JP3365514B2 - Absolute time recording method for DAT device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of recording an absolute time on a subcode recording section of a magnetic tape by a DAT device having a subcode recording function and a subcode recording function. . [0002] In a recording format of a magnetic tape by a DAT (Digital Audio Tape Recorder) device, in addition to a PCM recording section for recording a music signal, various information such as a song number and a playing time are recorded. A sub-code recording unit is provided. The sub-code recording section can be recorded later separately from the PCM recording section (so-called post-recording function). Many DAT devices record a start ID (song number) indicating the beginning of a song and an end mark indicating the end at the time of recording in the subcode recording section, and perform a high-speed search for the song during reproduction. it can. In addition, a function is provided for recording the elapsed time (hereinafter referred to as absolute time) from the beginning of the tape, or more precisely, the boundary between the leader tape and the magnetic material application portion, in the subcode recording section during recording. [0004] However, some portable DAT devices and the like do not have an automatic recording function of absolute time. Also, when recording from the middle of the tape, the absolute time may not be recorded. In these cases, it is convenient if the absolute time can be recorded later using the above-mentioned post-recording function. A problem at this time is that when a start ID and an end mark are recorded in the subcode recording section, the start ID and the end mark are erased by overwriting the absolute time. The present invention has been made in view of such circumstances, and an object thereof is to enable the absolute time to be recorded later without erasing a start ID and an end mark. SUMMARY OF THE INVENTION An absolute time recording method according to the present invention provides a DA code having a subcode recording function and a subcode recording function.
A method of recording an absolute time in a subcode recording section of a magnetic tape by a T device, the characteristic configuration of which is that a correct absolute time is recorded from a start end of the magnetic tape and a start I
A position on the subcode recording section (8b) where D or the end mark is not recorded is defined as a reference position (A '),
By counting the number of tracks from the reference position (A '), the absolute time of the position (A) of the start ID or end mark recorded first after the reference position (A') is obtained and stored. , From the reference position (A)
A high-speed search is performed on the tape end area to
Counting the next start ID or end
After detecting the position (B) where the data mark is recorded and rewinding to the reference position (A ′), the recording of the absolute time in the subcode recording section (8b) is performed at the reference position (A ′).
And when the stored absolute time is reached, the start ID or the end mark is recorded in the subcode recording section (8b) together with the absolute time , and
The recording of the absolute time in the recording unit (8b) is performed by the next star.
Location (B) where the ID or end mark is recorded
To a position (B ') obtained by subtracting a predetermined value from
Thus, the first recorded start ID or end mark is prevented from being erased. The correct absolute time is recorded from the beginning of the magnetic tape to a certain position, but the absolute time is not recorded after that position or the wrong time is recorded. . If that position is the reference position, the start ID
Alternatively, the absolute time of the position where the end mark is recorded can be uniquely calculated by counting the number of tracks from the reference position. Then, after storing the calculated absolute time and rewinding it to the reference position, the correct absolute time after the reference position is recorded, and if the absolute time reaches the above stored absolute time. The start ID or the end mark is recorded. However, when the start ID or the end mark is detected, the calculated absolute time is stored and the rewind is not immediately performed to the reference position . In the case of the start ID, the end mark is continuously searched at high speed, the approximate position of the end mark is stored as the number of FG pulses of the capstan motor, and then the end mark is rewound to the reference position. It can be executed up to the position before the position. As described above, according to the present invention, the absolute time can be recorded later without erasing the start ID and the end mark, which is convenient. Embodiments of the present invention will be described below with reference to the drawings. First, the outline of the DAT device will be described. FIG.
As shown in FIG.
b, etc., is pulled out of the cassette and wound around the rotating drum 3, and is sent by the pinch roller 4 and the capstan 5 at a constant speed (8.15 mm / sec). The two magnetic heads 3a and 3b provided on the rotating drum 3, which rotates at a high speed of 2000 revolutions per minute,
Music signals and the like are recorded on the magnetic tape 1. Magnetic head 3
Reference numerals a and 3b are used for both recording and reproduction. At the time of recording, a recording signal from a signal processing unit 6 passes through a recording / reproducing amplifier 7, and passes through a rotary transformer (not shown) to form magnetic heads 3a and 3b.
Given to. At the time of reproduction, a reproduction signal taken out of the magnetic tape 1 by the magnetic heads 3a and 3b is sent to the signal processing section 6 in a reverse route. The magnetic heads 3a and 3b of the rotating drum 3
Since the contact is made so as to obliquely cross the running direction of the magnetic tape 1, a signal is recorded on the magnetic tape 1 as a set of tracks 8 which are obliquely cut as shown in FIG. Each track 8 has a P for recording a music signal.
There are provided a CM recording section 8a, a subcode recording section 8b capable of recording various information such as a song number and a playing time, an ATF signal recording section 8c for tracking, and the like. The subcode recording section 8b can be recorded later separately from the PCM recording section 8a. This is a so-called post-recording function. A normal DAT device including the DAT device of the present embodiment has a start ID indicating the beginning of a tune at the time of recording.
There is provided a function of recording an end mark indicating the end of the tape (generally also used as a song number), an end mark, and an elapsed time (absolute time) from the tape start end in the subcode recording section. The magnetic tape cassette has a built-in prism.
The device can detect the tape start end, that is, the boundary between the leader tape (transparent portion) and the magnetic material application portion, by the optical sensor. A system controller 8, which is a main controller of the DAT device, is configured using a microcomputer, and controls recording and reproduction and controls a tape running system. The system control unit 8 also has a function of counting FG pulses of the capstan motor 5a.
Note that the above absolute time (sometimes called A-TIME)
Is displayed on the display unit 9 during reproduction. Next, a method for recording the absolute time (A-TIME) in the subcode recording section 8b later by the above-mentioned post-recording function will be described. That is, as shown in FIG. 1, the correct absolute time has already been recorded from the beginning of the tape 1 to a position (point A ′), but the absolute time has not been recorded after point A ′, or This is a method of recording an absolute time after the point A 'when an incorrect time is recorded. However, it is necessary not to erase the start ID recorded at the point A. The operation will be described with reference to the flowcharts shown in FIGS. The control of the flowchart starts from the point where the reference point A 'is reproduced (recorded) on track. First, the FG pulse counter for counting the FG pulses of the capstan motor 5a is reset. This FG pulse counter is
It is used to determine the tape travel amount during off-track playback (search) where the number of tracks cannot be counted. For convenience of explanation, it is assumed that the FG pulse counter is incremented at the time of feeding and decremented at the time of rewinding. Next, the number of tracks is counted while performing on-track reproduction. Eventually it reaches point A and the start ID
Is detected, the process proceeds to the process (b) of FIG. That is,
A-TIME at point A based on the number of tracks from point A '
Is calculated and stored. Next, a search operation by off-track reproduction is performed. When the search operation reaches the point B, an end mark is detected. However, if no end mark is recorded, the next start ID is detected. From the value of the FG pulse counter at this time, B
The approximate position of the point is determined, and a value obtained by subtracting a predetermined value from this value is stored as the position of the virtual point B ′. That is, since the virtual point B 'is the end position for recording the A-TIME as described later, the predetermined value is reduced before the point B so as to have a certain margin. Next, rewinding is performed until the value of the FG pulse counter becomes zero or less. In other words, the tape is rewound to the point A ', but actually returns slightly to the tape start end side from the point A' and stops due to the influence of inertia. Then, as shown in the processing (c) and thereafter, the A-TI is again reproduced by on-track reproduction.
The ME is read, and recording of A-TIME is started from point A '. It should be noted that recording in the sub-code recording section 8b such as A-TIME can be performed while performing on-track reproduction. That is, the above-described magnetic heads 3a and 3b are switched so as to function as a reproducing head in the PCM recording unit 8a and the like and as a recording head in the subcode recording unit 8b. When the A-TIME reaches the stored A-TIME at the point A, not only the A-TIME but also the start ID is recorded in the subcode recording section 8b. This start ID is recorded over 300 frames. In this way, the A-TIME is post-recorded (recorded) without erasing the start ID. The recording of A-TIME is continued even after the recording of the start ID is completed. That is, the process is continued until the value of the FG pulse counter reaches the value stored as the point B '. When point B 'is reached, point B' is newly added to reference point A '.
Then, assuming that point B is point A, the process returns to the top of FIG. 2 and the same processing is repeated. When the end mark is detected in the branch determination processing (a), the processing of (d) and thereafter is executed. In this case as well, the end mark is also recorded at the position where the end mark was originally recorded when the A-TIME was recorded, in the same manner as the processing when the start ID was detected. However, in this case, the A-TIME recording ends when the end mark recording for 300 frames ends. In the branch judgment processing (a), the start I
When the tape end (end part) is detected without detecting D or the end mark, the processing after (e) is executed. That is, after rewinding to the point A ', the A-TIME is recorded to the tape end. Incidentally, the tape end (end) is also detected by detecting the boundary between the magnetic material application portion and the trailer tape (transparent portion) by the optical sensor and the cassette built-in prism similarly to the tape start end. As described above, A-TIME recording (recording) up to the end mark or the tape end is performed without erasing the start ID and the end mark.
Hereinafter, another embodiment will be briefly described. In the above embodiment, the case where the correct absolute time has already been recorded from the beginning of the tape to the point A ′ has been described. However, if the absolute time has not been recorded at all from the beginning of the tape, the beginning of the tape has not been recorded. The processing of the embodiment may be performed after the absolute time is recorded in the vicinity of the section and the reference point A ′ is created. In the above-described embodiment, F used for obtaining the tape traveling amount at the time of off-track reproduction (search) is used.
F of the capstan motor as input of G pulse counter
Although the G pulse is used, an FG pulse signal of the reel motor may be used instead. In the claims, reference numerals are provided for convenience of comparison with the drawings, but the present invention is not limited to the configuration shown in the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory diagram of an absolute time recording method of a DAT device according to an embodiment of the present invention. FIG. 2 is a flowchart of an absolute time recording method (No. 1). FIG. FIG. 4 is a schematic diagram of a magnetic tape recording format. FIG. 5 is a schematic configuration diagram of a DAT device. [Description of References] 1 Magnetic tape 8b Subcode recording section A Start ID (or end mark) recording position A 'reference position

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-1-273286 (JP, A) JP-A-3-84791 (JP, A) JP-A-2-158962 (JP, A) JP-A-1- 271988 (JP, A) Hikaru Hira 3-57791 (JP, U) Heitaro Nakajima, Kentaro Odaka, Illustrated DAT Reader, Ohmsha, Japan, April 10, 1989, 1st edition, 2nd printing, p. 56-p. 58 (58) Field surveyed (Int.Cl. ⁷ , DB name) G11B 27/10-27/34 G11B 15/087

Claims (1)

(57) Claims 1. A method of recording an absolute time in a subcode recording section (8b) of a magnetic tape (1) by a DAT device having a subcode recording function and a reproducing function. The position on the subcode recording section (8b) where the correct absolute time is recorded from the start end of the magnetic tape and the start ID or end mark is not recorded is defined as a reference position (A ′). By counting the number of tracks from A ′), the absolute time of the position (A) of the start ID or end mark recorded first after the reference position (A ′) is obtained and stored, and the reference position is determined. From (A)
A high-speed search is performed on the tape end area to
Counting the next start ID or end
After detecting the position (B) where the data mark is recorded and rewinding to the reference position (A '), the recording of the absolute time in the subcode recording section (8b) is performed from the reference position (A'). Starting, when the stored absolute time is reached, the start ID or the end mark is recorded in the subcode recording section (8b) together with the absolute time, and the absolute time is recorded in the subcode recording section (8b).
Record the next start ID or end mark
Position obtained by subtracting a predetermined value from the position (B)
(B ') to obtain the first recorded
An absolute time recording method for a DAT device configured to prevent the erasure of a start ID or an end mark.