JPH04159659A - Code detection device - Google Patents

Abstract

PURPOSE:To enable write/read of information to be performed efficiently by measuring and memorizing an interval of a detection signal on a memory medium and achieving an interval for allowing for passage of only a code detection signal based on the difference. CONSTITUTION:A sector length difference measuring circuit 11 obtains a difference from a standard length of a sector length standard value circuit 12 based on a signal of a sector mark detection circuit 1 and memorizes each difference into a memory circuit 13 with a sector mark position as an address. A sector mark detection gate generation circuit 20 increases or decreases the standard length according to each differential value and then obtains a width of a gate signal. Therefore, no erroneous sector mark detection signal is transmitted, thus preventing write/read error for a memory disk having track of poor roundness and enabling access time to be reduced and efficiency to be improved.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is a code detection method that detects a code indicating the beginning position of each sector, that is, a sector mark, etc. when writing and reading data in sectors on a storage disk, etc. Regarding equipment.

[Prior Art] Some storage disks have tracks formed in concentric circles or spirals, and these tracks are divided into a plurality of sectors. This storage disk is provided with sector marks for recognizing the starting position of each sector. Therefore, when writing or reading data to or from a storage disk, the storage address is read by detecting the sector mark.

FIG. 4 is a block diagram of such a sector mark detection device.

A sector mark detection circuit 1 and a sector mark interpolation circuit 2 are provided, and the outputs of these circuits 1.2 are sent to a sector mark detection gate generation circuit 3. The sector mark detection circuit 1 detects the sector mark on the storage disk and determines the jf! It has a function of outputting a high-level sector mark detection signal as shown in Figure 5, and the sector mark interpolation circuit 2 outputs a pseudo sector mark detection signal when a sector mark is not detected by the sector mark detection circuit 1. It has a function to send out. On the other hand, the sector mark detection gate generation circuit 3 has a function of receiving the sector mark detection signal and sending out a gate signal corresponding to the sector mark detection signal. As shown in FIG. 5, this gate signal has a wider gate width GL than the sector mark detection signal.

With such a configuration, when a sector mark is detected by the sector mark detection circuit 1 while the gate signal is at a high level, the gate circuit (not shown) is opened by the gate signal and sends out a sector mark detection signal.

[Problems to be Solved by the Invention] However, since the gate width GL of the gate signal is wide, an erroneous detection signal of the sector mark detection signal is generated.

Here, the reason why the gate width GL is set wide is as follows. In other words, ■ Eccentricity of the track due to precision during manufacturing of the storage disk; ■ Misalignment between the center of the storage disk in the storage disk drive device and the rotation axis of the motor that rotates the storage disk; ■ Changes in the rotational speed of the motor; - This is because the detection interval of resector marks is not constant and fluctuates. Therefore, the gate width GL becomes wide because the mechanical characteristics mentioned above are so large that they cannot be ignored. Therefore, if this gate width GL is set to a constant value, an erroneous detection signal will be output.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a code detection device that can minimize the output of erroneous detection signals of sector mark detection signals and can efficiently write and output data.

[Means for Solving the Problems] The present invention provides a code detection device for detecting codes that appear on tracks at predetermined intervals on a storage medium having tracks formed in concentric circles or the like. a code detection circuit that detects and sends out a code detection signal; a code interval memory circuit that measures the interval between each code detected by the code detection circuit; determines and stores the mutual difference between these code intervals; This code detection device attempts to achieve the above object by including a permission signal generation circuit that generates a permission signal having a period in which only the code detection signal is permitted to pass based on the mutual difference in code intervals stored in a storage circuit.

In this case, the symbol interval storage circuit measures the interval between each symbol,
It has a function of determining and storing each difference between these code intervals and a standard code interval, or a function of determining and storing a difference between a previously determined code interval and a currently determined code interval.

[Operation] By providing such a means, when the code on the storage medium is detected by the code detection circuit, the code detection signal is sent out, the code interval is measured by the code interval storage circuit, and the code is detected. Find and store the mutual difference in intervals. Then, based on the stored difference between the code intervals, the permission signal generation circuit generates a permission signal having a period in which only the code detection signal is permitted to pass.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings. Note that the same parts as in FIG. 4 are given the same reference numerals, and detailed explanation thereof will be omitted.

FIG. 1 is a block diagram of a code detection device applied to detecting sector marks on a storage disk. The outputs of the sector mark detection circuit 1 and the sector mark interpolation circuit 2 are both sent to a sector length storage circuit 10 and a sector mark detection gate generation circuit 20. The sector length storage circuit 10 receives the sector mark detection signal output from the sector mark detection circuit 1, measures the interval between each sector mark, that is, the sector length, and calculates and stores the differences between these sector lengths and the sector length standard value. It has the function of Specifically, as shown in FIG. 2, it is comprised of a sector length difference measuring circuit 11, a sector length standard value circuit 12, and a storage circuit 13.

The sector length difference measuring circuit 11 has a function of receiving a sector mark detection signal, measuring the length of each sector, and determining each difference between these sector lengths and the sector length standard value stored in the sector length standard value circuit 12. There is. The storage circuit 13 stores each difference between the sector length and the sector length standard value.

The sector mark detection gate generation circuit 20 generates a gate signal that is kept at a high level for a period during which only the sector mark detection signal is allowed to pass, based on each difference between the sector length stored in the sector length storage circuit 10 and the sector length standard value. It has a function. In other words, the sector mark detection interval is one track per track when going from the outer circumference to the inner circumference of the storage disk.
It decreases at a constant rate as a period, and the rate shows a constant value regardless of the track position. Therefore, the sector mark detection gate generation circuit 20 determines the gate width of the gate signal based on the difference between the sector length and the sector length standard value and the sector mark detection interval.

Next, the operation of the apparatus configured as described above will be explained with reference to the operation timing chart shown in FIG.

When the storage disk rotates at a predetermined rotational speed, the sector mark detection circuit 1 detects a sector mark attached to the storage disk and outputs a sector mark detection signal. This sector mark detection signal is sent to the sector length difference measuring circuit 11.

The sector length difference measuring circuit 11 receives the sector mark detection signal, measures the length of each sector, and calculates each difference between these sector lengths and the sector length standard value stored in the sector length standard value circuit 12. Each difference between this sector length and the sector length standard value is sequentially stored in the storage circuit 13. In this case, each difference is stored in the storage circuit 13 using each measured sector mark position as an address. Then, when the differences between the sector length for the required number of sectors and the sector length standard value are stored, the sector mark detection gate generation circuit 20 increases or decreases the sector length standard value according to each difference value to increase or decrease the gate width of the gate signal. seek. Thus, the sector mark detection gate generation circuit 20 sends out a gate signal having a gate width as shown in FIG. With this gate width of the gate signal, an erroneous detection signal will not be sent.

In this way, in the above-mentioned embodiment, the sector length is measured based on the detection signal of the sector mark on the storage disk, the difference from the sector length standard value is determined, and the gate width of the gate signal is determined based on this difference. Therefore, it is possible to obtain a gate signal having a gate width that allows only the sector mark detection signal to pass through, thereby minimizing the possibility of sending out an erroneous sector mark detection signal. As a result, errors will not occur when data is written to a storage disk having tracks with poor circularity, and access time can be shortened, resulting in improved efficiency. Furthermore, even if the mechanical parts that attach the storage disk to the rotating shaft of the motor have low precision, an erroneous sector detection signal will not be sent out, and therefore mechanical parts with low precision and low manufacturing costs can be used. Moreover, the memory circuit 13
Since only the differences between the sector length and the sector length standard value are stored, the capacity can be made smaller than when all the sector lengths of the storage disk are stored. Furthermore, since the sector mark interpolation circuit 2 outputs a pseudo sector mark detection signal when the sector mark detection signal is not output, the measurement and storage are restarted during the measurement and storage operation of the sector length storage circuit 1o. can be done.

Note that the present invention is not limited to the above-mentioned embodiment, and may be modified without changing the gist thereof. For example, the sector length standard value may be programmable. Further, the sector length storage circuit 1o may store the difference between the sector length of one or several sectors before and the currently measured sector length in the storage circuit 13. Furthermore, the sector length difference measuring circuit 11 may average the sector lengths of a plurality of tracks. This makes it possible to reduce errors caused by variations in the rotational speed of the motor that rotates the storage disk. Further, the present invention is not limited to detecting sector marks, but can be applied to detecting codes attached at predetermined intervals.

[Effects of the Invention] As described in detail above, according to the present invention, it is possible to provide a code detection device that can minimize the output of erroneous detection signals of sector mark detection signals and can efficiently write and output data.

[Brief explanation of the drawing]

1 to 3 are diagrams for explaining one embodiment of a code detection device according to the present invention, in which FIG. 1 is a configuration diagram and FIG. 2 is a specific configuration diagram of a sector length storage circuit. , FIG. 3 is an operation timing diagram, FIG. 4 is a configuration diagram of a conventional device, and FIG. 5 is an operation timing diagram of the same device. DESCRIPTION OF SYMBOLS 1... Sector mark detection circuit, 2... Sector mark interpolation circuit, 10... Sector length storage circuit, 11... Sector length difference measurement circuit, 12... Sector length standard value circuit,
13... Memory circuit, 20... Sector mark detection gate generation circuit. Applicant's representative Patent attorney Atsushi Tsuboi Figure 1 Figure 2 Figure 3 Figure 4 Figure 5

Claims (3)

[Claims] (1) In a code detection device that detects codes attached to tracks at predetermined intervals on a storage medium having tracks formed in concentric circles or the like, detects codes on the storage medium and sends out a code detection signal. a code detection circuit that measures the intervals between the respective codes detected by the code detection circuit, and a code interval storage circuit that determines and stores the mutual difference between these code intervals; A code detection device comprising: a permission signal generation circuit that generates a permission signal having a period in which only the code detection signal is permitted to pass based on a mutual difference in intervals. (2) The code detection device according to claim 1, wherein the code interval storage circuit measures the interval between each code, and calculates and stores each difference between these code intervals and a standard code interval. (3) The code interval storage circuit determines and stores the difference between the previously determined code interval and the currently determined code interval.
) code detection device described.