SU1474553A1 - Tachometer for magnetic disk storage - Google Patents

Abstract

The invention relates to a measurement technique, namely, devices for measuring the angular velocity of rotation of magnetic disks by a storage device. The purpose of the invention is to reduce the error in the formation of the output signal by reducing the level of high-frequency interference. The position sensor 1 produces two sawtooth signals shifted by 90 ° relative to each other. The slope of the sawtooth voltage is determined by the speed of the carriage 4 with the magnetic head 3. To isolate the angular velocity signal, the sawtooth voltage of sensor 1 is differentiated by capacitor 10 and stored on capacitor 11. Differentiation and memory is carried out alternately in blocks 7 or 8 of the formation. The output signal of each of the blocks 7 (8) through the adder 9 is fed to the output bus 19. Alternately processing two signals shifted by 90 °, the front differentiation sections are excluded from the output signal and thereby the influence of the high frequency interference on the output signal is eliminated. 2 Il.

Description

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The invention relates to a measurement technique, namely, devices for measuring the speed of movement of magnetic heads in magnetic disk drives.

The purpose of the invention is to reduce the error in the formation of the output CHI-nal by reducing high-frequency interference.

FIG. 1 shows a tachometer block diagram; Fig. 2 shows timing diagrams for tachometer operation.

The tachometer contains a position sensor 1, made with a magnetic code disk 2 and a magnetic head 3 mounted on the carriage 4 of a magnetic storage device. The carriage 4 is connected to the drive 5. The device also contains a position signal converter 6, formation blocks 7 and 8, and an adder 9.

Each of the forming units is made up of a differentiating capacitor 10, a storage capacitor 119 with analog switches 12 and 13, and voltage repeaters 14 and 15.

The adder 9 is made on the operational amplifier 16 and the resistors 17 and 18, The output of the amplifier 16 is connected to the output bus 19 of the tachometer.

Tachometer works as follows.

The actuator 5 moves the carriage 4 with the magnetic head 3 of the sensor 1 position. When the magnetic head 3 is moved relative to the code disk 2 with concentrically located service signal tracks in the head 3, electrical signals are induced which are fed to the input of the transducer 6 of the position signals. The transducer 6 of the position signals on the input buses 20 and 21 of the blocks 7 and 8 form two sawtooth signals shifted by 90 ° relative to each other (Figs. 2 a, b). The slope of the sawtooth voltage is determined by the speed of movement of the carriage 4 with the magnetic head 3. On the input buses 22 and 23 of the blocks 7 and 8 by the transducer 6 of the position signals, antiphase pulse signals are formed (Fig. 2c, d)

As the sawtooth voltage increases, the current flowing through the capacitors 10 increases, and higher voltage levels are set at the outputs of the voltage followers 14 to which the storage capacitors are charged through open analog switches 13

11. At the same time, when one of the capacitors 11, for example, block 7 (8) is charged, the other of the capacitors 11 of block 8 (7) stores the result of the differentiation of the previous linearly

increasing part of sawtooth voltage.

Similar processes occur when the steepness of the sawtooth voltage decreases, and 5 capacitors 11 are discharged. Differentiating capacitors 10 are connected by analog switches 12 alternately to the outputs of the voltage followers 15. Resultant signal

0 tachometer is the sum of the voltages of the capacitors 11, alternately connected via the adder 9 to the output bus 19.

Introduction of an additional block

5 7 (8) formation and adder 9 eliminates from the output signal the areas of differentiation of the front of the saw voltage and thereby exclude the effect on the output signal

0 high frequency interference.

Claims (1)

Invention Formula Tachometer for magnetic disk drive containing sensor 5 position, made with a magnetic code disk and a magnetic head mounted on the drive carriage, a position signal converter, the input of which is connected to a magnetic 0 by the head, and the forming unit, made in the form of differentiating and storing capacitors, the first and second voltage followers, and the first and second analogue 5 keys, one of which is connected between the input of the first voltage follower and the output of the second, and the other between the output of the first voltage follower and the input of the second, 0 with this storage capacitor connected to the output of the second analog switch, a differentiating capacitor is connected between the input of the first repeater and the first input bus 5 of the forming unit, the control input of the first and the control input of the second analog switches are connected respectively to the second and third input bus of the forming unit, the output awl of which is connected to the output of the second voltage follower, and the analog and two discrete outputs of the position signal converter are connected respectively to the first one The second and third input buses of the formation unit, characterized in that, in order to reduce the error in generating the output signal by reducing high-frequency interference, it is bzheno an adder and an additional shaping unit, the first input module of which is connected to an additional, analog analog output of the position signal converter, the second and third are connected respectively to the second and third bus of the main forming unit, the output buses of the forming blocks are connected to the inputs of the adder, and the last connected to the output bus tachometer. FIG.