JPH0714256A - Motor controller - Google Patents

Abstract

PURPOSE:To reduce a fast-feed/rewind time, improve a detection accuracy and make a tape travelling speed at the time of fast-feed/rewind constant without using a complicated circuit but with a simple constitution. CONSTITUTION:Photoreflectors 4 and 5 which detect the rotation period of a take-up side reel and the rotation period of a pay-off side reel and a microcomputer 6 which outputs control signals to a motor servo circuit 2 in accordance with the detection signals from the photoreflectors 4 and 5 are provided. Further, the microcomputer 6 performs a changeover operation between an analog switch 8 which connects a DCC control IC 1 to the motor servo circuit 2 and an analog switch 7 which connects the microcomputer 6 to the motor servo circuit 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used for a tape-shaped recording medium on which a reference signal serving as a reference of traveling speed is recorded, and a motor control for controlling a drive motor for traveling the recording medium. It relates to the device.

[0002]

2. Description of the Related Art In recent years, with the diversification of recording media, excellent tape-shaped recording media such as so-called DCC and R-DAT have been proposed. It is required to stabilize. Therefore, a reference signal that serves as a reference for the traveling speed is previously recorded on the recording medium. Correspondingly, a device for reproducing the recording medium is provided with a motor control device for controlling a drive motor for traveling the recording medium based on the reference signal.

For example, the DCC player incorporates a DCC capstan servo control device for performing phase servo (see FIG. 13). The DCC control IC 1 compares the phase of the PLL signal reproduced from the head with the reference signal, and if the phase is not kept constant, the error is converted by PWM (pulse width modulation) to a modulation of 50% duty. Output to the motor servo circuit 2. The motor servo circuit 2 (the circuit diagram of which is shown in FIG. 14) converts this output signal into a voltage signal, compensates it, and outputs it to the speed terminal of the DCC motor 3.

As shown in FIG. 15, the voltage applied to the speed terminal of the DCC motor 3 and the rotational speed are in a proportional relationship. Further, the circuit of the DCC motor 3 is set so that the set rotation speed of the internal electric governor changes depending on the voltage applied to the speed terminal, as shown in FIG. Therefore, depending on the voltage of the speed terminal input from the motor servo circuit 2, DC
The rotation speed of the C motor 3 is controlled and the phase of DCC is kept constant.

To explain the above in brief, when the tape speed is slow, the PWM signal output from the DCC control IC 1 has a high duty ratio, and as a result, the voltage applied to the DCC motor 3 is high. As a result, the rotation speed of the motor increases and the tape speed increases. On the contrary, when the tape speed is high, the PWM signal output from the DCC control IC1 has a low duty ratio,
As a result, the voltage applied to the DCC motor 3 decreases, the number of rotations of the motor decreases, and the tape speed decreases.

By the way, in the case of fast-forwarding and rewinding a tape-shaped recording medium such as DCC or R-DAT, it is general to change the running speed of the tape during the fast-forwarding and rewinding in several stages. According to this method, the tape is pulled at a high speed at the tape end, and damage such as the tape being cut can be prevented.

[0007]

However, when fast-forwarding and rewinding a tape-shaped recording medium, it is necessary to perform this at a constant speed in order to shorten the fast-forwarding and rewinding time and also to reduce the level fluctuation of the APC. It is also the most effective from the viewpoint of holding down. However, in order to keep the traveling speed of the tape constant during the fast-forward rewind, a complicated circuit is required, which causes a problem that the configuration becomes complicated.

Therefore, conventionally, a system in which the traveling speed is switched stepwise as described above has been adopted, but the following problems have been pointed out in this system. That is, 1. It cannot be expected that the fast-forward and rewind time will be shortened to the extent that control is performed at a constant speed. 2. When the counter is displayed, the speed at which the counter changes suddenly changes, which causes a feeling of strangeness. 3. If the tracks overlap at the moment when the tape running speed is switched, there is a risk of erroneous detection due to tape slack or noise.

The present invention solves the above problems to shorten the fast-forward / rewind time and improve the detection accuracy.
An object of the present invention is to provide a motor control device capable of maintaining a constant tape traveling speed at the time of fast-forward rewinding with a simple configuration without using a complicated circuit.

[0010]

In order to achieve the above object, the present invention provides a drive motor for moving a recording medium from a take-up reel to a take-up reel, and a motor servo for controlling the drive motor. A motor control device including a circuit and a reproduction control unit that outputs a control signal to the motor servo circuit based on the reference signal when reproducing the recording medium, wherein a reel on the take-up side during fast-forward rewinding of the recording medium And a reel cycle detection unit that detects the rotation cycle of the reel on the winding side and outputs a detection signal, and a fast-forward that outputs a control signal to the motor servo circuit based on the detection signal from the reel cycle detection unit. The rewinding control unit is connected to the reproduction control unit and the motor servo circuit when reproducing the recording medium, and the fast-forwarding is performed when the recording medium is fast-forwarding and rewinding. Characterized by comprising a connection switching means for connecting rewind control unit and the said motor servo circuit.

[0011]

According to the present invention having the above-described structure, at the time of fast-forward rewinding, the reel cycle detecting section detects the rotation cycle of the winding side reel and the rotation cycle of the winding side reel, and the detection signal is fast-forwarding and rewinding. Output to the control unit. When performing fast-forward / rewind, the connection switching means switches from the connection between the reproduction controller and the motor servo circuit to the connection between the fast-forward / rewind controller and the motor servo circuit. Therefore, the fast-forward / rewind controller receives the detection signal and outputs the control signal to the motor servo circuit based on the detection signal. The motor servo circuit controls the drive motor based on this control signal. As a result, the traveling speed of the tape during fast-forward rewinding can be kept constant.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIGS.
It will be specifically described with reference to. This embodiment is adopted for DCC. The same members as those shown in FIG. 8 are designated by the same reference numerals and the description thereof will be omitted.

[Arrangement of this Embodiment] FIG. 1 is a block diagram showing the arrangement of this embodiment. In the figure, reference numerals 4 and 5 are photoreflectors which are reel cycle detectors. The photo reflectors 4 and 5 are the FWD side reel 9 and the RE, respectively.
It is arranged below the V-side reel 10 and both are composed of photoreflectors. In addition, each reel 9,
On the surface of 10, a mirror sheet having reflective surfaces and non-reflective surfaces alternately arranged at equal intervals is attached.

Reference numeral 6 is a microcomputer which also serves as a fast-forward / rewind controller and connection switching means, 7 is an analog switch for connecting the DCC control IC 1 and the motor servo circuit 2, and 8 is an analog for connecting the microcomputer 6 and the motor servo circuit 2. It is a switch. The microcomputer 6 is provided with a PWM signal output terminal 6a and control output terminals 6b and 6c connected to the analog switches 7 and 8. The microcomputer 6 outputs a PWM signal from the PWM signal output terminal 6a based on the detection signals from the reel cycle detectors 4 and 5 to control the motor servo circuit 2 and at the time of DCC reproduction and fast forward rewind. It is configured to switch the outputs of the output terminals 6b and 6c.

[Operation of the present embodiment] In the present embodiment having the above-mentioned configuration, the analog switch 7 is turned off and the analog switch 8 is turned on during DCC reproduction, whereby the microcomputer 6 and the motor servo circuit 2 are connected. And the DCC control IC 1 and the motor servo circuit 2 are connected. On the other hand, during the DCC fast-forward rewind, the analog switch 7 is turned on and the analog switch 8 is turned off to disconnect the DCC control IC 1 and the motor servo circuit 2 and connect the microcomputer 6 and the motor servo circuit 2.

In such a state, the photo reflectors 4, 5
Is an ON detection signal on the reflective surface and OF on the non-reflective surface as the FWD-side reel 9 and the REV-side reel 10 rotate.
The detection signal of F is output to the microcomputer 6. The microcomputer 6 which receives these detection signals outputs a PWM signal having a predetermined duty ratio to the motor servo circuit 2 in order to control the motor servo circuit 2. A series of routines of the microcomputer 6 at this time will be described with reference to the flowcharts of FIGS. 2 is a reel cycle count routine, FIG. 3 is a PWM signal duty ratio calculation routine, and FIG. 4 is PW.
9 shows an M signal control routine.

Reel Cycle Counting Routine Each of the reels 9 and 10 is checked every Ts time, but this Ts is set to be sufficiently smaller than the cycle of the reels 9 and 10. When this Ts time has elapsed (step 11) and the detection signals from the reels 9 and 10 are turned from ON to OFF, and the time from the next ON to OFF is reached, the counter is counted once at Ts. Is incremented. In the flow chart, the reel on the take-up side and the reel on the take-up side are used. However, at the time of fast-forwarding, the reel 9 on the FWD side is the reel on the take-up side and REV.
The side reel 10 is wound up to become a side reel, and at the time of rewinding, the REV side reel 10 is taken up and the FWD side reel 9 is taken up to become a side reel.

First, the detection signal from the take-up reel is O
The cycle of the reel is input to the cycle memory by moving the number of the reel counter to the cycle counter when it is turned off from N (steps 12, 13, 14). However,
When the detection signal from the take-up reel does not change from ON to OFF, the take-up reel counter is incremented by 1
Then (step 15), and if the reel is not counted, the counter of the take-up reel is reset (step 16).

Subsequently, when the detection signal from the winding reel changes from ON to OFF, the number of the reel counter is moved to the cycle counter to input the cycle of the reel into the cycle memory (step 17, 18, 19).
However, the detection signal from the reel on the winding side turns from ON to O
If it is not FF, the counter of the reel on the winding side is incremented by 1 (step 20), and if the reel is not counted, the counter of the reel on the winding side is reset (step 21).

Reel Cycle Count Routine First, in step 31, the cycle memory of the winding side reel is divided by the cycle memory of the winding side reel to obtain a ratio S between the winding cycle and the winding cycle.

Next, in the equation as shown in step 32,
From this S, the "H" level time of the PWM signal, that is, the duty ratio HN is obtained. At this time, HN * Ts becomes the time of TH in FIG. 5 (output waveform diagram of PWM signal).

At step 33, the "L" level time of the PWM signal is obtained. At this time, LN * Ts becomes the time of TL in FIG. The total time of TH and TL is PW
It is the period T of the M signal.

PWM signal control routine H calculated by the PWM signal duty ratio calculation routine
N and LN are respectively moved to the HN counter buffer and the LN counter buffer, and when the PWM signal "H" level is output, the HN counter buffer is decremented by one every Ts time and the PWM signal "L".
When the level is output, the LN counter buffer is decremented by one every Ts time.

This will be described with reference to the flowchart of FIG. First, in step 41, it is judged whether or not the Ts time has elapsed, and if the Ts time has elapsed, step 4
At 2, it is determined whether the PWM signal is at "H" level.
If the PWM signal is at "H" level, it is judged whether the HN counter buffer is 0 (step 43),
If the HN counter buffer is not 0, the HN counter buffer is decremented (step 44) and the process returns to step 41. On the other hand, when the HN counter buffer is 0, the numerical value LN stored in the LN counter is called to the LN counter buffer (step 45), and the PWM signal is switched from "H" level to "L" level (step 4).
6).

In step 41, the PWM signal is "H".
If it is not the level, the routine proceeds from step 42 to step 47, and it is judged whether or not the LN counter buffer is 0. If the LN counter buffer is not 0, decrement the LN counter buffer (step 48).
If the LN counter buffer is 0, the numerical value HN stored in the HN counter is called to the HN counter buffer (step 49), and the PWM signal is switched from the "L" level to the "H" level (step 45).

As described above, the microcomputer 6 detects the position of the tape from the ratio S between the winding cycle and the winding cycle, and accordingly, the PWM signal having a predetermined duty ratio is sent to the motor servo circuit 2. Can be output. The motor servo circuit 2 can control the drive motor 3 based on such a PWM signal.

[Reason that the tape running speed can be kept constant] The reason why the tape running speed at the time of fast-forward and rewind can be kept constant by the PWM signal will be described below. As shown in the graph of FIG. 6, the relationship between tape speed υ, tape winding diameter r and angular velocity V is υ = 2πrV
Therefore, the winding diameter r and the angular velocity V are in inverse proportion. That is, if the winding diameter r is small, the angular velocity V is high, and the winding diameter r
Is larger, the angular velocity V becomes slower.

Next, FIG. 7 shows the relationship between the winding diameter r and the tape position. (A) is a tape start position, (B) is a tape center position, and (C) is a tape end position. That is, at the tape start position, the winding diameter on the winding side is large and the winding diameter on the winding side is small. Therefore, the angular velocity on the winding side becomes slow and the rotation cycle becomes long. As a result, S is a value obtained by dividing the winding cycle by the winding cycle.
(Step 3 in the reel cycle count routine
1) becomes smaller.

At the tape center position, the winding cycle and the winding cycle are the same, and S is 1.
Further, at the tape end position, the tape start position is completely opposite, and the value of S becomes large.

FIG. 8 shows the above situation, that is, a graph showing the relationship between the tape position and the ratio S between the winding cycle and the winding cycle. That is, S increases from the tape start position toward the tape end position. Further, regarding the relationship between the value of S and the tape speed, as shown in FIG. 9, when the value of S is small, the tape speed is small, and when the value of S is large, the tape speed is large. The relationship between the duty ratio in the PWM signal and the tape speed (FIG. 10) shows that when the duty ratio is small, the voltage applied to the DCC motor 3 and the number of rotations of the motor are low, so that the tape speed is slow and the duty ratio is large. Therefore, the tape speed is high because the voltage applied to the DCC motor 3 and the rotation speed of the motor are high.

Therefore, as for the relationship between the duty ratio and the value of S, as shown in FIG. 11, the duty ratio decreases when S increases, that is, when the tape speed is high. Low du
When the PWM signal having the ty ratio is input to the motor servo circuit 2, the motor servo circuit 2 lowers the voltage applied to the DCC motor 3 and the motor rotation speed is reduced, and as a result, the tape speed is reduced. On the contrary, when S decreases, that is, when the tape speed is small, the duty ratio increases. When the motor servo circuit 2 has a high duty ratio, the motor servo circuit 2 increases the voltage applied to the DCC motor 3 to increase the rotation speed of the motor, resulting in an increase in the tape speed. In this way, the tape speed can be kept constant (see FIG. 12).

According to this embodiment as described above, the following effects can be exhibited. That is, a. Since the difference in speed between the tape start position and the tape end position can be reduced, the fast-forward / rewind time can be shortened overall. b. Since the existing motor servo circuit is used and only two analog switches are required to increase the number of circuits, it is easy to simplify the configuration. c. At the time of so-called cueing, a change in level due to a change in tape speed can be reduced, so that erroneous detection can be prevented.

In the present invention, not only DCC but R-
It goes without saying that it can also be applied to DAT.

[0034]

As described above, according to the present invention, the reel cycle detecting section for detecting the rotation cycle of the reel on the winding side and the reel on the winding side, and the detection signal from the reel cycle detecting section are used. With the configuration that includes a fast-forward / rewind controller that outputs a control signal to the motor servo circuit that controls the drive motor, the fast-forward / rewind time is shortened and the detection accuracy is improved, and a simple circuit is not used. With this configuration, the tape running speed during fast-forward rewinding could be kept constant.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.

FIG. 2 is a flowchart showing a reel cycle counting routine in the microcomputer 6 of this embodiment.

FIG. 3 is a PWM signal d in the microcomputer 6 of the present embodiment.
Flow chart showing the duty ratio calculation routine

FIG. 4 is a flowchart showing a PWM signal control routine in the microcomputer 6 of this embodiment.

FIG. 5: Output waveform of PWM signal

[Fig. 6] Tape speed υ, tape winding diameter r, and angular velocity V
Graph showing the relationship with

FIG. 7 is a graph showing a relationship between a winding diameter r and a tape position, (A) shows a tape start position, (B) shows a tape center position, and (C) shows a tape end position.

FIG. 8 is a graph showing a relationship between a tape position and a ratio S of a winding cycle and a winding cycle.

FIG. 9 is a graph showing the relationship between the S value and tape speed.

FIG. 10 is a graph showing the relationship between the duty ratio of the PWM signal and the tape speed.

FIG. 11 is a graph showing the relationship between the duty ratio and the value of S.

FIG. 12 is a graph showing that the tape speed is constant.

FIG. 13 is a block diagram of a DCC capstan servo control device.

FIG. 14 is a circuit diagram of a motor servo circuit 2.

FIG. 15 is a graph showing the relationship between the voltage applied to the speed terminal of the DCC motor 3 and the rotation speed.

FIG. 16 is a circuit diagram of the DCC motor 3.

[Explanation of symbols]

 1 DCC control IC 2 Motor servo circuit 3 DCC motor 4,5 Photoreflector 6 Microcomputer 7, 8 Analog switch 9 FWD side reel 10 REV side reel ST ... Each step of the procedure

Claims (1)

[Claims] 1. A drive which is used for a tape-shaped recording medium on which a reference signal serving as a reference of running speed is recorded, and which runs the recording medium from a winding reel to a winding reel. A motor control device comprising a motor, a motor servo circuit for controlling the drive motor, and a reproduction control section for outputting a control signal to the motor servo circuit based on the reference signal when reproducing the recording medium, Based on the detection signal from the reel cycle detection unit, which detects the rotation cycle of the winding side reel and the rotation cycle of the winding side reel at the time of fast-forwarding and rewinding the medium, and outputs a detection signal. A fast-forward rewind control unit that outputs a control signal to the motor servo circuit, and connects the reproduction control unit and the motor servo circuit when reproducing the recording medium, A motor control device comprising: a connection switching unit that connects the fast-forward / rewind control unit and the motor servo circuit at the time of fast-forward / rewind of the recording medium.