Magnetic disk storage apparatus with phase sync circuit having controllable response characteristics

• US 5,633,766 A
• Filed: 12/21/1994
• Issued: 05/27/1997
• Est. Priority Date: 10/30/1989
• Status: Expired due to Term

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Hirano, Akihiko, Kojima, Shinichi, Uragami, Akira, Horita, Ryutaro, Miyazawa, Syoichi, Hase, Kenichi
• Primary Examiner(s): KIM, WON TAE C
• Application Number:
  US08/360,426
• Time in Patent Office: 888 Days
• Field of Search: 360/46, 360/51, 360/60, 375/120, 331/17, 331/25, 331/34, 331/185
• US Class Current: 360/51
• CPC Class Codes: G11B 20/1403 characterised by the use of two levels
• CPC Class Codes: G11B 2020/10916 Seeking data on the record carrier for preparing an access to a specific address
• CPC Class Codes: G11B 5/012 Recording on, or reproducing or erasing from, magnetic disks G11B17/00, G11B19/00 take precedence
• CPC Class Codes: H03K 3/2821 Emitters connected to one another by using a capacitor
• CPC Class Codes: H03L 2207/06 Phase locked loops with a controlled oscillator having at least two frequency control terminals
• CPC Class Codes: H03L 7/089 the phase or frequency detector generating up-down pulses H03L7/087 takes precedence
• CPC Class Codes: H03L 7/0895 Details of the current generators H03L7/0893 takes precedence
• CPC Class Codes: H03L 7/0898 the source or sink current values being variable H03L7/0896 takes precedence
• CPC Class Codes: H03L 7/093 using special filtering or amplification characteristics in the loop H03L7/087 - H03L7/091 take precedence
• CPC Class Codes: H03L 7/095 using a lock detector H03L7/087 takes precedence
• CPC Class Codes: H03L 7/099 concerning mainly the controlled oscillator of the loop
• CPC Class Codes: H03L 7/1072 by changing characteristics of the charge pump, e.g. changing the gain
• CPC Class Codes: H04L 7/033 using the transitions of the received signal to control the phase of the synchronising-signal-generating means, e.g. using a phase-locked loop

Abstract

A magnetic disk storage apparatus provides with a phase locked loop or a phase sync circuit including a phase comparator, a charge pump, a filter and a voltage-controlled oscillator. The phase sync circuit includes a register which is connected to an information processing system and adapted to store therein the response characteristics of the phase comparator, the charge pump, the filter and the voltage-controlled oscillator as instructed from the information processing system. In this way, in accordance with the information on the response characteristics from the information processing system, the phase sync circuit is controlled thereby to assure a stable operation even in the case of the data transfer speed varying between inner and outer track such as occurs in a magnetic disk.

Claims

1. A magnetic disk storage apparatus comprising:

a phase sync circuit for generating a read clock signal for controlling reading of data from a magnetic disk-type storage medium, the phase sync circuit having a controllable response characteristic;

means for generating an instruction for controlling the response characteristic of the phase sync circuit and outputting the instruction to a computer bus, the instruction being generated based on an access position on the magnetic disk-type storage medium at which data is to be read; and

means for receiving the instruction from the computer bus, storing the instruction, and outputting the instruction to the phase sync circuit to control the response characteristic of the phase sync circuit in accordance with the instruction;

wherein the phase sync circuit includes a phase-locked loop circuit including;

a phase comparator for receiving a pulse signal and a clock signal and comparing the pulse signal to the clock signal, the pulse signal being a data signal reproduced from the magnetic disk-type storage medium;

a charge pump connected to an output of the phase comparator, the charge pump having a gain which may be a controllable gain;

a filter connected to an output of the charge pump, the filter having a filter characteristic which may be a controllable filter characteristic; and

a voltage-controlled oscillator connected to an output of the filter for generating a clock signal and outputting the clock signal to the phase comparator; and

wherein the instruction generated by the generating means includes at least one of information for controlling the gain of the charge pump and information for controlling the filter characteristic of the filter.

2. A magnetic disk storage apparatus comprising:

a phase sync circuit for generating a read clock signal for controlling reading of data from a magnetic disk-type storage medium, the phase sync circuit having a controllable response characteristic;

means for generating an instruction for controlling the response characteristic of the phase sync circuit and outputting the instruction to a computer bus, the instruction being generated based on an access position on the magnetic disk-type storage medium at which data is to be read, the instruction being effective for preventing a false operation of the phase sync circuit caused by interference between data read from the magnetic disk-type storage medium, the interference occurring as a result of a shift in peaks of data stored at the access position; and

means for receiving the instruction from the computer bus, storing the instruction, and outputting the instruction to the phase sync circuit to control the response characteristic of the phase sync circuit in accordance with the instruction;

wherein the phase sync circuit includes a phase-locked loop circuit including;

a phase comparator for receiving a pulse signal and a clock signal and comparing the pulse signal to the clock signal, the pulse signal being a data signal reproduced from the magnetic disk-type storage medium;

a charge pump connected to an output of the phase comparator, the charge pump having a gain which may be a controllable gain;

a filter connected to an output of the charge pump, the filter having a filter characteristic which may be a controllable filter characteristic; and

a voltage-controlled oscillator connected to an output of the filter for generating a clock signal and outputting the clock signal to the phase comparator; and

wherein the instruction generated by the generating means includes at least one of information for controlling the gain of the charge pump and information for controlling the filter characteristic of the filter.

3. An information processing system comprising:

a magnetic disk storage apparatus including

a phase sync circuit for generating a read clock signal for controlling reading of data from a magnetic disk-type storage medium, the phase sync circuit having a controllable response characteristic,

means for generating an instruction for controlling the response characteristic of the phase sync circuit and outputting the instruction to a computer bus, the instruction being generated based on an access position on the magnetic disk-type storage medium at which data is to be read, and

means for receiving the instruction from the computer bus, storing the instruction, and outputting the instruction to the phase sync circuit to control the response characteristic of the phase sync circuit in accordance with the instruction,

wherein the phase sync circuit includes a phase-locked loop circuit including

a phase comparator for receiving a pulse signal and a clock signal and comparing the pulse signal to the clock signal, the pulse signal being a data signal reproduced from the magnetic disk-type storage medium,

a charge pump connected to an output of the phase comparator, the charge pump having a gain which may be a controllable gain,

a filter connected to an output of the charge pump, the charge pump having a filter characteristic which may be a controllable filter characteristic, and

a voltage-controlled oscillator connected to an output of the filter for generating a clock signal and outputting the clock signal to the phase comparator, and

wherein the instruction generated by the generating means includes at least one of information for controlling the gain of the charge pump and information for controlling the filter characteristic of the filter; and

information processing means connected to the magnetic disk storage apparatus for processing data read from the magnetic disk-type storage medium.

4. A magnetic disk storage apparatus comprising:

delay means for receiving a first data signal reproduced from a magnetic disk-type storage medium and outputting a second data signal and a third data signal each corresponding to the first data signal, the delay means providing a controllable delay between the second data signal and the third data signal, thereby providing a controllable phase difference between the second data signal and the third data signal;

a phase sync circuit for receiving the second data signal and outputting a read clock signal synchronized with the second data signal;

a decoding circuit for receiving the third data signal and the read clock signal and decoding the third data signal based on the read clock signal; and

means for controlling the delay of the delay means based on an access position on the magnetic disk-type storage medium at which the first data signal is being reproduced;

wherein the phase sync circuit includes;

a phase-locked loop circuit including a plurality of circuit elements, the circuit elements including at least one circuit element having a controllable response characteristic;

means for generating an instruction for controlling the response characteristic of each of the at least one circuit element having a controllable response characteristic and outputting the instruction to a computer bus; and

means for receiving the instruction from the computer bus, storing the instruction, and outputting the instruction to the at least one circuit element having a controllable response characteristic to control the response characteristic of each of the at least one circuit element having a controllable response characteristic in accordance with the instruction;

wherein the phase-locked loop circuit includes;

a phase comparator for receiving the second data signal and a clock signal and comparing the second data signal to the clock signal;

a charge pump connected to an output of the phase comparator, the charge pump having a gain which may be a controllable gain;

a filter connected to an output of the charge pump, the filter having a filter characteristic which may be a controllable filter characteristic; and

a voltage-controlled oscillator connected to an output of the filter for generating a clock signal and outputting the clock signal to the phase comparator, the voltage-controlled oscillator, the clock signal being output from the phase sync circuit as the read clock signal synchronized with the second data signal; and

wherein the instruction generated by the generating means includes at least one of information for controlling the gain of the charge pump and information for controlling the filter characteristic of the filter.

5. A magnetic disk storage apparatus comprising:

an oscillator for generating a reference clock signal when data is to be written on a magnetic disk-type storage medium;

a phase sync circuit for receiving the reference clock signal and outputting a write clock signal synchronized with the reference clock signal for controlling writing of the data on the magnetic disk-type storage medium based on an access position on the magnetic disk-type storage medium at which the data is to be written;

an encoding circuit for receiving the write clock signal and the data to be written on the magnetic disk-type storage medium and encoding the data into a data signal based on the write clock signal;

writing means for receiving the data signal and writing the data signal on the magnetic disk-type storage medium at the access position at which the data is to be written;

out-of-phase detection means connected to the phase sync circuit for detecting an out-of-phase condition of the phase sync circuit wherein the write clock signal is out of phase with the reference clock signal; and

means, connected to the writing means and the out-of-phase detection means, for preventing the writing means from writing the data signal on the magnetic disk-type storage medium when the out-of-phase detection means detects the out-of-phase condition of the phase sync circuit;

wherein the phase sync circuit includes;

a phase-locked loop circuit including a plurality of circuit elements, the circuit elements including at least one circuit element having a controllable response characteristic;

p1 means for generating an instruction for controlling the response characteristic of each of the at least one circuit element having a controllable response characteristic and outputting the instruction to a computer bus; and

means for receiving the instruction from the computer bus, storing the instruction, and outputting the instruction to the at least one circuit element having a controllable response characteristic to control the response characteristic of each of the at least one circuit element having a controllable response characteristic in accordance with the instruction;

wherein the phase-locked loop circuit includes;

a phase comparator for receiving the reference clock signal and a clock signal and comparing the reference clock signal to the clock signal;

a charge pump connected to an output of the phase comparator, the charge pump having a gain which may be a controllable gain;

a filter connected to an output of the charge pump, the filter having a filter characteristic which may be a controllable filter characteristic; and

a voltage-controlled oscillator connected to an output of the filter for generating a clock signal and outputting the clock signal to the phase comparator, the clock signal being output from the phase sync circuit as the write clock signal synchronized with the reference clock signal; and

wherein the instruction generated by the generating means includes at least one of information for controlling the gain of the charge pump and information for controlling the filter characteristic of the filter.

6. A magnetic disk storage apparatus comprising:

a phase sync circuit for generating a read clock signal for controlling reading of data from a magnetic disk-type storage medium, the phase sync circuit having a controllable response characteristic; and

means for generating an instruction for controlling the response characteristic of the phase sync circuit and outputting the instruction to a computer bus, the instruction being generated based on an access position on the magnetic disk-type storage medium at which data is to be read;

wherein the phase sync circuit includes;

a phase-locked loop circuit having a controllable response characteristic; and

means for receiving the instruction from the computer bus, storing the instruction, and outputting the instruction to the phase-locked loop circuit to control the response characteristic of the phase-locked loop circuit in accordance with the instruction, thereby controlling the response characteristic of the phase sync circuit;

wherein the phase-locked loop circuit includes;

a phase comparator for receiving a pulse signal and a clock signal and comparing the pulse signal to the clock signal, the pulse signal being a data signal reproduced from the magnetic disk-type storage medium;

a charge pump connected to an output of the phase comparator and having a gain, the gain of the charge pump constituting a first parameter;

a filter connected to an output of the charge pump and having a filter characteristic, the filter characteristic of the filter constituting a second parameter; and

a voltage-controlled oscillator connected to an output of the filter for generating a clock signal and outputting the clock signal to the phase comparator;

wherein at least one parameter selected from the group consisting of the first parameter constituted by the gain of the charge pump and the second parameter constituted by the filter characteristic of the filter is a controllable parameter; and

wherein the instruction generated by the generating means includes information for controlling each of the at least one parameter.

7. A magnetic disk storage apparatus comprising:

a phase sync circuit for generating a read clock signal for controlling reading of data from a magnetic disk-type storage medium, the phase sync circuit having a controllable response characteristic; and

means for generating an instruction for controlling the response characteristic of the phase sync circuit and outputting the instruction to a computer bus, the instruction being generated based on an access position on the magnetic disk-type storage medium at which data is to be read, the instruction being effective for preventing a false operation of the phase sync circuit caused by interference between data read from the magnetic disk-type storage medium, the interference occurring as a result of a shift in peaks of data stored at the access position;

wherein the phase sync circuit includes;

a phase-locked loop circuit having a controllable response characteristic; and

means for receiving the instruction from the computer bus, storing the instruction, and outputting the instruction to the phase-locked loop circuit to control the response characteristic of the phase-locked loop circuit in accordance with the instruction, thereby controlling the response characteristic of the phase sync circuit;

wherein the phase-locked loop circuit includes;

a phase comparator for receiving a pulse signal and a clock signal and comparing the pulse signal to the clock signal, the pulse signal being a data signal reproduced from the magnetic disk-type storage medium;

a charge pump connected to an output of the phase comparator and having a gain, the gain of the charge pump constituting a first parameter;

a filter connected to an output of the charge pump and having a filter characteristic, the filter characteristic of the filter constituting a second parameter; and

a voltage-controlled oscillator connected to an output of the filter for generating a clock signal and outputting the clock signal to the phase comparator, the voltage-controlled oscillator having a gain;

wherein at least one parameter selected from the group consisting of the first parameter constituted by the gain of the charge pump and the second parameter constituted by the filter characteristic of the filter is a controllable parameter; and

wherein the instruction generated by the generating means includes information for controlling each of the at least one parameter.

8. An information processing system comprising:

a magnetic disk storage apparatus for reading data from a magnetic disk-type storage medium; and

information processing means connected to the magnetic disk storage apparatus for processing data read from the magnetic disk-type storage medium;

wherein the magnetic disk storage apparatus includes;

a phase sync circuit for generating a read clock signal for controlling reading of data from the magnetic disk-type storage medium, the phase sync circuit having a controllable response characteristic; and

means for generating an instruction for controlling the response characteristic of the phase sync circuit and outputting the instruction to a computer bus, the instruction being generated based on an access position on the magnetic disk-type storage medium at which data is to be read;

wherein the phase sync circuit includes;

a phase-locked loop circuit having a controllable response characteristic; and

means for receiving the instruction from the computer bus, storing the instruction, and outputting the instruction to the phase-locked loop circuit to control the response characteristic of the phase-locked loop circuit in accordance with the instruction, thereby controlling the response characteristic of the phase sync circuit;

wherein the phase-locked loop circuit includes;

a phase comparator for receiving a pulse signal and a clock signal and comparing the pulse signal to the clock signal, the pulse signal being a data signal reproduced from the magnetic disk-type storage medium;

a charge pump connected to an output of the phase comparator and having a gain, the gain of the charge pump constituting a first parameter;

a filter connected to an output of the charge pump and having a filter characteristic, the filter characteristic of the filter constituting a second parameter; and

a voltage-controlled oscillator connected to an output of the filter for generating a clock signal and outputting the clock signal to the phase comparator, the voltage-controlled oscillator having a gain;

wherein at least one parameter selected from the group consisting of the first parameter constituted by the gain of the charge pump and the second parameter constituted by the filter characteristic of the filter is a controllable parameter; and

wherein the instruction generated by the generating means includes information for controlling each of the at least one parameter.

9. A magnetic disk storage apparatus comprising:

delay means for receiving a first data signal reproduced from a magnetic disk-type storage medium and outputting a second data signal and a third data signal each corresponding to the first data signal, the delay means providing a controllable delay between the second data signal and the third data signal, thereby providing a controllable phase difference between the second data signal and the third data signal;

a phase sync circuit for receiving the second data signal and outputting a read clock signal synchronized with the second data signal, the phase sync circuit having a controllable response characteristic;

means for generating an instruction for controlling the response characteristic of the phase sync circuit and outputting the instruction to a computer bus;

a decoding circuit for receiving the third data signal and the read clock signal and decoding the third data signal based on the read clock signal; and

means for controlling the delay of the delay means based on an access position on the magnetic disk-type storage medium at which the first data signal is being reproduced;

wherein the phase sync circuit includes;

a phase-locked loop circuit having a controllable response characteristic; and

means for receiving the instruction from the computer bus, storing the instruction, and outputting the instruction to the phase-locked loop circuit to control the response characteristic of the phase-locked loop circuit in accordance with the instruction, thereby controlling the response characteristic of the phase sync circuit;

wherein the phase-locked loop circuit includes;

a phase comparator for receiving the second data signal and a clock signal and comparing the second data signal to the clock signal;

a charge pump connected to an output of the phase comparator and having a gain, the gain of the charge pump constituting a first parameter;

a filter connected to an output of the charge pump and having a filter characteristic, the filter characteristic of the filter constituting a second parameter; and

a voltage-controlled oscillator connected to an output of the filter for generating a clock signal and outputting the clock signal to the phase comparator, the voltage-controlled oscillator having a gain, the gain of the voltage-controlled oscillator constituting a third parameter, the clock signal being output from the phase sync circuit as the read clock signal synchronized with the second data signal;

wherein at least one parameter selected from the group consisting of the first parameter constituted by the gain of the charge pump and the second parameter constituted by the filter characteristic of the filter is a controllable parameter; and

wherein the instruction generated by the generating means includes information for controlling each of the at least one parameter.

10. A magnetic disk storage apparatus comprising:

an oscillator for generating a reference clock signal when data is to be written on a magnetic disk-type storage medium;

a phase sync circuit for receiving the reference clock signal and outputting a write clock signal synchronized with the reference clock signal for controlling writing of the data on the magnetic disk-type storage medium based on an access position on the magnetic disk-type storage medium at which the data is to be written, the phase sync circuit having a controllable response characteristic;

means for generating an instruction for controlling the response characteristic of the phase sync circuit and outputting the instruction to a computer bus;

an encoding circuit for receiving the write clock signal and the data to be written on the magnetic disk-type storage medium and encoding the data into a data signal based on the write clock signal;

writing means for receiving the data signal and writing the data signal on the magnetic disk-type storage medium at the access position at which the data is to be written;

out-of-phase detection means connected to the phase sync circuit for detecting an out-of-phase condition of the phase sync circuit wherein the write clock signal is out of phase with the reference clock signal; and

means, connected to the writing means and the out-of-phase detection means, for preventing the writing means from writing the data signal on the magnetic disk-type storage medium when the out-of-phase detection means detects the out-of-phase condition of the phase sync circuit;

wherein the phase sync circuit includes;

a phase-locked loop circuit having a controllable response characteristic; and

means for receiving the instruction from the computer bus, storing the instruction, and outputting the instruction to the phase-locked loop circuit to control the response characteristic of the phase-locked loop circuit in accordance with the instruction, thereby controlling the response characteristic of the phase sync circuit;

wherein the phase-locked loop circuit includes;

a phase comparator for receiving the reference clock signal and a clock signal and comparing the reference clock signal to the clock signal;

a charge pump connected to an output of the phase comparator and having a gain, the gain of the charge pump constituting a first parameter;

a filter connected to an output of the charge pump and having a filter characteristic, the filter characteristic of the filter constituting a second parameter; and

a voltage-controlled oscillator connected to an output of the filter for generating a clock signal and outputting the clock signal to the phase comparator, the clock signal being output from the phase sync circuit as the write clock signal synchronized with the reference clock signal;

wherein at least one parameter selected from the group consisting of the first parameter constituted by the gain of the charge pump and the second parameter constituted by the filter characteristic of the filter is a controllable parameter; and

wherein the instruction generated by the generating means includes information for controlling each of the at least one parameter.

11. A magnetic disk storage apparatus comprising:

a phase sync circuit for generating a read clock signal for discriminating data from a pulse signal read out from an access position on a magnetic disk-type storage medium, the phase sync circuit having a controllable response characteristic; and

means for generating an instruction for controlling the response characteristic of the phase sync circuit and outputting the instruction to a bus, the instruction being an instruction for setting a response characteristic of a phase-locked loop circuit to a suitable response characteristic, the suitable response characteristic being a response characteristic suitable for generating the read clock signal such that the read clock signal is effective for discriminating data from the pulse signal read out from the access position on the magnetic disk-type storage medium;

wherein the phase sync circuit includes;

a phase-locked loop circuit having a controllable response characteristic; and

means for receiving the instruction from the bus, storing the instruction, and outputting the instruction to the

phase-locked loop circuit to set the response characteristic of the phase-locked loop circuit to the suitable response characteristic, thereby controlling the response characteristic of the phase sync circuit;

wherein the phase-locked loop circuit includes;

a phase comparator for receiving (1) the pulse signal read out from the access position on the magnetic disk-type storage medium and (2) a clock signal, and comparing the pulse signal to the clock signal;

a charge pump connected to an output of the phase comparator and having a gain, the gain of the charge pump constituting a first parameter;

a filter connected to an output of the charge pump and having a filter characteristic, the filter characteristic of the filter constituting a second parameter; and

a voltage-controlled oscillator connected to an output of the filter for generating a clock signal and outputting the clock signal to the phase comparator;

wherein at least one parameter selected from the group consisting of the first parameter constituted by the gain of the charge pump and the second parameter constituted by the filter characteristic of the filter is a controllable parameter; and

wherein the instruction generated by the generating means includes information for controlling each of the at least one parameter.

12. An information processing system comprising:

a magnetic disk storage apparatus for reading data from a magnetic disk-type storage medium; and

information processing means connected to the magnetic disk storage apparatus for processing data read from the magnetic disk-type storage medium;

wherein the magnetic disk storage apparatus includes;

a phase sync circuit for generating a read clock signal for discriminating data from a pulse signal read out from an access position on the magnetic disk-type storage medium, the phase sync circuit having a controllable response characteristic; and

means for generating an instruction for controlling the response characteristic of the phase sync circuit and outputting the instruction to a bus, the instruction being an instruction for setting a response characteristic of a phase-locked loop circuit to a suitable response characteristic, the suitable response characteristic being a response characteristic corresponding to a data transfer speed of the pulse signal read out from the access position on the magnetic disk-type storage medium;

wherein the phase sync circuit includes;

a phase-locked loop circuit having a controllable response characteristic; and

means for receiving the instruction from the bus, storing the instruction, and outputting the instruction to the phase-locked loop circuit to set the response characteristic of the phase-locked loop circuit to the suitable response characteristic, thereby controlling the response characteristic of the phase sync circuit;

wherein the phase-locked loop circuit includes;

a phase comparator for receiving (1) the pulse signal read out from the access position on the magnetic disk-type storage medium and (2) a clock signal, and comparing the pulse signal to the clock signal;

a charge pump connected to an output of the phase comparator and having a gain, the gain of the charge pump constituting a first parameter;

a filter connected to an output of the charge pump and having a filter characteristic, the filter characteristic of the filter constituting a second parameter; and

a voltage-controlled oscillator connected to an output of the filter for generating a clock signal and outputting the clock signal to the phase comparator;

wherein at least one parameter selected from the group consisting of the first parameter constituted by the gain of the charge pump and the second parameter constituted by the filter characteristic of the filter is a controllable parameter; and

wherein the instruction generated by the generating means includes information for controlling each of the at least one parameter.