KR940005020Y1 - Device for checking index signal in disc - Google Patents

Abstract

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Description

Disc index signal detection device

1 is a block diagram of an index signal detection apparatus for a disc according to the present invention.

FIG. 2 is an exemplary view of an index signal detection unit employed in the index signal detection apparatus according to FIG.

* Explanation of symbols for main parts of the drawings

100: sector mark pulse detection unit 200: address mark pulse detection unit

300: data reading unit 400: index signal detection unit

401: microprocessor 402: 8-bit latch

403, 415: D flip-flop 404: 4-bit 2-value counter

405, 413, 416: ANDGATE 406, 407, 409, 410: OAGATE

408, 414: Inverter 411: 8-bit shift register

412: 8-bit comparator

The present invention relates to an apparatus for detecting an index signal of a disc, and more particularly to an apparatus for detecting an index signal indicating a track starting point in a track of a disc.

There is no index signal in the current international standard media format for magneto-optical discs. However, since the disc has a spiral structure, in order for the head to keep the same track, the same track is maintained only once when the disc is rotated once. If the track jump point is not at the beginning of the track, that is, the sector "0" point, the track held by the head will include the latter half of the track and the first half of the next track unless the track is exactly the same. If you do not include), you have to issue a track jump command again to perform 1 track jump.

Accordingly, an object of the present invention is to provide an index signal detection apparatus for a disc that maintains the same track by detecting an index signal generated at a track start point of the disc by using hardware.

In order to achieve the above object, the present invention includes a sector mark pulse detection unit for detecting a sector mark pulse; An address mark pulse detection unit for detecting an address mark pulse; A data reading unit for generating a read reference clock signal and a non-zero return inversion signal used for reading data from the disk; And an index signal detector for detecting an index signal by receiving a sector mark pulse detection signal of the sector mark pulse detection unit, an address mark pulse detection signal of the address mark pulse detection unit, a read reference clock signal of the data reading unit, and a nonzero return inversion signal, respectively. It is characterized by.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

1 is a block diagram of an index signal detection apparatus for a disc according to the present invention.

Referring to FIG. 1, the index signal detection apparatus of the present invention includes a sector mask pulse detection unit 100 for detecting a sector mark pulse SPDET, an address mark pulse detection unit 200 for detecting an address mark pulse AMDET, A data reading unit 300 for generating a read reference clock signal RRCLK and a non-zero return inversion signal NRZI used for reading data from the disc; the sector mark pulse detection unit 100 and the address mark pulse detection unit 200; And an index for detecting an index signal by receiving a sector mark pulse SPDET, an address mark pulse AMDET, a read reference clock signal RRCLK, and a non-zero return inversion signal NRZI transmitted from the data reading unit 300, respectively. It comprises a signal detection unit 400.

The present invention having the configuration as described above will be described with reference to an embodiment of the index signal detection unit 400 shown in FIG.

1 and 2, the microprocessor 40 constituting the index signal detection unit 401 executes a built-in program to store data for recording the last sector number of the track in the 8-bit latch 402. Transfer to 8-bit latch 402.

At this time, when the head reads the head portion of the disc standard model, that is, the first sector mark portion, the sector mark pulse detection unit 100 detects the sector mark pulse SPDET and forms the D-flop flip constituting the index signal detection unit 400. 403 and the 4-bit binary counter 404 to the clear terminal (CLR) while the load terminal (LOAD) of the 8-bit sea register 411 and one terminal of the end gate (416).

As such, the D-flop 403 to which the sector mark pulse SPDET is applied to the clear terminal CLR has an output terminal. Outputs a "high" signal. Output terminal of the D-flop flip 403 When the "high" signal is output and applied to the other end of the oragate 406, the read reference clock signal (RRCLK) of the data reading unit 300 applied to one end of the oragate 406 is blocked and at the same time 4-bit binary counter 404 and 8-bit shift register 411 It is loaded with 1H value.

On the other hand, when the address mark pulse AMDET is applied to the clock pulse terminal CP of the D flip flop 403 by the address mark pulse detection unit 200, the D flip flop 403 is cleared and the read reference clock signal RRCLK is applied. Acts as the clock pulse (CP) of the 4-bit binary counter 404 through the oragates 406 and 407. At this time, since the output signal of the AND gate 405 connected to the output terminals Q ₀ to Q _{3 of the} 4-bit binary counter 404 is at the "low" level, the output signal of the OR gate 410 is always "high". The 8-bit shift register 411 does not operate.

Since the disc identification structure consists of the number of 16-bit tracks and the number of 8-bit sectors, when the read reference clock signal RRCLK enters the 4-bit binary counter 404 16 times, that is, when the number of tracks is passed, the AND gate 405 ) Is at the "high" level, and the output signal of the oragate 407 is always at the "high" level.

When the output signal of the oragate 407 becomes the "high" level, the 4-bit binary counter 404 does not operate.

If the output signal of the AND gate 405 is at the "high" level, the output signal of the inverter 408 is at the "low" level, and the read reference clock signal RRCLK passes through the oragate 410 to allow an 8-bit shift register 411. Acts as a clock signal. In addition, the read reference clock signal RRCLK acts as a clock pulse of the 8-bit shift register 411 and at the same time, a serial non-zero return reversal signal transmitted from the data reading unit 300 through the oragate 409. NRZI acts as input data through the input terminal Din of the 8-bit shift register 411.

On the other hand, if the serial NRZI signal is repeated eight times and applied to the 8-bit shift register 411, the serial 8-bit data of the NRZI signal is latched to the output signal of the 8-bit shift register 411 and the 8-bit shift register 411 Output terminal Q ₇ outputs a "high" level signal.

When the output terminal Q ₇ of the 8-bit shift register 411 outputs a "high" level signal, the output signals of the oragates 409 and 410 always become a "high" level so that the 8-bit shift register 411 is output. Will not work.

At this time, if the same as the signal that is the signal that is output via the output terminals (Q ₀ ~ Q ₄₎ of the 8-bit latch 402 outputs at the output terminals (Q ₀ ~ Q ₄₎ of the 8-bit shift register 411. AND gate ( The output signal of the 8-bit comparator 412 applied to the other end of 413 is in the "high" level state. At this time, since the level of the output terminal Q ₇ of the 8-bit shift register 411 is "high", the output signal of the AND gate 413 is changed from the "low" level to the "high" level, and the clock of the D flip-flop 415 It is transmitted to the pulse terminal CP.

Therefore, the output terminal Q of the D flip-flop 415 outputs a "high" level signal, and when the next sector mark is detected, the sector mark pulse SPDET outputs the index pulse INDEX through the AND gate 416. Done.

As described above, the present invention has the effect of reducing the track jump time by detecting the index signal and searching the same track starting point of the disc.

Claims (1)

A sector mark pulse detection unit 100 for detecting sector mark pulses, an address mark pulse detection unit 200 for detecting address mark pulses, a read reference clock signal and a non-zero return inversion signal for reading data from a disc; The data read unit 300, the sector mark pulse signal of the sector mark pulse detection unit 100, the address mark pulse detection signal of the address mark pulse detection unit 200, and the read reference clock signal of the data read unit 300. And an index signal detection unit (400) for receiving an inversion return signal and detecting an index signal, respectively.