JPS62189676A - Automatic characteristic measuring instrument for medium defect detecting circuit - Google Patents

Abstract

PURPOSE:To attain the automatic control of an error detecting circuit by providing an interface circuit between a drop-out simulator DOS and a central control part. CONSTITUTION:A drop-out-simulator (DOS)1 which is connected to input the control signal (a) of a DOS and then the synchronizing signal (b) is provided together with a central control part 5 connected for input of a pseudo waveform (c) of the DOS1, a medium defect detecting circuit 2 connected for input of the test level setting signal (d) of the part 5, an error processing circuit 3 connected for input of the error signal (e) of the circuit 2, the part 5 connected for input of the error information (f) of the circuit 3, and an interface circuit 4 connected for input of the interface control signal (g) of the part 5 respectively. The circuit 4 is controlled by the signal (g) of the part 5 and produces the signal (a) to the DOS. Then the part 5 controls the DOS1 and the circuit 2 based on the error information and collected data and supplies the error information repetitively for measurement of characteristics.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an automatic characteristic measuring device for a medium defect detection circuit.

[Conventional technology]

A conventional characteristic measuring device for a medium defect detection circuit is a DO that outputs a pseudo waveform containing errors included in successive waveforms of the medium.
S, a medium defect detection circuit that detects an error from the successive waveform of the medium and outputs an error signal, and an error processing circuit that determines the length of the error and the location of the error from the error signal.
An error detection level setting section for setting an error detection level in a medium defect detection circuit and a synchronization signal generation section for generating a synchronization signal input to the DOS are constructed.

DO3 is a pseudo waveform of the medium continuous waveform, that is, it contains one error such as a missing bit error (hereinafter referred to as MB), a modulation error (hereinafter referred to as MOD error), a spike error (hereinafter referred to as SP), or none at all. Output a waveform that does not contain The waveform is synchronized with the synchronization pulse input to the DOS, and is output after a set time from the synchronization pulse, including an error of the set length. 1)
O8 sets the temporal position, length, level, and waveform level of the F-error in panel operation through operator intervention.

To explain the definition of each error here, the track average value (hereinafter referred to as TAA) indicates the average of one shift per track of the medium output signal. MB error occurs when the media output signal is TA
This indicates when the value is below the MB error detection test level of TAAxα (where α is O×α×1) based on A. After writing to the medium, EB error is erased by direct current, and the medium output signal becomes T A
Indicates when A x α is above the EB error detection test level. MOD errors include PMOD errors and NMO
PMOD error when the envelope output signal of the medium output signal is above the PMOD error detection test level of TAAX(1+α).% The envelope output signal is below the NMOD error detection level of TAAx(1-α) NMOD error occurs. Further, an SP error indicates when the medium output signal is equal to or higher than the SP error detection test level of the envelope signal x α.

The medium defect detection circuit detects each of the above errors while reading the sine wave signal written on the medium. That is, the output signal of the medium is amplified to create an amplified signal, an envelope signal is extracted from the amplified signal, and a TAA signal is generated from the envelope signal. An error signal is generated if there is an error compared with the error detection test level.

The error processing circuit generates and stores error information from the error signal, ie, temporal position and length data from the synchronization pulse. That is, the period from the synchronization signal until the error signal becomes active is counted using a clock that divides one revolution of the medium by 256, the count value is taken as the error position, and the period from when the error signal becomes active until it becomes non-active is counted. The period between them is counted using a clock with the same period as the waveform frequency, and the count value is taken as the error length.

The error detection level setting unit sets an error detection level to the medium defect detection circuit.

The synchronization signal generator generates a pulse signal synchronized with one revolution of the medium.

[Problem that the invention seeks to solve]

The above-mentioned conventional apparatus requires operator intervention in the DOS to output pseudo waveforms containing various errors necessary for measuring the characteristics of the medium defect detection circuit, making it impossible to automatically measure the characteristics of the medium defect detection circuit. Therefore, there is a drawback that it takes a lot of time to adjust the medium defect detection circuit.

[Means for solving problems]

The automatic characteristic measuring device for a medium defect detection circuit of the present invention includes a D08 that outputs a pseudo waveform containing an error included in a read waveform of a medium, and a medium defect detection circuit that detects an error from the read waveform of a medium and outputs an error signal. and an error processing circuit that calculates the length of the error and the location of the error from the error signal, the level of the waveform output by the DOS, the type of error included in the waveform, the level of the error, the length of the error, and the location of the error. an interface circuit that generates a DOS control signal to set the DOS and inputs it to the DOS;
outputting an interface control signal to the interface to generate a synchronization signal input to the OS, an error detection level setting signal input to the medium defect detection circuit, and the DOS control signal; and a central control section that inputs the error detection level setting signal, the DOS control signal, and the interface control signal and outputs the same again.

[Example] Next, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing one embodiment of the present invention. DOSI 0 is connected to input the DOS control signal and synchronization signal, and the center is connected to input the pseudo waveform C of DOS 1. a medium defect detection circuit 2 connected to input the test level setting signal d of the control unit 5;
an error processing circuit 3 connected to input the error signal e of the medium defect detection circuit 2; a central control unit 5 connected to input the error information f of the error processing circuit 3;
The interface circuit 4 is connected to input the interface control signal g of the central control unit 5.

DOS1 is DOS1i generated by interface circuit 4.
The I control signal a controls the type, level, temporal position, length, etc. of errors included in the pseudo waveform, and outputs the pseudo waveform necessary for adjustment without relying on panel operations.

The interface circuit 4 is controlled by the interface control signal g of the central control unit 5, and the D081i
lI control signal a is generated.

The central control unit 5 inputs the error information f from the error processing circuit 3, totals the temporal position and length of detected errors, the number of each error, etc., displays them on a display, and prints them out on a printer if necessary. Furthermore, the DOS 1 and the medium defect detection circuit 2 are controlled based on the above error information and the collected data, and the error information is repeatedly input to measure the characteristics.

FIG. 2 is a flowchart showing the flow of control in the central control section. For convenience of explanation, it is assumed that El, EV: Level of generated error LENG: Length of error PO8f: Position of error.

(2) In parameter setting, a total of six types of parameters are set, including the level of the output waveform, the type, length, level (ELEV) and position of the error to be generated, and the ninth slice level for error detection (A).

■ Setting the number of measurements and determining completion (B, C) ■ DO
Generate a waveform containing an error with the generated error level as °I'' in S, input the error type, length (LENG), and position (posx) from the error processing circuit, and confirm that the generated error type is as set. Check whether Furthermore, E.L.E.
V and LENG are stored as a set of data, and the error frequency is counted for each obtained error position. (D)■
The measurement results will be shared with the MLEV and LBfSJG.
The relationship between 31 and its frequency is displayed in a table or graph. <E) ■ Decide to end the measurement. (k゛) [Effects of the Invention] The device of the present invention has the following features: 1) By adding an interface circuit between the OS and the central control unit, the DOS can be connected to the central control unit based on error information input from the error processing circuit. Therefore, by outputting various error waveforms for adjusting the medium defect detection circuit, the error detection circuit can be automatically adjusted, which has a great effect on reducing the number of errors.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention, and FIG. 2 is a flow chart explaining the functions of the central control section shown in FIG. 1...DOS (dropout simulator)
, 2... Medium defect detection circuit, 3... Error processing circuit, 4... Interface circuit, 5
... Central control section, a ... DOS control signal, b ... Synchronization signal, C ... Pseudo waveform, d ... Test level Setting signal, e...
・Error signal, f...Error information, g.Old...
Interface control signal. /・Representative Patent Attorney Susumu Uchihara・15,1゛・−゛Figure 1Figure 2

Claims (1)

[Claims] A drop out simulator (hereinafter referred to as DOS) that outputs a pseudo waveform containing errors included in the medium read waveform, and a medium defect detection circuit that detects errors and types of errors from the medium read waveform and outputs error signals. and an error processing circuit that calculates the error length and error occurrence position from the error signal, the frequency and level of the waveform output by the DOS, the type of error included in the waveform, the error level, the error length, and the error. an interface circuit that generates a DOS control signal for setting the occurrence position and inputs it to the DOS; a synchronization signal input to the DOS; an error detection level setting signal input to the medium defect detection circuit; and generates the DOS control signal. For this purpose, an interface control signal is output to the interface, the length of the error detected from the error processing circuit and the position of the error are input, and the error detection level setting signal and the DOS
1. An automatic characteristic measuring device for a medium defect detection circuit, comprising: a control signal; and a central control unit that changes the interface control signal and outputs it again.