JPS592264A - Random access device of magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To ensure a quick random access action and a racking action to obtain a sufficient amount of reproduced signals, b providing a potentiometer to know the rough position of a head and a detecting circuit for presence of track recording signals. CONSTITUTION:A potentiometer 12 is moved with a shift of a head 10. An output corresponding the shift degree of the head 10 is obtained and compared with the value set previously to a setting device 2 through a counter 4. Thus a driver 5 is driven and stopped. As a result, the head 10 is shifted quickly up to a desired track to reproduce the corresponding signal. In this case, the output of a reproducing circuit 17 is sliced by a slicing circuit 18 after wave detection to obtain a slice output 16 when the head 10 is shifted up to its rough position and in case a magnetic sheet 11 is extended due to a temperature change, etc. The output 16 is fed to the counter 4, and a motor 6a is driven until the output 16 is set at a high level. Then the head 10 is shifted. In such a way, a recording signal can be reproduced with a sufficiently high level.

Description

[Detailed Description of the Invention] The present invention enables recording and recording of signals on a magnetic recording medium potting soil such as a magnetic sheet.
The present invention relates to a random access device in a playback device.

FIG. 1 shows a conventional random access device. In FIG. 1, 1 is a switch. For example, if address 10 is required, switch 1 must be pressed 10 times. The number of times the switch 1 is pressed is detected by the setting device 2. The number of pulses from the oscillator 6 and the output from the setter 2 are compared by a counter 4. The counter 4 transmits the signal supplied from the oscillator 6 to the pulse driver 5 and drives the pulse motor 6 until the comparison result becomes 0. Pulse black is driven and rotates 1".

A head 1υ is attached to the arm 9, which moves via a pulley 7 and 8 belts, and a magnetic sheet 1
10 can be moved to any signal track 1 on 2.

As is clear from this example, if the number of drive pulses of the pulse motor 6 and the trunk position of the hect 10 are matched in advance, random access can be easily performed. However, if the magnetic sheet groans due to temperature, humidity, etc., or if the pulley 7
If there is play in the arm drive mechanism system such as the belt 8, etc., the head will not move 1° to a desired signal track, resulting in inconveniences such as not being able to obtain sufficient owner signals. In addition, a pulse motor must be used as the drive source, and fast random access operations cannot be performed. It is an object of the present invention to provide a random access device for a magnetic recording/reproducing machine capable of performing tracking to obtain a signal.

In the present invention, in order to achieve the above object, a potentiometer is provided to know the approximate position, and a circuit for detecting the presence or absence of a track recording signal is provided so that the signal of any track can be sufficiently reproduced.

An embodiment of the present invention will be described below with reference to the drawings.

Components having the same functions as those in FIG. 1 are designated by the same reference numerals. The second figure shows a block diagram of a device for setting a rough position using a potentiometer. As in the conventional case, the desired address is set in the setting device 2 by the switch 1, and the motor 6a is driven by the driver 5. Conventionally, the motor 6a required a pulse motor, but when using the present invention, a DC motor is required.
It is inexpensive and has good responsiveness, such as speed and speed (a simple motor may be used as the driving means. When the motor 6a is driven).

Arm 9 moves via pulley 7 and belt 8, and magnetic head 10 moves on magnetic sheet 11 in the tracking direction. Along with the movement of the head 10, the newly provided potentiometer 12 is moved, and an output corresponding to the amount of movement of the head 10 is obtained at the potentiometer 12. If the counter 4 compares the value preset in the setting device 2 with the output of the potentiometer 12 and drives and stops the driver 5, will the head 10' be at the track position set in the setting device 2? : You can quickly move to the desired track and play that signal. However, at this time, if the magnetic sheet 11 expands due to temperature changes or the like, the magnetic hect 10 can be moved to the approximate position of the desired track, but it may be located at a location away from the signal track.

The recording signal cannot be held at a sufficient level. Therefore, in the present invention, tracking is performed using a track crossing signal generated when the magnetic head crosses a recording signal track. FIG. 3 is a conceptual diagram showing the state of signal recording on the magnetic sheet 11.

In FIG. 3, when the magnetic head 10 moves on the magnetic sheet 11 in the trafking direction, the signal recording section 13a,
Guard band portions 15b appear alternately. 14 is the result of envelope detection of the magnetic head reproduction signal. The signal is reproduced in the signal recording portion 1+a, but the guard band portion has no signal and therefore has a low level. If this signal is sliced with the Swiss output /L/15, the slice output will be 1
6 is obtained. The slice output 16 is at a high level at a portion corresponding to the recording portion on the magnetic sheet, and at a low level at a guard band portion. As mentioned in the explanation of FIG. 2, when the recorded signal is not sufficiently reproduced due to sheet elongation or the like during random access operation, if the head is moved using the spacer output 16 shown in FIG. Recorded signals can be reproduced at a sufficient level. The operation will be explained using FIG. 4. In FIG. 4, the body meter 12
The motion of moving the head 1oyf to the approximate position using . When the head 10 has moved to the approximate position, the output of the reproducing circuit 17' is detected and sliced by the slicing circuit 18 to obtain the slice output 16 shown in FIG. Input this output to counter 4 and slice output 1
The motor 6a is driven until the signal 6 reaches a high level. The setting device n is set to the trunk position with the magnetic sheet 11 retracted in advance to set the setting position of both the two meter 12.

The feeding direction of the magnetic hexagonal 10 may be one direction.

Further, if the method χ of the present invention is utilized, an address signal is inserted into the signal recorded on the magnetic sheet 11, and control is performed using this signal, a more accurate random access operation can be performed.

As described above, according to the present invention, the random access operation of a magnetic recording/reproducing machine can be performed easily and quickly, and the inconveniences such as slow tracking and insufficient signals due to temperature rise, etc. can be eliminated. You can get the equipment.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of a conventional random access device, FIG. 2 is a block diagram configuring the random access device according to the present invention, and FIG. 3 is a conceptual diagram showing a signal recording state on a magnetic sheet. FIG. 4 is a schematic diagram of a random access device according to the present invention. 1...Switch 6...Pulse motor 6a...Motor 10...Magnetic head 11...Magnetic sheet 12...Potency stomach meter 1oa...Signal recording section 13b...Gart band 16 ...Slice output 17...Cornerization circuit 18...Detection/slicing circuit 1 Figure 3 Figure 71- Figure

Claims (1)

[Claims] In a magnetic recording/reproducing device that includes a magnetic head and a device for moving the magnetic head to a desired location, and records and reproduces signals on a disc-shaped magnetic recording medium, the magnetic head moving mechanism detects the amount of movement of the magnetic head. A random access device for a magnetic recording and reproducing machine, characterized in that it is equipped with a potentiometer and a device that performs envelope detection of a magnetic torv reproduction signal and detects the presence or absence of a signal recorded on a magnetic recording medium. .