JPS61236073A - Digital signal recording device - Google Patents

Abstract

PURPOSE:To rerecord correctly and easily the signal at the recording position of the recording signal by discriminating the signal area recorded for each track on the basis of the tracking control signal used since the rotating head correctly catches the track at the time of reproduction. CONSTITUTION:A tracking control signal already recorded is detected by a tracking signal detecting circuit 23, and the recording position is determined by a discriminating signal generating circuit 24 on the basis of the position. A signal area discriminating signal is generated on the basis of the tracking control signal for one track, simultaneously, changed over from the reproducing condition to the recording condition, the signal is repeatedly written and recorded, thereby only a PCM signal or a sub-code signal can be rewritten. By executed the repeated writing with such a method, the partial repeated writing and recording onto the already recorded data can be easily and correctly executed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a recording device for digital signals, 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 an audio signal into a PCM signal and records it on a magnetic tape is a rotary head type digital audio tape recorder that uses a rotary head to record.

In this rotary head type digital audio tape recorder, a subcode signal is recorded as additional information in an independent area along with a PCM signal.

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 No. 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 re-recording and can record without causing positional deviation.

[Summary of the invention]

The digital signal recording device of the present invention detects the 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. 1st
The figure shows a recording device of a rotating head type PCM recorder. In the figure, 1 is an input terminal for the main audio signal recorded as a PCM signal, 2 is an input terminal for an additional information signal recorded as a sub-food signal, and 3 is an input terminal for overwriting either the PCM signal or the subcode signal at the time of overwriting. 5 is an input terminal for an overwrite selection signal that determines the force used to perform
6 and 7 are clock generation circuits,
8 is a random access memory (RAM) that stores data.
), a write address generation circuit that generates an address for writing the 9GtPCM signal and the subcode signal into the RAM;
10 is a read address generation circuit for reading data written in RAM; 11 is a read address generation circuit 10
12 is a correction code generation circuit that adds a correction code to each block of data written in the RAM; 13 is a RAM when generating correction codes;
correction code address generation circuit for setting the address of 14;
15 is an address switching circuit for switching each address, 15 is a data bus for exchanging data between each circuit and RAM 14, and 16 is a 1 for data read from RAM 8.
A recording signal generation circuit adds signals such as a synchronization signal to each block and signals such as a tracking control signal to each track to form a recording signal, 17 is a modulation circuit, 18 is a recording circuit, and 19 is a recording and reproducing circuit. 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 is a discrimination circuit for generating a signal for determining a PCM signal area or a subcode signal area. Signal generation circuit, 25 is rotary head 2
This is a servo circuit that controls zero tape tracking.

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 to a digital signal, and then the additional information signal is sent to the data bus 1 as it is.
5 to the RAM 8. At this time, the address of RAM 8 to be written is generated by write address generation circuit 9 which operates with the clocks from clock generation circuits 6 and 7. The generated write address specifies the address of the RAM 8 through the address switching circuit 14,
Data from data bus 15 is written to RAM 8.

A correction code is added to each block of the written data to detect and correct errors during reproduction. One block of data read out by specifying the address of the RAM 8 by the correction code address generation circuit 13 is sent via the data bus 15 to the correction code generation circuit 12 that adds the correction code. The correction code generation circuit 12 generates a correction code based on the data, and then transfers the correction code to the data bus 15.
send to. The correction code address generation circuit 13 specifies the address of the RAM 8 for storing the correction code and writes the correction code. still,.

Since the correction code is added to each block, the above correction code generation is repeated as many times as the number of blocks of data recorded in the RAM 8.

The data to which the correction code has been added is read out from RAM 8 in order to be recorded on the magnetic tape. The address generated by the continuous read address generation circuit 10 is transferred to the address switching circuit 1.
4, and specify the address of RAM8. At this time, the read address generation circuit 10 is controlled by the read address control circuit 11, and generates an address and reads data from the RAM 8 only when the rotary head is at a predetermined position on the magnetic tape.

The read data is sent to the recording signal generation circuit 16 via the data bus 15, one block at a time.

A block is configured by adding a synchronization signal, block address, etc. The constructed signal block is modulated by a modulation path 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 control signal that has already been recorded is detected by the tracking signal detection circuit 23, 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, data on the magnetic tape 21 is transferred to the playback circuit 2 through the one-rotation head 20.
Sent to 2. The tracking signal detection circuit 23 detects a tracking signal used for accurately tracking 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 discrimination signal, the read address control circuit 11 controls the read address generation circuit 20, sets the address of the RAM 8, and reads 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, a signal area discrimination signal is generated for each track based on the tracking control signal, and at the same time, the reproduction state is switched from the recording state to the recording state.
By overwriting and recording signals, it becomes possible to rewrite only the PCM signal or subfood signal. 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 overwriting using this method,
Partial overwriting of recorded silver data can be easily and accurately performed.

FIG. 2 is an example of a recording pattern on a magnetic tape.

In the same figure, 30 is the track margin, 31 is the PCM
Areas 32 and 33 are areas for recording sub-food signals related to PCM signals, areas 34 and 55 are areas for recording time-sharing tracking control signals used by the rotary head for accurate tracking, and 36 is an area for recording signals. An area for recording a preamble signal, 37 a margin area provided between each signal, 38 an area representing one block in a data signal, 39 an area for recording a synchronization signal in one block, and 40 a control signal. 41 is an area for recording block addresses, 42 is an area for recording parity added to the control signal 40 and block address 41, and 43 is an area for recording data.

The time-division tracking control signal 34.55 is a pilot signal for tracking control as specified in Japanese Patent Laid-Open No. 58-122606, and the preamble signal 36 is specified in Japanese Patent Laid-Open No. 58-143432. This is a synchronization signal like this.

The PCM signal area 31 is composed of 128 blocks, and each block has a synchronization signal of 39 degrees and a control signal of 40 degrees.
, block address 41, and parity 42 are 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. Furthermore, parity 42 is added to control signal 40 and block address 41, and is used to check whether or not they are correct during reproduction.

The sub-food signal areas 52 and 33 each consist of 8 blocks, and the block configuration is similar to that of the PCM signal area 31.
is the same as In addition, the tracking control signal area 34
, 35 are 5 blocks each, preamble signal area 3
6 has a length of 2 blocks, the track margin 30 has a length of 11 blocks, and the inter-signal margin 37 has a length of 3 blocks.

One track shown in FIG. 2 has a length of 196 blocks.

FIG. 3 is a timing chart of the signal area (PCM signal area and subfood 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, 54 is a subcode signal area discrimination signal, 5
5 is a rotating head scanning section.

The rotating head scanning section 55 of the rotating head output signal 50 is
This corresponds to the recording pattern shown in FIG. 2, and in this example,
Since two recording/reproducing heads are used and the magnetic tape 21 is wound at a 90° angle, the rotary head output signal is 50°.
In the figure, the rotating head scanning section 55 is displayed at 90° every 180°. A tracking control signal 52 is obtained by inputting the rotary head output signal 50 to the reproduction circuit 22 and tracking signal detection circuit 25 shown in FIG.

PCM signal area 31, subcode signal areas 32 and 3
5. The positional relationship of the tracking control signals 34 and 35 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, the starting position of a PCM signal area for each track varies, and this variation depends on the mechanical accuracy of the rotating head or the like.

Therefore, when overwriting the magnetic tape 21 recorded by different devices, if the position of the rotary head 20 is used as a reference, if the signal to be recorded, for example, the subcode signal, is to be overwritten, the signal that has already been recorded will be overwritten. Although it is necessary to record at the same position as the recorded sub-food signal, there is a possibility that the sub-food signal is overwritten and recorded in an area other than the sub-food 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 used to generate a signal for determining the data signal area, that is, the PCM signal area 31 or the subfood signal areas 32 and 33. Using the signal area discrimination signals 53 and 54, the RAM 5
By controlling the read address generation circuit 10 and the recording/reproduction switching circuit 19, it is possible to rewrite only the portion to be overwritten and recorded.

FIG. 4 shows the configuration of the signal region discriminating signal generation circuit 24. In the figure, S60 is an input terminal for a signal that selects the PCM signal 31 or subfood signals 32 and 33, and 63 and 64 are detection signals for tracking control signals, respectively. , 65 is an OR circuit, 70 is a counter, 67 and 68 are input terminals for load values given to the counter, 70
is a load value switching circuit, 71 is a counter load signal input terminal, 72 is a counter load value input terminal R73 is a counter clock signal input terminal, 75 is an external clock signal input terminal, 76 is a decoder for setting a data area, 77 is a signal This is an output terminal for an area 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. number of blocks,
In this embodiment, it is a counter that counts 392 blocks.

The decoder 76 generates a signal area discrimination signal that sets the data area as %1' and other areas as 10' based on the value of the counter 74. At this time, data selection signal input terminal 6
The selection signal input from 0 selects which of the PCM signal area discrimination signal 53 and the subcode signal area discrimination signal 54 is to be generated.

Tracking control signal detection borrowed blade terminals 63° 64,
When the detection signals of the tracking control signals 54 and 55 are input, they are applied to the counter 74 through an OR circuit 65 as a load signal for loading the counter 74.

Now, the tracking control signal 34 is input to the detection signal input terminal 63.
Assume that a detection signal of is input. The detection signal is given as a load signal to the counter 74 and at the same time selects the load value from the load value input signal terminal 67. 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 as the load value when the tracking control signal is detected, the counter can be adjusted to the actual value. It becomes possible to operate according to the data signal.

The value of this counter is input to the decoder 76, and
In step 6, a signal region discrimination signal is generated based on this value. Similarly, when the detection signal of the tracking control signal 35 becomes a counter load signal, 1. The counter load value input terminal 68 when the tracking control signal 35 is detected.
The load value from is selected and loaded into counter 74.

Although the tracking control signal is used in this embodiment, it is also conceivable to use the preamble signal 36 instead of this signal to generate the data area discrimination signals 53 and 54. In FIG. 2, the preamble signal 36 is a PCM
It is located immediately before the signal area 31 and subcode signal areas 32 and 35. Therefore, based on the preamble signal 36,
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 indicating the presence or absence of the tracking control signals 34 and 65, and 62 is a position detection signal input terminal 166 that indicates the position of the rotating head. 69 is a load value input terminal which is selected when the load signal is a rotary head position detection signal.

When the tracking control signals 34 and 35 are detected, the load signal of the counter 74 is changed to the tracking control signal detection signals 65 and 64 by the load signal switching circuit.
is selected, and the load value is also selected by the load value switching circuit 70.
The load value at the time of tracking control signal detection is 67,
68 is selected. However, in this case, if the tracking control signals 34 and 35 are not detected, the load signal disappears and the counter 74 is not loaded. In this embodiment, even in such a case, the counter 74 is correctly set.
When the special tracking control signals 34 and 55 are not detected,
In response to the tracking control signal detection signal inputted from the input terminal 61, the load signal selection circuit 66 selects the rotary head position detection signal as the load signal for the counter 74. At the same time, the load value from the input terminal 69 is selected as the load value and loaded into the counter 74. The counter 74 starts counting from this value, and the decoder 76 generates a signal region discrimination signal.

Therefore, even when the tracking control signals 35 and 56 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, and it is possible to generate a normal signal area discrimination signal by overwriting the data. Can be rewritten.

〔Effect of the invention〕

According to the present invention, it is possible to accurately determine the PCM signal area or subcode signal area in the reproduced digital signal, and with this determination signal, partial rewriting of previously recorded data can be performed, that is, the PCM signal area or the subcode signal area can be accurately determined. or only the subfood signal can be rewritten accurately.

Furthermore, 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 drawings]

FIG. 1 is a block diagram showing an embodiment of a recording device for a rotary head type PCM recorder using the present invention, FIG. 2 is a diagram showing an example of a recording pattern on a magnetic tape, and FIG.
FIG. 2 is a timing chart showing a signal reproduced from a recording pattern 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 overwrite selection signal, 5... A/D
Converter, 6.7... Rack generation circuit, 8... Random access memory (RAM), 9...
Write address generation circuit, 10-... Read address generation circuit, 11... Read address control circuit 1
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--Record/reproduction switching circuit, 20--Rotating head, 21--Magnetic tape, 22--Reproducing circuit, 23--Tracking control signal detection circuit, 24--・・・
Discrimination signal generation circuit, 65...OR circuit, 66, 70...switching circuit, 74...counter, 76...decoder. b - ~ h
Trout Octopus
Kozue o h Crying Pigeon Biting Turtle ; Yar Chi Dan procedural amendment (spontaneous) Indication of the case 1985 Patent Application No. 74252 Title of the invention
Name of the patent applicant (5101 Hitachi Tsuji Co., Ltd.) Manufacturer's agent who corrected the digital signal recording device (11 cases) Figure 5 of the drawing.

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 rotary head, the plurality of types of digital signals being recorded on a magnetic recording medium. a memory circuit for storing data at once, a memory circuit control circuit for controlling storage and reading of data in the memory circuit, a code generation circuit for adding an error correction code to the plurality of types of digital signals, and the tracking control circuit. A digital signal recording device comprising a tracking control signal generation circuit that generates a 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. a tracking control signal detection circuit for detecting a tracking control signal by reproducing a signal from the tracking control signal; and an area in which 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 the
A digital signal recording device comprising a control circuit and a recording/reproduction switching circuit for performing recording only in an area where at least one type of digital signal among the plurality of digital signals is recorded according to the discrimination signal. 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 the rotary head.