cycle was the pulse of (Q+1) t.

The present invention also proposes a kind of double frequency motor frequency pulse generator signal generation device of CD-ROM drive, comprise: a frequency period computing unit, learn that according to a FG signal and a reference signal this Spindle Motor revolves that this reference signal can produce M frequency when turning around, and can notify N pulse of generation, and carry out according to a frequency multiplication numerical value

Calculating and obtain (Q+R/N), wherein the Q value is a quotient, and the R value is a remainder; This R value can be kept in and transmit to one residual value register; Adjustment unit, one location receives a Spindle Motor synchronizing signal, this R value, and this N value, calculates a R _nA value and a P _nThis P of value back output _nValue, wherein R _n=R _N-1+ R-N * P _N-1, $P_n=\left[\right|2\×\frac{R_n}{N}\left|\right];$ And a double frequency pulse generation unit can receive this Q value and this P _nValue, and according to (Q+P _n) value and this reference signal produce an actual frequency multiplication FG signal.

According to the double frequency motor frequency pulse generator signal generation device of described CD-ROM drive, wherein this adjustment unit, location comprises: a totalizer receives this a R value and a Rn-1 value and produces one (Rn-1+R) value; One subtracter receives and is somebody's turn to do (Rn-1+R) value and this N value and produces one (Rn-1+R-N) value; One first multiplexer, receive should (Rn-1+R) value with should (Rn-1+R-N) value and selection by a Pn-1 value, should (Rn-1+R) value or be somebody's turn to do (Rn-1+R-N) value and be set at a Rn value; One second multiplexer receives this Rn value and this Rn-1 value and the selection by this actual double frequency motor frequency pulse generator signal, this Rn value or this Rn-1 value are exported and is become this Rn value; One Rn register can receive this Rn value of this second multiplexer output by the control of this reference signal, and is set at this Rn-1 value when output; One multiplier receives this Rn value and multiply by 2 back outputs, one 2Rn value; And a comparer, receive this N value and this 2Rn value, when N value during greater than the 2Rn value, a Pn value of output is 0, otherwise this Pn value of output is 1.

Can change cycle of pulse dynamically according to the double frequency motor frequency pulse generator signal generating method of CD-ROM drive of the present invention and device, make that the positioning error between actual frequency multiplication FG signal and the desirable frequency multiplication FG signal continues maintenance less than t/2.Therefore can solve in the known CD-ROM drive servo-control system, positioning error is excessive, causes the centrifugal error compensation effect of servo control unit not good, with cause CD-ROM drive relatively poor follow rail and relatively poor servo loop problem.

Description of drawings

By following accompanying drawing and explanation, further understand the present invention:

Figure 1 shows that the synoptic diagram of known CD-ROM drive servo-control system.

Figure 2 shows that the track of discs coideal and the synoptic diagram of the track of reality.

Fig. 3 A is depicted as Spindle Motor 13 output FG signal schematic representations.

Fig. 3 B is depicted as the Spindle Motor synchronizing signal.

Fig. 3 C is depicted as the relation between discs position of rotation and the FG signal.

Fig. 4 A is depicted as the synoptic diagram that frequency multiplication numerical value is 3 frequency tripling FG signal.

Fig. 4 B be the discs anchor point with corresponding pulse between synoptic diagram.

Fig. 5 A is desirable frequency tripling FG signal.

Fig. 5 B is first kind of actual frequency tripling FG signal.

Fig. 5 C is second kind of actual frequency tripling FG signal.

Figure 6 shows that the comparison between second kind of actual frequency tripling FG signal and the desirable frequency tripling FG signal.

Fig. 7 A is depicted as the actual frequency tripling FG of the present invention signal.

Fig. 7 B is depicted as the positioning error relation between the present invention's actual frequency tripling FG signal and the desirable frequency tripling FG signal.

Figure 8 shows that equation of the present invention calculates the relation between actual frequency tripling FG signal in back and the desirable frequency tripling FG signal.

Figure 9 shows that the CD-ROM drive servo-control system block scheme of using frequency multiplication FG signal generation device of the present invention.

Figure 10 shows that the present invention locatees the circuit diagram of adjustment unit.

Wherein, description of reference numerals is as follows:

11,81 optical read-write heads

13,83 Spindle Motors

15,85 optical read-write head driving devices

17,87 Spindle Motor drive units

19,89 servo control units

90 frequency multiplication FG signal generation devices

91 frequency period computing units

93 residual value registers

Adjustment unit, 95 location

97 double frequency pulse generation units

101 totalizers, 102 subtracters

103 comparers, 104 first multiplexers

105 second multiplexers, 106 Rn registers

107 Pn registers 108 or door

109 not gates 110 first and door

111 second with the door 112 multipliers

20 desirable discs tracks

21 actual discs tracks

Embodiment

The present invention proposes a kind of production method and device of frequency multiplication FG signal of CD-ROM drive, make no matter CD-ROM drive is being operated under operation or the slow-speed of revolution fixed angular speed under the high rotating speed fixed angular speed, the actual frequency multiplication FG signal of FG signal is compared with desirable frequency multiplication FG signal, its positioning error not only is less than half cycle reference signal (t/2), and the multiple of its positioning error and CD-ROM drive fixed angular speed is irrelevant.

Because the pulsed time of actual frequency multiplication FG signal must be synchronous with reference signal, therefore, the present invention can compare the pulsed time in pulsed time in the actual frequency multiplication FG signal and the desirable frequency multiplication FG signal constantly, when the error between the two surpasses half cycle reference signal (t/2), a cycle reference signal of pulsed time delay (t) in the then actual frequency multiplication FG signal.

With frequency tripling FG signal is example, suppose that it is Trev that Spindle Motor 13 revolves the time of turning around, and reference signal can produce 22 clocks, and the cycle of each clock is t.Therefore, actual frequency tripling FG signal comprises 9 pulses (pulse 0, pulse 1, pulse 2, pulse 3, pulse 4, pulse 5, pulse 6, pulse 7, pulse 8).The cycle of strobe pulse 0 is 2t, and therefore the triggered time with desirable frequency tripling FG signal pulse 0 differs

The cycle of supposing strobe pulse 1 is that 2t can make triggered time of pulse 1 of actual frequency tripling FG signal and desirable frequency tripling FG signal differ by more than t/2, also is

So the cycle of pulse 1 must be selected 3t, therefore the triggered time with desirable frequency tripling FG signal pulse 1 differs

In like manner, the sharp triggered time that can obtain other pulse in a like fashion.Be depicted as the actual frequency tripling FG of the present invention signal as Fig. 7 A.And Fig. 7 B is depicted as the positioning error comparison sheet between the present invention's actual frequency tripling FG signal and the desirable frequency tripling FG signal.By Fig. 7 B as can be known, the pulsed time all can be less than half cycle reference signal (t/2) in pulsed time and the desirable frequency multiplication FG signal in the actual frequency multiplication FG signal.

In order to realize frequency multiplication FG signal generation device of the present invention with hardware circuit, the present invention proposes following equation and realizes above-mentioned method.Supposing that the Spindle Motor 13 frequency multiplication FG signal that rotates a circle can produce N pulse, is t and reference signal can produce the cycle of M clock and each clock.Therefore, the cycle of desirable frequency multiplication FG signal is $\frac{M}{N}t=(Q+R/N)t,$ Wherein, Q is a quotient, and remainder is R.In addition, the cycle of n pulse is set at Q+P _n, and 0≤n≤N-1, and n is an integer.And $P_n=\left[\right|2\×\frac{R_n}{N}\left|\right],$ Wherein [] is Gaussage, || be absolute value; In addition, R _n=R _N-1+ R-N * P _N-1, and R _-1=0, P _-1=0.

With above-mentioned frequency tripling FG signal is example, N=9, M=22, Q=2, R=4, and 0≤n≤8.

When n=0, R ₀=R _-1+ R-N * P _-1=0+4-9 * 0=4,

${\mathrm{<figure-callout\; id="0"\; label="P"\; filenames="A20071008412600171.png,A20071008412600181.png"\; state="\{\{state\}\}">P</figure-callout>}}_0=\left[\right|2\&times;\frac{R_0}{N}\left|\right]=\left[\right|2\&times;\frac{4}{9}\left|\right]=\left[\frac{8}{9}\right]=0,$ So the cycle of pulse 0 is (Q+P ₀) t=(2+0) t=2t.

When n=1, R ₁=R ₀+ R-N * P ₀=4+4-9 * 0=8,

${\mathrm{<figure-callout\; id="1"\; label="P"\; filenames="A20071008412600171.png,A20071008412600181.png"\; state="\{\{state\}\}">P</figure-callout>}}_1=\left[\right|2\&times;\frac{R_1}{N}\left|\right]=\left[\right|2\&times;\frac{8}{9}\left|\right]=\left[\frac{16}{9}\right]=1,$ So the cycle of pulse 1 is (Q+P ₁) t=(2+1) t=3t.

When n=2, R ₂=R ₁+ R-N * P ₁=8+4-9 * 1=3,

${\mathrm{<figure-callout\; id="2"\; label="P"\; filenames="A20071008412600171.png,A20071008412600181.png"\; state="\{\{state\}\}">P</figure-callout>}}_2=\left[\right|2\&times;\frac{R_2}{N}\left|\right]=\left[\right|2\&times;\frac{3}{9}\left|\right]=\left[\frac{6}{9}\right]=0,$ So the cycle of pulse 2 is (Q+P ₂) t=(2+0) t=2t.

When n=3, R ₃=R ₂+ R-N * P ₂=3+4-9 * 0=7,

${\mathrm{<figure-callout\; id="3"\; label="P"\; filenames="A20071008412600181.png,A20071008412600201.png"\; state="\{\{state\}\}">P</figure-callout>}}_3=\left[\right|2\&times;\frac{R_3}{N}\left|\right]=\left[\right|2\&times;\frac{7}{9}\left|\right]=\left[\frac{14}{9}\right]=1,$ So the cycle of pulse 3 is (Q+P ₃) t=(2+1) t=3t.

When n=4, R ₄=R ₃+ R-N * P ₃=7+4-9 * 1=2,

${\mathrm{<figure-callout\; id="4"\; label="P"\; filenames="A20071008412600181.png,A20071008412600191.png"\; state="\{\{state\}\}">P</figure-callout>}}_4=\left[\right|2\&times;\frac{R_4}{N}\left|\right]=\left[\right|2\&times;\frac{2}{9}\left|\right]=\left[\frac{4}{9}\right]=0,$ So the cycle of pulse 4 is (Q+P ₄) t=(2+0) t=2t.

When n=5, R ₅=R ₄+ R-N * P ₄=2+4-9 * 0=6,

${\mathrm{<figure-callout\; id="5"\; label="P"\; filenames="A20071008412600181.png,A20071008412600211.png"\; state="\{\{state\}\}">P</figure-callout>}}_5=\left[\right|2\&times;\frac{R_5}{N}\left|\right]=[2\&times;\frac{6}{9}]=\left[\frac{12}{9}\right]=1,$ So the cycle of pulse 5 is (Q+P ₅) t=(2+1) t=3t.

When n=6, R6=R5+R-N * P5=6+4-9 * 1=1,

${\mathrm{<figure-callout\; id="6"\; label="P"\; filenames="A20071008412600181.png,A20071008412600211.png"\; state="\{\{state\}\}">P</figure-callout>}}_6=\left[\right|2\&times;\frac{R_6}{N}\left|\right]=\left[\right|2\&times;\frac{1}{9}\left|\right]=\left[\frac{2}{9}\right]=0,$ So the cycle of pulse 6 is (Q+P ₆) t=(2+0) t=2t.

When n=7, R ₇=R ₆+ R-N * P ₆=1+4-9 * 0=5,

${\mathrm{<figure-callout\; id="7"\; label="P"\; filenames="A20071008412600181.png,A20071008412600211.png"\; state="\{\{state\}\}">P</figure-callout>}}_7=\left[\right|2\&times;\frac{R_7}{N}\left|\right]=\left[\right|2\&times;\frac{5}{9}\left|\right]=\left[\frac{10}{9}\right]=1,$ So the cycle of pulse 7 is (Q+P ₇) t=(2+1) t=3t.

When n=8, R ₈=R ₇+ R-N * P ₇=5+4-9 * 1=0,

${\mathrm{<figure-callout\; id="8"\; label="P"\; filenames="A20071008412600211.png,A20071008412600231.png"\; state="\{\{state\}\}">P</figure-callout>}}_8=\left[\right|2\&times;\frac{R_8}{N}\left|\right]=\left[\right|2\&times;\frac{0}{9}\left|\right]=\left[\frac{0}{9}\right]=0,$ So the cycle of pulse 8 is (Q+P ₈) t=(2+0) t=2t.

Therefore, be illustrated in figure 8 as equation of the present invention and calculate relation between actual frequency tripling FG signal in back and the desirable frequency tripling FG signal.As shown in Figure 8, the pulsed time all can be less than half cycle reference signal (t/2) in pulsed time and the desirable frequency multiplication FG signal in the actual frequency multiplication FG signal.

Please refer to Fig. 9, it is depicted as the block scheme of the CD-ROM drive servo-control system of using frequency multiplication FG signal generation device of the present invention.This CD-ROM drive servo-control system mainly comprises: an optical read-write head 81, a Spindle Motor 83, an optical read-write head driving device 85, a Spindle Motor drive unit 87, a servo control unit 89, with a frequency multiplication FG signal generation device 90.This frequency multiplication FG signal generation device 90 is according to reference signal action, and it comprises: a frequency period computing unit 91, a residual value register 93, adjustment unit, a location 95 and a double frequency pulse generation unit 97.

At first, by the light signal of optical read-write head 81 outputs, servo control unit 89 can be controlled the action that optical read-write head 81 focused on, jumps onto the tracks, locked rail and follows rail by optical read-write head driving device 85.In addition, servo control unit 89 also can be controlled the rotation of Spindle Motor 83 by Spindle Motor drive unit 87, and Spindle Motor 83 also can be according to the rotating speed of itself, export a FG signal to servo control unit 89, after servo control unit 89 receives the FG signal, can learn the rotating speed of Spindle Motor 83 and carry out the rotating speed control of Spindle Motor 83 by Spindle Motor drive unit 87.And servo control unit 89 can also receive the location that frequency multiplication FG signal carries out discs, and carries out centrifugal compensation.

According to embodiments of the invention, frequency period computing unit 91 can learn that Spindle Motor 83 revolves the reference signal that turns around and can produce M frequency according to FG signal and reference signal, its cycle is all t, in addition, according to a frequency multiplication numerical value, frequency period computing unit 91 can learn that frequency multiplication FG signal can produce N pulse.And carry out

Calculating and acquisition (Q+R/N), Q is a quotient, and remainder is R.Therefore, frequency period computing unit 91 exportable these Q values, R value, with the N value.And the R value can be deposited to residual value register 93 and is sent to adjustment unit, location 95.

Adjustment unit, location 95 can receive a Spindle Motor synchronizing signal, frequency multiplication FG signal, R value, with N value afterwards calculating Rn value and Pn value, Rn=Rn-1+R-N * Pn-1 wherein, $\mathrm{Pn}=\left[\right|2\&times;\frac{P_n}{N}\left|\right].$ Double frequency pulse generation unit 97 then receives Q value and Pn value, and produces this frequency multiplication FG signal according to (Q+Pn) value and this reference signal.Also promptly, if the Pn value is 1, then the generation cycle is the pulse of (Q+1) t, if the Pn value is 0, then the generation cycle is the pulse of Qt.

Please refer to Figure 10, it is depicted as the circuit diagram that the present invention locatees adjustment unit 95.Wherein, totalizer 101 receives R value and Rn-1 value and carries out the action of Rn-1+R; And subtracter 102 receives (Rn-1+R) value and N value and carries out the action of Rn-1+R-N; First multiplexer 104 according to the Pn-1 value select (Rn-1+R) value or (Rn-1+R-N) value as the Rn value; Second multiplexer 105 can upgrade the Rn value to Rn register 106 according to frequency multiplication FG signal, that is to say that when frequency multiplication FG signal did not trigger as yet, Rn register 106 bolt-locks (Latch) were lived the Rn-1 value, when frequency multiplication FG signal triggering, Rn register 106 upgrades and bolt-lock Rn value.

In addition, multiplier 112 becomes 2Rn and input comparator 103 after receiving Rn values and multiply by 2, and comparer 103 reception N value and 2Rn values and comparing, and when N value＞2Rn value, the Pn value is 0; When N value＜2Rn value or N value=2Rn, the Pn value is 1.Therefore, Pn register 107 can store and export the Pn value, and by frequency multiplication FG signal and collocation of Spindle Motor synchronizing signal or door 108, can be with 107 replacements (Reset) of Pn register when frequency multiplication FG signal or the triggering of Spindle Motor synchronizing signal.

Since frequency multiplication FG signal generation device 90 of the present invention Spindle Motor 83 revolve turn around after, must reset in order to get back to initial setting and continuation generation frequency multiplication FG signal.Therefore, utilize Spindle Motor synchronizing signal collocation not gate 109 and first and the 110 Pn value of can resetting; In like manner, utilize Spindle Motor synchronizing signal collocation not gate 109 and second and the 111 Rn value of can resetting.

Therefore, frequency multiplication FG signal generation device of the present invention can change the cycle of pulse dynamically, makes that the positioning error between actual frequency multiplication FG signal and the desirable frequency multiplication FG signal continues to keep less than t/2.Thus, can solve in the known CD-ROM drive servo-control system, positioning error is excessive, causes the centrifugal error compensation effect of servo control unit 89 not good, with cause CD-ROM drive relatively poor follow rail and relatively poor servo loop problem.

In sum; though the present invention discloses as above with preferred embodiment; yet it is not in order to limit the present invention; one of ordinary skill in the art without departing from the spirit and scope of the present invention; can do various changes and retouching, so protection scope of the present invention should be looked the scope that accompanying Claim defines and is as the criterion.

Claims (6)

1. CD-ROM drive servo-control system comprises:

One optical read-write head is used for reading discs and produces a light signal;

One Spindle Motor rotates this discs by control, and exports a motor frequency pulse generator signal and a Spindle Motor synchronizing signal;

One double frequency motor frequency pulse generator signal generation device, receive this motor frequency pulse generator signal, this Spindle Motor synchronizing signal, a reference signal and a frequency multiplication numerical value after, produce an actual double frequency motor frequency pulse generator signal; And

One servo control unit in order to controlling this Spindle Motor and this optical read-write head, and carries out the centrifugal compensation of this discs according to this actual double frequency motor frequency pulse generator signal;

Wherein, this double frequency motor frequency pulse generator signal generation device is according to this reference signal and this frequency multiplication numerical evaluation one desirable double frequency motor frequency pulse generator signal, makes the trigger action time point gap of this actual double frequency motor frequency pulse generator signal and this ideal double frequency motor frequency pulse generator signal within half cycle reference signal.

2. CD-ROM drive servo-control system as claimed in claim 1, wherein this double frequency motor frequency pulse generator signal generation device comprises:

One frequency period computing unit, revolve when turning around in order to calculate this Spindle Motor according to this motor frequency pulse generator signal and this reference signal, this reference signal can produce M frequency, and should can produce N pulse by actual double frequency motor frequency pulse generator signal, and carry out according to this frequency multiplication numerical evaluation

Calculating and obtain (Q+R/N), wherein the Q value is a quotient, and the R value is a remainder;

This R value is kept in and transmitted to one residual value register;

Adjustment unit, one location receives this Spindle Motor synchronizing signal, this actual double frequency motor frequency pulse generator signal, this R value and this N value, calculates this Pn value of a Rn value and Pn value back output, wherein, and Rn=Rn-1+R-N * Pn-1, $\mathrm{Pn}=\left[\right|2\&times;\frac{R_n}{N}\left|\right],$ And O≤n≤N-1, n are integer; And

One double frequency pulse generation unit receives this Q value and this Pn value, and produces this actual double frequency motor frequency pulse generator signal according to (Q+Pn) value and this reference signal.

3. CD-ROM drive servo-control system as claimed in claim 2, wherein this adjustment unit, location comprises:

One totalizer receives this a R value and a Rn-1 value, and then produces one (Rn-1+R) value;

One subtracter receives and is somebody's turn to do (Rn-1+R) value and this N value and produces one (Rn-1+R-N) value;

One first multiplexer, receive should (Rn-1+R) value with should (Rn-1+R-N) value and selection by a Pn-1 value, should (Rn-1+R) value or be somebody's turn to do (Rn-1+R-N) and be worth as a Rn value;

One second multiplexer receives this Rn value and this Rn-1 value and the selection by this actual double frequency motor frequency pulse generator signal, this Rn value or this Rn-1 value are exported and is become this Rn value;

One Rn register is connected in this second multiplexer, and the control by this reference signal receives this Rn value, and is set at this Rn-1 value when output;

One multiplier after receiving this Rn value and multiply by 2, is exported a 2Rn value; And

One comparer receives this N value and this 2Rn value, and when N value during greater than the 2Rn value, a Pn value of output is 0, otherwise this Pn value of output is 1.

4. the double frequency motor frequency pulse generator signal generating method of a CD-ROM drive is that the reference signal of t is moved according to the cycle, comprises the following steps:

Receive a motor frequency pulse generator signal, this reference signal, revolve when turning around in order to calculate a Spindle Motor, this reference signal can produce M frequency;

Receive a frequency multiplication numerical value, revolve in order to calculate this Spindle Motor that an actual double frequency motor frequency pulse generator signal can produce N pulse when turning around;

Calculate And obtain (Q+R/N), wherein the Q value is a quotient, and the R value is a remainder;

Calculate Rn and Pn, Rn=Rn-1+R-N * Pn-1 wherein, $\mathrm{Pn}=\left[\right|2\&times;\frac{R_n}{N}\left|\right],$ And 0≤n≤N-1, and n is an integer; And

When (Q+Pn) value equals the Q value, the pulse that this actual double frequency motor frequency pulse generator signal generation cycle is Qt, when (Q+Pn) value equals (Q+1) value, the pulse that this actual double frequency motor frequency pulse generator signal generation cycle is (Q+1) t.

5. the double frequency motor frequency pulse generator signal generation device of a CD-ROM drive comprises:

One frequency period computing unit learns that according to a motor frequency pulse generator signal and a reference signal this Spindle Motor revolves when turning around, and this reference signal can produce M frequency, produces N pulse and be worth notifying according to a frequency, and carries out

Calculating and obtain (Q+R/N), wherein the Q value is a quotient, and the R value is a remainder;

This R value is kept in and transmitted to one residual value register;

Adjustment unit, one location receives a Spindle Motor synchronizing signal, this R value and this N value, calculates this Pn value of a Rn value and Pn value back output, wherein, and Rn=Rn-1+R-N * Pn-1, $\mathrm{Pn}=\left[\right|2\&times;\frac{R_n}{N}\left|\right];$ And

One double frequency pulse generation unit receives this Q value and this Pn value, and produces an actual double frequency motor frequency pulse generator signal according to (Q+Pn) value and this reference signal.

6. the double frequency motor frequency pulse generator signal generation device of CD-ROM drive as claimed in claim 5, wherein this adjustment unit, location comprises:

One totalizer receives this a R value and a Rn-1 value and produces one (Rn-1+R) value;

One subtracter receives and is somebody's turn to do (Rn-1+R) value and this N value and produces one (Rn-1+R-N) value;

One first multiplexer, receive should (Rn-1+R) value with should (Rn-1+R-N) value and selection by a Pn-1 value, should (Rn-1+R) value or be somebody's turn to do (Rn-1+R-N) value and be set at a Rn value;

One second multiplexer receives this Rn value and this Rn-1 value and the selection by this actual double frequency motor frequency pulse generator signal, this Rn value or this Rn-1 value are exported and is become this Rn value;

One Rn register can receive this Rn value of this second multiplexer output by the control of this reference signal, and is set at this Rn-1 value when output;

One multiplier receives this Rn value and multiply by 2 back outputs, one 2Rn value; And

One comparer receives this N value and this 2Rn value, and when N value during greater than the 2Rn value, a Pn value of output is 0, otherwise this Pn value of output is 1.

Images