JPH0442474A - Magnetic head positioning circuit - Google Patents

Abstract

PURPOSE:To suppress the sampling noise of a position pulse signal by performing a charge operation further after holding a peak value by a charge current in an area where the peak value of the position pulse signal is increased, and performing a discharge operation after holding the peak value by the charge current in an area where it is decreased. CONSTITUTION:A charge control circuit 3 inputs the position pulse signal 1 in which positioning information is read out by a magnetic head, and a gate signal 2 representing a timing which holds the peak value of the signal and outputs the charge current 4 to hold the peak value of the position pulse signal 1 when the gate signal 2 is operated. In the area where the position pulse signal 1 is increased, the charge operation is performed further after holding the peak value of the position pulse signal by the charge current 4, and in the area where it is decreased, the discharge operation is performed after holding the peak value by the charge current 4. Therefore, a peak holding signal 18 with low step can be outputted. In such a way, the sampling noise of the position pulse signal 1 when a position signal is demodulated from the peak holding signal 18 can be suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a magnetic head positioning circuit, and particularly to a magnetic head positioning circuit having a peak hold circuit that holds the peak value of a position pulse signal that is position information of a magnetic head of a magnetic disk device. The present invention relates to a magnetic head positioning circuit.

[Conventional technology]

Conventional magnetic head positioning circuits have a peak hold circuit that holds the peak value of a position pulse signal, which is position information of the magnetic head of a magnetic disk device. The peak value of the position pulse signal is held by inputting the read position pulse signal to a peak hold circuit, and the position signal indicating the position of the magnetic head is demodulated to control the positioning of the magnetic head.

In such a conventional peak hold circuit, as shown in FIG. 2, the charging control circuit 23 inputs a gate signal 2 indicating the timing to hold the peak values of the position pulse signal 1 and the position pulse signal l. , outputs a charging current 4 for holding the peak value of the position pulse signal 1 when the gate signal 2 is in the operating state. The charging current 4 charges the capacitor 36.

After the voltage at the same level as the peak value of the position pulse signal 1 holds the peak value of the device pulse signal l composed of the buffer amplifier 17 as the peak hold signal 18, the voltage charged in the capacitor 36 is discharged by the discharge v control circuit. It is discharged in proportion to the rectified speed signal 5 indicating the absolute value of the speed of the magnetic head inputted to the magnetic head 19, and is outputted from the buffer amplifier 17 as a peak bold signal 18 in the same way as during charging.

FIG. 4 is a waveform diagram showing the waveforms of the peak bold signal, position pulse signal, and gate signal of the circuit of FIG. 2.

As shown in FIG. 4, the peak hold signal I8 is generated in a region (decreasing region) 2 in which the peak value of the position pulse signal 1 decreases.
0, even if a discharging operation is performed after holding the peak value of the position pulse signal 1, the step where the peak hold signal 18 switches from the discharging state to the charging state is small, but the peak value of the 5 position pulse signal 1 increases. . On the other hand, in the i region (increase region) 19 where the peak value of the position pulse signal I increases, even though the peak value of the position pulse signal 1 increases, the discharge operation is performed after the peak value is maintained. The step at the point where the peak bold signal 18 switches from the discharging state to the charging state becomes large, and the peak hold signal 18 changes to the position pulse signal 1 when demodulating the position signal.
sampling noise increases.

[Problem to be solved by the invention]

As described above, in the conventional magnetic head positioning circuit, the step where the peak hold signal 18 switches from the discharging state to the charging state becomes large, and the peak hold signal 18
This has the disadvantage that the sampling noise of the position pulse signal 1 becomes large when the position signal is demodulated from the position signal.

An object of the present invention is to eliminate the drawbacks of the conventional magnetic head positioning circuit as described above, and in a region where the peak value of the position pulse signal l increases (increase region), the peak value of the position pulse signal l is changed to the charging current. In a region where the peak value of the position pulse signal decreases (decreasing region) by performing a further charging operation after holding the position pulse signal with the charging current, the peak value of the peak hold signal is It is an object of the present invention to provide a magnetic head positioning circuit which has a small step difference when switching from a discharging state to a charging state and has small sampling noise of a position pulse signal when demodulating a position signal from a peak hold signal.

[Means to solve the problem]

The magnetic head positioning circuit of the present invention inputs a position pulse signal obtained by reading out positioning information written in advance on a magnetic disk by a magnetic head, and generates a first charging current for holding the peak value of the position pulse signal. A first charging control circuit that outputs a rectifying speed signal indicating the absolute value of the speed of the magnetic head and a charging/discharging switching signal are input, and when the charging/discharging switching signal is in the charging state, the rectifying speed signal is changed to the rectifying speed signal. a second charging control circuit that outputs a proportional second charging current; and a second charging control circuit that inputs the rectifying speed signal and the charging/discharging switching signal so that the charging/discharging switching signal outputs a proportional second charging current that is proportional to the rectifying speed signal when the charging/discharging switching signal is in a discharging state. A discharge control circuit outputs a discharge current, a track follow mode/seek mode switching signal indicating the positioning state of the magnetic head, a seek direction signal indicating the seek direction, and a peak hold signal are inputted to the track follow mode/seek mode. When the mode switching signal is in the track follow state, the charge/discharge switching signal indicating the discharging state is output, and when the track follow mode/seek mode switching signal is in the seek mode, the charge/discharge switching signal indicates the charging state or the discharging state. a charging/discharging control circuit that outputs a signal; a summing point that outputs a charging/discharging current that is a sum of the first charging current, the second charging current, and the discharging current; and a peak value of the position pulse signal. The device includes a capacitor that holds the voltage level at the charging/discharging current, and a buffer amplifier that outputs the voltage level of the capacitor as the peak hold signal.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing a peak hold circuit according to an embodiment of the present invention.

In FIG. 1, the charging control circuit 3 receives a position pulse signal 1 obtained by reading out positioning information written in advance on a magnetic disk using a magnetic head, and a gate signal 2 indicating the timing to hold the peak value of the position pulse signal 1. is input, and a charging current 4 for holding the peak value of the position pulse signal 1 is output when the gate signal 2 is in the operating state.

The charging control circuit 6 receives the rectification speed signal 5 and the charging/discharging control circuit 1.
The charging/discharging switching signal 8 from 3 is input, and the charging current 7 is output. The charge/discharge switching signal 8 is a control signal for controlling whether to perform further charging or discharging after charging with the charging current 4 from the charging control circuit 3 . This is a charging current for further charging after charging with the charging current 4 and holding the peak value of the position pulse signal 1. The discharge control circuit 9 is
A rectification speed signal 5 and a charge/discharge switching signal 8 from a charge/discharge control circuit 13 are input, and a discharge current 10 is output. The discharge current 10 is a control signal for causing discharge after holding the peak value of the position pulse signal 1 charged by the charging current 4 from the charging control circuit 3. Charge/discharge control circuit 13
is a track follow mode/seek mode switching signal (mode switching signal) that indicates the positioning status of the magnetic head.
11, a seek direction signal 12 indicating the seek direction, and a peak hold signal 18 that holds the peak value of the position pulse signal 1.
When the mode switching signal 11 is in the track follow state, the charge/discharge switching signal 8 indicating the discharge state is output, and when the mode switching signal 11 is in the seek mode, the seek direction signal 12 and the peak hold signal 18 are output. A charging/discharging switching signal 8 for switching between the charging state of the charging control circuit 6 and the charging state of the discharging control circuit 9 according to the voltage level of the
Output. The summing point 14 outputs a charging/discharging current 15 that is a sum of the charging current 4, the charging current 7, and the discharging current 10. The capacitor 16 holds the peak value of the position pulse signal 1 by the charging/discharging current 15. Buffer amplifier 1
7 outputs a voltage at the same level as the voltage of the capacitor 16 as a peak hold signal 18.

Next, the operation of the above embodiment will be explained with reference to FIG.

FIG. 3 is a waveform diagram showing the waveforms of the peak hold signal, position pulse signal, and gate signal of the circuit of FIG. 1.

When the mode switching signal 11 is in the track follow state,
The charging control circuit 3 outputs a charging current 4 in order to hold the peak value of the position pulse signal 1 at the timing of the operating state of the gate signal 2. The charging current 4 passes through a summing point 14 to charge a capacitor 16 as a charging/discharging current 15, passes through a buffer amplifier 17, and is output as a peak hold signal 18. After charging with the charging current 4 from the charging control circuit 3 and holding the peak value of the position pulse signal 1, the discharge control circuit 9 increases the discharge current 10 in order to perform the discharging operation until the next peak of the position pulse signal 1. Output. The discharge current 10 causes the capacitor 16 to discharge through the summing point 14 to lower its voltage, which is then output as a peak hold signal 18 through the buffer amplifier 17.

When the mode switching signal 11 is in the seek mode state, after the charge control circuit 3 holds the peak value of the position pulse signal 1 as in the track follow state, the charge/discharge control circuit 13 changes the seek direction of the magnetic head. It inputs the seek direction signal 12 shown and the peak hold signal 18 of the output of the buffer amplifier 17, determines whether to further charge or discharge the capacitor 16 based on these voltages, and outputs the charge/discharge switching signal 8. The charge/discharge switching signal 8 is input to the charge control circuit 6 and the discharge control circuit 9. When the charging/discharging switching signal 8 indicates a charging state, the charging control circuit 6 operates to output a charging current 7 proportional to the rectification speed signal 5 to further charge the capacitor 16. When the charge/discharge switching signal 8 indicates a discharge state, the discharge control circuit 9 operates to output a discharge current 10 proportional to the rectification speed signal 5 to discharge the capacitor 16.

As shown in FIG. 3, in an increasing region 19 where the peak value of the position pulse signal 1 increases, after the peak value of the position pulse signal 1 is held by the charging current 4, a further charging operation is performed.
In the decreasing region 20 where the peak value of the position pulse signal 1 decreases, by holding the peak value of the position pulse signal 1 with the charging current 4 and then performing a discharging operation, it is possible to output a peak hold signal 18 with a small step difference. .

〔Effect of the invention〕

As explained above, in the increasing region 19 of the position pulse signal 1, the magnetic head positioning circuit of the present invention further performs a charging operation after holding the peak value of the position pulse signal 1 with the charging current 4, and In the decreasing region 20, the peak value of the position pulse signal 1 is held by the charging current 4, and then the discharging operation is performed, which has the effect that the peak hold signal 18 with a small step can be output. Therefore, it is possible to reduce the sampling noise of the position pulse signal when demodulating the position signal from the peak hold signal.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a peak hold circuit according to an embodiment of the present invention, FIG. 2 is a block diagram showing a peak hold circuit as an example of a conventional magnetic head positioning circuit, and FIG. 3 is a block diagram showing a peak hold circuit according to an example of a conventional magnetic head positioning circuit. FIG. 4 is a waveform diagram showing the waveforms of the peak hold signal, position pulse signal, and gate signal. FIG. 4 is a waveform diagram showing the waveforms of the peak hold signal, position pulse signal, and gate signal of the circuit of FIG. 1...-Position pulse signal, 2...Gate signal, 3-6, 23...Charging vibration damping circuit, 4-7
...Charging current, 5... Rectification speed signal,
8・-・・・・Charge/discharge switching signal, 9・19・・・・
・Discharge control circuit, 10...--discharge current, 11...
...Mode switching signal, 12...Seek direction signal, 13...Charge/discharge control circuit, 14/34
・・・・・・Addition point, 15・・・−・Charging/discharging current, 16・36・・・・Capacitor, 17・37・−
...Buffer amplifier, 18...Peak hold signal, 19...Increase region, 20...
・Decrease area.

Claims (1)

[Claims] 1. A position pulse signal read out by a magnetic head from positioning information previously written on a magnetic disk is input, and a first charging current is outputted to maintain the peak value of the position pulse signal. a first charging control circuit that inputs a rectifying speed signal indicating the absolute value of the speed of the magnetic head and a charging/discharging switching signal, so that the charging/discharging switching signal is proportional to the rectifying speed signal when in the charging state. a second charging control circuit that outputs a second charging current; and a second charging control circuit that inputs the rectifying speed signal and the charging/discharging switching signal to discharge a voltage proportional to the rectifying speed signal when the charging/discharging switching signal is in a discharging state. A discharge control circuit that outputs a current, a track follow mode/seek mode switching signal indicating the positioning state of the magnetic head, a seek direction signal indicating the seek direction, and a peak hold signal are inputted to control the track follow mode/seek mode.
When the seek mode switching signal is in the track follow state, the charge/discharge switch signal indicating the discharge state is output, and when the track follow mode/seek mode switch signal is in the seek mode state, the charge/discharge switch signal indicates the charge state or the discharge state. a charging/discharging control circuit that outputs a switching signal; a summing point that outputs a charging/discharging current that is a sum of the first charging current, the second charging current, and the discharging current; and a peak of the position pulse signal. A magnetic head positioning circuit comprising: a capacitor that holds a value with the charging/discharging current; and a buffer amplifier that outputs the voltage level of the capacitor as the peak hold signal. 2. When a position pulse signal read out by a magnetic head from positioning information previously written on a magnetic disk and a gate signal indicating the timing to hold the peak value of the position pulse signal are input and the gate signal is in an operating state. a first charging control circuit that outputs a first charging current for holding the peak value of the position pulse signal, and a rectifying speed signal indicating the absolute value of the speed of the magnetic head and a charging/discharging switching signal. and a second charging control circuit that outputs a second charging current proportional to the rectification speed signal when the charge/discharge switching signal is in a charging state, and inputting the rectification speed signal and the charge/discharge switching signal. a discharge control circuit that outputs a discharge current proportional to the rectified speed signal when the charge/discharge switching signal is in a discharge state; a track follow mode/seek mode switching signal indicating the positioning state of the magnetic head; and a seek direction. The track follow mode is activated by inputting the seek direction signal and peak hold signal.
When the seek mode switching signal is in the track follow state, the charge/discharge switching signal indicating the discharge state is output, and when the track follow mode/seek mode switching signal is in the seek mode state, the seek direction signal and the peak hold signal are output. a charging/discharging control circuit that outputs the charging/discharging switching signal for switching between the charging state of the second charging control circuit and the charging state of the discharging control circuit according to the voltage level; a summing point that outputs a charging/discharging current obtained by adding the second charging current and the discharging current, a capacitor that holds the peak value of the position pulse signal at the charging/discharging current, and a voltage level of the capacitor that is set to the A magnetic head positioning circuit comprising a buffer amplifier that outputs a peak hold signal.