JP2948445B2 - Rotary head digital data recording / reproducing method and apparatus - Google Patents

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 apparatus 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 to form a magnetic track. 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 reads digital signals on these tracks by scanning the original recording tracks.

[0003] In addition to the normal recording and reproducing modes, the above-mentioned recording / reproducing apparatus includes an "after recording mode".
ode) "is acceptable. In the subsequent recording mode, when scanning the recording track 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 signals in some other areas.

[0004] In the post-recording mode, in order to accurately control the timing of reproduction and recording, the reproducing apparatus must accurately know the relative position between the magnetic head and the magnetic track. In other words, recording is performed in the “post-recording” area, and reproduction is performed in other areas. If the relative position is accurately aligned relationship between the recording heads and the magnetic track, sometimes Shirezu may is not performed completely overwrite the rear storage area, also the region other than the rear storage area is overwritten by mistake .

[0005] With the conventional recording / reproducing apparatus, it is impossible to accurately control the relative position between the recording head and the recording medium. In addition, in designing the format of the recording medium, no consideration is given to the method by which the recording / reproducing device detects the relative position between the magnetic head and the magnetic track. Therefore, when a conventional recording / reproducing apparatus and a traditional magnetic track format for post-recording are used, it is difficult to accurately control the recording / reproducing function to overwrite a specified area.

A typical example of the 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 a rotating magnetic drum. When the drum rotates, these magnetic heads scan the magnetic tape following the rotation. The magnetic head performs recording on a magnetic track that is oblique to the running direction of the tape,
It also reproduces the recording on the magnetic tape. R / D shown in FIG.
The track format of the AT is SUB-1 area, AT
F-1 area, PCM area, ATF-2 area, SUB-2
It consists of areas and the IBG signals between these areas. 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 an audio frequency signal subjected to pulse code modulation. These sub-areas and PCM areas are constituted by data blocks. FIG. 2 shows a block format. At the beginning of each block is a block synchronization signal. As shown in FIG. 3, two bytes of W1 and W2 following this block synchronization signal
D (identification) code, frame address and 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 an automatic track detection signal.

[0007] The "post-recording" 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 in other areas. As another method, the PCM area is overwritten, and the remaining area is left as it is. Switching of the recording / reproducing operation during post-recording is traditionally controlled in two ways.

Method 1: A drum phase generator (DP) is used as a reference for determining a relative position between a magnetic head and a magnetic tape.
G) Utilize signals. The disadvantage of this method is that the accuracy depends on the mechanical components and 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, even if the measurement error is several cycles, a large error may occur. Further, since the ATF signal has a waveform, it is impossible to prevent a spurious ATF signal from acting as an erroneous reference signal.

The preamble area, postamble area and inter-block gap (IBG) area surrounding the data area shown in FIG. 1 give an allowable error in the accuracy of overwriting when performing post-recording by a conventional method. . Nevertheless, the mechanical specifications are still limited in Method 1 and there is still the potential for serious consequences of spurious ATF signals when using Method 2.

[0011]

An object of the present invention is to provide a signal
The present invention provides a rotary head type digital data recording / reproducing method and apparatus for processing digital data with high reliability .

Another object of the present invention is to provide a method for recording a post-recording operation.
Method and method for controlling switching of reproduction with high accuracy and high reliability
And equipment .

[0013] An object of the present invention is to provide a rotary head, wherein each of a plurality of magnetic tracks defined obliquely with respect to the running direction of a tape includes a plurality of data areas, and each data area includes a plurality of data blocks each having a block address. In a method of recording / reproducing data on a plurality of magnetic tracks by a type recording / reproducing apparatus, a data area previously recorded on a magnetic track is reproduced, and at least one of a plurality of data blocks in the reproduced data area is reproduced. seeking the block address of the block parts, with the block address found
A continuity check is performed, an area signal indicating the end of the reproduced data area is generated from the block address subjected to the continuity check, and the data is stored in a subsequent data area of the same magnetic track using the area signal. It consists determining the correct position of the rotary head for rotation f
Said step of determining the correct position of the pad
Changes to the track format counter in response to
Start loading information about the location of the data area and
Generate select signal by rack format counter
And supply the select signal to the track area selector.
Data can be recorded in the subsequent data area
The present invention is attained by a data recording / reproducing method including the steps of: That is, the present invention utilizes the data block structure of the magnetic track of the recording medium. Reproducing apparatus, when reproducing the data area of the recording track, for determining the relative position of the magnetic head and the magnetic track, it uses a sequence of blocks to be played.
Further, a continuity check is performed on the block address. As a result, higher accuracy can be obtained than the above two methods,
This is because the processing can be performed based on the time of the data bit regardless of the precision of the mechanical parts. In addition, since the data block format is coded for the purpose of detecting or correcting an error, the reliability of the result is improved.

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

FIG. 4 shows a preferred embodiment of the present invention. During playback, the signal on the magnetic tape is played back, amplified, and conditioned so that the signal P
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 synchronization detector 31 detects whether the PBDT signal has any synchronization signal for the data block. When a sync signal is detected,
A pulse SYNCDTD appears on line 210, which notifies 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. For the activated block, when the timing controller 80 receives the pulse signal SYNCDTD on line 210, it uses this signal as a reference to control the timing of the demodulator 32 and 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 erroneous. The operation of the continuity check block 60 checks by comparison whether the block addresses of two consecutive blocks reproduced are consecutive. During recording, the block address is incremented by one from the previous block address. Using the continuity of the block address, the continuity check block 60 performs another check on the reproduced block address in addition to the check by the block 33 of the parity check. If the signal AC representing the result of the continuity check is “1”, the signal AC on the line 207 indicates that the block addresses of the block being reproduced and the preceding n blocks are continuous. n is an integer, 0
It can be considered as having 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, an accurate address cannot be obtained from the signal being reproduced. In such a state, a captured value can be used as the predicted value of the block address. The CKADCNT signal on line 502 increments the address counter count by one at the end of each block interval. The signal LDADCNT on the line 503 is for loading a highly reliable block address appearing on the bus line 501 into the block address counter 50. 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 being played. If the area is other than the area being reproduced, the area signal on the line 208 is “0”. In the present invention, the falling edge of the area signal 208 is controlled by referring to the count value of the block address counter 50, but the block address loaded into the block address counter 50 is double-checked for parity and continuity. ing. Therefore, the falling edge of the area signal has very high reliability. The RAM controller 34 is used for a 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 where the reproduced data is recorded.
The ECC encoder and decoder 35 decodes the error correction code. The 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 playback device.

During normal recording mode, the pulse signal DPG on line 301 from the servo controller indicates the relative position of the magnetic head and the magnetic tape. After some delay, signal CLEAR on line 302 instructs track format counter 15 to clear the count by forming a pulse, and recording of the track is started at that point. 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, increments the count by one. A select signal generated on the line 305 from the value of the track format counter 15 informs the track area selector 13 of an area to be recorded.
The REDT data on the line 306 is recorded on a magnetic tape by a magnetic head after performing signal conditioning such as amplification or equalization. The PCM data to be recorded is supplied from an input / output controller and stored in a buffer R
AM 36 is written. Then, the ECC encoder and the decoder encode the error correction code. This encoding includes reading the PCM data from the buffer RAM 36 and writing the encoded parity to the buffer RAM 36 for error correction. The RAM controller 34 reads an output from the timing controller 80 and determines an address of a 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, as shown in FIG. 1, the gap signal is MARGIN, AMBLE, IBG, AFT, or the like. Thus, the track area selector 13 selects modulation data from the modulator 12 by using the select signal on the line 305 as a reference, or forms a content to be recorded by generating a GAP signal from the gap generator. 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 a falling edge in 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 LOAD signal. An instruction is issued to load an 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 falling edge block address has a high accuracy because it is checked for parity and continuity. Therefore, the falling edge of the area signal 208 contains information about the relative position between the magnetic head and the magnetic edge. With this signal, the setting of the track format counter is corrected, and the format of the post-recording is completed.

In summary, the count value of 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
Is controlled by updating the count value at the falling edge of the area signal of the reproduced data area. The object of the present invention is achieved because the accuracy and reliability of the falling edge of the area signal are doubled by the parity check and continuity check of the reproduced block address. FIG. 6 shows that during post-recording of the PCM area, a pulse is generated in the signal LOAD of the line 303, and the value “21” is loaded into the track format counter 15 at the falling edge of the area signal of the sub-area. .
FIG. 6 also shows that a pulse is generated in the signal LOAD on the line 303 during normal reproduction or post-recording of the sub area,
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 the drawings]

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

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

FIG. 3 shows the contents of W1 and W2 bytes shown in FIG. 2;

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

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

FIG. 6 (a) is a partial diagram showing a head switching signal (H);
SW); partial diagram 6 (b) is a recording signal; partial diagram 6 (b ')
6C is an enlarged view of a recording signal with a marker of a track format counter; FIG. 6C is a drum phase generator clock signal (DPG); FIG. 6D is a CLEAR signal;
FIG. 6E is an area signal in a normal recording mode;
Part (f) of FIG. 6 is an area signal at the time of post-recording of the PCM area; part (g) of FIG. 6 is a LOAD signal at the time of the normal recording mode or post-recording of the PCM area; Area signal at the time of recording; FIG. 6 (i) is a LOAD signal at the time of post-recording of the sub area.

[Explanation of symbols]

 11 Parity and Block Address Generator 12 Modulator 13 Track Area Selector 14 Gap Generator 15 Track Format Counter 16 Area Position Table 21 Crystal Oscillator 22 System Controller 23 Display and Panel Block 31 Synchronization 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 Area separator

Continuation of the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G11B 15/467 G11B 20/10

Claims (8)

(57) [Claims] 1. A rotary head type recording apparatus, wherein each of a plurality of magnetic tracks defined obliquely with respect to a running direction of a tape includes a plurality of data areas, and each data area includes a plurality of data blocks each having a block address. In a method for recording / reproducing data on a plurality of magnetic tracks by a / reproducing apparatus, a data area previously recorded on a magnetic track is reproduced, and at least one of a plurality of data blocks in the reproduced data area is reproduced . seeking the block address of the block, the block address determined subjected to continuity check, from the block address subjected to continuity check, generates an area signal indicating the end of the reproduced data area, by using a region signal, Determine the correct position of the rotating head for storing data in a subsequent data area of the same magnetic track Ri Na from step, the step of determining the correct position of the rotary head in response to changes in the area signal, the track format Cow
Start loading information about the location of the data area into the
And a select signal is generated by the track format counter.
And supplies the select signal to the track area selector to
A switch that enables recording of data in the data area.
A data recording / reproducing method comprising a step . 2. The method of claim 1, further comprising the step of performing a parity check on a block address used to generate the area signal. 3. The rotary head type recording / reproducing apparatus is a digital audio tape recorder, wherein a previously recorded data area is a PCM area and a subsequent data area is a sub area. the method of. 4. The rotary head type recording / reproducing apparatus is a digital audio tape recorder, wherein a previously recorded data area is a sub area and a subsequent data area is a PCM area. the method of. 5. A plurality of magnetic tracks, wherein each of the plurality of magnetic tracks defined obliquely with respect to the running direction of the tape includes a plurality of data areas, and each data area includes a plurality of data blocks each having a block address. A rotary head type data recording / reproducing apparatus for recording / reproducing data on a demodulator for receiving a reproduced data signal for reproducing a previously recorded data area of a magnetic track; and an input connected to an output of the demodulator, At least some of the data blocks in the data area where the output was reproduced
A block address counter that gives a count of the block address of the block, an input responsive to the output of the demodulator, and an output
The continuity of the block address applied to the counter is correct
A continuity check circuit for indicating whether or not the input has an input , an input connected to the output of the block address counter, an output providing an area signal indicating an end of the reproduced data area, and an input being an output of the area separator is connected to the output Ri is Na more a controller for providing a signal indicating the correct position of the rotary head for recording the subsequent data area of the same magnetic track data, the controller detects and outputs the change of area signals smell
Control to start the generation of the LOAD signal
Controller and a timing controller for the input to receive the LOAD signal.
Connected to the output of the
Rack format counter and input connected to output of track format counter
Output allows data to be recorded in subsequent data areas
A rotary head type data recording / reproducing apparatus, comprising: 6. A parity check circuit having an input connected to an output of the demodulator and an output indicating whether a block address applied to a block address counter has a correct parity. Rotary head type data recording / reproducing device. 7. The rotary head type recording / reproducing apparatus is a digital audio tape recorder, wherein a previously recorded data area is a PCM area, and a subsequent data area is a sub area. Rotary head type data recording / reproducing device. 8. The rotary head type recording / reproducing apparatus is a digital audio tape recorder, wherein a previously recorded data area is a sub area and a subsequent data area is a PCM area. Rotary head type data recording / reproducing device.