JPH0563858B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a magnetic recording and reproducing device, and particularly to a digital audio tape recorder (hereinafter referred to as
This invention relates to overwriting control of subcode data in devices such as DAT (simply referred to as DAT).

[Prior Art] Conventionally, as a magnetic recording/reproducing apparatus for recording PCM signals on a magnetic tape, there is one that uses a rotating head, such as a DAT. In this method, the recording track on the magnetic tape has signal areas arranged in the order of subcode area, ATF area, PCM area, ATF area, and subcode area along the running direction of the head, as shown in Figure 4. .
The track can be divided into 196 blocks, and each area consists of the number of blocks shown in the figure. 1
A block consists of 32 symbols, and one symbol consists of 8 bits. PCM audio data and the like are recorded in the PCM area, and ATF signals for automatic tracking detection are recorded in the ATF area. Furthermore, subcode regions of interest to the present invention include various controls,
Subcode data (for example, time information and track number information) used for display etc. is recorded.

As shown in Figure 4, a total of 16 blocks (8 blocks above and below) are allocated to the subcode area, but since the data length of the subcode data can be lengthened or shortened as necessary, the data length of the subcode data can be lengthened or shortened as necessary. does not necessarily require 16 blocks.
For example, in some cases, only two blocks are required.
In such a case, the remaining 14 blocks will become empty areas, but in this case, the remaining 14 blocks of subcode area will be wasted. Therefore, conventionally, the same subcode data is repeatedly and continuously recorded in empty areas to prevent misreading. Write this N times (N=
8, 4, 2, 1).

FIG. 5 is a block diagram showing a conventional DAT recording system capable of N-multiple writing of subcode data.
Further, FIG. 6 is a diagram showing a subcode data storage area in the memory 4 shown in FIG. 5. Fifth
In the figure, an analog signal (for example, an audio signal) that enters a low-pass filter 1 from the outside is sampled by a sample-hold circuit 2 after its high-frequency components are removed, and converted into a digital signal by an A/D converter 3. converted. On the other hand, the subcode data sent from the microcomputer 5 is once written into the memory 4 having a buffer function in order from block address 0 along the memory map recording direction l in FIG. Here, P in FIG. 6 indicates C1 parity, that is, an error correction code (consisting of 8 symbols). Note that at the stage when parity is created, two blocks are combined into one block, and the parity is ultimately stored together in odd-numbered blocks.

By the way, as mentioned above, subcode data is not necessarily stored in all blocks of block addresses 0 to F. For example, the subcode data may be stored only in block addresses 0 and 1, and in this case, the same subcode data can be written 8 times on the magnetic tape. In the same way, if subcode data is stored in blocks with block addresses 0 to 3, quadruple writing is possible, and if subcode data is stored in blocks with block addresses 0 to 8, Double writing is possible. Also, block address 0~
If subcode data is stored in all blocks of F, only single writing is possible. Microcomputer 5 accesses memory 4 multiple times depending on the data length of the subcode data (ie, how many blocks of subcode data there are), and reads the subcode data to signal processing circuit 6. The signal processing circuit 6 processes the digital signal from the A/D converter 3 a plurality of times (sometimes once).
Add the read subcode data and output.
The output of the signal processing circuit 6 is amplified by a head amplifier 7 and then recorded on a magnetic tape 9 by a magnetic head mounted on a rotating drum 8.

[Problems to be solved by the invention] As mentioned above, in the conventional magnetic recording and reproducing device,
When overwriting subcode data, the microcomputer 5 has to access the memory 4 multiple times, which poses a problem in that the burden on the microcomputer becomes heavy. Moreover,
Since multiple accesses had to be made at high speed, a high-speed microcomputer was required, which also raised the cost.

This invention was made in order to solve the above-mentioned conventional problems, and it is possible to lighten the burden on the microcomputer and speed up access for reading subcode data without increasing costs. The object of the present invention is to provide a magnetic recording/reproducing device that can perform the following operations.

[Means for Solving the Problems] A magnetic recording and reproducing device according to the present invention is for recording a PCM signal on a magnetic recording medium and reproducing the PCM signal recorded thereon. storage means for pre-storing subcode data to be recorded in a subcode area of the recording medium;
An address counter that counts the applied clock signal and generates a multi-bit address signal while sequentially incrementing it, a plurality of gate means provided for each bit of the address signal, and a microcontroller that controls opening and closing of each gate means. It is characterized in that it comprises gate control means consisting of a computer, and the outputs of the plurality of gate means are applied to the storage means as address signals for reading subcode data.

[Operation] In the present invention, the same address can be given to the storage means several times in succession simply by the microcomputer controlling the opening and closing of each gate means, and as a result, the burden on the microcomputer is lightened.

[Embodiment] FIG. 1 is a block diagram showing a recording system of a magnetic recording/reproducing apparatus according to an embodiment of the present invention. In the figure, this embodiment has the same configuration as the conventional device shown in FIG. 5 except for the following points, and corresponding parts are given the same reference numerals and the explanation thereof will be omitted as appropriate. In the figure, a microcomputer 50 constitutes gate control means and outputs a clock signal and gate control signals A to D. The clock signal includes 16 clock pulses and is applied to an address counter 61 provided within the signal processing circuit 60. Address counter 61 counts clock pulses included in the clock signal and outputs a 4-bit address signal. These 4-bit address signals are applied to one input of each of AND gates 11-14, respectively.
The gate control signals A to D are applied to respective local inputs of the AND gates 11 to 14, respectively.
The outputs of the AND gates 11 to 14 are used as address signals for specifying the block address of the subcode data storage area (see FIG. 6).
given to.

Next, the operation of the embodiment shown in FIG. 1 will be explained.
First, the operation when performing octet writing of subcode data will be explained. In this case, the gate control signals A, which are output from the microcomputer 50,
B, C, and D are set to (1, 0, 0, 0).
Therefore, only AND gate 11 allows the address output of address 61 of address counter 61 to pass through. FIG. 2 is a diagram showing changes in the 4-bit address signal of the address counter 61 with respect to 16 clock pulses. As mentioned above, in the case of 8-overwriting, only the AND gate 11 passes the output (lowest bit) of the address counter 61, so the block address given to the memory 4 is (0, 0, 0, 0). (0,
0, 0, 1) are given 8 times alternately. Therefore, on the magnetic tape 9, as shown in FIG. 3a, the subcode data of block addresses 0 and 1 of the memory 4 are written eight times each, that is, eight times.

Next, when subcode data is written in four layers, the gate control signals A, B, C, D are (1,
1, 0, 0). In this case, only AND gates 11 and 12 are connected to address counter 61.
The block address given to memory 4 is (0, 0, 0, 0).
and (0, 0, 0, 1) (0, 0, 1, 0,) (0,
0, 1, 1) will be repeated four times each.
Therefore, on the magnetic tape 9, as shown in FIG. 3b, the block addresses 0, 1,
The second and third subcode data are each written four times, that is, four times.

Similarly, in the case of double writing and single writing, the gate control signals A, B, C, and D are (0,
1, 1, 1), (1, 1, 1, 1), and the subcode data is written in double or single writing as shown in FIG. 3c and d.

[Effects of the Invention] As explained above, according to the present invention, the microcomputer does not need to access the storage means multiple times when overwriting subcode data, and can simply control opening and closing of the gate means. This reduces the burden on the microcomputer. Furthermore, since the storage means is accessed at high speed in response to the counting operation of the address counter, there is no need to use a high-speed microcomputer, and the device can be constructed at low cost.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a recording system of a magnetic recording/reproducing apparatus according to an embodiment of the present invention. Figure 2 is 16
address counter 6 for clock pulses
FIG. 1 is a diagram showing a change state of a 4-bit address signal of 1; FIG. 3 shows subcode data written in 8 layers, 4 layers, and 2 layers in the embodiment shown in FIG.
FIG. 4 is a diagram showing recording states on a magnetic tape and corresponding gate control signals in the case of overwriting and single writing. FIG. 4 is a diagram showing the configuration of recording tracks on a magnetic tape in a conventional DAT. Fifth
The figure is a block diagram showing a recording system of a conventional magnetic recording/reproducing device. FIG. 6 is a diagram showing a subcode data storage area provided in the memory 4 shown in FIG. 5. In the figure, 1 is a low-pass filter, 2 is a sample and hold circuit, 3 is an A/D converter, 4 is a memory, 7 is a head amplifier, 8 is a rotating drum, 9 is a magnetic tape, 11 to 14 are AND gates, and 50 is a micro computer, 60 is a signal processing circuit, 61
indicates an address counter.

Claims (1)

[Scope of Claims] 1. A magnetic recording and reproducing device for recording a PCM signal on a magnetic recording medium and reproducing the PCM signal recorded thereon, which comprises: an address counter that counts applied clock signals and generates a plurality of bits of address signals while sequentially incrementing them; and a plurality of gate means provided for each bit of the address signal. , and gate control means comprising a microcomputer that controls opening and closing of each of the gate means, and outputs of the plurality of gate means are provided to the storage means as an address signal for reading the subcode data. A magnetic recording and reproducing device.