JPH0729257A - Rotary-head type digital recording/reproducing method and device - Google Patents

Abstract

PURPOSE: To control the switching of recording/reproducing in a recording operation under high precision and reliability by checking the continuity of reproduced parity data and a block address, generating a zone terminating end signal and determining the position of the head on a recording medium in accordance with the signal. CONSTITUTION: The relative position between a magnetic head and magnetic tape is expressed with a pulse signal DPG on a line 301 from a servo controller during a normal recording mode. The zone to be recorded into a selector 13 is informed with a select signal generating on a line 305 from the value of a counter 15. REDT data on a line 306 are recorded into the magnetic tape with the magnetic head. The output of a controller 80 is read with a RAM controller 34 to determine and address of data to be recorded. Coded data of a buffer RAM are read to a parity and block address generator, the block address and a parity bit of ID are generated, and REDT data on the line 306 are recorded with the magnetic head via a modulator 12 and selector 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital recording / reproducing method and device using a rotary head.

[0002]

2. Description of the Related Art Generally, a magnetic recording / reproducing apparatus utilizes the action of a magnetic head. During recording, the magnetic head scans the recording medium to record signal data on the medium and form magnetic tracks. The digital signals on the magnetic tracks may be of different types. By dividing the magnetic track into a number of areas according to the type, it is possible to record various types of signals. During reproduction, the magnetic head scans the original recording tracks to read the digital signals on these tracks.

In addition to the normal recording and reproducing modes, the above-mentioned recording / reproducing apparatus has a "after recording mode".
ode) ”is acceptable. In the subsequent recording mode, when the recording track is scanned by the magnetic head, recording is performed on a part of the divided area and reproduction is performed on the other area.
The effect of this mode is to "overwrite" a new signal in one particular area while retaining the signal in some other areas.

After that, in the recording mode, in order to accurately control the timing of reproduction and recording, the reproducing device must accurately know the relative position of the magnetic head and the magnetic track. In other words, recording is performed in the "post-recording" area and reproduction is performed in the other areas. If the relative positions of the recording head and the magnetic track are not in an accurate alignment relationship, complete overwriting may not be performed in the post-recording area, and areas other than the post-recording area may be erroneously overwritten.

The conventional recording / reproducing apparatus cannot accurately control the relative position of the recording head and the recording medium. In addition, in designing the format of the recording medium, no consideration has been given to the method of detecting the relative position between the magnetic head and the magnetic track by the recording / reproducing apparatus. Therefore, when the conventional recording / reproducing apparatus and the traditional magnetic track format for post-recording are used, it is difficult to accurately control the recording / reproducing function to overwrite the designated area.

A typical example of the above recording / reproducing apparatus is a digital audio tape recorder (R / DAT) using a rotary head. In this R / DAT, the magnetic head A and the magnetic head B are fixed on the rotating magnetic drum. When the drum rotates, these magnetic heads follow the rotation and scan the magnetic tape. The magnetic tape records on a magnetic track that is oblique with respect to the tape running direction,
Also, the recording on the magnetic tape is reproduced. R / D shown in FIG.
The AT track format is SUB-1 area, AT
F-1 area, PCM area, ATF-2 area, SUB-2
It consists of regions and the like and IBG signals between these regions. SU
The B-1 area and the SUB-2 area are sub areas for recording pack data. The PCM area is an area for recording a voice frequency signal subjected to pulse code modulation. These sub area and PCM area are composed of data blocks. FIG. 2 shows a block format. There is a block sync signal at the beginning of each block. The two bytes W1 and W2 following this block synchronization signal are, as shown in FIG.
It consists of a D (identification) code, a frame address and a block address. In FIG. 2, the bytes following W1 and W2 are the parity bytes of W1 and W2. ATF-
Areas 1 and ATF-2 are areas for recording automatic track detection signals.

The "post-record" effect of R / DAT is to overwrite the sub-area of the magnetic tape occupied by the already recorded signal and to keep the original signal intact in other areas. Alternatively, overwrite the PCM area and leave the rest of the area untouched. The switching of the recording / reproducing action during the post-recording is traditionally controlled in two ways.

Method 1: A drum phase generator (DP) as a reference for determining the relative position of the magnetic head and the magnetic tape.
G) Utilize the signal. The disadvantage of this method is that the precision depends on the mechanical parts and the precise control is not possible.

Method 2: A specific signal in the ATF area is detected as a reference for determining the relative position between the magnetic head and the magnetic track. However, since the frequency of the ATF signal is low, the measurement error may be a large error even for several cycles. Furthermore, since the ATF signal has a waveform, it cannot prevent the spurious ATF signal from acting as a false reference signal.

The preamble area, the postamble area, and the inter-block gap (IBG) area shown in FIG. 1, which encloses the data area, give a tolerance to the accuracy of overwriting when performing post-recording by the conventional method. . However, even so, the mechanical specifications of Method 1 are still limited, and there is still the risk of spurious ATF signals having serious consequences when using Method 2.

[0011]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method of processing signals in a recording / reproducing apparatus with high reliability.

Another object of the invention is the recording / recording of post-recording actions.
It is an object of the present invention to provide a method for controlling reproduction switching with high accuracy and high reliability.

The above objective is accomplished by the present invention which utilizes the data block structure of a magnetic track on a recording medium. When reproducing the data area of the recording track, the reproducing apparatus determines the relative position between the magnetic head and the magnetic track, and thus can use the sequence of reproduced blocks. As a result, higher accuracy is obtained than the two methods described above, because the processing can be performed based on the time of the data bit regardless of the accuracy of the mechanical parts. In addition, the data block format is coded for error detection or correction purposes, thus improving the reliability of the results.

The present invention will be described below in detail with reference to the accompanying drawings.

FIG. 4 illustrates a preferred embodiment of the present invention. During reproduction, the signal on the magnetic tape is reproduced, amplified, and subjected to conditioning, so that the signal P on the line 201 is reproduced.
Appears as BDT. The signal PBCK at the terminal 202 is a clock signal extracted from the PBDT by a phase locked loop (PLL). The sync detector 31 detects whether the PBDT signal has any sync signal for the data block. When a sync signal is detected,
A pulse SYNCDTD appears on the line 210, which informs the timing controller 80 and controls the demodulator 32 to demodulate the reproduced data. The block 33 for performing the parity check is used to check the accuracy of the parity information of the block. When the timing controller 80 receives the pulse signal SYNCDTD on line 210 for the activated block, it uses this signal as a reference to control the timing of the demodulator 32 and the parity check block 33. The result of the parity check is sent to the timing controller 80. If the signal PCOK on line 211 from the parity check block is "1", the result of the check is correct. If this signal is "0", the result is incorrect. The operation of the continuity check block 60 checks by comparison whether the block addresses of two consecutive blocks that have been regenerated are contiguous. At the time of recording, the block address is incremented by 1 from the previous block address. Utilizing the continuity of the block address, the continuity check block 60 performs another check on the regenerated block address in addition to the check by the block 33 of the parity check. When the signal AC representing the result of the continuity check is "1", the signal AC on the line 207 indicates that the block address of the block being reproduced and the block addresses of the n blocks before the block are continuous. n is an integer, 0
Can be considered to have a larger value. If the signal AC is "0", it indicates a case other than that. The block address counter 50 predicts the block address of the block being reproduced. If the block address is missing or has a random error in it, the correct address cannot be obtained from the signal being reproduced. In such a state, the captured value can be used as the predicted value of the block address. The CKACNT signal on line 502 increments the address counter count by one at the end of each block interval. The signal LDDRCNT on line 503 is for loading the block address counter 50 with a highly reliable block address appearing on the bus line 501. Area separator 70
Are used to generate area signals corresponding to each area on the magnetic track. If the area signal is "1",
The corresponding area is playing. The area signal on the line 208 is "0" except for the area being reproduced. Although the present invention controls the falling edge of the region signal 208 by referring to the count value of the block address counter 50, the block address loaded in the block address counter 50 is double checked for parity and continuity. ing. Therefore, the falling edge of the region signal is very reliable. The RAM controller 34 is used for the read / write operation of the buffer RAM 36. When the parity check of the block being reproduced is completed, the data being reproduced flows from the bus line 205 to the bus line of the buffer RAM 36. The RAM controller 34 reads the output of the address counter 50 and determines the address of the buffer RAM for recording the reproduced data.
The ECC encoder and decoder 35 decodes the error correction code. This decoding includes reading data from the buffer RAM 36 for error detection and writing corrected data to the buffer RAM 36. The input / output controller 37 reads the decoded data from the buffer RAM 36 and sends the data from the reproducing device.

During the normal recording mode, the pulse signal DPG on the line 301 from the servo controller represents the relative position of the magnetic head and the magnetic tape. After some delay, the signal CLEAR on line 302 instructs the track format counter 15 to clear the count value by forming a pulse, at which point recording of the track is started. The track format counter 15 outputs a signal C on line 304 from the timing controller 80 at the end of each block interval.
Triggered by LOCK, increment the count by 1. A select signal generated on the line 305 from the value of the track format counter 15 informs the track area selector 13 of the area to be recorded.
The REDT data on the line 306 is recorded on a magnetic tape by a magnetic head after being subjected to signal conditioning such as amplification or equalization. The PCM data to be recorded is supplied from the input / output controller to the buffer R
Written to AM36. Then, the ECC encoder and decoder encode the error correction code. This encoding includes reading PCM data from the buffer RAM 36 and writing encoded parity to the buffer RAM 36 for error correction. The RAM controller 34 reads the output from the timing controller 80 and determines the address of the data block to be recorded. The encoded data in the buffer RAM is read out to the parity and block address generator 11.
The function of the parity and block address generator is to add the block address to the data block and generate the block address and the parity bit of the ID code. The modulator 12 performs 8-10 modulation for converting 8-bit data into 10-bit data. The gap generator 14 forms a gap between the data areas. In R / DAT, the gap signals are MARGIN, AMBLE, IBG, AFT, etc., as shown in FIG. Thus, the track area selector 13 selects the modulation data from the modulator 12 by using the select signal on the line 305 as a reference, or generates the GAP signal from the gap generator to form the content to be recorded. The crystal oscillator 21 generates a system clock for the timing controller 80.

The system controller 22 determines the system mode by the display and panel block 23, instructs the timing controller 80 to operate according to the system mode, and controls the setting of the area position table 16.

In the post-recording mode, when the timing controller 80 detects the falling edge of the area signal 208 from the area separator 70, it sends a LOAD signal to the track format counter 15 via the line 303, and this counter outputs the area. Instruct to load the output value from the position table 16. The falling edge of the area signal is controlled by the value of the block address counter 50. The block address at the falling edge has a high accuracy because it is checked for parity and continuity. Therefore, the falling edge of the region signal 208 contains information about the relative position of the magnetic head and the magnetic edge. This signal corrects the setting of the track format counter and completes the post-recording format.

In summary, the count value of the track format counter 15 shown in FIG. 4 determines the type of signal REDT on line 306 as shown in FIG. In the post-recording mode, the track format counter 15
The counting accuracy of is controlled by updating the count value at the falling edge of the area signal of the reproduced data area. The object of the invention is achieved because the accuracy and reliability of the falling edge of the region signal is double verified by the parity check and the continuity check of the regenerated block address. FIG. 6 shows that during post-recording in the PCM area, a pulse is generated in the signal LOAD on the line 303, and the value "21" is loaded into the track format counter 15 at the falling edge of the area signal in the sub area. .
FIG. 6 also shows that a pulse is generated in the signal LOAD on the line 303 during normal reproduction or after-recording of the sub-region,
At the falling edge of the area signal in the PCM area, the value "16"
3 ”is loaded into the track format counter 15.

[0020]

[Brief description of drawings]

FIG. 1 is a format of a magnetic track in R / DAT.

FIG. 2 is a block format of R / DAT.

FIG. 3 shows the contents of the bytes shown in FIG.

FIG. 4 is a block diagram for implementing the present invention.

FIG. 5 is a signal timing diagram for synchronization detection, parity and block address check, and area signal generation.

FIG. 6 is a partial diagram (a) showing a head switching signal (H
SW); partial figure 6 (b) shows a recording signal; partial figure 6 (b ')
Is an enlarged view of a recording signal with a marker of a track format counter; Partial view 6 (c) is a drum phase generator clock signal (DPG); Partial view 6 (d) is a CLEAR signal;
Part (e) of FIG. 6 is an area signal in the normal recording mode;
Part (f) of FIG. 6 is an area signal during post recording of the PCM area; Part (g) of FIG. 6 is a LOAD signal during normal recording mode or post recording of the PCM area; Part (h) of FIG. 6 is after the sub area. Area signal during recording; partial FIG. 6 (i) is a LOAD signal during post-recording of the sub area.

[Explanation of symbols]

 11 Parity and Block Address Generator 12 Modulator 13 Track Region Selector 14 Gap Generator 15 Track Format Counter 16 Region Position Table 21 Crystal Oscillator 22 System Controller 23 Display and Panel Block 31 Sync Detector 32 Demodulator 33 Parity Check Block 34 RAM controller 35 ECC encoder and decoder 36 Buffer RAM 37 Input / output controller 50 Block address counter 60 Continuity check block 70 Domain separator

Claims (11)

[Claims] 1. A digital signal recording / reproducing method for determining the position of a read / write magnetic head on a recording medium comprising tracks each having a data area and a non-data area, wherein the data area is main data and a synchronization pattern. A plurality of contiguous blocks including a block address having a value greater than the address value of the previous block by 1 and parity data associated with each block address, wherein the non-data area comprises a plurality of gap signals; When reproducing the track data area, both the reproduced parity data and the block address are checked to generate an area end signal, and the position of the read / write magnetic head on the recording medium is determined according to the area end signal. A method comprising steps. 2. The method according to claim 1, wherein a part of the data area is overwritten and another data area is used for a post-recording mode for reproducing the recorded data. 3. The method of claim 1, wherein the parity check is performed by checking the reproduced parity data associated with the block address of the block being reproduced. 4. The block address check is performed by checking the continuity between the block being reproduced and the n blocks reproduced before it, and n is a positive integer. Item 3 method. 5. A data area having a plurality of contiguous blocks containing main data, a synchronization pattern, a block address having a value greater than the address value of the previous block by one and parity data associated with each block address, and a plurality of non-blocks. A digital signal recording / reproducing apparatus for determining a position of a read / write magnetic head on a recording medium having a track composed of a non-data area having a data signal, for detecting a sync pattern signal. A detection means, a parity check means for checking the validity of the reproduced parity data related to the block address of the block being reproduced, and a block address count for counting the block address of the reproduced data block in each data area. Means and regenerated data blocks Continuity checking means for checking the continuity of the reproduction block address, area separation means for generating an area signal for each data area to indicate that the signal in the data area is being reproduced, and reading in each track. A device comprising: track format counting means for determining the position of a write magnetic head, wherein the track format counting means is checked by a parity check means and a continuity check means. 6. The apparatus according to claim 5, wherein a part of the data area is overwritten and another data area has a post-recording mode in which recorded data is reproduced. 7. The parity checking means outputs one logical state, for example, one output signal if the parity associated with the data block being reproduced is correct, and another logical state if the parity of the data block being reproduced is incorrect. ,
6. For example, having an output signal of 0.
Equipment. 8. The continuity checking means checks the continuity of the reproduced block address of the data block being reproduced and the n blocks reproduced before it, and n is a positive integer. The device of claim 5, wherein 9. The continuity checking means outputs an output signal of a parity check relating to the block being reproduced and the n blocks preceding the block, and the reproduced block addresses of these n + 1 blocks are consecutive. 9. Device according to claim 8, characterized in that it has one logic state, for example an output signal of 1, and another logic state, for example an output signal of 0. 10. The block address counting means counts the block being reproduced by 1 every block interval unless the output of the parity check means is 1 and the output of the continuity check means is not 1 in the data area being reproduced. 10. Apparatus according to claim 9, characterized in that it has a counter that is triggered to increment by 1 and said counter is loaded with the replayed block address of the replaying block if the output of the continuity checking means is one. . 11. The area signal generated by the area separating means has one logic state, eg 1, if the associated data area is being reproduced, and another logic state otherwise.
11. Device according to claim 10, characterized in that it has for example 0 and the change from 1 to 0 is controlled by the output value of the block address counting means.