JPH0312008A - Magnetically recorded information reproducing device - Google Patents

Abstract

PURPOSE:To automatically adjust the gain of a head amplifier and to easily obtain specified output by intermittently moving an inserted magnetic recording medium in accordance with a program set in a CPU and converting the output into digital information. CONSTITUTION:In the case of performing the readjustment by a magnetic recorded information reproducing device, a mode changeover switch 18 is switched to an adjustment mode and the specified program is executed by the CPU 13. When a magnetic card 1 is inserted into a magnetic head 2, the data is read out and the output from an amplifier 3 is converted into the digital information by an A/D converter 12. The converted value is compared with the set reference values of gain adjusting means 10 and 11 by the CPU 13. In the case that it is not equal to the set reference value, the magnetic card 1 is moved again and the output information at the time of such movement is converted into the digital information to be compared with the set reference value. When the compared results are coincident, the card 1 is discharged and the output level of the amplifier 3 is automatically set to be a standard value without necessitating manual aid such as the use of a measuring apparatus and the like.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a magnetic recording information reproducing device for reading information recorded on a magnetic recording medium such as a magnetic card or magnetic tape.
In particular, the present invention relates to a magnetically recorded information reproducing device suitable for reading information from a magnetic card.

[Conventional technology]

FIG. 2 is a block diagram of a conventional magnetic recording information reproducing apparatus.

In Fig. 2, 1 is a magnetic recording medium such as a magnetic card; 2 is a magnetic recording medium such as a magnetic card;
is a magnetic head, 3 is an amplifier, 4 is an output terminal, 5 is a ground terminal, R1, R2, R3, R4 are fixed resistors, VR2, VR
4 is a variable resistor.

By bringing the magnetic card 1 into contact with the magnetic head 2 and moving it in either direction, an output corresponding to the bit recorded on the magnetic card 1 is output from the output terminal of the magnetic head 2. Normally, the output from the magnetic head 2 is very small, so it is amplified by a head amplifier. The head amp is amplifier 3,
Resistance R], R2゜R3, R4, variable resistance VR2, VR4
The output is taken out from the output terminal 4 and the ground terminal 5.

The gain of this amplifier 3 is expressed by the following formula, assuming that the amplifier 3 is an ideal amplifier. However, R1=R3R2=R4.

My eyes are wide open.

[Problem to be solved by the invention] And 7 However, like this, variable resistor VR2゜VR
4. In order to operate the magnetic recording information reproducing device normally, the reproducing device reads information recorded on a standard magnetic recording medium such as a card. The output level of the head amplifier must be adjusted to the standard value, but in conventional methods, this variable resistor uses a type that is adjusted by a human using a driver, etc. Let me read 1. - There was a drawback that the output level of the rad amplifier had to be adjusted to the standard value. Also, when the set value changes due to aging etc., R1
(R1+R2+VR4) (11, By adjusting the values of VR2 and VR4 to be the same as shown in equation (2), the gain on the inverting side and the gain on the non-inverting side can be matched, and the gain In addition, VR2 and VR4 serve to absorb variations in the parts that make up the head amplifier (there were problems such as having to bring in measuring instruments).The present invention is based on standard information. An object of the present invention is to provide a magnetically recorded information reproducing device that automatically adjusts the gain of a head amplifier and obtains a predetermined output by inserting a magnetic recording medium such as a magnetic card having recorded thereon.

(Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention provides gain adjustment means for adjusting the gain of the amplifier using digital information;
An A/D converter that converts analog information output from the amplifier into digital information, R and A M that write the output information of the A/D converter, and a magnetic recording medium on which standard information is recorded to the magnetic head. a non-volatile memory that stores digital information corresponding to a predetermined output value of the standard information obtained through the amplifier and a digital comparison means that compares the digital information output from the non-volatile memory and the RAM; , a correction means for sending digital information of the difference obtained from the comparison means to the gain adjustment means and correcting the gain, and a CPU for controlling the operation of each of the means;
It is composed of a ROM that stores the control procedure.

[For production]

The magnetic recording information reproducing device of the present invention is configured as described above,
Record standard informationj5. When a magnetic recording medium such as a magnetic recording medium is inserted into the magnetic head, the magnetic card is intermittently moved and operated according to the program set in the microcomputer, and the output information at the time of movement is converted into digital information. , 5 Compare the digital information with digital information corresponding to a predetermined output level of the tth set amplifier; 1. The digital information of the difference is repeatedly sent to the gain adjustment means to finely adjust the gain of the amplifier. This allows the output level to be automatically set to a standard value.

〔Example〕

FIG. 1 is a block diagram of an embodiment of the present invention. In this embodiment, a case will be explained in which a magnetic card is used as the magnetic recording medium.

In FIG. 1, 1 is a magnetic card, 2 is a magnetic head, and 3 is a magnetic card.
is an amplifier, 4 is an output terminal, 5 is a ground terminal, R1, R2,
R3 and R4 are fixed resistors, and except for RV2 and RV4, the structure is the same as that of the conventional magnetic recording information reproducing apparatus shown in FIG. 10
．． 11 is a gain adjustment means, 12 is an A/D converter, 1
3 is a CPU, 14 is a ROM, 15 is a RAM, 16 is a nonvolatile memory, 17 is a coincidence display circuit, and 18 is a mode changeover switch.

In this embodiment, RV2. of FIG. RV4 is replaced with gain adjustment means 10.11, respectively.

The gain adjustment means 10.11 are controlled by the CPU 13. An A/D converter 12 that converts an analog signal into a digital signal is connected to the output of the amplifier 3, and the output digital signal can be read out by the CPU 13. Reference numeral 16 denotes a non-volatile memory (for example, electrically rewritable EEPROM, etc.), in which the set reference value and corrected value of the gain adjustment means 10.11 are stored.

Reference numeral 15 denotes a RAM, in which values etc. during automatic setting of the gain adjustment means 1011 are stored. 17 is gain adjustment means 10
．． This is a coincidence indicator that notifies the end of the automatic adjustment when the set standard value of 11 and the correction value are 14&. This can be replaced with a buzzer or the like. 18 is a mode changeover switch for switching between adjustment mode and actual operation. 1
4 is a ROM that stores a program that controls the CPU 1.3 and performs automatic adjustment operations.

FIG. 4 is an operational flowchart of the embodiment of FIG. 1.

The operation of this embodiment will be described in detail below with reference to FIG. First, the mode changeover switch 18 is switched to the adjustment mode. As a result, the CPU 13 executes the automatic adjustment mode program. First, the setting reference value of the gain adjustment means 10.11 stored in the nonvolatile memory 16 in advance is read out, and this value is stored in the RAM 1.5 as a temporary value of the gain adjustment means 10.11. 10
11 and waits for the magnetic card to be read.

When a card is taken in, it is regarded as a standard card, data is read out, -8 is stopped, and the value is set at 7.

At this time, the output voltage from the amplifier 3 is transferred to the A/D converter 12.
cPUI3 converts this value into digital information and sends it to the RA.
Load into M1.5. This read value is compared with the set reference value of the gain adjustment means 10.11 of the nonvolatile memory 16, and if the read value is larger than the set reference value, the RAM
The value of the temporary gain adjustment means 10.11 stored in 15 is minus 1, and in the opposite case, it is plus 1. Set this value again in the gain adjustment means 10.11, move the stopped card again, read the data again, and
Stop the card and repeat the same operation as above. By repeating this series of operations, when the value read from the A/D converter 12 matches the set reference value of the gain adjustment means 10.11 of the non-volatile memory 16, the card is ejected and the number display is displayed. 17 indicates that the setting operation has been completed. At this end display, a person can switch the mode to 1.
8 to switch to the actual operation mode as a magnetic card reproducing device.

In the above operation, it has been explained that the gain adjustment means 10.11 is adjusted by simply increasing the setting value by ±1, but the setting reference value of the gain adjustment means 10.11 stored in the nonvolatile memory 16 and the When the difference in the values from the D converter 12 is large, if the difference is ±1, the number of times the card will be operated and the output voltage will be read increases. It is clear that the method of increasing the number of units in steps can be easily achieved by simply changing the control program of the CPU 3.

FIG. 3 is a block diagram of an embodiment of the gain adjustment means 10.11 of FIG. 1. In FIG. 3, (1) the first embodiment uses a photoconductive cell 21 in the variable resistance section, inputs digital information from the CPU 13 to input terminals d and d2, and inputs digital information to input terminals d and d2.
This is an example in which the analog information is converted into analog information via the converter 23, the current flowing through the light emitting diode LED 22 is changed, the amount of light of the LED 22 is changed, and the resistance of the photoconductive cell 21 is changed. (2) The second embodiment uses a magnetoresistive element 24 in the variable resistance part, inputs digital information from the CPU 13 to a programmable DC power supply 26 via input terminals d, d2, and generates a DC current flowing through a coil 25. This is an example in which the resistance of the magnetoresistive element 24 is changed by changing the magnetic field applied to the magnetoresistive element 24. (3) The third embodiment is a resistor array 27 in which a large number of resistors with small resistance values are arranged.
This is an example in which the total resistance value is changed by switching the individual resistances of the resistors using the analog switch 28. The analog switch 28 is controlled by an analog switch control section 29, and the control section 29 controls the analog switch 28 so that the resistance value corresponds to the digital input.

In the embodiment shown in FIG. 1, a magnetic card is used as an example of the magnetic recording medium, but it goes without saying that the present invention can also be applied to magnetic recording media such as magnetic tapes and flexible disks.

〔Effect of the invention〕

According to the present invention, since the gain of the head amplifier can be automatically adjusted, it has the advantage that it can be adjusted at the location where the device is installed by simply bringing a standard card, making maintenance easy and short. The effect is that it can be done with Also,
Since there are no parts to be adjusted by humans using a screwdriver, etc., the magnetic head, head amplifier, control circuit, etc. can all be sealed with resin, making it suitable for high-security magnetic card playback devices where you do not want the circuits to be inspected. . moreover,
The setting values of the variable resistors of each gain adjustment means are written in non-volatile memory, so if the case is opened by unauthorized means, the setting values will be erased, and normal operation will not be possible unless a standard card is obtained. It can also be expected to have the effect that it is easy to make it impossible to do so.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of the present invention, FIG. 2 is a block diagram of a conventional magnetic recording information reproducing apparatus, and FIG. 3 is a block diagram of an embodiment of the gain adjustment means 10.11 in FIG. FIG. 4 is an operation flowchart of the embodiment of FIG. 1. DESCRIPTION OF SYMBOLS 1... Magnetic card, 2... Magnetic head, 3... Amplifier, 4... Output terminal, 5... Ground terminal, 10.1
1... Gain adjustment means, 12... A/D converter, 13
...CPU, 14...ROM, 15...RAM,
16...Nonvolatile memory, 17...-Number display, 1
8... Mode changeover switch, 21... Photoconductive cell, 22... LED, 23... D/A converter, 24...
... Magnetoresistive element, 25... Coil, 26... Programmable DC power supply, 27... Resistance array, 28...
- Analog switch, 29...analog switch control section. FIG. 1 is a configuration diagram of an embodiment of the present invention. FIG. 2 is a configuration diagram of a conventional magnetic recording information reproducing device. (1) First embodiment (2) Second embodiment (3) Third embodiment Gain adjustment means 10゜■ Fig. 1 Block diagram of the embodiment of Fig. 1 Operation flowchart of the embodiment of Fig. 4 Fig. 4

Claims (1)

[Claims] 1. Consists of a magnetic head that reads information recorded on a magnetic recording medium, an amplifier that amplifies the output of the magnetic head, and gain adjustment means that sets the output of the amplifier to a predetermined value. A magnetic recording information reproducing apparatus comprising: a gain adjusting means for adjusting the gain of the amplifier using digital information; an A/D converter for converting analog information output from the amplifier into digital information; and the A/D converter. a nonvolatile memory that stores digital information corresponding to a predetermined output value of the standard information obtained from the magnetic recording medium on which the standard information is recorded via the magnetic head and the amplifier; digital comparison means for comparing digital information output from a non-volatile memory and the RAM; correction means for sending difference digital information obtained from the comparison means to the gain adjustment means and correcting the gain; C that controls the operation of each means
A magnetically recorded information reproducing device comprising a PU and a ROM that stores the control procedure.