JPH03118479A - Record reproducing apparatus and multiplier - Google Patents

Abstract

PURPOSE:To make it possible to detect the speed so that the occurrence of ripples is prevented by performing operation based on two position signals whose phases are different by 90 degrees. CONSTITUTION:A disk 33 wherein data are recorded is rotated with a disk motor 35. A pickup 3 is moved in the radial direction by the rotation of the motor 1, and the data are read out. Position detectors (Hall elements) 9 output the voltages corresponding to the rotation of a magnet 47 which is attached to a shaft 45 of the motor 1, and the amount of rotations is detected. The outputs of the detectors 9a and 9b are added 301 and subtracted 303. The added and subtracted results are differentiated in differentiating devices 13a and 13b and rectified in rectifiers 15a and 15b. The results are added in an adder 17. Thus the speed signal is obtained. In this way, the output signals of the detectors 9a and 9b whose phases are different by 90 degrees are added and subtracted, the absolute values of the output signals of an adder 301 and a subtractor 303 are equal even if there is dispersion in sensitivity, and the speed signal without ripples can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to an optical recording/reproducing device such as a CD-ROM drive.

(Prior art) Conventionally, as a position detector used in recording and reproducing devices, etc.
There is one described in Japanese Patent Application No. 82-260185. This position detector detects the position of the pickup by detecting the amount of rotation of the pickup feeding motor.

The pickup is mounted on a rack gear, and a pinion gear meshing with the rack gear is rotationally driven by a motor. A magnet is attached to the rotating shaft of this motor,
Two Hall elements are arranged near this magnet, and when the magnet rotates with the rotation of the motor, signals having a phase difference of 90 degrees are output from the two Hall elements.

(Problem to be Solved by the Invention) However, there is usually a variation in sensitivity of Hall elements of about 20%, and if there is a difference in sensitivity between the two Hall elements used here, the difference in sensitivity shown in Fig. 6(a) As shown, a difference occurs in the absolute value of the output signal ASB.

When this output signal is differentiated, rectified and added and used as the speed signal C, a ripple occurs in the speed signal C due to the output voltage difference as shown in FIG. 6(b).

The present invention has been made in view of these problems, and its purpose is to provide a recording/reproducing device that does not cause ripples in the speed detection signal even if there are variations in sensitivity between the two detection elements. It is about providing.

[Configuration of the Invention (Means for Solving the Problems) To achieve the above object, the present invention provides a recording and reproducing apparatus that reads information recorded on a disk via a pickup, in which the pickup is moved in the radial direction of the disk. a pair of detection means for detecting the position of the pickup by the driving means and outputting two signals having phases different by 90 degrees; and an addition for adding the two signals having phases different by 90 degrees. a subtracter for subtracting the two signals whose phases differ by 90 degrees; a speed signal detection means for differentiating the outputs of the adder and the subtracter to obtain a speed signal of the pickup; and means for comparing the speed signal with a reference speed signal and feeding back the difference signal to the driving means.

(Operation) In the present invention, since two signals having a phase difference of 90 degrees are added and subtracted, the absolute values of the output signals of the adder and the subtracter become equal.

Therefore, when such a signal is differentiated, rectified, and then added to obtain a speed signal, no ripple occurs in the speed signal because the absolute values of the two output signals are equal.

(Example) Hereinafter, an example of the present invention will be described in detail based on the drawings.

FIG. 1 is a block diagram showing the configuration of a recording/reproducing apparatus according to an embodiment of the present invention.

As shown in the figure, this recording/reproducing device has a motor 1,
pickup 3, tracking servo circuit 5, switch 305, position detector 9 as 9 bs adder 301,
Subtractor 303, Exclusive or Game) (EXOR
) 205, differentiators 13a, 13b, rectifiers 15a, 15
It has a bs adder 17, a controller 21, a counter 23, a position error detection circuit 25, a switch 27a, a comparator 29, and a power amplifier 31.

FIG. 2 is a diagram showing a schematic configuration of the reading portion of the disc 33. As shown in FIG. A disk 33 on which information has been recorded is rotated by a disk motor 35.

The motor 1 that moves the pickup 3 for reading detailed information recorded on the disk 33 rotates the pinion gear 41. This pinion gear 41 meshes with the rack gear 39, and when the motor 1 rotates, the pickup 3
It moves in the radial direction of the disk 33.

Position detectors 9a and 9b detect the amount of rotation of motor 1.

FIG. 3 is a schematic diagram of the vicinity of the position detector 9a s 9 b, and FIG. 4 is a plan view of the vicinity of the position detector.

As shown in the figure, a magnet 43 and a pinion gear 41 are attached to a motor shaft 45 of the motor 1 attached to a base 43.

The position detectors (Hall elements) 9a and 9b are magnets 4
When 7 rotates, it outputs a corresponding voltage.

In FIG. 1, a tracking servo circuit 5 performs tracking servo of the pickup 3.

FIG. 5 is a circuit diagram showing the configuration of the main parts of the recording/reproducing apparatus shown in FIG. 1. In addition, in FIG. 5, the pickup 3 and tracking servo circuit 5 are omitted.

The output signals of terminals ■ and ■ of the position detector 9a are sent to an adder 301 and a subtracter 303, respectively.

The output signals of terminals ■ and ■ of the position detector 9b are sent to an adder 301 and a subtracter 303, respectively.

The adder 301 includes an operational amplifier 307 and a resistor 309.31.
It consists of 1.313.314.315.316.

The subtracter 303 includes an operational amplifier 317 and a resistor 319.32.
It consists of 1.323.325.327.329.

Adder 301 adds the output signals of position detectors 9a and 9b.

The subtracter 303 subtracts the output signals of the position detectors 9a and 9b.

A differentiator 13a is configured by an operational amplifier 53a, a capacitor 55a, and a resistor 58a.

Differentiator 13a differentiates the output signal of adder 301.

The waveform shaping circuit 12a includes an operational amplifier 65a1 and a resistor 57a.
, 69a.

This waveform shaping circuit 12a shapes the waveform of the output signal of the operational amplifier 307.

The output signal of the waveform shaping circuit 12a is transmitted through the diode 201a.
The signal is inputted to the exclusive OR gate 205 through the gate, and also inputted to the transistor 81b.

Similarly, the output signal of waveform shaping circuit 12b is input to exclusive OR gate 205 and transistor 81a via diode 201b.

The exclusive OR gate 205 is the waveform shaping circuit 12
A clock signal is generated from the output signals of the counters 23a and 12b and sent to the counters 23a and 23b.

The rectifier 15a includes an operational amplifier 71a1 and resistors 73a and 75.
a, 77a, 79a,) transistor 81a.

The rectifier 15a rectifies the output signal of the differentiator 13a.

When the transistor 81a is on, the operational amplifier 71a functions as a non-inverting amplifier with a gain of "1", and when the transistor 81a is off, the operational amplifier 71a has a gain of "-".
1" functions as an inverting amplifier.

The configurations of the position detector 9b, differentiator 13b1 and rectifier 15b are similar to the position detector 9a, differentiator 13a1 and rectifier 15a described above.

The adder 17 includes resistors 83a and 83b and a connection point 85.

The adder 17 adds the output signals of the rectifier 15a and the rectifier 15b.

The controller 21 performs processing such as setting preset data in the counter 23 and switching the switches 27a and 305 using the switch control signal SW.

The counter 23 consists of 8-bit counters 23a and 23b that count down.

The position error detection circuit 25 includes a counter 23 a s 23
The output signal of b is converted into an analog signal by a ladder resistor.

When the switch control signal SW is "1", the transistor 27a is turned on and the output signal of the position error detection circuit 25 is sent to the comparator 29.

Moreover, the switch control signal SW is the switch 30
5, the switch control signal SW is
1, the switch 305 is open.

When the switch control signal SW is "0", the transistor 27a is turned off and the switch 305 is turned on.

An operational amplifier 91, a resistor 93, and capacitors 95 and 97 constitute a comparator 29 and a power amplifier 31.

The operational amplifier 91 compares the output signal of the gain switch 19 with the speed reference voltage, amplifies it, and sends it to the motor 1 .

The AND circuit 101 calculates the maximum value of the counters 23a and 23b.
The output signals of the terminals are ANDed and this is inputted to the 5TOP terminal of the controller 21 as a counter up signal.

The operational amplifier 103 converts impedance.

The track jump direction switching circuit 105 includes an operational amplifier 107, a transistor 109, and resistors 111.113.1.
Consists of 15.117.

This track jump direction switching circuit 105 operates according to the signal output from the F/R terminal of the controller 21.
This is for switching the track jump direction.

When the F/R signal is "1", the transistor 109 is turned on, so the operational amplifier 107 functions as a non-inverting amplifier with a gain of "1". When the F/R signal is "0", the transistor 109 is turned off, so the operational amplifier 107 functions as an inverting amplifier with a gain of "-1".

Next, the operation of this embodiment will be explained.

First, the general operation of this embodiment will be explained based on FIG. 1.

When the motor 1 rotates, the magnet 47 rotates accordingly, and signals HIP and H2P are output from the terminals ■ of the position detectors 9 a s 9 b. Further, a signal HINSH2N is output from each terminal (2).

These signals are added and subtracted by operational amplifiers 307 and 317, respectively, and then differentiated by a differentiator 13a113b to output signals HID and H2D.

If there is a difference in sensitivity between the position detectors 9a and 9b and their output signals A1 and B1 have a difference in absolute value as shown in FIG.
2 and B2 are as shown in FIG. 6(a), and their absolute values are equal.

For example, if the output signal of the position detector 9a is As1nθ and the output signal of the position detector 9b is Bcosθ, the output signal of the adder 301 is As1nθ+B
cosθ −Jk2+B2s in (θ+α), and the output signal of the subtracter 303 becomes As1nθ−B cosθ −J'A2+B2s i n (θ−α), and the absolute values of the output signals of the adder 301 and the subtracter 303 become equal. .

This signal is differentiated by differentiators 13a and 13b, and then rectifier 15
The signal C2 rectified by a and 15b and added by the adder 17 is
Since the absolute values of the output signals of adder 301 and subtracter 303 are equal, no ripple occurs. Also, the adder 30
1. The output signal of the subtracter 303 is sent to the waveform shaping circuit 12 a
The waveform is shaped by %12b and the signal H1sSH
2S is output. Further, the signal HIDSH2D is rectified by rectifiers 15a and 15b, respectively, and the signal HIDSH2D is rectified by the rectifiers 15a and 15b, respectively.
V and H2V are output.

These signals HIV and H2V are added by an adder 17, compared with a speed reference signal by a comparator 29, amplified by a power amplifier 31, and fed back to the motor 1.

During position control, the controller 21 sets the switch control signal SW to "0". At this time, the switch 27 selects the output signal of the tracking servo circuit 5, and this output signal is used as the speed reference signal, so the control is performed so that the output signal of the adder 17 matches the output signal of the tracking servo circuit 5. will be held.

During speed control, the controller 21 sets the switch control signal SW to "1".

At this time, the switch 27 selects the output signal of the position error detection circuit 25, so this output signal is used as the speed reference signal, and control is performed so that the output signal of the adder 17 matches the output signal of the position error detection circuit 25. will be held.

Next, the operation of this embodiment will be explained in detail based on FIG.

(1) Operation during position control The controller 21 sets the switch control signal SW to "0" during position control. Therefore, the transistor 27a is turned off, the switch 305 is turned on, and so-called feed servo is performed.

(2) Operation during speed control During speed control, the controller 21 determines whether the destination point to which the pickup 3 is to be moved is in the forward or reverse direction from the current location of the pickup 3, and determines the direction.

In the case of the positive direction, the F/R signal is set to "1" and the transistor 109 is turned on. At this time, the operational amplifier 107 functions as a non-inverting amplifier with a gain of "1", and the operational amplifier 107 functions as a non-inverting amplifier with a gain of "1".
3 is sent to the operational amplifier 91 via the transistor 27a.

In the case of the reverse direction, the controller 21 sets the F/R signal to "0" and turns off the transistor 109.

At this time, the operational amplifier 107 functions as an inverting amplifier with a gain of "-1" and sends a signal obtained by inverting the output signal of the operational amplifier 103 to the operational amplifier 91.

Next, the controller 21 sets data corresponding to the distance from the terminal DO to D7. Then, the signal LOAD is set to "0", and the data set from the terminal DO to D7 is preset to the counters 23a and 23b.

Next, the signal LOAD is returned to "0" to start counting, and the switch control signal SW is set to "1".

Therefore, the transistor 27a is turned on, the switch 27b is turned off, and the transistors 61a and 61b are turned on.
Eight switches are turned on.

At this time, the operational amplifier 91 includes the position error detection circuit 25a.
and the output signal H of the rectifiers 15a and 15b.
2V and HIV are input, VE/R99 --(H2V/R83a +HIV/R83b)
It is controlled so that

The signals H2V, I (IV) are almost equal to O since they rotate at very low speeds. Therefore, the motor 1 is fully accelerated in the predetermined direction.

When the motor 1 rotates, position signals HIS and H2S are generated, the count values of the counters 23a and 23b decrease, and the magnitude of the signal VE also decreases.

Therefore, the reference speed voltage of the motor 1 also decreases, and the number of revolutions becomes the lowest when the values of the counters 23a and 23b are "1".

When the pickup 3 reaches the target position, the counter 23
The count values of a and 23b become "0", and the counter 23
Since the output signals of the terminals MAX of a and 23b are both "1", a signal 1 is sent to the 5TOP terminal via the AND gate 101.

When the 5TOP signal becomes “1”, the controller 21
The switch control signal SW is set to "0" to return to the position control state described above.

Note that the present invention can be modified in various ways within the scope of its technical idea.

For example, in this embodiment, speed detection is performed using position detectors 9a and 9.
Although the output signal b was obtained by differentiating the output signal, a so-called moving magnet type speed detector using a magnet and a coil may be provided separately.

Furthermore, a magnetic, optical, or electrostatic position detector may be used.

As the motor 1, various motors such as a linear motor, an electrostatic motor, a brushless morph, a stepping motor, etc. can be used.

The position detectors 9a and 9b are of a two-phase type, but a polyphase type can also be used.

Furthermore, although the position of the pickup during a track jump is detected by pulse counting, a velocity integral method or a potentiometer method may also be used.

FIG. 7 is a block diagram showing the configuration of the multiplier. This multiplier is a waveform adjustment circuit 601a, 601b1 adder 60
3. Subtractor 605, exclusive or gate 607.
It consists of 609.611.

FIG. 8 is a waveform diagram of signals at each part of this multiplier.

Signals S5 and S6 are signals obtained by adding and subtracting signals S3 and S4, which are obtained by adjusting the waveforms of signals S1 and S2.

Signal S7 is an exclusive OR signal of signals S3 and S4, signal S8 is an exclusive OR signal of signals S5 and S6, and signal S9 is an exclusive OR signal of signals S7 and S8. .

As shown in the figure, the signal S9 has four times as many pulses.

Furthermore, by performing addition and subtraction processing, multiplication by 2n times becomes possible.

FIG. 9 is a block diagram showing the configuration of a multiplier that multiplies the signal by 2n times.

As shown in the figure, this multiplier consists of n adders 70
1-1,... 701-n and n subtracters 703-
1,... 703-n, and the i-th adder 70
1-i has the (i-1)th adder 701-(i-1
) and the output signal of subtractor 703-(i-1) are input,
The i-th subtractor 703-1 includes the (i-1)-th adder 701-(i-1) and the subtracter 703-(i-1).
The output signal of is input.

By providing this multiplier with an exclusive OR gate, the signal can be multiplied by 2n times.

[Effects of the Invention] As described in detail above, according to the present invention, it is possible to provide a recording/reproducing device that does not cause ripples in the speed detection signal even if there is variation in sensitivity between the two detection elements. .

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the overall configuration of a recording/reproducing apparatus using a feed servo circuit according to an embodiment of the present invention, FIG. 2 is a schematic diagram of the vicinity of the pickup, and FIGS. 3 and 4 are position detection Figure 5 is a circuit diagram showing the configuration of the feed servo circuit, Figure 6 is a waveform diagram of the output signal of the position detector and adder, and Figure 7 is the configuration of the multiplier. The block diagram shown in FIG. 8 is a waveform diagram of the signals of each part of this multiplier, and FIG. 9 is a block diagram showing the configuration of the multiplier that multiplies the signal by a factor of 2n. 1...Motor 3...Pickup 9a, 9b...Position detector 3a, 13b...Differentiator 5a, 15b...Rectifier 7... ......Addition section 1...Controller 3...Counter 5...Position error detection circuit 7...・
...Switch 9...Comparator 1...Power amplifier 1...Adder 3... Subtractor ba hundred, two stitches ρ] 2nd 4th 3rd figure 4th figure: of;

Claims (3)

[Claims] (1) A recording and reproducing apparatus that reads information recorded on a disk via a pickup, comprising: a driving means for driving the pickup in a radial direction of the disk; and a position of the pickup detected by the driving means to detect the position of the pickup and detecting the position of the pickup. a pair of detection means that output two signals that differ in phase; an adder that adds the two signals that differ in phase by 90 degrees; a subtracter that subtracts the two signals that differ in phase by 90 degrees; speed signal detecting means for differentiating the output of the subtracter and the subtracter to obtain a speed signal of the pickup; and means for comparing the speed signal and a reference speed signal and feeding back a difference signal to the driving means. A recording and reproducing device included. (2) The recording/reproducing apparatus according to claim 1, wherein the driving means includes a brushless motor, and the detecting means detects the position of the brushless motor. (3) It has n (n is an integer) adders and n subtracters, and the n-th adder is the (n-1)-th adder and the (n-1)-th A multiplier that adds the output signals of the subtracters, and the n-th subtracter subtracts the output signals of the (n-1)-th adder and the (n-1)-th subtracter.