JPH03112388A - Rotary direction detector for rotary body - Google Patents

Abstract

PURPOSE:To detect inversion of the rotary direction of a rotary body before the rotary body rotates by 360/N (N is the number of pulse) at most by providing two or more types of different rotary direction detecting means. CONSTITUTION:Rotary direction of a capstan motor 1 is detected by providing a High level signal to the output terminal 53 of a microcomputer 5 during clockwise rotation of the capstan motor 1 and a Low level signal during counter clockwise rotation of the capstan motor 1. Consequently, the rotary direction is detected at the rising and falling times of a FG pulse (b) which is the output pulse from one FG3 of two frequency pulse generators(FG) 2, 3 generating output pulses having mutual phase shift of 90 deg.. By such arrangement, inversion of the rotary direction of the capstan motor 1 can be detected before the capstan motor 1 rotates by 180/N at most.

Description

[Detailed Description of the Invention] Industrial Field of Application The present invention relates to a magnetic recording and reproducing device (hereinafter referred to as VTR).
The present invention relates to a rotational direction detection device for a rotating body, such as a rotational direction detection device for a capstan motor.

BACKGROUND OF THE INVENTION FIG. 7 is a block diagram of a capstan motor rotation direction detection device in a conventional VTR.

In FIG. 7, 1 is a capstan motor for transporting the magnetic tape, 2 and 3 are both provided in the capstan motor 1, and a frequency pulse signal (hereinafter referred to as FG) with a frequency proportional to the rotational speed of the capstan motor 1 is provided. FG2. The FG3 is configured so that FG pulses having phases different by 90 degrees from each other can be obtained. 4 is a D-type flip-flop circuit,
Input data input to the data input terminal 41 is transmitted to the output terminal 43 at the rising edge of the clock pulse input to the clock pulse input terminal 42. The data input terminal 41 receives an FG pulse (hereinafter referred to as FG pulse a) generated from FG2, and the clock pulse input terminal 42 receives an FG pulse generated from FG3.
A G pulse (hereinafter referred to as FG pulse b) is input.

The operation of the conventional capstan motor rotation direction detection device configured as described above will be described below.

FG2 provided in the capstan motor 1. FG pulse a+FG pulse b generated from FG3 are each 9
As shown in FIG. 6, for example, when the capstan motor 1 rotates in the clockwise direction (hereinafter referred to as CW force direction), the FG pulse a is different from the FG pulse b.
is advanced by 90 degrees in phase, and when the capstan motor 1 rotates in a counterclockwise direction (hereinafter referred to as CC direction), FG
The phase of FG pulse a is delayed by 90 degrees with respect to pulse b.

In the D-type flip-flop circuit, the signal level (Hi
gh level, Low level) are transmitted to the output terminal 43 at the rising edge of the FG pulse b input to the clock pulse input terminal 42. A high level is output when the capstan motor 1 rotates in the CW direction, and a low level is output when the capstan motor 1 rotates in the CCW direction +B.

Therefore, the rotation direction of the capstan motor can be detected depending on whether the signal output to the output terminal 43 of the D-type flip-flop circuit 4 is at High level or Low level.

Problems to be Solved by the Invention However, the above-mentioned conventional capstan motor rotation direction detection device detects the rotation direction of the capstan motor 1,
- Two F whose output pulse phases differ by 9.0 degrees from each other
- FG (FG3) of G (FG2.FG3)
It is detected only at the rising edge of the output pulse (FG pulse b). Therefore, even if the rotation direction of the capstan motor 1 changes at a certain point, one FG (FG3
) until the rising edge of the output pulse (FG pulse b) arrives, it is not detected that the rotation direction of the capstan motor 1 has changed. That is, if the number of FG pulses obtained from one FG during one rotation of the capstan motor 1 is N, then in the above-mentioned capstan motor rotation direction detection device, the rotation of the capstan motor 1 at a certain point Even if the direction changes, there is a problem in that the change in the rotation direction of the capstan motor 1 is not detected until the capstan motor 1 rotates by a maximum of 360/N degrees after the rotation direction change.

In view of this point, the present invention provides a method for generating two frequency pulse signals when detecting the rotational direction of a rotating body in which at least two frequency pulse signal generation means are provided, the phases of which output pulse signals differ from each other by approximately 90 degrees. When the number of pulses obtained during one rotation of the rotating body by one of the frequency pulse signal generating means of the means is N, the number of pulses obtained during one rotation of the rotating body from the time when a change occurs in the rotational direction of the rotating body until the change in the rotational direction is detected. An object of the present invention is to provide a rotational direction detection device for a rotating body that makes the maximum rotational angle of the rotating body smaller than 360/N degrees.

Means for Solving the Problems In order to achieve the above object, the present invention provides first frequency pulse signal generating means for generating a first frequency pulse signal having a frequency corresponding to the rotational speed of a rotating body; a second frequency pulse signal generating means for generating a second frequency pulse signal having a phase different from the first frequency pulse signal at a frequency corresponding to the rotational speed of the first frequency pulse signal; The rotational direction detection means detects the rotational direction of the rotating body □ by determining the signal level of the second frequency pulse signal at the rising edge thereof, and the rotational direction detection means detects the rotational direction of the rotating body □ by determining the signal level of the second frequency pulse signal at the rising edge of the first frequency pulse signal. A rotational direction detection means for detecting the rotational direction of the rotating body by determining the signal level of the second frequency pulse signal when falling is a second rotational direction detection means;
A third rotation direction detection means is a rotation direction detection means for detecting the rotation direction of the rotating body by determining the signal level of the first frequency pulse signal at the rising edge of the frequency pulse signal, and When a fourth rotation direction detection means is used as a rotation direction detection means for detecting the rotation direction of the rotating body by determining the signal level of the first frequency pulse signal at the falling edge of the pulse signal,
Said 1st. 2nd degree: The present invention is equipped with at least two rotational direction detection means of the third or fourth rotational direction detection means. Second. With the configuration including two or more different types of rotational direction detection means among the third or fourth rotational direction detection means, the number of FG pulses obtained from one FG during one rotation of the capstan motor 1 can be reduced to N. Then, while the capstan motor 1 rotates 360/N degrees in the same direction, the rotation direction of the capstan tongue 1 is detected two or more times.

Embodiment FIG. 1 shows a block diagram of a rotational direction detection device for a capstan motor of a VTR, which is a first embodiment of the rotational direction detection device for a rotating body according to the present invention.

In FIG. 1, 1 is a capstan motor for transporting a magnetic tape, 2 and 3 are both provided in the capstan motor 1, and a frequency pulse signal (hereinafter referred to as FG) with a frequency proportional to the rotational speed of the capstan motor 1 is provided. FG2. The FG3 is configured so that FG pulses having phases different by 90 degrees from each other can be obtained. 5 is a one-chip microcomputer (hereinafter referred to as microcomputer 5), and an external interrupt pulse input terminal 51 receives the FG pulse (hereinafter referred to as FG pulse b) generated from the FG3; Entering capo,
An FG pulse (hereinafter referred to as FG pulse a) generated from FG2 is input to the -G terminal 52, respectively. Here, the microcomputer 5 is used so that an interrupt is generated at both the rising edge and the falling edge of the pulse input to the external interrupt pulse input terminal 51. An interrupt is generated at the rising edge and falling edge of the FG pulse b input to the FG pulse b, and external interrupt processing for detecting the rotational direction of the capstan motor 1 is performed.

FIG. 2 is a flowchart showing the procedure of external interrupt processing performed by the microcomputer 5. As shown in FIG.

In FIG. 2, processing 501 determines whether the interrupt edge of the FG pulse b input to the external interrupt pulse input terminal 51 is a rising edge or a falling edge. This is a process for determining whether the level is low or low. Process 502 is a process performed when it is determined in the process 501 that the external interrupt pulse input terminal 51 is at High level, that is, the interrupt edge is a rising edge, and the input port terminal 52 to which the FG pulse a is input is This is a process of detecting whether the signal is at a high level or a low level.

Process 503 is a process that is performed when it is determined in the process 501 that the external interrupt pulse input terminal 51 is at a low level, that is, the interrupt edge is a falling edge, and the input port to which the FG pulse a is input is This is a process of detecting whether the terminal 52 is at High level or Low level. Processing 504 is processing 50
If the input port terminal 52 is detected to be at a high level in step 2, and in step 503, the input port terminal 52 is detected to be at a high level.
This process is performed when it is detected that the output port terminal 53 is at a low level, and the output port terminal 53 is set to output a high level. Process 505 is a process that is performed when the input port terminal 52 is detected to be at a low level in process 502 and when the input port terminal 52 is detected to be at high level in process 503, and the output The port terminal 53 is cleared and a low level is output.

The operation of the capstan motor rotation direction detection device of this embodiment configured as described above will be described below.

In FIG. 1, the F provided in the capstan motor 1
G2. FG pulse a+FG pulse b generated from FG3 have phases different from each other by 90 degrees. For example, as shown in FIG. 6, the capstan motor 1 is rotated clockwise (hereinafter referred to as
CW force direction. ) When the capstan motor 1 rotates in a counterclockwise direction (hereinafter referred to as CCW direction), the FG pulse a has a phase advance of 80 degrees with respect to the FG pulse b. Pulse a is delayed in phase by 90 degrees. That is, as is clear from FIG. 6, when the capstan motor 1 rotates in the CW direction, the signal level of the FG pulse a at the rise and fall of the FG pulse b is respectively High level t and Low level, and the capstan motor 1 is rotated in the CW direction. When motor 1 rotates in the CCW direction,
F at the rise and fall of FG pulse b
The signal level of each G pulse a is Low level rH1g.
It is h level.

And the external interrupt pulse input terminal 51 of Mankosi 5
Each time a rising edge or a falling edge of the FG pulse b input to the FG pulse b arrives, the microcomputer 5 performs the external interrupt processing shown in the flowchart of FIG. First, in process 501, the external interrupt pulse input terminal 51
It is determined whether the interrupt edge of the FG pulse b input to the FG pulse b is a rising edge. In the process 501, F
When it is determined that it is the rising edge of G pulse b,
Process 502 is performed, and if it is determined in the process 50112-- that it is the falling edge of FG pulse b, process 503 is performed.

For example, when the capstan motor 1 rotates in the cW direction, the FG
When the rising edge of pulse b arrives, the process 5
02 is performed and the input port terminal 52 to which the FG pulse a is input is detected to be at a high level.
Process 504 is performed, the output port terminal 53 is set, and a high level is output. Further, when the falling edge of the εεFG° pulse b arrives when the capstan motor 1 rotates in the CW direction, processing 503 is performed, and it is detected that the input port terminal 52 to which the FG pulse a is input is at a low level. Therefore, processing 504 is performed, the output port terminal 53 is set, and a high level is output.

On the other hand, when the capstan motor 1 rotates in the ccw direction, the FG
When the rising edge of pulse b arrives, processing 502 is performed, and since it is detected that the input port terminal 52 to which FG pulse a is input is at a low level, processing 50 is performed.
5 is performed, the output port terminal 53 is cleared, and a low level is output. Also, the CC of capstan motor 1
When the falling edge of FG pulse b arrives during rotation in the W direction, processing 503 is performed, and since the input port terminal 52 to which FG pulse a is input is detected to be at a high level, processing 505 is performed, and the Capo terminal S3
is cleared and a low level is output.

That is, a high level is output to the output port terminal 53 of the microcomputer 5 when the capstan motor 1 rotates in the CW direction, and a low level is output when the capstan motor 1 rotates in the CCW direction.

Therefore, according to the capstan motor rotation direction detection device of this embodiment, the capstan motor 1 is detected depending on whether the signal output to the output port terminal 53 of the microcomputer 5 is at the Ht g h level or the Low level. The direction of rotation can be detected.

The capstan motor rotation direction detection device of this embodiment determines the rotation direction of the capstan motor 1 by the output pulse of one of the two FGs whose output pulse phases differ by 90 degrees from each other. This is to detect when the FG pulse b rises and falls. Therefore, if the number of FG pulses obtained from one FG during one rotation of the capstan motor 1 is N, then the capstan motor 1 moves 3E30/(2・N) degrees in the same direction, or 18
The rotation direction of the capstan motor 1 is detected once every 0/N degrees of rotation. Therefore, according to the capstan motor rotation direction detection device of this embodiment, if the rotation direction of the capstan motor 1 changes at a certain point in time, the capstan motor 1 rotates by a maximum of 180/N degrees after the rotation direction changes. Until then, a change in the rotational direction of the capstan motor 1 is detected.

As described above, according to this embodiment, the capstan motor 1
FG, which is the output pulse of one of the two FGs whose output pulse phases differ by 90 degrees from each other.
By adopting a configuration that detects the rise and fall of pulse b, it is possible to reduce the maximum The rotation angle is 180/N degrees, which can be smaller than 360/N degrees.

FIG. 3 is a block diagram of a device for detecting the rotational direction of a VTR capstan motor, which is a second embodiment of the device for detecting the rotational direction of a rotating body according to the present invention.

In FIG. 3, Hinoki element 1. 2. 3 indicates the same components as those with the same reference numerals in FIG. 6 is a one-chip microcomputer (hereinafter referred to as microcomputer 6).
The external interrupt pulse input terminals 61 and 63 each receive an FG pulse (hereinafter referred to as FG pulse b) generated from FG3.

FG pulse generated from FG2 (hereinafter referred to as FG pulse a)
It is called. ) is input, and input port terminal E32,
FG pulse a and FQ pulse b are input to 64, respectively. Here, the microcomputer 6 is used so that an interrupt is generated at both the rising edge and the falling edge of the pulse input to the external interrupt pulse input terminal 61. An interrupt is generated at the rising edge and falling edge of the FG pulse b input to the terminal 61, and external interrupt processing for detecting the rotational direction of the capstan motor 1 is performed. The microcomputer 6 also has an external interrupt pulse input terminal 6.
The microcomputer 6 uses the rising edge and the falling edge of the FG pulse a input to the external interrupt pulse input terminal 63 so that an interrupt can be applied to both the rising edge and the falling edge of the pulse input to the external interrupt pulse input terminal 63. An interrupt is also generated at the falling edge, and external interrupt processing for detecting the rotational direction of the capstan motor 1 is performed.

FIG. 4 is a flowchart showing the processing procedure of external interrupt processing performed by the microcomputer 6 each time the rising edge and falling edge of the FG pulse b arrive.

In FIG. 4, processing 601 determines whether the interrupt edge of the FG pulse b input to the external interrupt pulse input terminal 61 is a rising edge or a falling edge. This is a process for determining whether the level is low or low. Process 602 is a process performed when it is determined in process 601 that the external interrupt pulse input terminal 61 is at High level, that is, the interrupt edge is a rising edge, and the input port terminal 62 to which the FG pulse a is input is This is a process of detecting whether the level is High level or Low level. Process 603 is a process performed when it is determined in process 601 that the external interrupt pulse input terminal 61 is at a low level, that is, the interrupt edge is a falling edge, and the input port terminal 62 to which the FG pulse a is input is processed. This is a process of detecting whether the signal is at a high level or a low level.

In the process 604, the input port terminal 62 is set to H in the process 602.
If it is detected that the level is high, and processing 603
This process is performed when the input port terminal 62 is detected to be at a low level, and the output port terminal 65 is set to output a high level. Process 605 is a process that is performed when the input port terminal 62 is detected to be at the 50W level in process 602 and when the input port terminal 62 is detected to be at the High level in process 603. Clears the side port terminal 65 and outputs the 50W level.

FIG. 5 is a flowchart showing the procedure of external interrupt processing performed by the microcomputer 6 each time the rising edge and falling edge of the FG pulse a arrive.

In FIG. 5, processing 606 determines whether the interrupt edge of the FG pulse a input to the external interrupt pulse input terminal 63 is a rising edge or a falling edge. This is a process for determining whether the power is at the 50W level or the 50W level. Processing 607 is performed when it is determined in processing 606 that the external interrupt pulse input terminal 63 is at High level, that is, the interrupt edge is a rising edge. This process detects whether 64 is at High level or 50W level. Processing 608 is processing 6
This process is performed when it is determined that the external interrupt pulse input terminal 63 is at the 50W level, that is, the interrupt edge is a falling edge in 06, and the input port terminal 64 to which the FG pulse b is input is at a high level. This is a process of detecting whether the power is at the 50w level or not.

In the process 609, the input port terminal 64 is set to H in the process 607.
If it is detected that the level is high, and processing 608
This process is performed when the input port terminal 64 is detected to be at the 50W level, and the output port terminal 65 is cleared and the 50W level is output. Processing 610 is performed when it is detected that the input port terminal 64 is at the 50W level in processing 607, and when it is detected that the input port terminal 64 is at the 50W level in processing 608.
4 is detected to be at High level, and the output port terminal 65 is set to
Output the level.

20- The operation of the capstan motor rotation direction detection device of this embodiment configured as described above will be described below.

In FIG. 3, the F provided in the capstan motor 1
G2. FG pulse a+FG pulse b generated from FG3 have a phase difference of 90 degrees from each other, and as shown in FIG. 6, for example, when the capstan motor 1 rotates in the CW direction, FG pulse a is different from FG pulse b. When the phase advances by 90 degrees and the capstan motor 1 rotates in the CCW direction,
FG pulse a is delayed in phase by 90 degrees with respect to FG pulse b.

That is, as is clear from FIG. 6, when the capstan motor rotates in the r'icw direction, the signal levels of the FG pulse a at the rise and fall of the FG pulse b are High level and LOW level, respectively.
When the pulse a rises.

The signal levels of the FG pulse b at the time of falling are respectively 50W level and High level.

Also, when the capstan motor 1 rotates in the CCW direction,
F that smells at the rise and fall of FG pulse b
The signal levels of G pulse a are LOW level and HIGH level, respectively.
h level and l? The signal levels of the FG pulse b at the rise and fall of the Gzf pulse a are High level and 50W level, respectively.

Then, the external interrupt pulse input terminal 61 of the microcomputer 6
Each time a rising edge or a falling edge of the FG pulse b input to the FG pulse b arrives, the microcomputer 6 performs the external interrupt processing shown in the flowchart of FIG.

First, in process 601, the external interrupt pulse input terminal 6
When the interrupt edge of FG pulse b input to 1. It is determined whether the F in process 601
When it is determined that it is the rising edge of G pulse b,
Process 602 is performed, and if it is determined in process 601 that it is a falling edge of FG pulse b, process 603 is performed.
will be held.

For example, when the capstan motor 1 rotates in the CW direction, the FG
When the rising edge of pulse b arrives, process 602
is performed, and the input port terminal 62 to which the FG pulse a is input is detected to be at High level, so the process 604 is performed and the output port terminal 65 is set to High level.
gh level is output. Also, capstan motor 1
When the falling edge of FG pulse b arrives during rotation in the CW direction, processing 603 is performed, and since the input port terminal 62 to which FG pulse a is input is detected to be at a low level, processing 604 is performed. , the port terminal 65 is set and a high level is output.

On the other hand, when the capstan motor 1 rotates in the CCW direction, the FG
When the rising edge of pulse b arrives, process 602
is performed, and it is detected that the input port terminal 62 to which the FG pulse a is input is at a low level, so the process 6
05 is performed, the output port terminal 65 is cleared and becomes Low.
The level will be output. Also, C of capstan motor 1
When the falling edge of FG pulse b arrives during rotation in the CW direction, processing 603 is performed, and it is detected that the input port terminal 62 to which FG pulse a is input is at the High level, so processing 605 is performed. The output port terminal 65 is cleared and a low level is output.

Further, each time the rising edge and falling edge of the FG pulse a input to the external interrupt pulse input terminal 63 of the microcomputer 6 arrive, the microcomputer 6 performs the external interrupt process shown in the flowchart of FIG. First, in process 606, it is determined whether the interrupt edge of the FG pulse a input to the external interrupt pulse input terminal 63 is a rising edge. If it is determined in process 606 that this is the rising edge of FG pulse a, process 6
07 is performed, and if it is determined in process 606 that it is the falling edge of FG pulse a, process 608 is performed.

For example, when the capstan motor 1 rotates in the CW direction, the FG
When the rising edge of pulse a arrives, processing 607 is performed, and since the input port terminal 64 to which FG pulse b is input is detected to be at a low level, processing 61 is performed.
0 is performed, the output terminal 65 is set, and a high level is output. Also, when the capstan motor ↓ rotates in the CW direction, the FG
When the falling edge of pulse a arrives, process 608 is performed, and since the input port terminal 64 to which FG pulse b is input is detected to be at a high level, process 6 is performed.
10 is performed, and the output port terminal 65 is set to High.
h level is output.

On the other hand, when the capstan motor 1 rotates in the CCW direction, the FG
When the rising edge of pulse a arrives, process 607 is performed, and since the input port terminal 64 to which FG pulse b is input is detected to be at a high level, process 6 is performed.
09 is carried out, and the output port terminal 65 is cleared for a while and becomes Low.
The level will be output. Also, C of capstan motor 1
When the falling edge of the G pulse a arrives at the time of darkening in the CW direction, processing 608 is performed, and since the input port terminal 64 to which the FG pulse b is input is detected to be at a low level, processing 609 is performed, Output port terminal 65
is cleared and a low level is output.

That is, a high level is output to the output port terminal 65 of the microcomputer 6 when the capstan motor 1 rotates in the CW direction, and a low level is output when the capstan motor 1 rotates in the CCW direction.

Therefore, according to the capstan motor rotation direction detection device of this embodiment, the rotation of the capstan motor 1 is determined depending on whether the signal output to the output port terminal 65 of the microcomputer 6 is at High level or Low level. Direction can be detected.

The capstan motor rotation direction detection device of this embodiment determines the rotation direction of the capstan motor 1 by the output pulse of one of the two FGs whose output pulse phases differ by 90 degrees from each other. Detection is performed when the FG pulse b rises and falls, and when the FG pulse a, which is the output pulse of the other FG, rises and falls. Therefore, 1 of capstan motor 1
If the number of FG pulses obtained from one FG during rotation is N, then the capstan motor 1 moves 36 times in the same direction.
The rotational direction of the capstan motor 1 is detected once every time it rotates by 0/(4·N) degrees, that is, 90/N degrees. Therefore, according to the capstan motor rotation direction detection device of this embodiment, if the rotation direction of the capstan motor 1 changes at a certain point, the capstan motor 1 will rotate up to 907 N degrees after the rotation direction change. During this time, a change in the rotational direction of the capstan motor 1 is detected.

As described above, according to this embodiment, the rotation direction of the capstan motor 1 is determined by the output pulse of one of the two FGs whose output pulse phases differ by 90 degrees from each other.
By adopting a configuration in which detection is performed at the rise and fall of the G pulse b and at the rise and fall of the FG pulse a, which is the output pulse of the other FG, a change occurs in the rotation direction of the capstan motor 1. The maximum rotation angle of the rotating body from the time when a change in the rotational direction is detected is 90/N degrees, which can be smaller than 360/N degrees 27-.

In addition, 1. In the second embodiment, the rotating body to be detected in the rotational direction is a capstan motor of a VTR; however,
In particular, it is not limited to the capstan motor of a VTR.

Also, 1st. In the second embodiment, FG2°FG3
Although it is assumed that the configuration is such that FG pulses having phases different from each other by 90 degrees are obtained from 'FG2°FG3, any configuration may be used as long as it is possible to obtain FG pulses having mutually different phases from 'FG2°FG3.

Also, 1st. In the second embodiment, a configuration using a microcomputer is used, but a configuration using a flip-flop circuit, a logic circuit, etc. is also possible.

Further, the configuration includes a first frequency pulse signal generation means, a second frequency pulse signal generation means, and at least two rotational direction detection means among the first to fourth rotational direction detection means. Then, the period from when a change occurs in the rotational direction of the rotating body until the change in the rotational direction is detected is:
It is possible to make the maximum rotation angle of the rotating body smaller than 360/N degrees.

DETAILED DESCRIPTION OF THE INVENTION According to the present invention, when detecting the rotational direction of a rotating body in which at least two frequency pulse signal generation means are provided, the phases of the output pulse signals differing from each other, When the number of pulses obtained during one rotation of the rotating body by one of the frequency pulse signal generating means of the signal frequency pulse signal generating means is N, the rotation direction of the rotating body changes after a change occurs. The maximum rotation angle of the rotating body until the rotation angle is detected can be made smaller than 360/N degrees.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a rotational direction detection device for a capstan motor of a VTR, which is a first embodiment of the rotational direction detection device for a rotating body of the present invention, and FIG. 2 is a process for external interrupt processing in the same embodiment. A flowchart showing the procedure, FIG. 3 is a block diagram of a VTR capstan motor rotation direction detection device which is a second embodiment of the rotation direction detection device for a rotating body of the present invention, and FIGS. 4 and 5 are the same. Flowcharts 1 and 6 showing the processing procedure of external interrupt processing in the embodiment
The figure is a time chart showing the output pulse waveforms of two frequency pulse generators whose output pulse phases differ from each other by 90 degrees, and FIG. 7 is a block diagram showing an example of a conventional rotational direction detection device for a rotating body. 1... Capstan motor, 2, 3... Frequency/dimension pulse generator, -'5. E3...One-chip microcomputer.

Claims (1)

[Claims] (1) a first frequency pulse signal generating means for generating a first frequency pulse signal with a frequency corresponding to the rotational speed of the rotating body; and a first frequency pulse signal generating means with a frequency corresponding to the rotational speed of the rotating body; and second frequency pulse signal generating means for generating a second frequency pulse signal having a different phase, and determining the signal level of the second frequency pulse signal at the rise of the first frequency pulse signal. The rotational direction detection means for detecting the rotational direction of the rotating body is a first rotational direction detection means, and the signal level of the second frequency pulse signal is determined at the falling edge of the first frequency pulse signal. The rotational direction detection means for detecting the rotational direction of the rotating body is used as a second rotational direction detection means, and the signal level of the first frequency pulse signal is determined at the rising edge of the second frequency pulse signal. A rotation direction detection means for detecting the rotation direction of the rotating body is used as a third rotation direction detection means, and the rotation direction is determined by determining the signal level of the first frequency pulse signal at the falling edge of the second frequency pulse signal. When the rotational direction detection means for detecting the rotational direction of the body is the fourth rotational direction detection means, at least two of the first, second, third, or fourth rotational direction detection means; A rotational direction detection device for a rotating body, comprising: