JPH0542069B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a digital signal recording device, and particularly to a recording device suitable for rewriting a portion of a recorded signal.

[Background of the invention]

One type of digital audio tape recorder that converts audio signals into PCM signals and records them on magnetic tape is a rotary head type digital audio tape recorder that uses a rotating head to record. This rotary head digital audio tape recorder has
Along with the PCM signal, a subcode signal is recorded as additional information in an independent area. Therefore,
It is possible to rewrite only the PCM signal or subcode signal of the already recorded data into new data, or to record it later. Hereinafter, this will be referred to as overwriting. When performing this overwriting, it is necessary to accurately determine the relative position of the new data and the already recorded data. However, in the method of determining the recording position from the position of the rotating head, such as the position detection method during playback in JP-A-58-102307, the positional accuracy depends on mechanical accuracy, and the device that originally recorded When overwriting is performed using a different device, the relative position cannot be determined accurately.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a digital signal recording device that can accurately determine the recording position of a previously recorded signal on a tape during rerecording and record without causing any positional deviation.

[Summary of the invention]

The digital signal recording device of the present invention detects a previously recorded signal by determining the signal area based on the tracking control signal recorded for each track and used for the rotating head to accurately capture the track during playback. This allows re-recording at the recording position to be performed accurately and easily.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIG. FIG. 1 shows a recording device of a rotary head type PCM recorder. In the figure, 1 is the input terminal for the main audio signal recorded as a PCM signal, 2 is the input terminal for the additional information signal recorded as a subcode signal, and 3 is the input terminal for the PCM signal or the subcode signal when overwriting. 5 is an input terminal for an overwrite selection signal that determines whether or not to write.
6 and 7 are clock generation circuits; 8 is a random access memory (RAM) for storing data; 9 is a write address generation circuit that generates addresses for writing PCM signals and subcode signals into RAM; 10 is a read address generation circuit for reading data written in RAM; 1
1 is a read address control circuit that controls the read address generation circuit 10, 12 is a correction code generation circuit that adds a correction code to each block of data written to the RAM, and 13 is a circuit for generating correction codes.
14 is an address switching circuit that switches each address; 15 is a data bus for exchanging data between each circuit and RAM 14; 16 is a data bus for exchanging data between each circuit and RAM 14;
A recording signal generation circuit that adds signals such as a synchronization signal for each block and signals such as a tracking control signal for each track to the data read from the RAM 8 to form a recording signal, 17 is a modulation circuit, and 18 is a recording circuit. , 19 is a recording/reproduction switching circuit for switching between recording and reproduction, 20 is a rotary head, 21 is a magnetic tape, 22 is a reproduction circuit, 23 is a tracking control signal detection circuit, and 24 determines a PCM signal area or subcode signal area. A discrimination signal generation circuit 25 is used to generate a signal, and 25 is a servo circuit that controls tape tracking of the rotary head 20.

During recording, the signal is input from the PCM signal input terminal 1 and the subcode signal input terminal 2. The input signal is sent to the A/D converter 5 for the main audio signal and converted into a digital signal, and then the additional information signal is directly sent to the RAM 8 via the data bus 15.
written to. At this time, the address of the RAM 8 to be written is generated by a write address generation circuit 9 operated by the clocks from the clock generation circuits 6 and 7. The generated write address specifies the address of RAM 8 through the address switching circuit 14, and the data from the data bus 15 is
Written to RAM8.

Errors are detected during playback in the written data,
A correction code for correction is added to each block. Correction code generation circuit 12 that adds a correction code
, the correction code address generation circuit 13
One block of data read out by specifying the address of RAM 8 is sent via data bus 15. The correction code generation circuit 12 generates a correction code based on the data, and then sends the correction code to the data bus 15. Correction code address generation circuit 13
specifies the address of RAM 8 for storing the correction code and writes the correction code. Note that since the correction code is added to each block, the correction code generation described above is repeated as many times as there are blocks of data recorded in the RAM 8.

The data with the correction code added is read from the RAM 8 in order to be recorded on the magnetic tape. Reading is performed by selecting the address generated by the read address generation circuit 10 using the address switching circuit 14 and specifying the address of the RAM 8. At this time, the read address generation circuit 10 is controlled by the read address control circuit 11, and generates an address only when the signal is on the magnetic tape and the rotating head is at a predetermined position.
Data is read from RAM8.

The read data is sent via the data bus 15.
It is sent to the recording signal generation circuit 16, and for each block,
A block is constructed by adding a synchronization signal, block address, etc. The constructed signal block is modulated by a modulation circuit 17, passed through a recording circuit 18, and recorded on a magnetic tape 21 by a rotary head 20.

When overwriting, the recording operation is the same as normal recording, but since only the PCM signal or subcode signal of the signals already recorded on the track is rewritten, the recording position must be determined accurately. There is. Therefore, in the present invention, the tracking signal detection circuit 23 detects the tracking control signal that has already been recorded, and the recording position is determined by the discrimination signal generation circuit 24 using the detected position as a reference.

This position is determined as follows. When the recording/playback switching circuit 19 selects the playback state, the data on the magnetic tape 21 is transferred to the rotary head 2.
0 to the reproduction circuit 22. The tracking signal detection circuit 23 detects a tracking signal used for accurate tracking of the rotary head 20 on the magnetic tape 21 from the reproduction signal from the reproduction circuit. This signal is transmitted to the servo circuit 25
and is used as a signal to control the tracking of the rotating head. Further, based on the tracking signal, the discrimination signal generation circuit 24 generates a signal area discrimination signal for determining the recording area of the PCM signal or subcode signal. Using this signal area determination signal, the read address control circuit 11 controls the read address generation circuit 20,
Set the address of RAM8 and read the PCM signal or subcode signal. Simultaneously with reading, the recording/reproducing switching circuit 19 switches from the reproducing state to the recording state and performs overwriting recording. In this way, by generating a signal area discrimination signal for each track based on the tracking control signal, simultaneously switching from the playback state to the recording state, and overwriting the signal, it is possible to rewrite only the PCM signal or subcode signal. becomes possible. In addition,
Which of the PCM signal and the subcode signal is to be rewritten is determined by the overwrite selection signal input from the input terminal 3.

By performing overwriting using such a method, it is possible to easily and accurately perform partial overwriting recording on already recorded data.

FIG. 2 is an example of a recording pattern on a magnetic tape. In the figure, 30 is a track margin, 31 is an area for recording PCM signals, 32, 3
3 is an area for recording subcode signals related to the PCM signal; 34 and 35 are areas for recording time-division tracking control signals used by the rotary head to perform accurate tracking; 36 is an area for recording preamble signals; 37 is a margin area provided between each signal, 38 is an area representing one block in a data signal, 39 is an area for recording a synchronization signal in one block, 40 is an area for recording a control signal, and 41 is a block. area for recording addresses,
42 is a control signal 40 and a block address 41
area for recording parity to be added to 43
is an area for recording data.

Note that the time-division tracking control signals 34, 3
Numeral 5 is a pilot signal for tracking control as specified in Japanese Patent Application Laid-Open No. 58-122606, and preamble signal 36 is a synchronization signal as specified in Japanese Patent Application Laid-open No. 58-143432.

The PCM signal area 31 is composed of 128 blocks, and each block includes a synchronization signal 39, a control signal 40, a block address 41, and a parity 4.
2 is added. The control signal 40 is a control signal necessary for reproduction, such as the sampling frequency and the number of quantization bits, and the block address 41 is an address indicating the number of the block. During playback, the block position is determined by detecting this block address. Also, parity 42
is added to the control signal 40 and block address 41, and is used to check whether the address is correct or not during reproduction.

The subcode signal areas 32 and 33 each consist of 8 blocks, and the block configuration is PCM.
This is the same as the signal area 31. Further, the tracking control signal areas 34 and 35 each have 5 blocks,
The preamble signal area 36 is 2 blocks, the track margin 30 is 11 blocks, and the inter-signal margin is 3.
7 is 3 blocks long. One track shown in Figure 2 has a length of 196 blocks.

FIG. 3 is a timing chart of the signal area (PCM signal area and subcode signal area) discrimination signal. In the figure, 50 is a rotary head output signal, 51 is a reproduced data signal, 52 is a tracking control signal, 53 is a PCM signal area discrimination signal, and 54 is a tracking control signal.
55 is a subcode signal area discrimination signal, and 55 is a rotating head scanning section.

The rotary head scanning section 55 of the rotary head output signal 50 corresponds to the recording pattern shown in FIG. 2. In this embodiment, two recording/reproducing heads are used and the winding angle of the magnetic tape 21 is 90 degrees. ,
In the rotary head output signal 50, the rotary head scan interval 55 is represented by 90 degrees every 180 degrees. A tracking control signal 52 is obtained by inputting the rotary head output signal 50 to the reproducing circuit 22 and tracking signal detection circuit 23 shown in FIG.

PCM signal area 31, subcode signal area 32
and 33, tracking control signals 34 and 3
The positional relationship of 5 and 5 on the reproduced signal is as shown in FIG. However, the absolute position of the recorded signals on the magnetic tape 21 is not guaranteed. That is, for example, PCM for each track.
The initial position of the signal field varies, and this variation is due to the mechanical precision of the rotating head, etc.
Therefore, when overwriting the magnetic tape 21 recorded by different devices, if the position of the rotary head 20 is used as a reference, the signal to be recorded, for example, the subcode signal, will be overwritten. Although it is necessary to record in the same position as the previously recorded subcode signal, there is a possibility that the subcode signal is overwritten and recorded in an area other than the subcode signal. On the other hand, on the same track, the positions of the signals are constant and do not change. Therefore, in the present invention, the tracking control signals 34 and 35 recorded on the same track as the data signal are
data signal area, that is, PCM signal area 31 or subcode signal area 32 and 3.
By generating a signal for determining 3 and using these signal area determination signals 53 and 54 to control the read address generation circuit 10 and recording/reproduction switching circuit 19 of the RAM 8, only the signal portion to be overwritten and recorded can be recorded. Can be rewritten.

FIG. 4 shows the configuration of the signal region discrimination signal generation circuit 24. As shown in FIG. In the same figure, 60 is the PCM signal 31
63 and 64 are input terminals for detection signals of tracking control signals, respectively, 65 is an OR circuit, 70 is a counter, and 67 and 68 are input terminals for a detection signal of a tracking control signal. Input terminals, 70 is a load value switching circuit, 71 is a counter load signal input terminal, 72 is a counter load value input terminal, 73 is a counter clock signal input terminal, 75 is an external clock signal input terminal, 76 is a data area setting A decoder 77 is an output terminal for a signal region discrimination signal.

The counter 74 receives a detection signal of a synchronization signal for each block detected from the clock signal or data signal from the clock generation circuit 7 shown in FIG.
This counter counts the number of blocks corresponding to 180 degrees, which is 392 blocks in this embodiment. The decoder 76 generates a signal area discrimination signal that sets the data area to "1" and other areas to "0" based on the value of the counter 74. At this time, the data selection signal input terminal 60
Depending on the selection signal inputted from , it is selected whether the PCM signal area discrimination signal 53 or the subcode signal area discrimination signal 54 is generated.

Tracking control signal detection signal input terminal 6
When the detection signals of the tracking control signals 34 and 35 are input to 3 and 64, they are applied to the counter 74 as a load signal for loading the counter 74 through the OR circuit 65. Now, assume that the detection signal of the tracking control signal 34 is input to the detection signal input terminal 63. The above detection signal is from counter 7.
At the same time, the load value from the load value input signal terminal 67 is selected. The number of blocks from the tracking control signal to the PCM signal area is fixed and set by the decoder, so by giving the counter value that should be when the tracking control signal is detected as the load value, the counter is actually It becomes possible to operate according to the data signal. The value of this counter is input to the decoder 76, and the decoder 76 generates a signal region discrimination signal using this value as a reference. Similarly, tracking control signal 3
When the detection signal of 5 becomes the load signal of the counter,
The load value from the load value input terminal 68 of the counter when the tracking control signal 35 is detected is selected and loaded into the counter 74.

Although the tracking control signal is used in this embodiment, it is also possible to generate the data area determination signals 53 and 54 using the preamble signal 36 instead of this signal. In FIG. 2, the preamble signal 36 is located immediately before the PCM signal area 31 and subcode signal areas 32 and 33. Therefore, by using the preamble signal 36 as a reference, more accurate signal region discrimination signals 53 and 54 can be generated.

Another embodiment of the signal region discrimination signal generation circuit 24 of the present invention will be described with reference to FIG. In the figure, 61 is a detection signal input terminal that indicates the presence or absence of the tracking control signals 34 and 35, 62 is an input terminal for a position detection signal that indicates the position of the rotating head, and 66 is a detection signal for the tracking control signal as a load signal. A load signal switching circuit 69 selects whether to use the rotary head position detection signal, and 69 is a load value input terminal selected when the load signal is the rotary head position detection signal.

When the tracking control signals 34 and 35 are detected, the load signal switching circuit selects the tracking control signal detection signals 63 and 64 as the load signal of the counter 74, and the load value is also switched to the tracking control signal by the load value switching circuit 70. Load values 67 and 68 at the time of control signal detection are selected.
However, in this case, tracking control signal 3
If 4 and 35 are not detected, the load signal disappears and the counter 74 is not loaded. The present embodiment is characterized in that even in such a case, the counter 74 is operated correctly to generate a signal region discrimination signal.

When the tracking control signals 34 and 35 are not detected, the load signal selection circuit 6 is activated by the tracking control signal detection signal inputted from the input terminal 61.
6 selects the rotary head position detection signal as the load signal for the counter 74. At this time, the load value from the input terminal 69 is simultaneously selected as the load value and loaded into the counter 74. The counter 74 is
Counting starts from this value, and the decoder 76 generates a signal region discrimination signal. Therefore, even when the tracking control signals 35 and 36 are not detected, a normal signal area discrimination signal can be generated by switching the reference of the signal area discrimination signal from the tracking control signal to the rotary head position detection signal, thereby preventing overwriting of data. can be rewritten by

〔Effect of the invention〕

According to the present invention, in the reproduced digital signal,
The PCM signal area or subcode signal area can be accurately determined, and this discrimination signal can be used to partially rewrite previously recorded data. Rewriting can be performed accurately.

Further, by switching to a method of generating a discrimination signal based on the position of the rotary head when the tracking control signal is missing, it is possible to deal with the case where the tracking control signal is missing.

[Brief explanation of the drawing]

Figure 1 shows a rotating head type PCM using the present invention.
A block diagram showing an example of a recording device of a recorder, Fig. 2 is a diagram showing an example of a recording pattern on a magnetic tape, and Fig. 3 shows a signal reproduced from the recording pattern shown in Fig. 2 and a signal area discrimination signal. FIG. 4 is a block diagram showing an embodiment of a circuit for generating a signal area discrimination signal, and FIG.
The figure is a block diagram showing another embodiment of the discrimination signal generation circuit. 3...Input terminal for overwriting selection signal, 5...
A/D converter, 6, 7...Clock generation circuit, 8
...Random access memory (RAM), 9...
Write address generation circuit, 10... Read address generation circuit, 11... Read address control circuit, 12... Correction code generation circuit, 13... Correction code address generation circuit, 14... Address switching circuit, 15... Data bus , 16... recording signal generation circuit, 17... modulation circuit, 18... recording circuit, 19... recording/reproduction switching circuit, 20... rotating head, 21... magnetic tape, 22... reproducing circuit, 23... ...Tracking control signal detection circuit, 2
4...Discrimination signal generation circuit, 65...OR circuit,
66, 70...Switching circuit, 74...Counter, 7
6...Decoder.

Claims (1)

[Scope of Claims] 1. A recording device that records a plurality of types of digital signals and at least one tracking control signal as recording signals in one track on a magnetic recording medium using a rotating head, and records the plurality of types of digital signals as a recording signal in one track. a storage circuit for storing data, a storage circuit control circuit for controlling storage and reading of data in the storage circuit, a code generation circuit for adding an error correction code to the plurality of types of digital signals, and the tracking control signal. A digital signal recording device comprising a tracking control signal generation circuit that generates a tracking control signal, and a recording signal generation circuit that generates one track of recording signals from the plurality of types of digital signals, error correction codes, and tracking control signals that have already been recorded. a tracking control signal detection circuit that detects a tracking control signal by reproducing the signal; and the plurality of types of digital signals are recorded based on the tracking control signal detection signal detected by the tracking control signal detection circuit. A discrimination signal generation circuit that generates a discrimination signal for discriminating an area; a control circuit that uses the discrimination signal to perform recording only in an area where at least one type of digital signal among the plurality of digital signals is stored; and a recording/playback switching circuit. A digital signal recording device characterized by being provided with a circuit. 2. In the digital signal recording device according to claim 1, when the tracking control signal detection circuit cannot detect the tracking control signal, the reference signal of the discrimination signal generation circuit is determined from the tracking control signal detection signal. A digital signal recording device comprising a switching circuit for switching to a head position detection signal of a rotating head.