JPS63317988A - Magnetic disk recording and reproducing device - Google Patents

Abstract

PURPOSE:To detect quickly only a reproduced information signal having an error check code through the use of an error check code by arranging an error check code for reproduction error detection and an additional identification code for a check code as an information. CONSTITUTION:An additional code generating circuit 13 generates an error check code and an additional identification code in response to the data of a recording register 12 and gives the result to the register 12 and both the codes are arranged in the area of the digital information signal of the register 12. On the other hand, an identification code discrimination section 18 discriminates the presence or absence of the additional identification code of the reproducing information signal of the reproducing register 17 and outputs a resulting signal Sa in response to the presence or absence to the control section 11. Moreover, an error processing section 19 detects the presence or absence of the reproducing error of the reproduced information signal by using the signal of the location of an error check code and outputs the result signal Sb in response to the presence or absence to the control section 11. Thus, the reproducing information signal only having an error check code is detected quickly by using the error check code.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention provides a method for modulating an analog signal, such as a video signal of a captured still image, and a digital information signal, which partially has an arbitrary write area for data, using different modulation methods. The present invention relates to a magnetic disk recording and reproducing apparatus that modulates and performs frequency division multiplex recording on each track of a magnetic disk, and demodulates and separates the reproduced signal of each track into an analog signal and an information signal for reproduction processing.

[Conventional technology]

2. Description of the Related Art Conventionally, electronic cameras called electronic still cameras have been devised to record and reproduce still images taken using magnetic disks as recording media.

The magnetic disk of an electronic still camera is called a video floppy, and the video signal of one field or one frame of each still image captured by a charge-coupled device (CCD) type solid-state image sensor is stored on the video floppy. One field is recorded on each concentric track.

By the way, each track of a video floppy contains, for example, Utility Model Application Publication No. 61-83390 (HO4N 5/92
), video signals and digital information signals such as data necessary for playback control are modulated using different modulation methods.
That is, it is supposed to perform frequency division multiplexing recording by modulating using an FM modulation method and a phase modulation method.

FM modulation of the video signal is performed using a carrier wave of 6 to 7.5 MHz, and phase modulation of the digital information signal is performed using DPSK (Diff) using a carrier wave of approximately 200 kHz.
erentia7! Phase 5hift Keyi
ng) Due to the modulation method, a logical 0 bit does not change the phase of the carrier wave, and a logical 1 bit changes the phase of the carrier wave by 18
This is done by changing the angle by 0°.

Further, the signal format (hit arrangement) of each track (each one field) of the digital information signal is set as shown in Fig. 4 when recording and reproducing at 525 horizontal lines/frame, 60 fields, /sec. In the same figure, ■S is 7H from the field switching reference point DSP.
(H is the horizontal scanning period) The starting point of the delayed vertical synchronization signal, (a
), (b), (C), ((II), (
e) is 4H (1 bit) initial data, 8H (2 bit)
bit) field/frame identification data, 28H
This area shows the respective areas for track number data (7 bits), date data 76H (19 bits), and user data 108H.

The bit rate of areas (a) to (d) is defined as a 4H/1 bit rate in order to improve the reliability of recording and playback, but the bit rate of area (e) is 4H.
When the rate of 1 hit is selected for H or the rate of 1 bit for 2H, and the rate of 1 hit is set for 4H, it becomes possible to write 27-bit data in area (e).

Furthermore, areas (a) to (d) are the aforementioned initial data.

It is provided for writing prescribed data for reproduction control related to the video signal, such as identification data, and area (e) is provided as an arbitrary write area into which arbitrary data can be written at the time of manufacturing or use.

As described in the above-mentioned publication, a recording and reproducing apparatus for an electronic still camera, which is an example of this kind of magnetic disk recording and reproducing apparatus, uses an FM modulated signal of an image inputted video signal and digital information at the time of recording. The signal is additively multiplexed with a DPSK modulated signal and recorded on a video floppy, and at the time of playback, the playback signal of the video floppy is demodulated and separated to playback the video signal and the digital information signal, respectively, and at this time,
Based on the data of the reproduced areas (b) to (d),
Different fields and frames of the reproduced video signal.

It also performs playback control such as switching playback tracks.

[Problem that the invention seeks to solve]

By the way, the detailed circuit configuration of the recording and reproducing device of an electronic still camera, especially the recording of digital information signals.

The detailed circuit configuration for reproduction has not been invented.

On the other hand, when playing back a video floppy, if a dropout occurs in the playback signal due to poor contact between the floppy and the magnetic head for recording and playback, fluctuations in the rotation of the video floppy, scratches on the floppy, etc., playback errors may occur in the digital information signal. occurs.

In particular, areas (b) to (
When a reproduction error occurs in the data in d), if reproduction control is performed based on the reproduced digital information signal, that is, the reproduction information signal, so-called erroneous control will occur and correct reproduction will not be performed.

Therefore, it is necessary to detect the presence or absence of reproduction errors in information signals by some method to prevent erroneous control.

In order to prevent erroneous control based on playback errors, for example, the signal patterns of each playback information signal obtained by repeated playback of the same track are compared to detect the presence or absence of a playback error, and the signal pattern of all playback information signals is It is conceivable that the playback control is performed by assuming that there is no playback error in the playback information signal only when they match.

However, when detecting the presence or absence of reproduction errors by comparing signal patterns as described above, the presence or absence of reproduction errors in the reproduction information signal of the track must be determined after the same track has been repeatedly reproduced a set number of times. Not detected.

When the number of repeated playbacks is set to 5 to prevent false detection, the track is played once,
In other words, since it takes approximately 16 m5ec to reproduce one field, it always takes a long time of approximately 0.1 sec to detect the presence or absence of a reproduction error, making it impossible to quickly detect the presence or absence of an error in the reproduced information signal, and the reproduction control There is a problem that the processing speed is slow.

[Means for solving problems]

This invention was made with the above points in mind,
On each concentric track of the magnetic disc, an analog signal such as a video signal and a digital information signal having an arbitrary write area for data are modulated using different modulation methods and recorded using frequency division multiplexing, and the reproduced signal of the disk is recorded. In a magnetic disk recording and reproducing apparatus that demodulates and separates the analog signal and the information signal from the information signal and performs reproduction processing, an error check code for detecting reproduction errors and the check code are added to the arbitrary write area as the information signal in the recording block. an information signal forming means for forming a digital signal in which an identification code is arranged, and an identification code determining means for determining whether or not the reproduction block includes the additional identification code in the reproduction information signal demodulated and separated from the reproduction signal. , a reproduction error determining means for determining the presence or absence of a reproduction error in the reproduction information signal based on the processing result of the error check code position processing means. This is a tisuf recording/playback device.

[Effect]

Therefore, at the time of recording, a digital signal in which an error check code and an additional identification code are arranged in an arbitrary write area consisting of area (e) in FIG. 4, for example, is formed as a digital information signal, and this digital signal is modulated. multiplexed recording on a magnetic disk.

Furthermore, during reproduction, the presence or absence of an error check code is determined based on the determination of the presence or absence of an additional identification code, and if the reproduction information signal has an error check code, the reproduction information signal is reproduced using the error check code. detection or detection of errors;
The presence or absence of a reproduction error is determined from the correction results.

Therefore, when reproducing a self-recording magnetic disk or the like that has an error check code in the digital information signal, the presence or absence of a reproduction error in the reproduced information signal can be quickly determined and detected only from the reproduced information signal. When reproducing another recorded magnetic disk without an error check code, erroneous detection of the presence or absence of a reproduction error based on the erroneous processing result of the error processing means is prevented.

〔Example〕

Next, the present invention will be explained in detail with reference to FIGS. 1 to 3 showing one embodiment thereof.

Figure 1 shows the case where it is applied to a recording/playback device for an electronic still camera. In the figure, (1) is a video floppy with a plurality of tracks formed concentrically, and is rotated at a constant speed during recording and playback. Ru. (2) is a floppy full
access and record each track.

(3) is a recording video input terminal into which a recording video signal such as a captured still image is input; (4) is FM modulating the video signal of input terminal (3); The FM modulator (5) is an adder for signal multiplexing, which adds the FM modulation signal of the modulator (4) and the DPSK modulation signal (described later), and adds the video signal of the input terminal (3) and the video signal of FIG. A digital information signal in a signal format is frequency division multiplexed.

(6) is a recording amplifier that amplifies the output signal of the adder (5), (7) is a recording/reproducing switch having recording and reproducing contacts (r) and (p), and the switching piece is connected to the head (2). As well as being connected, the contact point (r), (
p), the output signal of the amplifier (5) is supplied to the head (2) from the contact (r) during recording, and the reproduction signal of the head (2) is output from the contact (p) during playback.

(8) is a reproduction amplifier connected to the contact (p) of the switch (7), which amplifies and outputs the reproduction signal of the head (2). (9) is F where the output signal of amplifier (8) is input.
The M demodulator performs FM demodulation on the reproduced signal of the head (2), demodulates and separates the reproduced video signal, and outputs the demodulated signal. (1o) is a reproduced video output terminal for outputting the reproduced video signal of the demodulator (9) to a video processing circuit section or the like.

(11) is a system control unit configured with a microcomputer, which includes data generation means for generating each data in areas (a) to (d) of the digital information signal, reproduction error determination means for determining the presence or absence of reproduction errors, and reproduction Recording of reproduction information processing means, etc. that reproduces and processes information signals.

It has various processing control means for reproduction, and controls recording and reproduction of the entire apparatus.

(12) is a recording register for temporarily storing the digital information signal, and data of areas (a) to (d) of the digital information signal is inputted from the control unit (11) during recording. (1
3) is an additional code generation circuit connected to the register (12), which forms an information signal forming means together with the control unit (II) *register (12), and generates an error check code according to the data in the register (12). The additional identification code is generated and output to the register (+2), and both codes are placed in the digital information signal area (e) of the register (12).

(14) is a DPSK modulator provided between the register (12) and the adder (5), which performs DPSK modulation on the digital information signal of the register (!2) having an error check code and an additional identification code. , and output the DPSK modulated signal to the adder (5).

(15) is a demultiplexing bandpass filter into which the output signal of the amplifier (8) is input, and extracts the low frequency component of the reproduced signal of the head (2), that is, the DPSK modulated signal. (+6) is a DPSK demodulator connected to filter 05), which performs DPSK demodulation on the output signal of filter (15), demodulates and separates the digital information signal included in the reproduced signal of head (2), and demodulates it. Outputs a reproduction information signal.

(17) is a reproduction register that temporarily stores the reproduction information signal of the demodulator (16), and transfers the reproduction information signal to the control section (1).

(18) is an identification code discriminating unit forming an identification code discriminating means, which discriminates the presence or absence of an additional identification code in the reproduction information signal of the register (17), and when it is determined that there is an additional identification code, it is high level (hereinafter referred to as H), and when it is not determined. At times, a low-level (hereinafter referred to as below) determination result signal Sa is output to the control section (11). (19)
is an error processing unit forming an error processing means, which detects the presence or absence of a reproduction error in the reproduction information signal of the register (17) using the signal at the position of the error check code of the reproduction information signal;
A signal indicating the result of the detection process.

In other words, it becomes L when there is no error and H when there is an error.
The detection result signal sb is outputted to the control section (11).

Note that the modulator tnt (14), the m adder (5), the amplifier (6), the register (+2), the forming section (14), and the control section (11) form a recording block (20), and the amplifier (8) ), demodulator +9) j (16), filter (+5), register (17) 2 discriminator (18) *Processing unit (19) and control unit (11)
1).

Next, the configuration and insertion position of the error check code and additional identification code will be explained.

As is clear from FIG. 4, when a reproduction error occurs in the reproduction control data in areas (b) to (d) of the digital information signal of an electronic still camera, erroneous control occurs.

Therefore, in this embodiment, the CRC code for error detection of data in areas (b) to (d) is used as an error check code,
Only the presence or absence of reproduction errors is detected.

Also, to indicate that it has an error check code, logic 1,
“0, 0, 1, 1, 0゜1.” which has the same number of 0 bits arranged.
An 8-bit pattern code of 0, 1" is used as the additional identification code.

Then, as shown in FIG.
l), (e2) and user area (e3) for users.
The additional identification code and error check code are divided into areas (el
), (e2).

The bit rate of the additional identification code and error check code is
As with the data in areas (a) to (d), the rate is set to 4H and 1 bit.

Then, when recording, 1 field (
A video signal of one frame (field recording) or one frame (frame recording) is converted into an FM modulated signal field by field by FM modulation of a modulator (4) using a carrier wave of 6 to 7.5 MHz, and the FM modulated signals are added. The signal is input to the device (5).

In addition, the initial data of areas (a) to (d), field/frame identification data, I-rack number data, year, month, and day data that are automatically determined depending on recording conditions etc. are stored in the control unit (1) to register (12). ) area (a)
~ (d) is output to the storage unit, and the generation circuit (13)
Therefore, the area (b) ~ held in the register (12)
An error correction code and an additional identification code are generated based on the data in (d), and both generated codes are transferred from the generation circuit (13) to the area (el) of the register (12), (
e2), and for each field of the video signal, the digital information signal in FIG. 2, that is, the area (e)
A digital signal in which an error check code and an additional identification code are arranged is formed, and the formed digital information signal shown in FIG. 2 is output from the register (12) to the modulator (14).

Then, the input digital information signal is converted to DP SK by the modulator (14) using a carrier wave of about 200 KHz.
The modulator (14) outputs a DPSK modulated signal of the digital information signal to the adder (5).

Further, an adder 15) multiplexes the FM modulation signal of the modulator (4) and the digital information signal of the modulator (14) for each field, and adds The multiplexed signal is sent to the amplifier (17) and the switch (7).
1 (7) The data is sequentially recorded on the tracks of the floppy il+ via the contact (r) and the head (2).

Therefore, each track of the floppy disk contains one field of video signal and digital information signal.
Each signal is subjected to DPSK modulation and recorded by frequency division multiplexing, and at this time, an error check code and an additional identification code are arranged in area (e) of the digital information signal.
Areas (b) to (d) with the same signal format as in Figure 4.
A digital information signal with an error check code and an additional identification code added to the data is recorded.

Note that when the user inputs data using a keyboard, etc., the data is transferred from the control unit (from 1 to the register).
12) is output to the storage section of area (e3) and recorded on the floppy disk [+1].

Meanwhile, when playing, the video floppy to be played.

For example, the playback signal of one fill of each track of a floppy disk (+1) is sent to the contact (p) of the head (2) switch (7),
Demodulator (9), filter (15) via amplifier (8)
The video signal is demodulated and separated from the reproduced signal by FM demodulation in the demodulator (9), and the reproduced video signal is output from the demodulator (9) to the output terminal (10).

In addition, from the reproduced signal input to the filter (15), only the low-frequency component containing the digital information signal is separated and extracted and input to the demodulator (16). The digital information signal is demodulated and separated, and a reproduced information signal is output from the demodulator (16) to the register (17).

Then, the determination unit (18) determines the presence or absence of the additional identification code from the signal in the area (el) of the register (17), that is, the bit pattern of the 8-bit pattern code.
A discrimination result signal Sa is sent from the discrimination section (18) to the control section (11).
is output.

In addition, the processing unit (19) regards the 16-bit signal at the area (e2) of the register (19) as an error check code, and performs a CRC check using the 16-bit signal to check the area (e2) of the register (19). The presence or absence of a reproduction error in each data of 1)) to (d) is detected, and the processing unit (19) sends the control unit (
11), the detection result signal sb is output.

By the way, the following four types of states can be determined from the combination of the signals Sa and Sb.

[11 With additional identification code, no playback error Sa, 5b=
-H, L) (2) Is there a playback error with an additional identification code? )(Sa, 5b
=H.

H) (3) Sa, 5b= without additional identification code and without playback error
L.

L) (4) Reproduction error without additional identification code 1) (Sa, 5
b=L.

H) Then, only when the signal Sa is H, that is, when there is an additional identification code, the detection result based on the H and L of the signal sb becomes the detection result of a reproduction error.

Therefore, the reproduction error determination means of the control unit (11) performs the following operations every time one feed or one piece of reproduction information is input to the register Q7).
The above-mentioned states +]l to (4) are determined from the combination of signals Sa and Sb, and when Sa, 5b = H, L, it is determined that there is a reproduction error in the reproduction information signal of the register (!no). It is determined that there is no reproduction error, and the reproduction information signal of the register (17) is immediately taken into the reproduction information processing means of the control section (1).

At this time, the playback information processing means determines the fields of the playback video signal, the type of frame processing, the track number, and the recording date from the takes of areas (b) to (d) of the input playback information signal. , playback processing of the video processing circuit section, playback control such as switching of playback tracks, display processing of track number 9, year, month, and day, etc. are executed.

On the other hand, Sa, Sb = H, H(7)+2) 0)
In this state, the presence of a playback error is detected by the error check code, but at this time, if the presence or absence of a playback error is determined after one track playback, a dropout may occur due to a random error caused by, for example, dirt attached. Even when this occurs, it is considered that there is a reproduction error, and the efficiency of capturing reproduction information is reduced.

Therefore, when Sa,5b=H,H, the reproduction error determination means determines that the reproduction is within the preset number of repetitions.

For example, the same track may be played back only five times or less.

Then, when a new reproduction information signal is input to the register (17) due to repeated reproduction, the determination unit (18) and l processing unit (19) execute processing based on the input reproduction information signal. , signal sb within the number of repetitions
When the signal sb becomes L, the reproduction determining means causes the reproduction information processing means to take in the reproduction information signal of the register (+7) at the time when the signal sb becomes L as a reproduction information signal without reproduction error, and repeats the reproduction a predetermined number of times. If the signal sb does not become L even after repeated playbacks, it is determined that there is a playback error, the presence of a playback error is detected, the register (17) is prohibited from taking in the playback information signal, and based on the playback information signal of the track in question. Prohibit playback control.

Also, Sa,5b=L,L (7) (In the state of 31, the additional identification information drops out and the signal S
Since there is a possibility that a is L, the playback error determination means controls the playback of the same track repeatedly within the set number of playback repetitions, as in the case of (2), and at this time, If the signal Sa becomes H within the number of times, the reproduction information signal in the register (17) at the time when the signal Sa became H is taken into the reproduction processing means as a reproduction information signal without reproduction error.

Furthermore, even after repeating the playback a specified number of times, Sa.

5b=L, L(7) [When the state becomes 31(7),
When the state (4) of Sa, Sb, and H occurs, the reproduction error determining means determines that there is no additional identification code based on the L of the signal Sa.

By the way, if the video floppy being played back is a floppy with other recording, that is, a floppy on which a digital information signal has been recorded without adding an error check code or an additional identification code, the signal Sa becomes L.

For floppies without an additional identification code, the presence or absence of a reproduction error is detected by a reproduction error determination means by comparing the signal patterns of reproduction information signals obtained by repeatedly reproducing the same track a specified number of times, for example, 5 times. be done.

That is, when the reproduction error determination means determines that there is no additional identification code based on the signal Sa, it controls the reproduction of the same track five times, and also controls the reproduction of all of the same track obtained by the five reproductions. The signal patterns of the information signals are compared, and if the signal patterns of all reproduced information signals are the same, it is determined that there is no reproduction error, and the register (17)
The reproduction processing means is made to take in the reproduction information signal and execute reproduction control, and if the signal patterns do not become the same, it is determined that there is a reproduction error and the acquisition of the reproduction information signal of the register (17) is prohibited.

Therefore, during playback, the discrimination section (+8), the processing section (1
Based on the signals Sa and Sb of 9), the presence or absence of a reproduction error in the reproduction information signal is determined and detected.

Based on the signal Sa, the reproduction information signal to which an error check code has been added by self-recording or the like and the reproduction information signal to which no error check code has been added is automatically determined, and the reproduction information signal to which an error check code has been added is automatically determined. Based on the result of detecting the presence or absence of a reproduction error using an error check code, that is, the signal sb, the presence or absence of a reproduction error is detected in at least one track reproduction, and the presence or absence of an error in the reproduction information signal can be quickly determined. Detected.

Furthermore, for reproduced information signals to which no error check code is added, presence or absence of reproduction errors is detected based on comparison of signal patterns of reproduced information signals repeatedly reproduced from the same track.

Therefore, regardless of the presence or absence of an error check code, it is possible to detect the presence or absence of reproduction errors in the reproduction information signal most efficiently and accurately.While maintaining so-called compatibility, false detections can be prevented and the presence or absence of reproduction errors can be detected. can be quickly detected and playback control can be performed quickly and accurately.

Note that the control unit (the third
As shown in the figure, Y and N in the figure indicate affirmation and negation.

Incidentally, in the above embodiment, the additional identification code is 8-bit data and the error check code is a 16-bit CRC code, but the number of bits of both codes may be set arbitrarily. A simple parity check code other than the CRC code, a Hamming code with correction ability, a BCH code, or the like may be used as the code.

When a code having a correction ability such as a Hamming code or a BO day code is used as an error check code, the signal Sa becomes H
Based on the H and L of the signal sb, the processing unit (19
) to detect and correct playback errors, and repeat playback only when corrections are not possible. It is also possible to compensate for short dropouts and restore the reproduced information signal.

Further, in the above embodiment, the recording bits and rate of the additional identification code and error check code are set to a rate of 1 bit in 4H, but it is of course possible to change the rate to 1 bit in 2H.

Further, in the above embodiment, the areas (b) to (d) are checked using the error check code to detect the presence or absence of reproduction errors in the reproduction information signal, but the areas (a) to (d) are checked using the error check code.
Of course, part or all of (e) may be inspected to detect the presence or absence of a reproduction error in the reproduction information signal.

In the above embodiments, the application is applied to a recording and reproducing device for an electronic still camera, but it can also be applied to various magnetic disk recording and reproducing devices other than the recording and reproducing device for an electronic still camera. The analog signal and the digital information signal may be frequency-multiplexed and divided onto a magnetic disk, and if there is no need to consider reproduction of a magnetic disk to which no additional identification code or error check code is added, for example, the signal Sa It may be determined that there is a reproduction error immediately when the value becomes L.

〔Effect of the invention〕

As described above, according to the magnetic disk recording and reproducing apparatus of the present invention, since a digital signal having an error check code and an additional code is recorded on the magnetic disk as a digital information signal in an arbitrary write area, a digital information signal without both codes is recorded. It is possible to record a digital information signal with both codes added in the same signal format as , and at the time of playback, the presence or absence of an error check code is determined based on the determination result of the presence or absence of an additional identification code. Since the presence or absence of a reproduction error is detected based on the detection, detection, and correction results using an error check code only for the reproduction information signal having a code, error check codes such as reproduction information signals of self-recording magnetic disks are detected. It is possible to automatically discriminate between a reproduced information signal having an error check code and a reproduced information signal without an error check code, and quickly detect only the reproduced information signal having an error check code using the error check code.

[Brief explanation of the drawing]

1 to 3 show one embodiment of the magnetic tape recording and reproducing apparatus of the present invention, in which FIG. 1 is a block diagram, FIG. 2 is an explanatory diagram of the arrangement of error check codes and additional identification codes, and FIG. FIG. 4 is a flowchart for explaining the operation of the system control section, and is an explanatory diagram of the signal format of the digital information signal recorded on the video floppy of the electronic still camera. [11. Video floppy, (2). Recording/playback head, (
3) Recorded video input terminal, (u-FM modulator, (
5) Adder, (6) Recording amplifier, (7) Recording/playback switch, (8) Playback amplifier, (9) FM demodulator, (10) Playback video input terminal, ( 11)...System control unit, (12)...Record register, (13)
...Additional code generation circuit, (14)...DPSK modulator, (15)...Band pass filter, (16)...D
'PSK demodulator, (17)...Reproduction register, (I8
)...Identification code discriminator, (19)...Error processing unit, (
20) Recording block, (21) Playback block.

Claims (1)

[Claims] (1) On each concentric track of a magnetic disk, an analog signal such as a video signal and a digital information signal having an arbitrary write area for data are modulated using different modulation methods and recorded using frequency division multiplexing, and the disk In a magnetic disk recording and reproducing apparatus that demodulates and separates the analog signal and the information signal from the reproduced signal of the magnetic disk and performs reproduction processing, the recording block includes at least an error check code for detecting reproduction errors in the arbitrary write area as the information signal. an information signal forming means for forming a digital signal in which an additional identification code of a check code is arranged, and an identification for determining the presence or absence of the additional identification code of the reproduction information signal demodulated and separated from the reproduction signal in the reproduction block; code discriminating means; error processing means for detecting or correcting the presence or absence of a reproduction error in the reproduction information signal using a signal at the position of the error check code; A magnetic disk recording/reproducing apparatus comprising: reproduction error determining means for determining whether or not there is a reproduction error in the reproduction information signal based on a processing result.