JPS63181175A - Magnetic reproducing device - Google Patents

Abstract

PURPOSE:To prevent a data having much error from being recorded on a magnetic tape by providing a modulation circuit modulating a data converted by a conversion circuit and outputting the result to a magnetic recorder via a transmission interface. CONSTITUTION:A memory 4 storing a signal, a detection circuit 6 detecting a flag, conversion circuits 8, 9 converting a data and a modulation circuit 13 modulating the data are provided. A signal reproduced from the magnetic tape is stored once in a memory 4 and if the data stored in the memory 4 has an error, it is corrected and a flag representing the correcting state is detected by the circuit 6. The data stored in the memory 4 is converted into a signal substantially being no information by the conversion circuits 8, 9 corresponding to the output of the circuit 6. The data is modulated by the modulation circuit 13 and sent to the magnetic recorder via the transmission interface. Then it is prevented that an error data is recorded on the tape as a correct data.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic reproducing device typified by R-DAT.

[Summary of the invention]

In the present invention, when errors in reproduced data are uncorrectable, the data is transmitted as substantially informationless data.

[Conventional technology]

In R-DAT, subcode data is recorded together with PCM audio data. Subcode data is 1
Two areas of the track (SUB-1, 5UB-2
) is recorded. The subcode data of each area consists of 8 blocks of data, and one block consists of 32 symbols (one symbol is 8 bits) of data. Each block is assigned an address from O to F (hexadecimal number), and a set of odd symbols and a set of even symbols in two blocks, a block with an even number address and a block with an odd number address that is 1 larger than the block with an even number address, are assigned one each. Error correction is performed as a unit.

Assuming that the odd symbols are error correction A blocks and the even symbols are error correction B blocks, there are two error correction blocks A and H in the two blocks. Each error correction block consists of 32 symbols, with 28 symbols being data and 4 symbols being parity.

In this subcode data, program time, absolute time, TOC information, etc. can be recorded as a pack (PACK). The subcode is not updated in one frame consisting of two consecutive tracks with different head azimuths. For example, time codes at the same time are recorded on the two tracks. Each pack consists of a 4-bit item (ITEM) and 60-bit data and parity, and the item represents the content (item) of the data.1For example, item (0001) is the program time, and (OO10) is the absolute time. Each represents (0000
) indicates no information (all data is O).

[Problem that the invention seeks to solve]

For example, when a signal reproduced by a first device is transmitted to a second device and recorded by the second device, even if the error in the data reproduced by the first device is uncorrectable, conventional The device was configured to transmit the subcode data as is to the second device. As a result, there was a risk that the device in tube 2 would record incorrect data on the tape as correct data.

[Means for solving problems]

The present invention provides a magnetic reproducing device including: a memory for storing signals reproduced from a magnetic tape; a detection circuit for detecting a flag indicating error correction status of data stored in the memory;
A conversion circuit that converts the data stored in the memory into a substantially informationless signal in response to the output of the detection circuit, and modulates the data converted by the conversion circuit and outputs it to the magnetic recording device via the transmission interface. A modulation circuit is provided.

[Effect]

Signals reproduced from the magnetic tape are temporarily stored in memory. If there is an error in the data stored in this memory, it is corrected, and a detection circuit detects a flag indicating the correction status. The data stored in memory is
Corresponding to the output of the detection circuit, it is converted into a substantially informationless signal by a conversion circuit. The data converted by the conversion circuit is modulated by the modulation circuit and transmitted to the magnetic recording device via the transmission interface.

〔Example〕

FIG. 1 shows the magnetic recording/reproducing device t! of the present invention. ! (Magnetic reproducing device) is a block diagram when applied to R-DAT.

In the figure, 4 is a memory (RAM).

Stores signals (subcode data) that are reproduced from a magnetic tape (not shown) and input via a data bus - If there is an error in the data stored in the memory 4, a processing circuit (not shown) is included in the data. The error is corrected using parity (C1 correction code). A 01 correction flag indicating the error correction status is stored in the memory 4. This flag can represent, for example, no errors, the number of corrected data, and uncorrectable.

Decoder 1 decodes the input data selection signal,
It is output to the timing signal generation circuit 2.

A timing signal generation circuit 2 generates a predetermined timing signal in response to the output of the decoder 1. The address generation circuit 3 outputs a predetermined address signal in synchronization with the input timing signal. This address signal is supplied to the memory 4 via the address bus, and data at the designated address is read out via the data bus.

The subcode data stored in the memory 4 is structured as shown in FIG. 4, for example. That is, on the magnetic tape, as shown in the 0th and 1st blocks, 32 symbols in even blocks and 24 symbols up to the 23rd symbol in odd blocks, a total of 56 symbols, are used as data, and data starts from the 24th symbol in odd blocks. For the 8 symbols up to the 31st symbol, the even symbols are recorded as the parity Pa of the error correction block A, and the odd symbols are recorded as the parity pb of the error correction block B.
The stored data is organized as shown in the second and third blocks, for example. Similarly, a total of 56 symbols, 32 symbols of even blocks and 24 symbols of odd blocks, are used as data, but parities Pa and Pb are not stored, and instead, a flag Fa indicating the error correction status is stored.
, Fb are stored. Flags Fa and Fb are flags for error correction blocks A and B, respectively. Or the fourth and fifth
As shown in the block (illustration of 56 symbols of data is omitted), the flag with the worse error correction status (for example, the one with a larger number of errors or the one that cannot be corrected) of the flags Fa and Fb is the flag Ft. is stored as.

Data read from the memory 4 is latched by the latch circuit 5, and further stored in the shift register 7, which also constitutes the memory. The detection circuit 6 detects a flag from data supplied from the latch circuit 5 or the shift register 7. The detection circuit 6 detects a flag (
For example, when the number of errors is greater than a predetermined reference value or an uncorrectable flag is detected, the multiplexer (MPX) 8 serving as a conversion circuit converts the subcode data output from the shift register 7 into virtually no information. (For example, set all data to O).

A sync generation circuit 10 generates a predetermined sync signal. Further, a process circuit 11 controlled by a microcomputer or the like (not shown) generates and outputs V, U, and C signals.

The (2) signal represents a validity flag regarding the reliability of the audio signal, the U signal represents data for the user (user data), and the C signal represents data regarding the channel status.

The outputs of multiplexer 8 , sync generation circuit 10 and process circuit 11 are selected by multiplexer 9 and supplied to parity generation circuit 12 .

The parity generation circuit 12 applies parity (P) to the input signal.
signal) is added and output to the modulation circuit 13.

The modulation circuit 13 performs pi-phase modulation on the input signal and outputs it to a magnetic recording device (not shown) via a transmission interface. A magnetic recording device processes signals transmitted via a transmission interface and records them on a magnetic tape.

FIG. 3 represents the format of the signals thus transmitted via the transmission interface. That is, 1440 frames of signals are transmitted during one rotation of a drum (not shown) to which a rotary head is attached. Each frame consists of a first channel subframe and a second channel subframe, and each subframe has a 4-bit preamble (sync) and an 8-bit AUX
It is composed of DATA (subcode data), 16-bit audio data, and 1-bit V, U, C, and P data each. The data of the first channel is arranged in the subframe of the preamble M, and the data of the second channel is arranged in the subframe of the preamble W, respectively. AUX of the first two subframes of one revolution
Flags Fa and Fb are arranged as DATA (flag F
(In the case of t, the subcode data is placed in the first one subframe), and 32 symbols of subcode data of the even address block are used as AUX DATA of the following 56 subframes.
The subcode data of 24 symbols of odd address blocks are arranged sequentially. Furthermore, the subsequent 6 (flag Ft
In the case of 7), data with no information (for example, all O's) is placed in the subframe.

FIG. 2 shows a flowchart when the operation of transmitting data in this manner is executed by a microcomputer or the like. As shown in FIG. 2(a), first, SYNC is sent out.

A sub-flowchart of this sink transmission is shown in FIG. 2(b). That is, a sync is generated by the sync generating circuit 10 and sent out via the multiplexer 9.

Next, it is determined whether the transmission of the C1 correction flag has been completed. In the first subframe of one rotation, no flag has been sent out yet. Therefore, as shown in the subflowchart of FIG. 2(c), for example, the flag Fa detected by the detection circuit 6 is transmitted via the multiplexer 8.9. be done.

Further, like the subcode data, audio (PCM) data stored in the memory 4 (or other memory may be used) and output from the shift register 7 is sent to the multiplexer 8.9.
Sent via . Thereafter, the V, U, and C signals generated by the process circuit 11 are transmitted via the multiplexer 9, and the parity generation circuit 12 generates the parity (P) signal.
signal) is transmitted.

After the data for the first subframe is transmitted in this manner, the data for the second subframe is transmitted in the same manner. At this time, flag Fb is transmitted instead of flag Fa. In the third and subsequent subframes, the sending of the flag has ended, so subcode data is sent instead of the flag. Subcode data exists only for the first 24 symbols in odd blocks,
Since there is virtually no data in the remaining 6 (7 in the case of flag Ft) symbols, they are all set to O.

Furthermore, when data substantially exists, the output of the shift register 7 is transmitted as is when the detection circuit 6 detects the correctable flag, as shown in the subflowchart of FIG. When , the data is substantially all zero.

On the other hand, when sending out the flag Ft, the process shown in FIG. 2(e) is performed. That is, the flags Fa and Fb are compared, and the flag that is less favorable is set as the flag Ft, and this flag Ft is sent out in place of the aforementioned flag Fa.

In this way, the subcode data and audio data are
is transmitted from the magnetic reproducing device to the magnetic recording device via the transmission interface according to the format shown in the figure,
stored in the memory of a magnetic recording device. A magnetic recording device processes the data 1 and records it on magnetic tape.

Detect flag Fa, Fb or Ft with a magnetic reproducing device,
When uncorrectability is detected, all the corresponding two blocks of subcode data are converted to O and sent. Therefore, the recording device only needs to add parity to two blocks of subcode data without detecting flags Fa, Fb or Ft, and no special processing is required.

〔effect〕

As described above, the present invention provides a magnetic reproducing apparatus that includes a memory for storing signals reproduced from a magnetic tape, a detection circuit for detecting a flag indicating the error correction status of data stored in the memory, and an output of the detection circuit. and a modulation circuit that modulates the data converted by the conversion circuit and outputs it to the magnetic recording device via a transmission interface. This makes it possible to prevent erroneous data from being recorded on the magnetic tape and causing the device that played it back to malfunction, without having to perform any special processing on the data received by the magnetic recording device. .

[Brief explanation of the drawing]

FIG. 1 is a block diagram of the magnetic recording/reproducing apparatus of the present invention, and FIG.
The figure is a flowchart, FIG. 3 is an explanatory diagram of the transmission format, and FIG. 4 is an explanatory diagram of the subcode data. 1...Decoder 2...Timing signal generation circuit 3...Address generation circuit 4...Memory 5...Latch circuit 6...Detection circuit 7...Shift register 8.9...Multiplexer 10...Sink generation circuit 11...Process circuit 12...Parity generation circuit 13...Modulation circuit or higher

Claims (1)

[Claims] A memory that stores signals reproduced from a magnetic tape, a detection circuit that detects a flag indicating the error correction status of the data stored in the memory, and data stored in the memory corresponding to the output of the detection circuit. A magnetic reproducing device comprising: a conversion circuit that converts data into a substantially information-free signal; and a modulation circuit that modulates the data converted by the conversion circuit and outputs the data to a magnetic recording device via a transmission interface. Device.