JPH0534744B2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a digital dubbing error detection method, and particularly to a method for digitally recording audio data on a magnetic tape using a rotating head, and reading and reproducing the audio data from the magnetic tape. The present invention relates to a digital dubbing error detection method for a digital audio device.

<Prior art> A digital audio device (R
- There is a DAT device). In such an R-DAT, similar to a video tape recorder (VTR), recording/playback heads are provided at intervals of 180 degrees from each other to form a rotating head, and the traveling locus of each head on the tape surface is parallel to the longitudinal direction of the magnetic tape. It is configured to be tilted with respect to the direction, and is configured to record 16-bit linear AD-converted audio data on a magnetic tape using a rotating head, and to reproduce and output the audio data read from the magnetic tape.

Furthermore, some R-DATs record not only audio data from analog sources but also audio data from digital sources such as compact disk devices (CD devices) (referred to as digital dubbing).
This is because some CD devices have recently become available that have a digital output terminal that directly outputs the digital data read from a compact disc.

<Problems to be Solved by the Invention> By the way, in the case of playback using an analog record player, if there is a skip, an abnormal sound will occur, and the skip can be easily detected. However, in the case of playback using a CD device, even if there is a skip, no abnormal sound is generated, so it is often possible to dub without noticing the skip. Furthermore, when dubbing is performed without listening to the reproduced sound, it is of course impossible to detect abnormalities such as skipping.

If digital dubbing is performed on a magnetic tape with skipping abnormalities, it is naturally impossible to record audio of good quality. However, conventionally, it has not been possible to easily detect skipping during digital dubbing.

In light of the above, an object of the present invention is to provide a digital dubbing error detection method that can easily detect skipping.

<Means for Solving the Problems> The present invention is a method for detecting digital dubbing errors in a digital audio device that digitally records audio data on a magnetic tape and also reads and reproduces audio data from the magnetic tape. In addition to monitoring the time from the start of dubbing to the current time, (b) comparing the current time with the time indicated by subcoding included in the digital data sent from the compact disk device, and (c) comparing both times. If the values are discontinuous, it is determined that a dubbing error has occurred.

<Function> In addition to monitoring the time ta from the start of dubbing,
This time is compared with the time ts specified by the subcoding included in the digital data sent from the compact disc device, and if both times are discontinuous, it is assumed that a dubbing error has occurred and the time ts is set during digital dubbing. Detect errors caused by skipping. Note that the time comparison is performed every predetermined time ΔT,
If both time differences |ts−ta| are within the allowable range, it is considered continuous, and if it is not within the allowable range, it is considered discontinuous. Then, in the case of continuous time, the current time ta is updated with the time ts specified by the subcoding (ts →
ta), and time comparisons are made every ΔT thereafter.

<Example> FIG. 1 is a schematic configuration diagram of a system that implements the present invention, and FIG. 2 is a flowchart of processing according to the present invention.

In FIG. 1, 11 is a CD device, 12 is an R-
It is DAT. The CD device 11 is provided with a digital output terminal 11a, and digital data read from a compact disc (CD) is sent directly to the R-DAT 12 via a signal line SL connected to this terminal. Therefore, R-DAT1
If the switch (not shown) is operated to set the digital dubbing mode, the R-DAT's processor 12a stores the digital data in the built-in RAM 12b.
Thereafter, the digital data is read from the RAM in synchronization with a predetermined clock of the R-DAT and recorded on the magnetic tape via the rotary head 12c. In FIG. 1, 13 is an analog source (for example, a record player), and 12d is an AD converter.

The digital dubbing error detection process according to the present invention will be explained below with reference to FIG.

(1) When digital dubbing is started, the CD device 11 will R the digital data read from the CD.
-Transfer to DAT12.

(2) The processor 12a of the R-DAT 12 immediately updates the current time ta as soon as the digital data is transferred.
is set to zero (0→ta), and thereafter a CRC check of subcoding is performed every predetermined time ΔT.

(3) If there is an error in the subcoding as a result of the CRC check, the processor updates the current time using the following equation ta + ΔT → ta, and performs a CRC check every ΔT thereafter.

(4) If there is no error in the subcoding by checking the CRC, the processor compares the current time ta with the time (absolute time from the start of the performance) ts indicated by the subcoding.

(5) Compare the current time ta and the time ts specified by subcoding, and if both times are discontinuous, it is assumed that there was a dubbing error due to skipping,
If it is continuous, it is assumed that there is no dubbing error. In addition, when the time difference between both |ts−ta| is found and the time difference is within the allowable range, in other words, when the following equation ΔT−Ta≦|ts−ta|≦ΔT+Ta holds true, time is considered continuous, and when it does not hold, time is considered continuous. Time is assumed to be discontinuous. However, Ta is the allowable time.

(6) If the time is continuous, the processor 12a calculates the current time ta at the time ts specified by the subcoding.
is updated (ts → ta), and the process from step (1) onwards is repeated.

(7) However, if the time is discontinuous, an error display is output and the dubbing error detection process is stopped.
In addition to the fact that there is a skip, the error display can also display the skip time. Also, even if an error is detected, the error detection process is not stopped and the number of error occurrences E is updated (E+
1→E) may be displayed and the processing may be continued as ts→ta.

<Effects of the Invention> According to the present invention, the time from the start of dubbing is monitored, and the time is compared with the time instructed by subcoding included in the digital data sent from the compact disc device. I configured it so that if both times are discontinuous, it is assumed that there was a dubbing error due to skipping.
You can easily detect skips during digital dubbing.

[Brief explanation of the drawing]

FIG. 1 is a schematic block diagram of a system to which the present invention can be applied, and FIG. 2 is a flowchart of processing according to the present invention. 11...CD device, 12...R-DAT, 12a
...Processor, 12b...RAM, 12c...
rotating head.

Claims (1)

[Claims] 1. A digital dubbing error detection method for a digital audio device that digitally records audio data on a magnetic tape and also reads and reproduces audio data from the magnetic tape, which monitors the time from the start of dubbing and The time is compared with the time indicated by sub-coding included in the digital data sent from the compact disk device, and if both times are discontinuous, it is determined that a dubbing error has occurred. Digital dubbing error detection method. 2. The time difference is compared at predetermined time intervals, and if both time differences are within an allowable range, the time difference is determined to be continuous, and if not within the allowable range, the time difference is determined to be discontinuous. Digital dubbing error detection method. 3. The digital dubbing error detection method according to claim 1 or 2, characterized in that, in the case of continuous recording, the current time is updated with the time indicated by sub-coding.