JPH0731411Y2 - Index position adjustment circuit in floppy disk drive - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of use] The present invention relates to index position adjustment of a floppy disk drive device, and in particular, the index detector and the start point of the track of the disk are arranged so as to be shifted in time, and The present invention relates to an index position adjusting circuit in which a time is adjusted by a timer and an appropriate index signal is sent out, and the time constant of the timer is constant even though there are two or more kinds of disk rotation speeds.

[Prior art and its problems]

Conventionally, in the case of this kind of index position adjustment circuit, the time constant of the timer differs depending on the rotation speed of the disk
A variable resistor of the time constant setting circuit is provided for each rotation speed to adjust it.

Therefore, the number of parts is large, and there are problems such as an increase in price, occupied space, and man-hours (mounting / adjustment).

[Problems to be solved by the device]

In order to solve the above-mentioned problems, the present invention provides an index position adjusting circuit which has a single timer time constant and does not cause the positional relationship between the track start point and the index detector to deviate depending on the type of disk rotation speed. This is an issue.

[Means for Solving the Problems]

In order to solve the above problems, the present invention adds a monostable multivibrator and a gate circuit to a timer of a method of integrating a reference clock pulse with a counter, and triggers the monostable multivibrator by the reference clock pulse. integrates the signal obtained by masking the reference clock pulse by vibrator set time T _o the counter is obtained by the accumulated numerical can be variably.

In this case, the time constant setting circuit of the monostable multivibrator is made variable, the timer time is made variable, and the integrated value is switched for each disk rotation speed, and the time constant of the monostable multivibrator is adjusted by one kind of rotation speed. With such a structure, it is possible to obtain an index signal suitable for the rotation speed even at other rotation speeds.

〔Example〕

FIG. 1 shows an embodiment of the present invention, 11 is a reference clock pulse oscillator, 12 is an AND gate, 13 is a monostable multivibrator, 14 is an OR gate, 15 is an n-ary counter, 16
Is an output selection circuit, 17 is a monostable multivibrator, 18 is a variable time constant setting circuit of the monostable multivibrator 13, 19
Is a D-type flip-flop (clock is effective for falling) for turning on and off the clock signal of the reference clock pulse oscillator 11.

The operation of each unit in FIG. 1 will be described below together with the time chart in FIG. The lowercase alphabetic characters enclosed in parentheses in the text correspond to those described in the time chart.

Now, when the disc rotation speed is N [rpm], the disc rotation speed signal is output to the output selection circuit 16 so that the integrated numerical value n is selected.
Input "H" as 23 (g).

The output signal 20 (a) of the index detector is an n-ary counter
When input as the clear signal of 15 and the clock signal of the D-type flip-flop 19, the D-type flip-flop 19 is generated at the falling edge of the output signal 20 (a) of the index detector.
Since the output (b) of "1" becomes "H" and is input to the AND gate 12, a signal synchronized with the reference clock signal 11 (c) is output from the output of the AND gate 12 which has been "L" until then. It Also, the n-ary counter 15 starts counting.

Ungated monostable multivibrator 13 as a trigger rise of output signals from 12 performs one-shot operation of the setting time T _o a (d). Even if the one-shot operation is completed, the one-shot operation is repeated by the trigger signal from the AND gate 12. The output of the AND gate 12 and the output of the monostable multivibrator 13 are input to the OR gate 14 to obtain the output (e). The output (e) of the OR gate 14 is input to the counter 15, and the value (f) of the counter 15 becomes _n after the time _{n n} times the set time T _o set in the monostable multivibrator 13, so that the timer output Signal n21 is “H”
And the disk rotation signal of the input signal of the output selection circuit 16
Since 23 (g) is "H", the timer output signal n21 side is selected and the output selection circuit 16 outputs "H". By using it as a trigger signal for the monostable multivibrator 17, an index signal 24 (h) with a predetermined pulse width is obtained.
Is sent. As a result, the index signal 24 (h) is transmitted after the time T _n from the input of the output signal 20 (a) of the index detector. This output selection circuit
The output signal from 16 is also input as the clear signal of the D-type flip-flop 19, and the output (b) of the D-type flip-flop 19 becomes "L" and is input to the ungate 12, so the reference clock signal 11 (C) is no longer output from the AND gate 12. Then, the monostable multivibrator 13
Does not repeat the one-shot operation.

Next, at the disk rotation speed M [rpm], the integrated value m (m <m
The case of selecting n) will be described.

Since the basic operation is the same as the case of the integrated value n,
Here, only the differences will be described.

Disk rotation signal 23 (g) for input signal of output selection circuit 16
Enter as “L”. Since the value (f) of the counter 15 becomes _m after the time T _{m which} is m−1 times the set time T _o set in the monostable multivibrator 13 after the counter 15 starts the integration, the timer output signal m22 becomes “ Since the disc rotation signal 23 of the input signal of the output selection circuit 16 is "L", the timer output signal m22 side is selected and the output selection circuit 16
Is output from. As a result, the index signal 24 (h) is transmitted after time T _m from the input of the output signal 20 (a) of the index detector.

In the embodiment, the timer time can be changed by changing the value of the variable resistor R.

[Effect of device]

According to the present invention, m times the set time T _o set in one of the monostable multivibrator 13, n times of the timer output signal 24
Therefore, the capacitance of the capacitor C of the external time constant setting circuit 18 can be reduced and the number of parts can be reduced, and the cost can be reduced.
The effect of shortening the adjustment time is obtained, and the effect is further enhanced by using a dedicated logic circuit.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention, and FIG. 2 is a time chart of signals of respective parts. 11 …… Reference clock pulse oscillator 12 …… And gate 13 …… Monostable multivibrator 14 …… OR gate 15 …… n-ary counter 16 …… Output selection circuit 17 …… Monostable multivibrator 18 …… Variable time constant setting circuit 19 …… D flip-flop 20 …… Index detector output signal 21 …… Counter output is n 22 …… Counter output m 23 …… Disk rotation speed signal 24 …… Index signal

Claims (1)

[Scope of utility model registration request] 1. A reference clock pulse oscillator 11, an AND gate 12 for inputting an output pulse of the reference clock pulse oscillator 11 and an output signal of an index detector, and a time constant setting using an output signal of the ungate 12 as an input signal. Circuit 18
A timer circuit A comprising a monostable multivibrator 13 having an n-ary counter 15 which receives as an input signal a sum signal of an output signal of the monostable multivibrator 13 and an output signal of the ungate 12. An output selection circuit 16 for selecting the counter value of the counter 15 by a disc rotation speed signal, and a pulse width setting circuit composed of a monostable multivibrator for sending an index signal of a predetermined pulse width using the output of the output selection circuit 16 as an input signal. Index position adjustment circuit in floppy disk drive consisting of