JP3612980B2 - Magnetic recording / reproducing device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a magnetic recording / reproducing apparatus.
[0002]
[Prior art]
A conventional magnetic recording / reproducing apparatus will be described below with reference to the drawings.
[0003]
FIG. 3 is a block diagram showing the configuration of a conventional magnetic recording / reproducing apparatus.
In FIG. 3, the magnetic tape 1 is transported by a capstan motor 19 and a pinch roller 20 and travels in contact with the movable post 7, posts 9 to 10, and the drum 8 attached to one end of the tension lever 2.
[0004]
The tension lever 2 is rotatably held on the base and is pulled in the direction of arrow A by the coil spring 3 to apply tension to the magnetic tape 1. A magnet 4 is attached to a predetermined position of the tension lever 2, and a magnetic sensor 5 is provided below the magnet 4. Depending on the relative position of the magnet 4 and the magnetic sensor 5, a voltage corresponding to the tape tension is taken out from the magnetic sensor 5.
[0005]
The output of the magnetic sensor 5 is amplified by the amplifier 18 and input to the A / D converter 17. The analog signal is converted into a digital signal by the A / D converter 17 and is taken into the CPU 14. The CPU 14 is connected to the RAM 15 and the ROM 16 and receives a mode command a. The mode command a is a command indicating the operating state of the VTR, such as PLAY or STILL.
[0006]
FIG. 4 is a flowchart showing the processing procedure of the CPU 14 which is a component of the conventional magnetic recording / reproducing apparatus. The process of this flowchart is set to process once every 1 msec.
[0007]
The CPU 14 first captures the output signal of the A / D converter 17 as A / D data and stores it in a variable on the RAM 15 called work1 (S201). Next, it is determined whether or not the mode is STILL (still image reproduction) mode (S202). In the STILL mode, the fixed value REF3 is stored in the tension reference value which is a variable on the RAM 15 (S204). When it is not STILL mode, it is determined whether or not it is FWD mode (S203), and when it is FWD (forward playback) mode, fixed value REF1 is stored in the tension reference value (S205), and REV (reverse playback) mode is set. At this time, the fixed value REF2 is stored in the tension reference value (S206).
[0008]
By switching the tension reference value according to the STILL mode, the FWD mode, or the REV mode, the tape tension corresponding to each mode can be obtained.
[0009]
Next, PID processing is performed on the difference between work1 and the tension reference value, and the result is stored in a variable tension_err on the RAM 15 (S207). The PID process is a process of passing a filter having a frequency characteristic set in advance by proportionality, integration, and differentiation. The entire control system is operated so that the difference between the work 1 and the tension reference value becomes zero.
[0010]
When the tension_err is stored in the D / A data (S208), the tension error signal b (digital signal) is output from the CPU 14 and applied to the D / A converter 13. The analog signal is converted by the D / A converter 13, the reel motor 11 is driven via the drive circuit 12, and a rotational force is applied to the reel 6 to apply tension to the magnetic tape 1.
[0011]
Three points where the tensions of the coil spring 3 and the magnetic tape 1 are balanced within the dynamic range of the magnetic sensor 5 are set and set as the tape tensions of the STILL mode, the FWD mode, and the REV mode, respectively.
[0012]
[Problems to be solved by the invention]
In such a conventional magnetic recording / reproducing apparatus, since the tension that can be set is limited by the dynamic range of the magnetic sensor, the optimum tension cannot be set in all of the STILL mode, the FWD mode, and the REV mode. there were. For example, if the dynamic range of tension that can be set is 10 to 20 g and the optimum tension in the STILL mode, FWD mode, and REV mode is 6 g, 12 g, and 20 g, respectively, the FWD mode and REV mode can be set, but the STILL mode is 10 g. Can only be set to As a result, since the tension setting in the FWD mode and the REV mode is given priority, the tension in the STILL mode cannot be sufficiently lowered, and there is a problem that the magnetic tape and the drum are damaged if left in the STILL mode for a long time. It was. In addition, there is a method of calculating and setting the STILL mode tension from the winding diameter, but the tension is not set correctly until the winding diameter is calculated, and there is a similar problem.
[0013]
[Means for Solving the Problems]
Magnetic recording and reproducing apparatus of the present invention in order to solve this problem, a tension lever to rotating according to the tension of the magnetic tape, the tension value detected to output a signal of tension values in accordance with the rotation angle of the tension lever Means, an amplifying means for inputting the output signal of the tension value detecting means and amplifying with a preset frequency characteristic, and at least when the mode command is in the still mode, the output signal of the amplifying means is set to n at a predetermined time interval. a total value calculation means for calculating a total value by turning sampling, and multiplying means for multiplying a predetermined coefficient to an output signal of the total value calculation means and an output signal of the output signal of the multiplying means of said amplifying means type, and switching means for selecting and outputting one according to the mode command, the output signal of said switching means, driving means for driving the reel motor Wherein the switching means may, when the mode command is the still mode is obtained by a configuration in which switching to supply to the drive means the output of said multiplying means.
[0014]
As a result, the tension in the STILL mode can be set low and accurately regardless of the dynamic range of the magnetic sensor, so that the magnetic tape or drum is not damaged even if left in the STILL mode for a long time. can do.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
A magnetic recording / reproducing apparatus according to an embodiment of the present invention will be described below with reference to the drawings.
[0016]
FIG. 1 shows a block diagram of a magnetic recording / reproducing apparatus according to an embodiment of the present invention. The block diagram is the same as the conventional magnetic recording / reproducing apparatus, but the processing procedure of the CPU 14 is different from the conventional one.
[0017]
FIG. 2 is a flowchart showing a processing procedure of the CPU 14 which is a component of the magnetic recording / reproducing apparatus according to the embodiment of the present invention. The process of this flowchart is set to process once every 1 ms.
[0018]
The CPU 14 first captures the output signal of the A / D converter 17 as A / D data and stores it in a variable on the RAM 15 called work1 (S101). Next, it is determined whether the mode is a FWD or STILL mode (S102). In the FWD or STILL mode, the fixed value REF1 is stored in the tension reference value (S103). In the REV mode, the fixed value REF2 is stored. Store (S104).
[0019]
Thus, by switching the tension reference value, the tape tension corresponding to each mode is obtained.
[0020]
Next, PID processing is performed on the difference between work1 and the tension reference value, and the result is stored in a variable tension_err on the RAM 15 (S105). The PID process is a process that passes through a filter having a frequency characteristic set in advance by proportionality, integration, and differentiation, and is operated so that the difference between the work 1 and the tension reference value becomes zero in the entire control system.
[0021]
Next, it is determined whether or not the STILL mode is selected (S106), and in the STILL mode, the variable cntr1 on the RAM 15 is incremented (S107). When cntr1 is 1000 or less (S110, S112), the tension_err is stored in the D / A data (S114). Since cntr1 is incremented once every 1 msec, less than 1000 means within 1 second.
[0022]
When cntr1 is greater than 1000 and less than or equal to 1100, tension_err is added to the variable work2 on the RAM 15 (S111), and the addition is continued until the sum of 100 times is reached. When cntr1 becomes larger than 1100 (S112), it is limited by 1101 (S113), and (work 2 * 6/10) / 100 is stored in D / A data (S115). This is because work2 contains the sum of 100 times of tension_err, and is divided by 100 to obtain an average value. The reason why the coefficient is multiplied by 6/10 is to make the tension 60% of the set tension of the FWD.
[0023]
When not in STILL mode, cntr1 and work2 are cleared (S108, S109).
[0024]
When stored in the D / A data (S114, S115), a tension error signal b (digital signal) is output from the CPU 14 and applied to the D / A converter 13. The analog signal is converted by the D / A converter 13, the reel motor 11 is driven via the drive circuit 12, and the magnetic tape 1 is tensioned by applying a rotational force to the reel 6.
[0025]
Two points where the tensions of the coil spring 3 and the magnetic tape 1 are balanced within the dynamic range of the magnetic sensor 5 are set, and are set as tape tensions in the FWD mode and the REV mode, respectively. In STILL mode, the tension of FWD mode is set until 1 second has passed after entering STILL mode, and then the average value of 100 tensions is calculated for 100 ms, and the tension is set to 60% of that value. Yes.
[0026]
【The invention's effect】
As described above, according to the present invention, the STILL mode tension can be set freely without being limited by the dynamic range of the magnetic sensor. Further, since the tension of the STILL mode is set based on the output signal of the magnetic sensor, it is possible to provide a stable tension regardless of the winding diameter of the tape. As a result, the STILL tension can be set low and accurately, and the magnetic tape and the drum can be prevented from being damaged even when left in the STILL mode for a long time.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of a magnetic recording / reproducing apparatus according to an embodiment of the present invention. FIG. 2 is a flowchart showing a processing procedure of a CPU that is a component of the magnetic recording / reproducing apparatus according to an embodiment of the present invention. FIG. 3 is a block diagram showing a configuration of a conventional magnetic recording / reproducing apparatus. FIG. 4 is a flowchart showing a processing procedure of a CPU that is a component of the conventional magnetic recording / reproducing apparatus.
DESCRIPTION OF SYMBOLS 1 Magnetic tape 2 Tension lever 3 Coil spring 4 Magnet 5 Magnetic sensor 6 Reel 7 Movable post 8 Drum 9-10 Post 11 Reel motor 12 Drive circuit 13 D / A converter 14 CPU
15 RAM
16 ROM
17 A / D converter 18 Amplifier 19 Capstan motor 20 Pinch roller

Claims (2)

And the tension lever for rotation in response to the tension of the magnetic tape,
A tension value detecting means for outputting a signal of tension values in accordance with the rotation angle of the tension lever,
Amplifying means for inputting an output signal of the tension value detecting means and amplifying the signal with a preset frequency characteristic;
A total value calculation means, at least a mode command to calculate the sampled n times to sum the output signal at a predetermined time interval of said amplifying means when the still mode,
Multiplying means for multiplying the output signal of the total value calculating means by a predetermined coefficient;
And switching means for the output signal of the amplifying means and inputs an output signal of said multiplication means, and outputs the selected one in accordance with the mode command,
Driving means for inputting an output signal of the switching means and driving a reel motor ;
Said switching means, toggle its magnetic recording and reproducing apparatus so as to supply to the drive means the output of said multiplying means when said mode instruction is still mode. The total value calculation means, the magnetic recording and reproducing apparatus according to claim 1 wherein to calculate the total value waits by a predetermined time enter the still mode.

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