KR19980037898A - Time Lapse V-Cal's Capstan Motor Brake System - Google Patents

Abstract

Disclosed is a capstan motor brake device of a time lapse VCR, which is a device for stopping a capstan motor, the first and second frequencies being proportional to the rotational speed of the capstan motor and having a phase difference from each other. First and second frequency signal generators for generating signals, respectively; A reverse rotation detection unit that detects a time point at which the capstan motor reverses based on the phase difference between the frequency signals generated from the frequency signal generators; And a controller configured to generate control signals for stopping the capstan motor when the detection result indicating the reverse rotation time is received from the reverse rotation detection unit. The capstan motor brake device of Time Lapse V-CAL has the effect of stopping the capstan motor driven intermittently (step) precisely at the time of stopping.

Description

Time Lapse V-Cal's Capstan Motor Brake System

SUMMARY OF THE INVENTION An object of the present invention is to provide a capstan motor brake device capable of accurately stopping a capstan motor at a time point at which a capstan motor should be stopped after every recording in a time lapse VCR that performs recording stepwise. have.

The present invention relates to a time-lapse V seed, and more particularly, to a capstan motor brake device for stopping the capstan motor.

In general, Time Lapse V-Cal captures scenes intermittently and records them on a video tape in a place where a surveillance state must be maintained at all times, such as a bank, so that the situation for a long time can be known.

1 is a view showing the operation of the capstan motor in the time-lapse V seed. Time Lapse V-Cal records the video taken at a certain time on one track of the video tape. At this time, the capstan motor is driven to transfer the video tape by exactly one track. When the capstan motor starts to rotate and reaches a certain speed during each recording, recording is performed on the video tape. After the recording, the rotation speed of the motor gradually decreases and stops.

In general time-lapse V CA, the capstan motor decreases the speed to reach the stop point, but does not stop exactly at the stop point. At this time, the motor rotates backward and pushes the video tape backward after the stop point. Therefore, there has been a demand for a device that can stop the motor accurately at the point of stopping the capstan motor.

1 is a timing diagram for explaining the operation of the capstan motor in a general time-lapse V seed,

2 is a configuration diagram showing a capstan motor brake device of a time-lapse V-Cal according to the present invention;

3 is a timing diagram for explaining the operation of FIG.

※ Explanation of code for main part of drawing

11: reverse rotation detection unit 12: microprocessor

The capstan motor brake apparatus according to the present invention, in the apparatus for stopping the capstan motor, the first and second frequencies, which are proportional to the rotational speed of the capstan motor and generate first and second frequency signals having a phase difference from each other, respectively. Signal generator; A reverse rotation detection unit that detects a time point at which the capstan motor reverses based on the phase difference between the frequency signals generated from the frequency signal generators; And a controller configured to generate control signals for stopping the capstan motor when the detection result indicating the reverse rotation time is received from the reverse rotation detection unit.

In addition, the capstan motor brake device according to the invention is characterized in that it is included in the time-lapse V seed.

Hereinafter, the present invention will be described in detail with reference to FIGS. 2 and 3.

Figure 2 shows a capstan motor brake device of a time-lapse V-Cal in accordance with the present invention. The capstan motor brake apparatus of the present invention proposes a method of using two frequency generators (FG) to detect the stop point of the capstan motor.

The apparatus of FIG. 1 receives the frequency signals FG1 and FG2 generated from two frequency signal generators (not shown), and includes a reverse rotation detection unit 11 and a reverse rotation detection unit for detecting a stop point of the capstan motor. And a microprocessor 12 for generating control signals for stopping the capstan motor according to the detection result of 11).

As described above, the operation of the configured invention will be described in more detail.

3 illustrates the input / output timing diagram of FIG. 2 for explaining the operation of the present invention.

In FIG. 2, the frequency signals FG1 and FG2 are generated as values proportional to the rotation of the motor from two frequency signal generators of a capstan motor, not shown, and as shown in FIG. 3A, depending on the position where the frequency signal generator is attached. Has a phase difference. These frequency signals FG1 and FG2 are input to the reverse rotation detection unit 11.

The reverse rotation detection unit 11 detects a time point at which the motor starts reverse rotation based on the phase difference between the input frequency signals FG1 and FG2. In more detail, the reverse rotation detection unit 11 including the D-flip flop inputs the frequency signals FG1 and FG2 to the clock terminal and the data input terminal, respectively. Receive. The reverse rotation detection unit 11 determines the level of the second frequency signal FG2 input to the data input terminal at the rising edge of the first frequency signal FG1 input to the clock terminal. When the motor rotates forward, the second frequency signal FG2 becomes a low level at the rising edge of the first frequency signal FG1. In the meantime, when the motor rotates in reverse, as shown in FIG. 3A, the phase of the second frequency signal FG2 is earlier than the phase of the first frequency signal FG1. In this way, the reverse rotation detection unit 11 detects a time when the phase of the second frequency signal is increased so that the second frequency signal becomes a high level at the rising edge of the first frequency signal. The reverse rotation detection unit 11 outputs a signal indicating the detection result to the microprocessor 12. Here, if the capstan motor is stopped immediately after the reverse rotation time is detected, a certain amount of reverse rotation will occur, so it must be compensated with the forward rotation again. To this end, the microprocessor 12 generates the control signals of FIG. 3B.

That is, the microprocessor 12 has a signal CAP F / R for changing the rotation direction of the capstan motor which is rotated in reverse to forward rotation, and a signal I for limiting the current supplied to the capstan motor after a predetermined time Δt1 therefrom. -LIMITER and also a signal (CM STEP SLOW) for stopping the capstan motor after a predetermined time [Delta] t2. The microprocessor 12 supplies these control signals to the capstan motor, which causes the capstan motor to stop exactly at its stop.

The frequency signal input to the clock terminal and the data input terminal in the above-mentioned reverse rotation detection unit is an arbitrary signal of two frequency signals, and therefore it is obvious that the input terminal can be changed.

As described above, the capstan motor brake device of the time-lapse VSR according to the present invention has the effect of stopping the capstan motor driven intermittently accurately at the stop point.

Claims (4)

An apparatus for stopping a capstan motor, First and second frequency signal generators that are proportional to the rotational speed of the capstan motor and generate first and second frequency signals having a phase difference from each other; A reverse rotation detection unit that detects a time point at which the capstan motor reverses based on a phase difference between frequency signals generated from the frequency signal generators; And Capstan motor brake device including a control unit for generating control signals for stopping the capstan motor when receiving the detection result indicating the reverse rotation time from the reverse rotation detection unit. 2. The capstan motor brake apparatus according to claim 1, wherein the reverse rotation detection unit comprises a D-flip flop. The method of claim 2, wherein the reverse detection unit receives the first frequency signal through a clock terminal and the second frequency signal through a data input terminal, and at the rising edge of the first frequency signal, the level of the second frequency signal. Capstan motor brake device characterized in that for detecting the reverse rotation time point of the capstan motor by determining. The capstan motor brake apparatus according to any one of claims 1 to 3, which is included in a time-lapse V seed.